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Civil Engineering is a branch of engineering that focuses on the design, construction, and maintenance of the physical and naturally built environment, including infrastructure such as roads, bridges, dams, and buildings. It encompasses various sub-disciplines, integrating principles of physics, mathematics, and materials science to ensure safety, sustainability, and functionality.
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BRIDGE ENGINEERING HANDBOOK: SUPERSTRUCTURE DESIGN
by Sadeq Sinan and 
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adonis bibat
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Method Statement for Construction Of Civil Works
by Sumesh Radhakrishnan
method statement for all the activities related to the construction of civil works.
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B.P.344 - Accessibility Law
by Michaela Gwen Domingo
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ICE manual of bridge engineering SECOND EDITION
by Jonggyun Paik
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IS 456 : 2000 Indian Standard PLAIN AND REINFORCED CONCRETE - CODE OF PRACTICE ( Fourth Revision
by rajeeb singh
10.1 Quality Assurance Measures
Fic. 1 MINIMUM DIMENSIONS OF REINFORCED CONCRETE MEMBERS FOR FIRE RESISTANCE
Fic. 2 TypicaL Support Conpimions ror LOCATING FACTORED SHEAR FoRcE
on area of section equal to b, d. e) For flanged beams, the values of (a) or (6) be modified as per Fig. 6 and the reinforcement percentage for use in Fig. 4 and 5 should be based
NOTE—When deflections are required to be calculated, the method given in Annex C may be used.
Fic. 5 MopiFicaTION FACTOR FOR COMPRESSION REINFORCEMENT
Fic. 6 Repucrion Factors FoR RATIOS OF SPAN TO EFFECTIVE DEPTH FOR FLANGED BEAMS 23.3 Slenderness Limits for Beams to Ensure Lateral Stability A simply supported or continuous beam shall be so proportioned that the clear distance between the lateral
27.1 Structures in which marked changes in plan dimensions take place abruptly shall be provided with expansion-on joints at the section where such changes occur. Expansion joints shall be so provided that the necessary movement occurs with a minimum resistance at the joint. The structures adjacent to the joint should preferably be supported on separate columns or walls but not necessarily on separate foundations. Reinforcement shall not extend across an expansion joint and the break between the sections shall be complete. 27.2, The details as to the length of a structure where expansion joints have to be provided can be determined after taking into consideration various factors, such as temperature, exposure to weather, the time and season of the laying of the concrete, etc. Normally structures exceeding 45. m in length are designed with one or more expansion joints. However in view of the large number of factors involved in deciding the location, spacing and nature of expansion joints, the provision of expansion joint in reinforced cement concrete structures should be left to the discretion of the designer. IS 3414 gives the design considerations, which need to be examined and provided for.
The lever arm z for a deep beam shall be detemined as below: where / is the effective span taken as centre to centre distance between supports or 1.15 times the clear span, whichever is smaller, and D is the overall depth.
NOTE — D, is the diameter of column or column head to be considered for design and d is effective depth of slab or drop as appropriate.
Fic. 14 Errect of Free EpGes ON CRITICAL SECTION FOR SHEAR 31.6.2.2 When unbalanced gravity load, wind, earthquake or other forces cause transfer of bending moment between slab and column, a fraction (1 — a) of the moment shall be considered transferred by eccentricity of the shear about the centroid of the critical section. Shear stresses shall be taken as varying linearly about the centroid of the critical section. The value of @ shall be obtained from the equation given in 31.3.3.
Fic. 15 Errecr oF OPENINGS ON CRITICAL SECTION FOR SHEAR
* Bent bars at exterior supports may be used if a general analysis is made. NOTE — D is the diameter of the column and the dimension of the rectangular column in the direction under -onsideration.
Fic. {17 EFFECTIVE SPAN FOR STAIRS SUPPORTED AT EACH END BY LANDINGS SPANNING PARALLEL WITH THE RISERS The effective span of stairs without stringer beams shall
cross-section in compression shall be limited by the area above the neutral plane, and the angle of slope or depth and location of steps shall be such that the design requirements are satisfied at every section. Sloped and stepped footings that are designed as a unit shall be constructed to assure action as a unit. where
Yield line theory or any other acceptable method may be used. Alternatively the provisions given in Annex D may be followed. Fic. 21 StTRESS-STRAIN CURVE FOR CONCRETE Fic. 22 Stress BLock PARAMETERS
Fic. 23 REPRESENTATIVE STRESS-STRAIN CURVES FOR REINFORCEMENT
If shear reinforcement is required, the total area of this NOTE — The approach to design in this clause is as follows: Torsional reinforcement is not calculated separately from that required for bending and shear. Instead the total longitudinal reinforcement is determined for a fictitious bending moment which is a function of actual bending moment and torsion;
D-2.1 When simply supported slabs do not have adequate provision to resist torsion at corners and to prevent the corners from lifting, the maximum
Fic. 26 EFFective LENGTH RATIOS FOR A COLUMN IN A FRAME WITH NO SWAY where the summation is to be done for the members framing into a joint at top and bottom respectively; and K, and K, being the flexural stiffness for column and beam respectively.
Fic. 27 EFFECTIVE LENGTH RATIOS FOR A COLUMN IN A FRAME WITHOUT RESTRAINT AGAINST SWAY
The average steel strain €,, may be calculated on the basis of the following assumption:
Since air entrainment reduces the strength, suitable adjustments may be made in the mix design for achieving required strength. Where freezing and thawing actions under wet conditions exist, enhanced durability can be obtained by the use of suitable air entraining admixtures. When concrete lower than grade M SO is used under these conditions, the mean total air content by volume of the fresh concrete at the time of delivery into the construction should be:
NOTES ‘able 4 Requirements for Concrete Exposed to Sulphate Attack
26.5.1.3 Side face reinforcement
(Clauses 40.2.1, 40.2.2, 40.3, 40.4, 40.5.3, 41.3.2, 41.3.3 and 41.4.3) NOTE — The term A, is the area of longitudinal tension reinforcement which continues at least one effective depth beyond the section being considered except at support where the full area of tension reinforcement may be used provided the detailing conforms to 26.2.2 and 26.2.3 Table 19 Design Shear Strength of Concrete, t,, N/mm?
For members in direct tension, when full tension is taken by the reinforcement alone, the tensile stress shall be not greater than the values given below:
NOTE — A, is that area of longitudinal tension reinforcement which continues at least one effective depth beyond the section being considered except at supports where the full area of tension reinforcement may be used provided-the detailing conforms to 26.2.2 and 26.2.3. (Clauses B-2.1, B-2.3, B-4.2, B-5.2.1, B-5.2.2, B-5.3, B-5.4, B-5.5.1, B.5.5.3, B-6.3.2,B-6.3.3 and B-6.4.3 and Table 21) Table 23 Permissible Shear Stress in Concrete When shear reinforcement is provided the nominal shear stress T, in beams shall not exceed , _ given in Table 24. When shear reinforcement is provided the nominal shear stress T, in beams shall not exceed Tf, given in Table 24.
(Clauses B-5.2.3, B-5.2.3.1, B-5.5.1 and B-6.3.1) Table 24 Maximum Shear Stress, 7. , N/mm’ ‘c max’?
equation in Table 27 a uw given in A Table 26 Bending Moment Coefficients for Rectangular Panels Supported on Four Sides with Provision for Torsion at Corners D-2.1.1 At least 50 percent of the tension reinforcement provided at mid-span should extend to the supports. The remaining 50 percent should extend to within 0.1 /, or 0.1 J, of the support, as appropriate.
Table 28 Effective Length of Compression Members NOTE — | is the unsupported length of compression member.
( Page 17, clause 7.1 ) — Substitute the following for the existing informal table: NOTE — For most of the placing conditions, internal vibrators (needle vibrators) are suitable. The diameter of the needle shall be determined based on the density and spacing of reinforcement bars and thickness of sections. For tremie concrete, vibrators are not required to be used (see also 13.3).
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BRIDGE ENGINEERING HANDBOOK: SEISMIC DESIGN
by adonis bibat
This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of... more
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Materials Science And Engineering Solutions Manual 9th Edition
by Aggressive Engineering 精進工程
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AN INTRODUCTION TO GEOTECHNICAL ENGINEERING Second Edition
by Xiomii Pimentel
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Structural Engineer's Professional Training Manual
by Kem Sochetra
Figure 1-1 Possibly the most enjoyable application of structural engineering! (Photo by Gustavo Vanderput)
| Figure 1-2 Empire State Building.
Figure 1-4 Brooklyn Bridge tower, cables, deck and suspenders.
Figure 1-5 Two types of suspension bridges in New York, designed in different time periods using timeless principles of engineering mechanics.
Figure 1-6 Data points with range of error from testing and “least squares” function. Errors that a structural engineer may make include those of intention, concept, or execution (Nowak 2000, pp. 294-296). Intentional errors result primarily from an abuse of the engineer’s moral obligation to the client, the company, and to society as a whole. These are commonly executed in the form of skipping design steps or not giving consideration to different aspects of a structure for the sake of
| Figure 2-1 Elegant skyscraper in China.
Figure 2-3 Plywood roof diaphragm testing. (Courtesy APA —The Engineered Wood Association) The ICC also administers an evaluation service, abbreviated as ICC-ES, which is a nonprofit, public-benefit corporation that performs technical evaluation and issues approvals for specific construction products, components, and methods according to historic principles that have been developed for more than 70 years. Reports directly address compliance with model codes and have detailed instruc- tions on how a component may be designed or used, which is of tremendous assistance to those who are charged with enforcing adopted codes. The process of
Figure 2-4 Relationship between basement floor and base flood elevation. (Courtesy Federal Emergency Management Agency)
| Figure 3-1 Downtown Winnipeg, Manitoba, Canada.
The Business of Structural Engineering Figure 3-2 Common engineering business hierarchical structure.
Figure 3-3 Common methods for bracing piping systems. (Courtesy U.S. Army Corps of Engineers)
Figure 3-4 Common methods for anchoring mechanical equipment. (Courtesy U.S. Army Corps of Engineers)
Figure 3-5 Indoor mullion and steel framing with block out for glass panel, requiring consi- deration of solid anchorage against seismic shaking.
Figure 3-6 Architectural railing system in need of structural anchorage against code-required horizontal forces, New Orleans.
ure 4-1 Oak Alley plantation residence, Louisiana.
Figure 5-18 Structural mechanics of bridge deck launching process. (Courtesy Enerpac, Milwaukee, Wisconsin)
Figure 5-15 Concrete piers for support of new bridge adjacent to existing bridge. (Reproduced by permission of the Virginia Department of Transportation)
| Figure 5-16 Typical structural elements of a simple concrete bridge system.
Figure 5-17 Launched deck construction of Millau Viaduct cable-stayed bridge, France. (Courtesy Enerpac, Milwaukee, Wisconsin)
Figure 4-2. Residence damaged in the Northridge Earthquake, California 1994. (Courtesy UCLA Department of Earth and Space Sciences) Though these systems are described in the seismic section of the standard, they also provide resistance to wind and other forces that will cause the structure to rack, overturn, or slide in relation to the ground below. The importance of having an adequate lateral force resisting system can be seen in Fig. 4-2, as prevention of building collapse prior to escape of occupants during a significant loading event is commonly accepted as an absolute minimum level of performance.
Coefficients of thermal expansion for different materials are tabulated in ASTM C1193, which also includes procedures for calculating the required joint width and range of potential movement that can impose forces significant enough to cause cracking in building elements. In cold regions, building materials will con- tract with falling temperature and enlarge the joint width, whereas hotter climates cause member expansion as temperature rises. A good, waterproofed joint includes a priming material, backer rod, bond breaker, and sealant. Masonry, concrete, metal, and wood surfaces require a primer to improve adhesion of the sealant, depending on limitations imposed by the manufacturer. A backer rod is installed at a certain depth to control thickness of the sealant, in addition to serving as a secondary waterproofing element. Finally, a sealant that is allowed to flex with structural movement, yet remain intact, is placed to fill the joint.
Figure 4-4 Common commercial building waste plumbing layout, identifying simple fixtures and pipe runs. Other plumbing that is commonly found in a building consists of sewage disposal, water drainage systems, fire suppression, and ventilation pipe runs in order to remove odors. Fixtures are provided to supply and collect water or waste, and those for use in waste lines must include a liquid-seal trap designed such that the passage of air and gases is prevented during the flow of liquid. Figure 4-4 shows a basic wastewater removal plumbing system that is common in buildings.
Figure 4-5 Means of egress (exterior stairway) from second floor of a commercial building, which requires positive anchorage against a high live load under emergency conditions.
Figure 4-6 Commercial building with stone cladding, subject to seismic shaking that may affect closure of the building envelope if not properly detailed.
Figure 4-7 Roof diaphragms placed at different levels can present a challenge in tracing lateral forces to the foundation.
building’s perimeter, which could be the location of required lateral force collecting elements.
Figure 4-10 Aesthetic challenge of fitting new buildings into a region with older, historic structures. The function of a commercial building is quite busy with a multitude of different activities being performed at the same time. In a typical hospital building, for example, administrative duties are carried out in one area while medical proce- dures are practiced in another and patients are sleeping soundly in yet another. Residential buildings, on the other hand, are primarily used as a type of retreat from everything else, where families can grow closer together and refresh them- selves for the following day’s activities.
Figure 4-11 Poor wood-frame construction detail with lack of proper load path and connections.
Figure 5-1 Canal Bridge Magdeburg, Germany. (Courtesy Dillinger Hutte)
Figure 5-3 Scotland’s Forth Bridge, cantilever steel-type for railroad use.
| Figure 5-4 Simple concrete grade-crossing bridges.
Figure 5-5 Placement of concrete bridge deck. (Reproduced by permis- sion of the Virginia Department of Transportation) Decks The structural deck of a bridge is critical in transferring all imposed forces, including environmental and live traffic loads, to supporting structural elements and different types have been used successfully over the years, including the concrete deck shown being placed in Fig. 5-5. Technological innovation has introduced the use of glass fiber-reinforced polymer (GFRP) panels that were shown by testing to act in a somewhat composite fashion with steel girders when properly connected (Stiller, Gergely, and Rochelle 2006), though the effectiveness of this behavior is not considered by many designers of great enough value to include in analysis.
Figure 5-6 Original Severn Bridge crossing between Wales and England, using a steel battledeck floor.
Figure 5-7 Different types of concrete bridge piers depending on site and economy. Abutments and Retaining structures I!he two most common abutment types are the seat-type, which allows for relative movement of the deck, and the integral-type. Design of any form of abutment according to DOT requirements typically assumes linear behavior when subjected to load, but nonlinear behavior during a strong seismic event may occur in response to cracking and yielding of the material, in addition to changes in stiffness of the supporting soil. This has an effect on the dynamic response of the superstructure itself. When a complete structural model is created for analysis, a properly reinforced concrete approach slab extending far enough beyond an abutment can be counted on for rotational restraint and considered in determining the dynamic response of the bridge.
Figure 5-9 Cable-stayed pedestrian bridge with added support for fabric shade canopy.
| Figure 5-8 Different steel suspension bridge tower configurations.
| Figure 5-10 Different types of bridge bearings.
Figure 5-11 Demonstration of composite action between steel girder and cast-in-place concrete deck through strain compatibility.
Figure 5-12 London Bridge, combination suspension and movable- type.
Figure 5-13 Movable bridge with towers that have become city landmarks (Sacramento, California).
Figure 6-1 Millau Viaduct cable-stayed bridge, France. (Courtesy Enerpac, Milwaukee, Wisconsin)
ure 6-2 Concrete shear wall system with openings
| Figure 6-4 Ohio River flood in Paducah, Kentucky, 1937.
| Figure 6-5 Simple, yet interesting floor support challenge.
Figure 7-1 Geisel Library at the University of California, San Diego. provides simple enough information on each subject to send an engineer in the right direction, but most of the skills discussed in this chapter can only be learned in detail in a practical working environment, where they can be put to use under imposing consequences when appropriate seriousness is not given to a situation. Some consequences of poor communication that may be experienced in the “real world” include loss of job, loss of client, failure of a structure with subsequent loss of life and finances, loss of reputation, and certainly other unfortunate situa- tions that cannot be taken lightly.
Figure 7-2 Three-dimensional steel frames can be difficult to visualize regarding support of loads and analysis strategy. not restricted to any particular assumptions of material behavior. Whether by hand or computer, analysis of structural elements involves a discov- ery of six independent degrees of freedom, three serving translation, and three defining rotation about these translational axes by which every member follows. Refer to Fig. 7-2 for a three-dimensional frame structure that would require care- ful consideration of all dimensions. As load is applied, this frame will not only deflect but also twist, and forces must be resolved back to provide supports. Under some conditions, it may be necessary to look at other characteristics to serve as degrees of freedom, which can include beam deflection shapes or mode of vibration amplitudes in a dynamic analysis. All variables and constants used in structural analysis are subject to two basic physical laws: Equilibrium (static or dynamic) and compatibility (preservation of structural continuity). Coupling these physical truths with principles of virtual work provides a basis for analyzing support of forces by elastic and inelastic bodies or systems, since the concept is not restricted to any particular assumptions of material behavior.
| Figure 7-3 Typical simply supported beam loading and reaction diagrams.
Figure 7-4 Erection of structural steel-framed, antenna-supporting tower. (Courtesy Conlan Engineering and Construction)
Figure 7-5 Partial floor plan in region with different shapes and spe- cial challenges.
Figure 7-6 Wood truss bottom chord tension failure. (Courtesy Lane Engineers, Inc.)
Figure 8-1 Residence in Louisiana with first floor raised for flood protection.
| Figure 8-2 Blizzard in Jamestown, North Dakota, 1966.
Rain loading can be significant on flat roofs which deflect to such a degree that water ponds during a heavy storm faster than it is allowed to run off, usually requiring a close review for roof systems with a drop of less than !/4 in over a run of 12 in (1.19°) (ASCE/SEI 7-05, Section C8.4; NFPA 5000, Section 35.1.2.8.8). Water is often channeled off the roof through a gutter and downspout combination
Figure 8-4 Mathematical model of multiple degree-of- freedom dynamic system.
Figure 8-6 Damage to building sustained in the Northridge Earthquake, California 1994. (Courtesy UCLA Department of Earth and Space Sciences)
Figure 8-7 An early strong-motion accelerometer built first in 1935. (Courtesy U.S. Geological Survey)
A response spectrum is often used to develop a building’s elastic response to earthquake motion as though the problem were a simple one of statics. The response of multiple single degree-of-freedom systems is idealized as a graphical plot of relative displacement, velocity, or peak ground acceleration versus period of vibration. Figure 8-8 shows the basic shape of a design base shear response spectrum, which is constructed from measured site-specific, short- and long- period accelerations that have been truncated in recognition of physical limita- tions to the maximum considered earthquake within a region. Time histories of ground motion recorded on accelerographs during a seismic event can also be used as direct input for a computer model. The base shear coefficient, which is used in common strength-based design procedures, is determined from the spec- tra as a function of the fundamental period.
Figure 8-9 Concept of lateral force distribution on a horizontal plane using rigid diaphragm the- ory. (Courtesy U.S. Army Corps of Engineers) parameters. Current methodologies do a fine job of combining the art and science of earth- quake design, but an engineer must not lose sight of the fact that a structure’s true dynamic response to seismic excitation is quite complicated. Behavior of compo- nents located along the lateral force path often changes during a strong event and it is therefore necessary to use worst-case scenarios in the determination of struc- tural response. Simplified models and assumptions are important, but an engineer can explore greater freedom in design and different performance objectives by consideration of inelastic system relationships and site or structure-specific parameters.
| Figure 8-10 General material stress-strain curve. Stress and Strain The most basic diagram found in the study of elasticity is the stress-strain curve, such as that shown in Fig. 8-10. Strain is defined as change in a member’s length, or total deformation, divided by the original length and is a dimensionless quantity. Stress is defined as applied force per unit area or moment per section modulus and exists in the form of tension, compression, or shear. Bending stress is simply an image of a tension-compression couple applied about a member’s neutral axis, where stress has zero value along this line and varies linearly to a maximum value at the top and bottom (extreme) fibers of any cross-section. It is this understanding of how moments are resisted that allows an engineer to develop unique solutions to design problems, where an applied eccen- tric force creating moment in the carrying member may actually be transferred there by two simply supported elements setting up the necessary couple, facili- tating less-expensive connection requirements.
Hysteresis Hysteresis is a phenomenon that occurs in all materials where a history of applied loading is identified in a diagram (see Fig. 8-11) as a lag between application and removal of load and is fundamental to the understand- ing of material behavior under a cyclic-type force. This lag is identified as a shift in the looping pattern that is plotted on a diagram as magnitude of force versus system displacement. The relationship can be developed from a single framing element or an entire assembly, such as a frame or shear wall.
Figure 8-12 Concept of superposition, combining the effects of stress from axial load plus bending moment. Analysis of beams that are continuous over multiple supports is often simplified by placement of live load in different spans to create worst-case effects. For example, the maximum positive moment within a span is determined by placing live load on that span as well as on all other alternate spans. Maximum negative moment within a span is determined by placing live load on both adjacent spans and all other alternate spans. At an interior support point, maximum positive moment occurs in the beam when live load is placed on the two spans immedi- ately beyond the two spans adjacent to that support (one on each side), whereas
Figure 8-14 Buckling stiffness comparison of columns with different bound- ary conditions.
as fixed between floors and each segment around openings calculated accord- ingly. The combined rigidity of piers in series is determined simply by adding individual rigidities, whereas piers that are stacked require a different consideration. Individual shear wall segments separated by large openings can be considered as stiffened through proper design and connection of intermediate beams or panel segments which resist axial, shear, and flexural loads. Shear wall segments that have been properly coupled together will then act as frame-type elements instead of pure cantilevers.
| Figure 8-17 Vierendeel truss configuration.
Figure 9-1 Hoover Dam. (Courtesy U.S. Bureau of Reclamation)
Figure 9-2 Helpful soil survey documents may be obtained from the U.S. Department of Agriculture, Natural Resources Conservation Service.
| Figure 9-3 A variety of equipment is available for grading purposes.
Figure 9-4 Definition of a building story from ASCE/SEI 7-05, “Minimum design loads for buildings and other structures.”
Figure 9-5 Example of a poorly graded project site with standing boulders and loose soil. Figure 9-5 shows a foundation that has been placed on a poorly graded site, where large boulders were simply overlain with a thinner section of concrete for footing: rather than removed: Adverse settlement is extremely likely. Proper compactiot begins with the removal of larger solids and organic material, followed by excavatior of site soils to a predetermined depth. Engineered fill may also be specified if native soils are not particularly desirable in their natural condition for supporting a structure This fill is created using reconditioned site soils or imported material, placed anc compacted in lifts of thickness ranging between 6 and 12 in (152 and 305 mm).
| Figure 9-6 General soil stress-strain curve. Courses in geotechnical engineering define mechanical properties of soil as the interaction between individual particles and moisture that is present. An approximate representation of the stress-strain properties of a soil mass is shown in Fig. 9-6. Because of its low tensile strength, soil almost always fails in shear (Marxhausen and Bagley 2006), which occurs when particles begin to slide past one another and is dependent on the frictional and cohesive strength present in that interac- tion. Modes of soil shear failure below foundations include general shear failure, local shear failure, and punching shear failure. General shear failure is identified as slippage of one footing edge in relation to the ground surface, where tilting of the foundation and bulging of the adjacent soil may also occur. Local shear failure
| Figure 9-7 Pad footing awaiting placement of concrete. A spread footing is known to be shallow when its depth below the surrounding grade line is less than the footing’s least width, as seen in Fig. 9-7, otherwise it carries the title deep. Simple spread footing models, as well as strip footings to an approximate degree, have shown that stress carried by the soil diminishes with increasing depth from the bottom of a footing (Brown 1997, pp. 50-51; Winterkorn and Fang 1975, pp. 164-166). Position of the groundwater table com- plicates this distribution, as bearing capacity is weakened below that level due to
Figure 9-8 Influence of overlapping soil bearing pressure from adjacent pad footings.
Figure 9-9 Continuous footing with multiple pipes that may call for additional steel reinforcement.
Figure 9-11 Different load support mechanisms for deep foundations.
Figure 9-12 Soil moisture drainage system behind a retaining wall. (Courtesy U.S. Army Corps of Engineers) An active soil pressure condition may be assumed for design when the wall is allowed to translate at the top by a distance of 0.1% of wall height during back- filling. This condition is difficult to prevent, except by either a very stiff floor or roof diaphragm or wall tie-back anchors, therefore most design applications can likely assume an active state of soil pressure (Amrhein and Vergun 1994, p. 59). If the wall is restrained at the top in any fashion prior to backfilling, an at-rest soil pressure condition must be assumed. The bottom of a wall can be designed with fixity from 0 to 100%, which helps in the distribution of restraining forces nec- essary for equilibrium in an effort to prevent failure through sliding or excessive rotation about the base with a safety factor of 1.5 (minimum). Passive pressure develops on the other side of the footing as the structure is pushed against the earth. The effect of this is seen in a loading and resistance diagram for a sheet pile wall in
210-1 Concrete column reinforcing cage.
Figure 10-2 Aggregate grading chart. (Courtesy U.S. Army Corps of Engineers)
| Figure 10-3 General stress-strain curve for plain concrete. Understanding the Behavior of Concrete Structural plain concrete, whether cast-in-place or precast, is recognized by AC 318-05 only for members that are continuously supported by soil or some othe means (footings, slabs-on-grade), members by which arch action provides contin uous compression for all load combinations, or for walls with continuous vertica support and pedestals with a ratio of unsupported height to average least latera dimension less than or equal to three. Plain concrete columns, defined as member that primarily support longitudinal compression and are taller than pedestals, ar restricted against structural uses.
Figure 10-4 Reinforcing steel with identification stamp (16-mm bar shown).
Figure 10-6 Pattern of shear stress cracking in reinforced concrete bending member. Understanding the Behavior of Concrete
Behavior Under Axial Loading Multiple combinations of nominal axial load strength (P,,) and nominal moment strength (/_,) for a reinforced concrete column are defined along the curve of a strength interaction diagram, such as that shown in Fig. 10-7. Radial lines that project from the origin of the axes represent different values of axial load eccentricity, with e = 0 along the vertical axis and e = © along the horizontal axis. A balanced strain condition occurs at e = e, along the interaction curve, which divides the compression controls region (concrete compressive strain reaches 0.003 prior to yielding of the steel) from the tension
Figure 10-8 Bearing conditions of precast concrete sections in a parking garage. Prestressing is an operation where a concentric or eccentric force is applied in the longitudinal direction of a bending member in such a way that tensile stress at midspan (for simply supported elements) is either eliminated or greatly reduced, thus allowing full use of the compressive strength of concrete across the entire depth of an element. A prestressed structural system can be made either flexible or rigid without influencing strength through proper control of applied longitudinal force, developed by high strength steel in order to maintain the necessary pre- stressing force after normal losses occur, which can be in the range of 35 to 60 ksi (241 to 414 MPa). Pretensioning is the most common method for applying this axial force, where steel is tensioned prior to placement of concrete within forms and then cut once concrete has encased the tendons and hardened sufficiently to take up the compressive force transferred from tension in the steel.
ASTM A416 (uncoated seven-wire steel strand). Low-relaxation strands are con- sidered to be standard, but stress-relieved (normal-relaxation) material may be specially ordered. Stress-relieving is achieved by heating steel to about 1202°F (650°C) and maintained at that level for a period of time, after which the steel is slowly cooled. Either type of strand is available with a minimum ultimate strength of 250 or 270 ksi (1725 or 1860 MPa), where a strand is defined to be a group of wires having a center wire enclosed tightly by six helically placed outer wires. Finished strand sizes are available in diameters of 0.25 to 0.60 in (6.4 to 15.2 mm) and are designated by the nearest whole number in millimeters (i.e., a strand measuring 15.2 mm in diameter may be identified as #15).
Figure 10-10 Stress-strain comparison between mild steel and pre- stressing steel.
Figure 10-12 Concrete bridge damage from the Loma Prieta earth- quake, California 1989. Tests performed by Cheok and Stone (1990) on scale models of circular bridg columns defined a pattern of failure when subjected to cyclic loading that has bee: noted by other experimenters. Flexural cracks initiate within the plastic region near th column base, where they gradually extend around its body. Damage continues wit spalling of surface concrete away from the reinforced core, followed by yielding an subsequent fracture of spiral reinforcing, leading to eventual buckling and fracture o the longitudinal steel. Cyclic energy-absorption capacity decreases significantly whe confining reinforcement fractures, leading a designer to the conclusion that ties or spi rals are critical to assuring good flexural behavior during a seismic event. Whether b column, beam, connection, or joint, adequate absorption of cyclic energy is critical t structural success and failure can be catastrophic, as shown in Figs. 10-12 and 10-13
Figure 10-13 Concrete bridge failure during the Northridge earthquake, California 1994. (Courtesy UCLA Department of Earth and Space Sciences)
Figure 10-14 Mechanics of concrete shear wall deformation. (Courtesy Federal Emergency Management Agency)
| Figure 10-15 Boundary zone reinforcement in concrete shear wall.
Figure 10-16 Concrete cantilevered slab elements may be designed as special plates using charts or simple computer analysis methods. Understanding the Behavior of Concrete A typical moment-interaction diagram for a reinforced concrete column indicates that a moderate amount of axial force increases the moment capacity, but testing has shown that this relationship also holds true for flat plates, where inplane load- ing leads to increased capacity and flexural rigidity, though it depends greatly on shape and slenderness (Ghoneim and MacGregor 1994). Plates with large out-of- plane deflections tend to resist loading by creating a tension field near the mid- dle, held stable by a compressive field around the perimeter, resulting in increased capacity due to combined bending and tensile membrane actions.
Figure 10-17 Close placement of concrete shear wall jamb reinforcement calls for careful consolidation measures. Understanding the Behavior of Concrete
| Figure 10-18 Concrete finishing equipment.
| Figure 11-1 Concrete masonry unit wall construction.
Figure 11-2 Terminology of masonry wall construction elements. (Courtesy Masonry Institute of America)
Figure 11-3 Concrete masonry unit terminology. (Courtesy Masonry Institute of America) Understanding the Behavior of Masonry Construction
Figure 11-4 General stress-strain curve for concrete masonry units.
Figure 11-5 Glass masonry walls provide beauty with structural strength, provided they are properly anchored to supporting elements.
Figure 11-6 Clean out in concrete masonry wall construction for inspection and removal of mortar and other debris. Before grout can be placed, the masonry cavity must be cleared of debris and solid mortar that has squeezed out into the space between wythes or inside hollow block. Excess material is knocked to the bottom of the constructed assembly, often by use of a reinforcing bar from above, and removed from clean outs (see Fig. 11-6). After they have been inspected, holes are covered by mortaring brick or a face shell back into place. Depending on design requirements, grout either completely fills the void or is restricted to particular cells in a vertical or horizontal pattern by installing dams and screens during erection. Since it is a form of concrete placed around embedded items, grout must be properly consolidated within its tight space by the use of paddles for small lifts or thin vibrators for larger lifts.
Figure 11-7 Metal ties for brick masonry construction. (Courtesy U.S. Army Corps of Engineers)
Figure 11-8 Masonry walls may be constructed using blocks of differing widths for structural or architectural purposes.
Masonry lintels are not required to carry the total load distributed above an open- ing, as arching action tends to direct loading that occurs above a triangle’s apex (see Fig. 11-9) away from the opening. Any load, including the weight of the masonry itself, that is located above the triangular area shown does not need to be included in the design equations. One cautious observation, however, is the fact that there must be sufficient masonry along each side of the opening to coun- teract the arch’s thrust, as well as above the apex to support the arch’s compres- sive force. Concentrated forces are assumed to be distributed along a wall length of the bearing area plus 4t, where t = wall thickness (ACI 530-05, Section 2.1.9.1), and the portion along this distribution which falls within the triangular area above the lintel is to be added to the loading pattern. This is also demon- strated in Fig. 11-9. Standard lintels are limited in length by threat of cracking
Figure 11-10 Shear cracking pattern in masonry lintel from in-plane forces. (Courtesy Masonry Institute of America)
When load is applied normal to a wall’s surface, the masonry unit itself is sub- jected to compression and grout may not actually be stressed at all from flexural. It is important to remember that the weight of a wall and carried vertical loads provide great assistance in maintaining stability when subjected to lateral forces, especially in the case of unreinforced masonry assemblies, in addition to delaying the onset of masonry cracks due to a precompressive effect. Amrhein and Vergun (1994, p. 65) comments that the inherent flexibility of masonry walls perpendicular to their plane allows them to tolerate a significant amount of out-of-plane bending
Figure 11-12 Sample distribution of reinforcing steel around opening in a masonry wall.
Figure 11-13 Typical anchor bolt placement in the face of a concrete masonry unit wall. Understanding the Behavior of Masonry Construction
One such imperfection is known as a dislocation, which ordinarily moves easily through a crystal when external load is applied to a steel system. However, when an obstacle occurs to disrupt their movement—such as the abnormal boundary that is formed when different grains come together—these dislocations build up and cause strain-hardening of the metal, which was defined earlier. See Fig. 12-3 as an illus- tration of this phenomenon. Plastic (or inelastic) deformation of the material corre- sponds to the movement of a large number of these dislocations. Ductility is perhaps one of the most attractive mechanical properties of structural steel and is defined by this ability to deform plastically before failure. Measurements of ductility obtainec
| Figure 12-4 General stress-strain diagram for different steels.
Plate girders are simply built-up beams, where their shape can be defined accor ing to stress patterns and applied load and, since the bulk of the section is place where needed, these built-up cross sections, such as is shown in Fig. 12-5, can t quite economical in carrying large forces. Plate girders can become very dee resulting in slender webs that sometimes require stiffener plates spaced at varyir increments along the length in order to provide postbuckling shear strength throug tension field action. This can be visualized as a form of truss action, where flang« serve as top and bottom chords, the web resists diagonal tension forces, and tran verse stiffener plates act as compression web elements.
The interface between base metal and weld metal contains discrete zones with dif- ferent microstructures produced by heating and cooling cycles. These are shown in Fig. 12-7. The weld (mixed) zone is a mixed production of base and weld metals. The adjacent unmixed zone consists of a boundary layer of melted base metal that did not get incorporated with the weld zone and is produced by a flow of excess heat from that requiring melting as the source travels along beyond the previous region. A partially melted zone follows the unmixed zone, but is not always present during fusion depending on the chemical composition of the base metal. The heat- affected zone (HAZ) is a much broader area, sometimes thought to include the par- tially melted zone, defined as the portion of base metal where mechanical proper- ties or microstructure have been changed in some way by the heat of welding. The unaffected base metal is sometimes labeled as a final zone in the creation of a weld.
Figure 12-7 Distinction of weld zones. [From American Welding Society (AWS), Linnert, G.A. 1994, Welding Metallurgy-Carbon and Alloy Steels, Volume 1, 4th Edition, Miami: AWS] Understanding the Behavior of Structural Steel
ire 12-8 Groove welds that are in common use. When subjected to load, welds, and joined pieces must deform together and the sharing of stress to accomplish this is somewhat complex. The presence of resid: ual stresses due to weld cooling, poor welding procedures, and high joint restrain further complicate this phenomenon. Despite these complications, an enginee! should remember that the weld metal itself has a higher strength than the materi: als joined. This is due to the fact that the core wire used in the electrode is a pre mium grade of steel held to tight specifications, and the shielding of molten meta and certain ingredients in the electrode coating provide a uniformity of crysta structure and physical properties (Blodgett 1966, p. 1.13).
Figure 12-9 Buckling mechanism of steel I-girder. (From Timoshenko and Gere, Theory of Elastic Stability, McGraw-Hill, 1961) Lateral-torsional buckling of a beam is said to have occurred when deflection changes from being predominantly in the plane of applied load to a combination with lateral deflection and twisting (see Fig. 12-9), as the capacity for carrying load drops off because of significant lateral movement and yielding. Because of this complex action, bracing will only be effective if it restrains both lateral movement and twisting of the cross section. Lateral-torsional buckling strength is dependent on distance between braces and their stiffness, type and placement of transverse load, restraint of member at ends and interior supports, cross sectional geometry (some sections are more stable than others), inclusion of stiffening elements that restrain warping, material properties, residual stress, applied compressive loading.
Figure 12-11 Concentrically braced steel frame configurations. (Courtesy U.S. Army Corps of Engineers) An earthquake that occurred in Northridge, California on January 17, 1994 led to some important discoveries regarding the behavior of steel moment-resisting frames. The focal point of this 6.4 Richter magnitude event was about 19.8 miles (32 km) west-northwest of Los Angeles in the San Fernando Valley and was fol- lowed by more than 9000 aftershocks (Hall 1995, p. 4). Some areas produced
Figure 12-12 Eccentrically braced steel frame con- figurations. (Courtesy U.S. Army Corps of Engineers)
Figure 12-14 Plastic hinge formation in steel moment- resisting frame. (Courtesy Federal Emergency Management Agency)
A steel fabricator may be faced with three different types of contract issues related to selection, detailing, or designing connections (Ratterman 2003). In the traditional approach, the engineer-of-record either fully designs the connections himself or specifies the type of connections needed so that the fabricator can fully develop construction details on shop drawings that are subject to the engineer’s review. Another approach is where the engineer-of-record specifies connection types and related performance criteria and the fabricator’s engineering staf develops and designs these connections, affixing a professional seal and signature to the documents. A different approach that may be specified in a contract is that the fabricator will essentially become the engineer of record of connections Refer to Fig. 12-15.
jure 12-16 Rolled steel framing elements for roof and skylight system. Understanding the Behavior of Structural Steel
Figure 13-1 Drag strut detail in wood-frame construction to develop force into wood structural panel diaphragm.
Figure 13-2 Plywood structural diaphragm testing. (Courtesy APA— The Engineered Wood Association) Particleboard was originally created from a need to dispose of sawdust, shavings and other somewhat homogeneous mill waste. Some have even incorporated non wood, agricultural residues and blends. It consists of discrete particles instead o fibers that are covered in adhesive, heated, and pressurized together in a fashio1 meeting the requirements of ANSI A208.1 and most applications are for interio use. Mechanical properties of particleboard are derived from the type of rav material used in production, additives, and manufacturing itself. When used a: underlayment, it is sometimes advisable to provide glue to the subfloor in orde: to control some of the instability in the longitudinal direction.
Figure 13-3 Steel straps installed at wood header to jack stud and horizontal blocking in narrow shear wall. Older timber trusses used a birdsmouth-type connection between web and chord members where a portion of the chord was notched out to allow for the place- ment of the web. Testing has indicated that the basic configuration exhibits good ductility as well as semirigid behavior through rotational capacity that occurs as a function of the width and level of compression of the web, the friction and skew angle of the connection (Parisi and Piazza 2000). Modern light-frame truss assemblies use metal side plates with many small teeth that are embedded into the wood by a hydraulic press, whose design values are typically based on load- slip curves generated in a testing laboratory.
yure 13-5 Pattern of wood fibers in the vicinity of a knot A knot is formed as a change in physical properties along the trunk where a branch has become ingrained within the structure of the stem, interrupting arrangement and continuity of cells (see Fig. 13-5). Wood fibers attempt to work their way around the knot, creating a pattern of distortion that includes several points of concentrated stress. Knots affect a member’s tensile, bending, shear, and compressive strengths as they essentially create large voids within a cross-section. Their effect on reducing a
logical structural position, such as providing support for a hanging load from above the neutral axis along a bending member. Simple connections under any loading condition are preferred as there is a better assurance of proper framing in the field. Toe-nails, for example, add needed simplicity but proper installation (see Fig. 13-4) is necessary to get the most out of such a connection. These are fasteners driven through the edge or end of an attached member, at a slope of about 30° with that member, into the carrying (main) piece, though they are more effective when driven through the edge.
member’s capacity depends on size and location, shape and soundness, local slope of grain, and character of loading. After a branch has died and the trunk continues to grow, the resulting knot may become encased within living wood fibers and its influence over mechanical properties will be lessened. In bending members, a knot located within the region of tension fibers will have an impact on flexural capacity. The lateral stiffness of a member under axial compression will be somewhat reduced in the presence of a large knot.
Figure 13-7 Nailing of plywood sheathing to complete a wood-frame structural diaphragm. Understanding the Behavior of Wood Framing
Figure 13-8 Horizontal plywood diaphragm testing. (Courtesy APA—The Engineered Wood Association)
Figure 13-9 Flexible, stiff, and rigid diaphragm definitions based on relative displacement. (Courtesy U.S. Army Corps of Engineers) A wood sheathed diaphragm fails either by nail heads pulling through the panel fac« or edge, splitting of framing members or panels, or buckling of the panels. It has beer shown, and is recognized by model building codes, that a diaphragm with applied lat eral forces in a direction perpendicular to continuous panel joints in an unblocke condition is stronger than a diaphragm which resists load applied parallel to thes joints. At high levels of force, nailed joints between sheathing and framing exhibi nonlinear behavior, except when adhesive is used along with the nails (Kamiya 1987) and are seen as the major factor affecting lateral deformation under load.
| Figure 13-11 Miscellaneous wood-frame truss configurations.
Figure 13-12 Anchored truss blocking panels to com- plete load path from diaphragm to shear wall.
Figure 13-13 Shear wall definitions based on design concept. (From Breyer et al. Design of Wood Structures, McGraw-Hill, 2007)
Section 1203.2 of the 2006 IBC requires enclosed attic and rafter spaces to be ven- tilated in order to prevent damage to wood framing due to environmental effects. The basic area of ventilation required is 1/150 of the total area of space enclosed, but may be reduced to 1/300 of the total area if certain conditions are met. Fifty percent of the ventilation provided must occur 3 ft (0.91 m) above eave or cornice openings and the balance taken through the eave or cornice. Some truss manufacturers provide blocks that include holes drilled for ventilation, otherwise a contractor will need to create some and cover the openings with a corrosion-resistant screen in buildings used for human occupancy (2006 IBC, Section 1203.2.1). Ridge venting is always something of a mystery when a roof diaphragm is expected to be continuously blocked around all edges. However, it is typically sufficient to provide blocked wood panel edges between every other roof framing member and simply double the nailing requirement at this blocking to make up for what was left out at the spaces.
Figure 13-15 Truss bottom chord tension failure in vicinity of knot. (Courtesy Lane Engineers, Inc.)
Figure 13-16 Load duration factors for allowable stress design according to NDS-2005. (Breyer et al, Design of Wood Structures, McGraw-Hill, 2007) One of the most tricky aspects of designing wood-frame structures is the con- sideration of irregular features as described in Tables 12.3-1 and 12.3-2 of ASCE/SEI 7-05. Many of these features involve an offset of elements within the lateral force resisting system, or those that are supported over a softer, more flexible layout of framing, such as the shear wall installed atop a beam shown in Fig. 13-17. In this particular photo, premanufactured roof trusses also require
Figure 13-17 Wood-frame trusses attached to struc- tural beam, requiring hangers and consideration of shear wall placement for diaphragm shear transfer.
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BRIDGE ENGINEERING HANDBOOK: SUBSTRUCTURE DESIGN
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BRIDGE ENGINEERING HANDBOOK: CONSTRUCTION AND MAINTENANCE
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CARA MENGHITUNG VOLUME PEKERJAAN PEMBAGUNAN RUMAH 2 LANTAI | Bag 1
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Pada Artikel ini kami menyajikan cara menghitung volume pekerjaan Pembangunan rumah 2 lantai, Karena Panjangnya artikel maka kami buat bersambung dan juga seharusnya setiap pembahasan agar dapat dimengerti disertai dengan gambar, tetapi... more
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a afectar el diseño de cimentaciones: el tipo de suelo (cohesivo, granular, granular con finos, de alta o baja plasticidad), la variación de estratos, la consistencia (media, blanda, dura), las propiedades físicas y mecánicas (cohesión,... more
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Page r laic Mrv 1NO. 7 m / .U 1 JL/eiallS OI ivV^l^ripe CUlVCll rNr^Uu rural lUaUs Overall VVIUUI /.J III 1 SI Plate JNO. 1 .01 Sections of abutment and return wall for spans 1 .5 m to 3 m and height up to 4.5 m in Masonry 1^A 1 J4 r laic... more
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DESIGN AND CONSTRUCTION OF SHEAR WALLS
by levi edwig
It consists of reinforced concrete walls and reinforced concrete slabs. Wall thickness varies from 140 mm to 500 mm, depending on the number of stories, building age, and thermal insulation requirements. In general, these walls are continuous throughout the building height; however, some walls are discontinued at the street front or basement level to allow for commercial or parking spaces. Usually the wall layout is symmetrical with respect to at least one axis of symmetry in the plan. ‘loor slabs are either cast-in-situ flat slabs or less often, precast hollow-core slabs. Buildings are
proved to be far stronger in seismic resistance when used in shear wall assemblies. Plywood is the traditional material used in the construction of Shear Walls. The creation of pre- fabricated shear panels have made it possible to inject strong shear assemblies into small walls that fall at either side of a opening in a shear wall. As well as the use of a sheet steel, and steel- backed shear panel (i.e. Sure-Board) in the place of structural use plywood in shear walls, has proved to be far stronger in seismic resistance when used in shear wall assemblies.
FIGURE : 4.5.2 Detailing of reinforcement sectional plan.
Fig 5.02-Provision of storey and grid data
Fig 5.03-ETABS main window
Fig 5.04-Addition of frame sections *There are many options in add such as add circle, steel joints and further more but we provide rectangular columns or beams in common and hence we add a rectangular section and then clic! on ok. Another window appears which gives details about section. Here we can provide section name i.e., either a beam or column and change the material to the one that is defined above. Provide the dimensions of the section as required and change the data according to the section provided. If a beam is to be provided then select the design type to beam and provide the required dimensions to the cover and if a column is provided select design type to column and then nominal cover is provided.
Fig 5.1.1-Columns of the Civil block
Fig 5.1.3-Beams after they are assigned
Fig 5.1.4-Columns after they are assigned
Fig 5.2.2-Slabs after they are assigned Fig 5.2.1-Building view options window
Fig 5.2.5-Wall after it is assigned
Define Static Load Case Names Fig 5.3.1-Defining Static loads
Fig 5.3.2-Frame/Line loads after they are assigned
Fig 5.3.3-Shell/Area loads after they are assigned
Fig 5.3.4-Different loads defined 5.4:Analysis:
Fig 5.2.10-Civil block before analysis
Fig 6.1.1-Excavation using heavy earth movers. and diggers. And in some cases if the land is very hard, blasting of site by using small amount Once the excavation is completely done the excavated material is not wasted. It should be generally reused in the same construction work so that construction work is reduced.
Once the excavation is completed marking of land for footings is carried out. 6.2: Foundation and Footings:
Fig 6.2.1-Footings laid for construction These footings are tied together by using tie beams so that the moment during lateral load is completely arrested.
Fig 6.3.2-Beams beneath shear wall
Fig 6.3.1-Columns beneath shear wall
Hence for this situation waffle slab is most preferred. Waffle slab:
Fig 6.3.5- Cured upper portion of waffle slab
Fig 6.3.4-Formwork for waffle slab
Fig 6.3.6-Lower view of waffle slab Once the parking and waffle slab is completely laid then it comes the part of shear walls.
Fig 6.4.1-Horizontal reinforcement of shear wall
Fig 6.4.2-Vertical Reinforcement of shear wall This reinforcement in the horizontal direction is usually tied as double strand single tie with GI wire, this process can also be done by using rebar machine.
MIVAN technology is suitable for constructing large number of houses in a short span of time using room size forms to construct walls and slabs in one continuous pour on concrete. In this system of formwork construction, cast—in-situ concrete wall and floor slabs cast monolithic provides the structural system in one continuous pour. To facilitate fast construction, early removal of forms can be achieved by hot air curing / curing compounds. Large room sized forms for walls and floor slabs are erected at site. These strong and sturdy forms are fabricated with using room size forms to construct walls and slabs in one continuous pour on concrete. In this
Wedge is of thin iron sheet mostly resembles the front view of frustum of cone. Its top size is 2 cm and base is of 1 cm.
Fig 6.7.2-Gaps left for plumbing lines The electrical lines in slabs and wall also have a design. The plumber and sewer lines are left with gap to place into the wall exactly.
Fig 6.9.1-Shear wall after removal of formwork Firstly the wedge is taken out by using a hammer and then pin is also removed. Now started from top and one side form is carefully removed.
Fig 6.10.1-Holes drilled in the slab
Fig 6.11.1-Electrical spaces left in wall When it comes to the server lines holes or empty gaps are left over. And in these empty spaces the sewer pipes are placed exactly to match the empty spaces.
In this way electrical and plumbing lines are placed.
Fig 6.12.1-Painting and finishing works plastering work. As the wall which is obtained is perfectly plain with exact finishes there is no need for and
In the case, when R, = Ry, = 0 for all the existing shear walls, Eqs. (8.11) and (8.12) simplify
Summary of rigidity characteristics
Design lateral force at various floor levels. Design lateral force at floor i: Two shear walls are provided as given in the problem to resist the seismic forces in each direction
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iii A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application.
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BS 8004
by Sinan Arslan
Generally, the more open and permeable the soil the simpler is the piezometer; fine-grained soils such as fine sands, silts and clays require special knowledge for selection of suitable piezometers. It is necessary to measure the water pressures in the pervious strata at a number of typical positions in or around the constructional site in order to:
Figure 6 — Permeability and drainage characteristics of soils
Adequate steps should be taken to avoid loss of ground from around the sump. The best method is to insert some filter medium between the ground and the sump. This can be done after the steel piling or timbering to the sumps has reached its final level. A cage of perforated metal is then installed and the space between the cage and the ground is filled with graded gravel filter material, the sheet piling or timbering being withdrawn as the filter material is placed. The method should not be used if upward flow of water from the base of the excavation causes unstable soil conditions. Also if only a thin impermeable stratum exists at the base of the excavation with further permeable beds below, there is a risk of upheaval of the base of the excavation due to the pressure of the water in the deeper permeable beds. In this case, the water pressure beneath the impermeable stratum will need to be relieved. This can be achieved by pumping from wells or well points inside or outside the cofferdam, or by vertical drains sunk from within the excavation. ee I EE EE EE There will be a risk of water bypassing the sumps, i.e. flowing between them into the main excavation. This trouble can be avoided by stepping in the excavation at the level of the impervious stratum and forming a drainage ditch (garland drain) at this level connected to a sump or sumps (see Figure 7). This method has the advantage of avoiding pumping from an unnecessarily low level and of preventing water collecting in and softening the impervious stratum at the formation level.
In all methods loss or disturbance of the ground should be prevented by the use of filters. Figure 9 — Stable excavated slopes resulting from flat gradient and provision of deep drainage trench
Figure 10 — Reduction of water levels below an excavation by bored well groundwater lowering system
Figure 12 — Reduction of ground level before installing well point system igure 11 — Multi-stage well point system for deep excavation
Amendments issued since publication This British Standard, having been prepared under the direction of the Civil Engineering and Building Structures Standards Committee was published under the authority of the Board of BSI and comes into effect on 30 September 1986.
2.2.2.3.1.3 Laboratory measurements. Strength and deformation characteristics are obtained from uniaxial tests on representative rock cores. The quantity of testing should be related to the variability of the rock or rock types present and the size of the foundation. Rock cores should be protected against loss of moisture immediately on extraction from the ground and should be tested at their natural water content. Dried out or partially dried out rock should not be resaturated. Strain measurements should be made by electrical resistance strain gauges bonded onto the rock cylinders or by transducers between girth clamps; measurement of strain between end caps will underestimate the modulus of the rock. For this and other reasons oedometer tests are not suitable for assessing the compressibility of rocks except in the more highly weathered state. Table 1 — Presumed allowable bearing values under static loading (see 1.2.3 and 1.2.4)
Table 2 — Classification and presumed bearing values for high porosity chalk A weathering scheme for weathered Keuper Marl is given in Table 3 (Chandler 1969). A range of presumed bearing values is given in the table against each of the weathering zones with the exception of the fully weathered, zone IVb marl since in this state the marl is properly regarded as a cohesive soil for purposes of estimating the allowable bearing pressure. Zone IVa and possibly zone III marls may also be amenable to soil testing procedures and analysis (see 2.2.2.3.3). Within each zone the coarser grained and more calcareous the marl the higher the presumed bearing value.
Table 3 — Weathering scheme and presumed bearing values for Keuper Marl Curves for selected values of allowable bearing pressure against rock strength and bedding and discontinuity spacing in the rock mass are presented in Figure 1(a) to Figure 1(d) for the preceding four rock groups using the strength and discontinuity classifications given in BS 5930. The bearing pressures shown have been calculated on the basis of rigid square foundations, with an arbitrarily chosen settlement ratio (settlement to foundation width) of 0.5 %, supported on homogeneous rock. Values of allowable bearing pressure for other settlement ratios may be obtained by direct proportion and for other shapes of rectangular foundation by reducing the bearing pressure by the customary shape factors. The derivation of the curves in Figure 1 is given in appendix A.
A rough correction for the effect of depth may be made (Department of the Environment 1976). Table 5 — Classification of sands and gravels by standard penetration test
2.2.2.3.3.4 Settlement. For cohesive soils it is always necessary to ensure that the foundation is safe against shear failure by taking a presumed bearing value not greater than the ultimate bearing capacit; divided by a suitable factor of safety, conventionally of the order of 2 to 3. Table 6 — Undrained (immediate) shear strength of cohesive soils ine nature or settlement 1n Cconesive SO1IS 1S discussed in 2.1.2.3.3. It is dependent on the bearing pressure, the compressibility of the soil and the dimensions of the foundation, namely depth, width and shape. As with non-cohesive soils, for the same bearing pressure wide foundations settle more than narrow foundations and, in general, the allowable bearing pressures on wide foundations will be smaller than on narrow foundations, in order to keep the settlements within acceptable limits. The magnitudes of the settlement of foundations on cohesive soils may be estimated from the results of
Table 8 — SS grade timber grade stresses
6.7.6.2 Consolidation or compaction grouting. In contrast to permeation, this approach forces grout into the soil under high pressures, locally disturbing the soil structure. The hydrofracture (or claquage) grouting technique uses fluids that cut in the form of tongues through planes and zones of weakness in the soil. It is used most frequently in heterogeneous and lensoidal soils with fine-grained inclusions. The resulting reticulation and interconnection of veins of grout permeating coarse lenses and compacting finer zones can lead to significant reductions in overall permeability. This technique allows a comparatively widely spaced array of injection holes leading to good economy where the volume of soil to be treated is large. Significant ground movements can accompany this kind of grouting in superficial soils depending on the treated volume and depth; due consideration has to be given to the effect of this disturbance on nearby structures. When confined by substantial overburden or in deep tunnels, hydrofracture grouting can be applied using repeated very high pressure injections to achieve effective consolidation of clayey or silt sized soils by successively squeezing out moisture to stabilize them sufficiently to allow safe excavations.
7.4.2.4.2 Transport. Care should be taken at all stages of transporting, lifting and handling to ensure that the piles are not damaged. If the piles are put down temporarily after being lifted, they should be placed on trestles or blocks located at the lifting points. Considerations of speed and economy and limitations of space generally require precast concrete piles to be lifted from the casting bed to a stack and later to be driven with the least possible delay. On the other hand, as thorough curing and hardening require time, a proper balance should be struck in deciding the minimum intervals which should elapse between the operations of casting, stacking and driving. Safety precautions relating to the handling and pitching of precast concrete piles are described in section 11. Table 13 — Curing periods for use in the absence of control cubes or steam curing
Table 14— Suggested slump details for typical concreting situations for cast-in-place piles 7.4.4,.2.2 Reinforcement. For reinforcement of driven cast-in-place piles see 7.4.2.2.2. 7.4.4.4 Formation of piles 7.4.4.3 Design
Table 15 — Nominal pile diameters
Table 17 — Concrete exposed to sulphate attack
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Erection and maintenance of site office and removal the same after completion of work in accordance with the conditions of contract. In addition to the office required for his own use, the Contractor shall provide and maintain furnished... more
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Past-Secretary of ACI 350 who served during a portion of the time required to create this document. † Past-Chairman of ACI 350 who served during a portion of the time required to create this document.
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Engineering Treatment of Soils
by song fangjia
Figure 1.1 (a) Grading triangle for soil classification (material finer than 60 mm); (b) Fuller description of gravels and sands. (Reproduced by permission of the Chief Executive, Transport Research Laboratory, Crowthorne, Berkshire)
‘igure 1.3 Estimation of the degree of expansiveness of a clay soil (after Williams and Jonaldson, 1980) oid ratio. If such a soil is saturated, then the load is initially carried by the pore vater which causes a pressure, the hydrostatic excess pressure, to develop. The xCess pressure of the pore water is dissipated at a rate which depends upon the ermeability of the soil mass, and the load is eventually transferred to the soil tructure. Primary consolidation is brought about by a reduction in the void ratio. ‘urther consolidation may occur due to a rearrangement of the soil particles. ‘his secondary compression is usually much less significant. In clay soils, yecause of their low permeability, the rate of consolidation is slow. The ompressibility of a clay is related to its geological history, that is, to whether it s normally consolidated or overconsolidated. The heave potential arising from stress release depends upon the nature of the liagenetic bonds within the soil. For example, when an excavation is made in ¢
Figure 1.4 Peak strength and residual strength of normally (N-C) and overconsolidated (O-C) clays (after Skempton, 1964)
Figure 2.1 Sheet piling and the possibility of instability at the base of an excavation due to upward seepage pressure.
Figure 2.2 (a) Steel sheet piling with bracing in variable soil conditions; (b) steel sheet piles used for forming a caisson in alluvial soils, near Kings Lynn, Norfolk
Figure 2.4 Precast concrete panels placed in slurry trench to form part of basement wall which is anchored back
Figure 2.5 Beam method of forming a cut-off by driving or vibrating an I-beam. The length of the I-beam has to be at least equal to the depth of the cut-off being constructed
Figure 5.2 (a) A jetting shoe. The latter is attached to the riser pipe. A strainer is located in the recess of the jetting shoe and retained by the retaining collar; (b) Disposable wellpoint and riser pipe; (c) PVC wellpoint
Figure 5.3 Wellpoint system showing wellpoint, riser pipe, header main and pump
Figure 10.8 Influence of the addition of lime on the compaction curves of clay soil (from Bell, 1988)
Figure 10.13 Installation of lime piles
Figure 2.6 Construction of a reinforced diaphragm wall. General procedure for excavation of panels during which time the excavation is kept filled with bentonite suspension; (a) first one end, then opposite end of panel is excavated to full depth; (b) third and last stage is the excavation of the centre panel. General procedure for concreting panels when the bentonite is displaced by concrete: (c) steel stop-end pipes and reinforcement cage positioned and concrete placed through tremie pipe; (d) section through completed panel showing guide walls and steel; (¢) illustrating variety of uses of steel stop-end pipes as required tension forces due to moisture content, and with no osmotic force between slurry ee, ee ee ee er ee. ee ee ae ee
Figure 2.7 Guide wall and excavator (after Goto and Iguro, 1989)
Figure 2.8 Diagrammatic outline of the Soletanche Hydrofraise rig
Figure 3.1 Thermal conductivity of soil (from Mitchell, 1981) The mechanical properties of frozen ground are much more dependent on the ime taken in freezing and the ground temperature than on the nature of the soils nvolved. Consequently, artificial ground freezing is less sensitive to geological conditions than other methods of ground treatment and may be used in any moist oil, irrespective of its structure, grain size or porosity (Jessberger, 1985). Weak, running or bouldery ground, and ground in which the pore-water pressures are nigh, lend themselves to freezing. Soil profiles, too heterogeneous to grout oredictably, are also amenable to freezing. However, in heterogeneous soils the ‘rozen zone tends to be irregular in shape. For a certain refrigerant temperature he frozen ground is usually thinner in silts, clays and organic soils than in sands and gravels (Figure 3.2). As these commonly are the weaker strata, design may oe dictated by the former three soil types. When clay soils are frozen, vertical cracks may form in the soil between the frozen columns and the soil may bulge near the zone being frozen. The fibrous structure of organic soils tends to be altered permanently by freezing.
Figure 3.2 Content of unfrozen water in frozen soil (after Frivik and Thorbergsen, 1981) 3.2 METHODS OF GROUND FREEZING
Figure 3.5 Ground freezing with liquid nitrogen
Figure 4.1 Filter drain incorpoating synthetic fabric (geotextile), showing development of a filter zone within the soil
Figure 4.4 Permeability reduction of geotextile installed in the field (after Van der Merwe and Horak, 1989)
Figure 4.6 Excavation A was made to provide a level recreational area for a school. The ground, being near the bank of a large river in its lower reaches, consisted chiefly of alluvium. Movement started on slip line SL but was unnoticed, forit was seasonal and not very active. Later, a road was to be constructed for access to the school; this work (excavation B) was found to be impossible until the hillside was stabilized. Counterfort drains, C, were constructed about every 3 m over the length of the moving section. The depth of the slip had been found to be about 2.5 m. It eventually became possible to build the roadway
as i The effects of soil disturbance due to the installation of sand drains that can give rise to a smear zone about a drain should be taken into account when assessing the coefficient of consolidation for radial flow (Richart, 1959). The development of a smear zone depends upon how the hole for the sand drain is formed in that mandrels are more likely to give rise to smear than augering. In addition, the density and pore-water pressure of the soil may affect the development of a smear zone. The extent of the smear zone may be quantified in terms of the altered zone so that a smear ratio, SR, can be defined as
Figure 4.11 (a) Typical vertical drain installation layout; (b) theoretical pattern of drainage through a sand drain
Figure 4.13 Emplacement of a sand drain. Equipment is designed to jet through varying subsoils and leave a vertical column of graded media in the ground Several types of flat band drains are available (Table 4.2). Most consist of a flat plastic core containing drainage channels surrounded by a thin filter layer (Figure 4.14). Engineering filter fabrics are now more commonly used than treated paper wrappings. Lee et al. (1989) referred to the use of fibre drains made from jute and coir which have functioned for periods of 12-15 months. In countries where these materials are abundant, the principal advantage of fibre drains is their low cost. Although the permeabilities of the wrappings, especially of paper, may be as low as 10°° m/s, they are thin and offer little resistance to flow. The permeability of the filter should not be higher than that required for the discharge capacity (Hansbo, 1979). This means that filter permeability of existing prefabricated drains need not exceed 0.01-0.1 m/y, irrespective of whether drains are placed in clay or silt. The mechanical characteristics of band drains are important. In particular, the tensile strength usually ranges from 0.5 to 2 kN and elongation at yielding is between 6 and 10%. The discharge capacity of band-shaped drains varies considerably, depending vaAnn tha hrrana nf denin aioon TE alan toa a funnthinn at tha affantxra: latarml aarth
Figure 4.14 Typical cross-sections of plastic band drains: (a) with filter sleeve; (b) without filter sleeve
Figure 5.11 An ejector or eductor system
Figure 5.12 (a) A deep-well system; (b) well in more detail
Figure 5.15 A typical cathode well system
Figure 6.1 A compaction curve indicating maximum dry density and optimum moisture content
Figure 6.3 Applicability of deep compaction methods (after Mitchell, 1970, with permission of ASCE)
Figure 6.4 Principle of precompression using surcharge loading (i.e. load in excess of final load to accelerate settlement). The length of time to achieve the required amount of settlement has to be assessed, or alternatively the magnitude of the surcharge, A,, required to ensure that settlement, AH, will be completed in time, t,, has to be determined. If the surcharge is left in place until time t,, then it will give the same amount of settlement as that which would occur under the final load at time t,.
Figure 6.5 (a) Time factor, T,, versus degree of consolidation, U. Where the consolidating layer drains from both the top and bottom, that is, the layer is open, then curve (1) is used. Where drainage takes place in one direction only, that is, the consolidating layer is half- closed, the curve used depends upon the initial excess pore-water pressure as shown in (b). (b) Initial variations in excess pore water pressure in a half-closed layer. If the layer is half-closed, then H/2 is used in eq. (6.4).
Figure 6.6 Surcharge to reduce rate of secondary compression (after Bjerrum, 1972, with permission of ASCE). It is assumed that o’)+q+Aq is well above pre-compression pressure, p,, in each layer (where o’) is the initial effective stress) so that the representative point C in the e-log p graph is on the virgin curve. Because secondary compression may cause large amounts of total settlement in some soils (mostly organic clays and peat), the effect of surcharge must be analysed with reference to this secondary compression. If one considers the e-log p graph, the primary compression path is ABC and secondary compression can be represented according to Bjerrum by CD. In most cases the actual path is represented by the dotted line between B and D because secondary compression starts during the primary compression period. A precompression project with surcharge is represented by ABC D’ (or ABD’) and surcharge removal is D 'E. The degree of secondary consolidation can be read on the set of e-log p curves giving the equilibrium void ratio at different times of sustained loading (0.1 year, 1 year, 10 years, etc.). Hence, due to surcharge, a much greater degree of secondary consolidation (100 years) can be achieved than without: a state which is represented by point D (6 months)
Figure 6.7 Excess pore-water pressure distribution with depth at times of degree o consolidation U; and U». For a degree of consolidation U4,,,=U1, although 4H, i: achieved, there can still be values of excess pore-water pressure, 4u,, much larger than 4q in the central part of the layer. On the other hand, in the upper portion (and in the lowe portion when both boundaries are pervious) excess pore pressures are much less than Aq Consequently, after removal of surcharge the upper and lower parts of the clay layer maj heave and the central part continues to undergo progressive settlement due to primary consolidation. To eliminate further primary consolidation following the removal o! surcharge it is necessary to wait until the degree of consolidation is equal to U2. Surcharge helps develop secondary consolidation settlement and the degree of secondary consolidation is much higher than for simple precompression. Also, the rate of furthe consolidation is much smaller. This procedure also assumes that excess pore-wate: pressures are dissipated in due time and that effective stresses are able to induce prope! secondary consolidation bentonite-cement mixture). Values of 60-70% vacuum are generally attained
Figure 6.8 Preloading by vacuum. In pressure diagrams o’ is effective pressure and u is pore-water pressure. The pressure diagram on the left is for ground conditions prior to treatment; that on the right indicates the changes that occur when vacuum is applied, notably the development of negative pore-water pressure and the increase in effective pressure which lead to consolidation
Figure 6.11 Effect of fines content on increase in penetration resistance by vibroflotation (after Saito, 1977)
Figure 6.14 (a) Vibroflot suspended from a crawler crane (courtesy of Cementation Ground Engineering Ltd)
Clay soils are largely unaffected by induced vibrations. Nevertheles vibrocompaction is also used to treat clay soils. In this case stabilization brought about by columns of densely compacted coarse backfill (Figure 6.17 These stone columns utilize the passive resistance of the soil, thereby increasir its bearing capacity and reducing settlement (Figure 6.18). Stabilization is al: aided by the increased rate of dissipation of excess pore-water pressures due the presence of the columns and the gain in shear strength consequent upon radi drainage (Figure 6.19). Radial drainage means that settlement occurs mo rapidly. Stone columns are also a means of reinforcing soil. A large proportion of any load imposed at the surface is initially borne by tl
Figure 6.18 The effect of stone columns on anticipated foundation settlement (after Greenwood, 1970)
Figure 6.27 Tamping rig attached to crawler crane erratic. Indeed, the pore water acts as a lubricant facilitating the rearrangement of grains. The reduction of the void space in soil results in the displacement of a large volume of water, the quantity depending on the depth, original void ratio and amount of densification attained. eee ‘et ws
Figure 6.29 Arrangement for blasting. The charges i, i+1, i+2 being detonated in the second phase (after Carpentier et at., 1985) are backfilled. The presence of a surface crust of impervious material inhibits the expulsion of excess pore water from the soil. Hence, it must be removed, disturbed or fractured.
Grid reinforcement systems consist of polymer or metallic elements arranged in rectangular grids, metallic bar-mats, and wire mesh. The two-dimensional grid- soil interaction involves both friction along longitudinal members and passive bearing resistance developed on the cross-members. Hence grids are more resistant to pull-out than strips, however, full passive resistance is only developed with large displacements of the order of 50-100 mm (Schlosser, 1990). The most frequently used polymeric materials in earth-retaining structures are high-density polyethylene and polypropylene grids (see Chapter 8). Several systems of bar and mesh reinforcement have been developed. For example, crude grids have been formed by cross-linking steel-reinforcing bars to form a coarse welded-wire bar-mat. Welded-wire reinforcing mesh similar to that used for reinforcing concrete has also been used to reinforce granular soil, especially in the United States. Attamnte have hean mada tn reinforrea eni] hy including fihre within it Tha
Figure 7.3 Pull-out tests of high adherence and smooth strips (after Schlosser, 1987). The peak and residual values of the apparent coefficient of friction depend on the density of the backfill, the nature of the surface of the reinforcement and the overburden pressure. In dense granular soils, the values of the apparent coefficient of friction, f*, are usually significantly greater than the values obtained from direct shear tests. This is mainly due to the fact that, under the effect of the shear the soil tends to increase in volume and the denser the fill the more dilatant it will be for a given stress. This volume change is restrained by the surrounding soil and the confining effect results in an increase of the normal stress exerted on the reinforcement and consequently in a high value of the apparent coefficient of friction. The dilatancy effect in a soil can be enhanced by forcing more material to be sheared during the pull-out of the strip. In the case of high adherence (HA) strips this is achieved by the ribs. Another interesting effect of shearing a larger quantity of soil is that the peak, which occurs for a slightly larger displacement, is much flatter. This indicates that the value of the coefficient of friction used in the design of structures is the maximum value for high adherence reinforcements and the residual value for smooth reinforcements. For a given density, a soil will be less dilitant if the confining pressure is higher. This explains why the favourable effect of dilatancy on the apparent coefficient of friction decreases when the average overburden stress (_ H) increases. In the case of high adherence reinforcements, the ribs force the shear surface to be within the soil. Thus, under high overburden stress, the coefficient of friction approaches tan, being the internal friction angle of the soil. In the case of smooth strips, under high overburden stress, the coefficient of friction approaches tan w, w being the soil reinforcement friction angle. The value of tan w is approximately equal to 0.5 tan. Soil having a soil reinforcement friction angle of less than 22° should be rejected
Figure 7.7 Active and resistant zones in a reinforced earth wall
Figure 7.12 Schematic cross-section of anchored geosynthetic ‘spider netting’ used with soil nails to stabilize a slope (after Koerner and Robins, 1986) piles is strongly influenced by their three-dimensional geometric or root-like arrangement (Figure 7.13). The holes are formed by a high-speed rotary drill and, as drilling proceeds, a steel casing is gradually driven into the hole to prevent its collapse and to limit loosening of the soil. Reinforcement, usually a single steel bar, is placed in the centre of the casing. The hole is then filled with a high slump, cement-rich, small aggregate concrete. During withdrawal of the casing additional concrete is placed by pumping or compressed air pressure. This produces an intimate contact between concrete and soil, forces penetration of the concrete into cracks and fissures and, in the case of compressible soils, produces a pile of larger diameter than the original casing. Reticulated micropiles can be installed in gravels, sands, silts and clays. Drilling can take place in restricted areas and does not produce detrimental vibrations. A cluster of reticulated micropiles, usually containing some installed at a
Figure 7.14 Protection of tunnel by reticulated micropiles
Figure 7.16 Dowelling in soil (after Gudehus and Schwarz, 1985) particles able to permeate the soil, radial penetration of grout forming a large anchor from a small-diameter borehole (Figure 7.18(a)). Resistance to withdrawal is govemed principally by side shear but an end-bearing component may be included when calculating the pull-out capacity. Anchors in such ground are designed to resist safe working loads of 80t (Littlejohn, 1970). The construction of the anchorage is carried out by drilling and driving a casing (102 mm nominal diameter) to the required depth, lowering a prepared steel cable or bar and then injecting grout under a nominal pressure (30-1000 kN/m2) as the casing is withdrawn over the fixed anchor length. a a ee a . i : a a a ie i ee: i, ae ocr fy pee
Figure 7.18 Various types of soil anchorages L=length of anchorage, d= diameter of anchorage
Figure 10.4 (a) Relationship between cement content and unconfined compressive strength for soil-cement mixture; (b) effect of curing time on unconfined compressive strength of some soil-cement mixtures (from Anon., 1990(d))
Figure 8.1 Typical fabric pore size distributions (after McGown, 1976) properties which approach that of steel mesh (Figure 8.2). These woven fabrics, therefore, can be used instead of steel or aluminium strips in earth reinforcement. On the other hand, some non-wovens have relatively low strengths with breaking strains approaching 150% and high creep tendencies (Figure 8.3). The stress- strain characteristics of fabrics provide an indication of their relative toughness. In situations where large strains have to be accepted, extensible non-wover fabrics prove suitable. Conversely, the use of a stiffer woven fabric is necessary when strains in the soil must be limited. TS scores | lee sane oben sawew eee imeorbawes lew Bice Doe wick Ta Sa cashitn be Elec ew
Figure 8.2 Stress-strain curves for various filaments (from Hoare, 1987) The peak tensile strength and strain measured under plane strain conditions offers an indication of the maximum load capacity of a fabric and the strain required to achieve this. Woven fabrics, on a weight for weight basis, afford much higher resistance to breaking than non-woven types. The latter generally are characterized by relatively low strength and high failure elongation. In general, the percentage loss in strength is much less for non-woven than for woven fabrics. However, the higher initial strength of woven fabrics must be borne in mind. The structural arrangement of a fabric may give rise to various degrees of anisotropy in terms of strength and extensibility. Changes in the internal structural mobility, interfibre friction and the surface texture of geotextiles are likely to occur according to the level and nature of confinement. In this way the load-extension and surface friction characteristics of a fabric are altered. In fact, Ingold (1991) referred to a transition point at which the mechanism controlling tensile failure underwent a change, the time at which this occurred being affected by polymer type, environmental conditions and any damage caused by construction operations. Because the tensile strengths of different geosynthetic products differ and are affected to differing degrees in different environments, the new British code of practice for reinforced soils (Anon., 1991) has adopted the concept of partial factors of safety, using a partial load factor and a partial material factor to obtain a margin of safety against failure.
Figure 8.3 Typical plane strain data for different types of geotextiles, normalized to 300 g/ m? fabric weight (after McGown, 1976)
Figure 8.9 Double liner system containing two flexible membrane liners (FML) for disposal of hazardous waste
Figure 9.2 (a) Viscosities and shear strengths for cement pastes with varying water/ cement ratios (after Raffle and Greenwood, 1961). (b) Viscosities of various grouts; heavy lines indicate the solution concentrations normally used in the field (after Karol, 1982, with permission of ASCE)
Figure 9.5 (a) Effect of water/cement ratio on strength development of ordinary Portland cement (OPC) and rapid hardening Portland cement (RHPC). (b) Gain in strength of set grouts. (From Littlejohn, 1982, with permission of ASCE)
Figure 9.7 Effect of water content on grout properties (after Littlejohn, 1982, with permission of ASCE)
Figure 9.8 The Joosten method of grouting
Figure 9.12 Detail of the tube-a-manchette
Figure 9.13 Jet grouting: (a) mixing grout with soil; (b) replacement jet grouting using compressed air and water to remove soil for simultaneous replacement by grout using column, panel and wing methods
Figure 9.14 Sub-horizontal jet-grouting execution sequence for tunnels: (a) jet grouting ahead of the face; (b) excavation; (c) jet grouting at next stage; (d) geometrical scheme of treatment. Jet-grouted columns are formed ahead of the tunnel face, the overlapping sub- horizontal columns forming a protective shell around the excavation. The length of treatment is normally between 10 and 15 m but excavation stops 2 or 3 m before the end of the treated zone so as to leave sufficient support for roof stability (after Dugnani et al., 1989)
Figure 9.15 C onstruction of horizontal grout membrane
Figure 9.16 Serre Poncon dam: (a) typical cross-section; (b) distribution of grout holes in the central part of the grouted cut-off
Figure 10.3 Loss in strength due to delay in compaction for two soils stabilized with 10% cement; standard compaction (from Ingles and Metcalf, 1972)
Figure 10.14 Scheme for deep thermal treatment of soil (after Litvinov, 1960): 1, compressor; 2, cold air pipeline; 3, liquid fuel container; 4, pressurized fuel pump; 5, fuel pump line; 6, filters; 7, nozzle; 8, combustion chamber; 9, borehole; 10, stabilized zone
Table 1.1 Symbols used in the Casagrande soil classification
Table 1.6 Some typical properties of gravels, sands and silts
Figure 1.5 Grading curves of laterites (after Madu, 1977)
Table 1.8 Municipal waste materials incorporated in fills (after Sowers, 1973)
Table 4.1 Sand or gravelly sand filters and fine-grained soils (from Sherard et al., 1984b)
Table 4.2 Main characteristics of some common types of band drains
not applicable to deep compaction of materials in situ.
Table 6.3 Effect of vibroflotation in cohesionless soils (after Mitchell, 1970) because a quick condition is developed which reduces the shearing resistance of the sand, thereby facilitating the movement of particles into a denser condition. Liquefaction occurs within the immediate vicinity of the vibroflot, that is, up to a distance of about 500 mm. Beyond this, liquefaction is incomplete because of damping effects. On the other hand, the presence of layers of clay, excessive amounts of fines, ee ee a 2 a: es Oe ot oe Oo no) er er se
“*'“ Notes" Durability," long-term filtration properties, particle’ ‘retention, water/liquid. permeability, thickness and weight are all properties which depend upon the fabric construction process and have to be considered where appropriate.
Table 8.2 Typical grab tensile characteristics of some fabric types used in civil engineering (normalised to 200g/m?) (after McK eand and Sissons, 1978) than tear initiation, is another important property. In some applications such as river bank and coastal protection, this may be one of the major requirements of
Table 8.3 Typical values of Mullen burst for some fabric types used in civil engineering (normalised to 200g/m2) (after McK eand and Sissons, 1978)
Table 8.4 Criteria for preventing soil piping in one-way flow situations (after Giroud, 1982) aLU ytY Oil ili LQWLU U.T. Fabrics have been used to form various types of drains such as linear drains where fabric encapsulates granular material in a trench, drainage blankets beneath fills, or fin drains (see Chapter 4). In the latter case the geocomposite consists of a sandwich of thin, high-porosity filter fabric enclosing a core able to collect water. This runs to a perforated unplasticized PVC pipe around which it is wrapped (see Figure 4.3). The core is formed from an extruded polyethylene mesh sheet. Geocomposite is used to drain both sides of French drains, and in
Table 9.2 Hydraulic gradient to maintain flow in non-Newtonian grouts (from Bell, 1975) lAKE INO dCCOUllt Wile Creep PrOperwles OL We set QrOut. The development of the shear strength of a cement grout is affected by the water/cement ratio (Figures 9.2(a) and 9.5) and the particle size— the larger the water content and particle size, the lower the strength. The rate of shear strength development can be changed by the addition of accelerators or developers. Under optimum curing conditions, and when not subjected to chemical attack, a set grout continues to increase in strength over a prolonged period. Cements with a low rate of hardening tend to have a higher ultimate strength due to slow formation of denser gel during the initial stages of setting. Generally, ordinary Portland cement grout has a set strength at 28 days of approximately 60-70% of ultimate strength (Figure 9.5). This amount of strength may be obtained in about three days with high early strength cement.
Table 9.3 Limits of penetration of cement grout into granular soils
Table 9.5 Common additives to cement grout used to impart specific properties to the final product (after Littlejohn, 1982)
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Les principaux essais géotechniques au laboratoire
by Zakaria Zinoun
Ce document illustre lucidement le mode opératoire de la majorité des essais géotechnique qui peuvent être effectué au laboratoire en adaptant chaque essais à un cas réel de sol.
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Eric Fleming-Construction Technology - An Illustrated Introduction [buildings, architecture-Wiley-Blackwell (2005)
by Alberth Corimayhua
Fig. 1.1(a) Solid and perforated bricks.
Fig. 1.1(b) Single shallow frogged bricks.
Fig. 1.2 Coordinating and working dimensions of the standard metric brick.
Fig. 1.4 Types of brick by shape. Bricks can be manufactured to fulfil differ- ent functions, i.e. strength, resistance to water
Fig. 1.3 A lintel over a window opening in a brick wall.
The walls are built in stretcher or common bond, i.e. all the main bricks show a stretcher face and overlap by half a brick length
Fig. 1.5 Whole brick and half batt dimensions.
Fig. 1.7 The use of a closer in a one brick thick wall built in English bond. The drawing shows the two adjacent courses at the end of a wall as well as the face view of the wall over a number of courses. The cut illustrated is called a queen closer and is formed by cutting a brick ina plane vertical to the bed and along the centre line of the long axis of the brick. Note that there is a whole brick in alternate courses at the end of the wall next to the queen closer. This brick is referred to as the quoin header. We will explain the terminology properly as we look at particular bonds and bonding in more detail.
Fig. 1.8 Quarter batt.
Fig. 1.9 Half batt. We will find out shortly in this chapter where and when to use these cuts when we look at how the various bonds are laid out course-by-course and situation-by-situation. What we must ask ourselves now is ‘why do we bother to bond in any particular way at all?’ Anyone who has played with old fashioned wooden blocks or their modern
Fig. 1.12 Queen closer. widening area of brickwork, thus dissipating the load. This is illustrated in Figure 1.14. widening area of brickwork, thus dissipating the load. This is illustrated in Figure 1.14.
Fig. 1.10 Three-quarter batt. equivalent, Lego, will understand the need to connect vertical layers of these units together to increase the stability of an increasing height of built work. The broader the base and the more comprehensive the bonding of the layer, the higher the structure can be made. So it is with brick and blockwork walls. As we build we overlap the bricks in adjacent layers, thus ensuring that there is never a complete verti- cal layer joined only to the remainder of the structure with a layer of mortar.
Fig. 1.13 Bevelled closer. Fig. 1.11 King closer. The second criterion is to spread any verti- cal loading on a part of the wall to an ever-
Fig. 1.15 Parts of a wall — scuntion, intersection and quoin.
Fig. 1.14 Loadings on walls which are not bonded and those which are bonded.
Fig. 1.16 Half brick thick wall in stretcher or common bond.
Fig. 1.18 One and one half brick thick wall in English bond.
Fig. 1.19 One brick thick wall in Flemish bond. Fig. 1.20 One and one half brick thick wall in Flemish bond.
Fig. 1.21 Quetta bond — wall is always one and one half bricks thick. Neither of these bonds is as strong as Flemish bond but they are used in situations where strength is not such an issue, e.g. garden walls.
Fig. 1.23 Rattrap bond by one - wall is always one brick thick. As in Quetta bond, the bricks are laid on edge, resulting in an interesting face pattern. The notes regarding Quetta bond apply equally to Rattrap bond, with an even lesser chance of keeping weather effects out of the build- ing. A stronger bond than Quetta, it could be used for industrial or agricultural build- ings and of course can be made more weath- erproof by over-cladding. The bond is usually one stretcher to one header but it can also be
English garden wall bond
Fig. 1.24 Rattrap bond — orthographic view of quoin. Before leaving the patterns of bond, the ver- tical alignment of perpends must be studied. Two points in particular:
Fig. 1.28 Risbond joint at one course high wall venti- lator.
Fig. 1.29 Honeycomb brickwork. This is a method of building a half brick thick wall similar to stretcher or common bond but leaving a space between every brick in each course, as shown in Figure 1.29. Therefore the bond can be by quarters or thirds, which describes the overlap of bricks in adjacent courses. With a quarter lap the void is half a brick wide, and with a lap of a third, the void is a third of a brick wide.
Fig. 1.30 Alternative use of term quoin.
using snap headers in its construction. Indeed some of the cuts in the ‘solution’ would be termed snap headers. The term arises because any headers which show on the face of the wall are just ‘headers’ (whole bricks) snapped in two with the decorative header face show- ing and the rough cut end on the inside. This is illustrated in Figure 1.31.
Fig. 1.32 Scuntion of one brick thick wall built both sides fair face; bricks finished one stretcher and two header faces.
Fig. 1.34 Weather struck joint in pointing or jointing. It is more usual to strike the mortar off at an angle or some other shape to emphasise the joint and also to add to its weather shedding properties, as shown in Figure 1.34. The figure
Fig. 1.33 Quoin of one brick thick wall built both sides fair face; bricks finished one stretcher and two header faces. show finished faces. In this case the cutting is best done with a power saw. If you doubt that, just go back and look at Figure 1.28 and the perpends at the half bricks. The wavy edge of a brick cut with a chisel or a brick hammer is clearly seen.
Fig. 1.35 A selection of joint shapes.
Fig. 1.37 Bucket handle pointing /jointing tool. General principles of bonding
Sectional bond lines through back to front of wall as shown by heavy lines
Fig. 1.41 150 thick block wall quoin.
Fig. 1.40 100 thick block wall quoin. Unlike brickwork, block cutting is generally confined to cutting to a particular length to
Fig. 1.39 Standard metric block dimensions and type by shape.
Fig. 1.43 Drum concrete mixer. Fig. 1.42 Schematic of drum and pan mortar/concrete mixing machines.
Fig. 1.44 Use of gauging box for proportioning ingre- dients in a mortar. Frost and snow
Fig. 2.1 Site with topsoil removed — concrete founda- tion in foreground.
Fig. 2.3 Minimum depth to avoid frost heave.
Fig. 2.4 Minimum depth in shrinkable clay.
Fig. 2.2 Foundation penetrating mixed layer into sub- soil.
Fig. 2.6 Foundation with width calculated — thick- ness?
Fig. 2.5 Protection from heave in shrinkable clay.
Fig. 2.8 Increasing width, increasing thickness.
Fig. 2.7 Calculation of thickness of plain foundation.
Fig. 2.9 Wall on footing on plain concrete foundation.
Fig. 2.10 Bending failure of plain concrete foundation.
Fig. 2.11 Shear failure of plain concrete foundation.
Fig. 2.12 Reinforcement of bottom layer of concrete foundation. in placing; don’t think things like that never happen-they do with monotonous regularity.
Fig. 2.13 Top layer reinforcement of concrete foun- dation. Trench fill is sometimes referred to as deep strip but to avoid confusion this text will refer only to trench fill.
Fig. 2.14 Deep strip foundation. The operatives do not need to work in the trench as is the case with strip foundations. Support for the foundation is not just from the bottom of the trench but can also be from the friction of the sides of the foundation in the ground. This is illustrated in Figure 2.14.
Fig. 2.15 Deep strip foundation in shrinkable clay. Trench fill foundations do not fail by bend- ing or punching shear. Shrinkable clay is often suitable for trench fill foundations. In this case the sides of the foundations should be lined with a ‘crushable’ material such as expanded polystyrene sheet. The additional work is il- lustrated in Figure 2.15.
Fig. 2.16 Sketch of benchmark symbol. As shown in Figure 2.17, a wooden peg driven into the ground and set round with
Fig. 2.19 Finished ground level at lower level than original ground level. Frost cover dictates that the bottom of the foundation is 450 below finished ground level, as shown in Figure 2.19. There should be no difficulty reaching a bearing with that min- imum depth. The foundation bottom must
Fig. 2.18 Finished ground level at same level as orig- inal ground level.
Fig. 2.17 Temporary benchmarks.
Fig. 2.20 Finished ground level at higher level than original ground level. reach down to bearing strata, as shown in Fig- ure 2.20. Cover is generally no problem. Note the large amount of filling. reach down to bearing strata, as shown in Fig- ure 2.20. Cover is generally no problem. Note the large amount of filling.
Fig. 2.21 Bearing strata sloping in relation to ground level (1).
Fig. 2.22 Bearing strata sloping in relation to ground level (2).
Fig. 2.23 Step in foundation — the rules.
Fig. 2.25 Peg with nail, used to mark corner of a build- ing on site. Having found two corners of the proposed building, set out and mark the others. Use
Fig. 2.24 1:500 site plan.
Fig. 2.26 Finding position of peg from two points. the Pythagoras theorem in any combination of right angled triangles, as shown in Figure 2.28.
Fig. 2.27 Pegs on the building line marking building corners. We need profile boards, as illustrated in Fig- ure 2.31. Profile boards are set up at each cor- ner of the building. Each set ‘looks’ two ways along adjacent walls, as shown in Figure 2.32. To ‘see’ the outline of the building’s concrete foundation and walls, builder’s lines may be stretched from profile to profile. With all that string around, there is no room to get in to excavate for the foundation, but see how ex- cavations are marked out below.
Fig. 2.29 Checking the diagonals.
Fig. 2.28 Using the Pythagoras theorem to find other corners of building.
Fig. 2.30 Losing markers for building corners when excavating. Of course you may end up working for a large company which can afford electronic position and distance measurement (EPDM) equipment, and then there is no need for all these pegs and profiles. One or two strategi- cally placed pegs with a nail in the top, well
With builder's line stretching from notch to notch in opposite profile boards, the intersections of the strings mark the corners of various parts of the substructure. The black dot marks the corner of the wall to be built and should be exactly over the original peg and nail. Only put up builder’s line for the outline of excavation/concrete; people with picks and shovels or an excavator could break the
Fig. 2.34 Banksman and traveller.
Fig. 2.33 JCB-type excavator. Heavy lines indicate hydraulic rams to operate arms etc. Accuracy is important so as not to waste money:
Fig. 2.35 Banksmen and traveller between profile boards.
Fig. 2.36 Traveller in use in an excavation. IIR IEEE mee Excavating into the ground for any pur- pose can be dangerous due to the possible col- lapse of the sides. The deeper one goes, and the more friable the subsoil, the more dan- gerous it becomes. In certain circumstances it is impossible to excavate at all unless one uses timbering. This is the short-hand term for shoring, strutting and waling — a range of systems to support the sides of excavations to prevent collapse and protect workmen down in the excavation. Appendix F describes the techniques involved. Shoring, strutting and waling is temporary work and is, by conven- tion, never shown on drawings. It will not be Travellers are made of timber, and the criti- cal dimension is the height.The depth at which the concrete must be laid has already been de- termined. We know the level of the top of the profile boards. The height of the traveller is made slightly less than the difference between these two levels. The traveller is used by plac- ing it at the bottom of the excavation and having the banksman sight across the pro- file boards past the cross bar on the traveller,
Fig. 2.38 Trimming sides of excavation.
Fig. 2.40 Finding corner of wall on concrete founda- tion. Alignment of this first course of bricks is done using a builder’s level, with reference to the
Fig. 2.39 Using the traveller to set concrete foundation thickness. Building the corner out trench and all measure of concrete thickness so provision must be made to allow this mea- surement to be made or maintained. The pro- file boards provide us with a unique reference line to control both thickness and the level of the upper surface. Reduce the height of the traveller so that it extends from top of profile to top of concrete. Drive pegs into the bottom of the trench such that the traveller intercepts the line of sight across the profiles, as shown in Figure 2.39. Pegs are spaced out about 1 metre apart down the centre of the trench.
Fig. 2.41 Setting the first brick of the corner of wall on the foundation.
Fig. 2.43 Keeping the first course of bricks aligned on the foundation.
Fig. 2.44 Racking back. With the first few courses infilled, corners are built up again and infilling continued, as shown in Figure 2.46. Brickwork is built to a maximum of 1.50 m (20 courses) high in any one working day, irrespective of wall width. This height is referred to as a lift. Building any higher on unset mortar brings the risk
Fig. 2.42 Setting up the first five to six bricks at corners on the foundation. With corners built at each end of a length of wall, a builder’s line is strung from the
Fig. 2.46 Corners extended and ready for the next lift.
Fig. 2.49 Wall section with dimensions and annota- tion.
Fig. 2.48 Use of correct line thickness.
Fig. 2.47 Wall detail—symbols for materials in section.
Fig. 2.50 Simple non-domestic substructure/ ground floor interface.
Fig. 2.53(a) Galvanised steel twisted wall ties.
Fig. 2.53(c) Stainless steel chevron wall ties. Fig. 2.53(b) Galvanised steel wire butterfly wall ties.
Fig. 2.53(d) Stainless steel wire wall ties.
Fig. 2.51 Hollow wall/single layer concrete floor suit- able for domestic construction.
Fig. 2.52 Hollow wall/double layer concrete floor suitable for domestic construction.
Fig. 2.55 Loadbearing block partition built off con- crete subfloor.
Fig. 2.54 Non-loadbearing block partition built off concrete subfloor.
Fig. 2.56 Joists and boarding schematic.
Fig. 2.57 Hollow wall/timber hung floor interface suitable for domestic construction.
Fig. 2.58 Alternatives A, B and C of joist support.
Fig. 2.59 Alternatives D and E.
Fig. 2.60 Precast concrete T-beam and filler block floor. joists may be of concrete or wood and very occasionally of galvanised cold rolled steel.
Fig. 2.61 Alternative filler block floor construction. The thickness of any screed placed over the sub-floor depends on the purpose to which the floor will be put and the type of fin- ish placed on the screed. Insulation may be placed over the floor under the screed, in which case a minimum thickness of 65 screed would have to be laid. In addition, some thin screeds would benefit from the inclusion of a light steel reinforcement — galvanised chicken wire would be adequate to prevent serious cracking due to temperature and/or moisture movement". A floor incorporating heating cables or pipes must have a minimum screed thickness of 65.
Fig. 2.62 Permanent formwork for hung concrete, cast in-situ floors.
Fig. 2.65 Sleeper walls in the above substructure. ULLILVOCL LI GALLIC VV CGI CUIIOLIULCLUUIE Tit Vi aoa na li UU. Figure 2.64 is a photograph of a fairly sim- ilar construction, the main differences being We will return to this detail when we look at timber frame wall construction in Chapter 3.
Fig. 2.64 Photograph of substructure as detailed in Figure 2.63.
Fig. 2.63 Solid blockwork wall and brick/block cav- ity wall as a substructure for a timber frame panel construction.
Fig. 3.1 Frames with and without racking.
Fig. 3.3 Cracking in lightweight concrete wall with dense concrete lintel.
Fig. 3.4 Schematic of cavity wall. Cavities have been set at a standard width of 50 (or 2 in) since their introduction. Wider cavities can have advantages in terms of be- ing able to hold more insulation, but going beyond 75 makes the use of ordinary wall ties a problem structurally. A wall with a wider cavity has to be specially designed, perhaps having special wall ties and so on. In addition to the structural problems, a wider cavity al- lows the air in the cavity to start circulating.
Fig. 3.5 Block cavity wall. Wall ties are no longer made of wrought iron (which resisted corrosion well) but of gal- vanised mild steel, stainless steel or plastic.
Fig. 3.6 Selection of wall tie types. Some metal ties are made of wire, some of sheet or plate. Plastic ties are injection moulded from polypropylene. All have split or shaped ends to build into the mortar bed, and shanks with various forms of drip. Fig- ure 3.6 shows sketches of several different types of tie:
Fig. 3.7 Keeping the cavity clear of mortar droppings.
Fig. 3.8 Possible placement of wall insulation.
Fig. 3.9 Retaining clip for partial fill insulation in cavity. Problems of dampness crossing the cavity have been experienced and have been largely due to mortar droppings left on wall ties. In the ‘clean’ cavity, the foam seals round the shank of the wall tie. If there are mortar
Fig. 3.10 Wall strapping on inner face of wall with insulation and boarding.
Ifa very positive moisture seal is required, it is possible to have the laminate made up with a polythene or foil layer between the foam and the board. The joints of the boards can be made up with a rebate and the two layers of film or foil can be sealed together. This is illustrated in Figure 3.11. Adhesives used are generally
Fig. 3.13 Starting a timber frame building off a con- crete floor slab.
Fig. 3.12 Timber joisted floor as base for traditional timber frame building.
Fig. 3.14 Schematic showing platform and balloon frame construction.
Fig. 3.15 Some joints in traditional frame construc- tion.
Fig. 3.16 Traditional timber cladding and improved methods of cladding over insulated walls.
Fig. 3.18 Modern timber frame — eaves/wallhead detail. that construction at eaves level, and Fig- ure 3.19 shows the junction of an upper floor with the timber panels. Note that a lot of the annotation has been omitted for the sake of clarity. On properly scaled detail drawings the annotation would be complete, either on the detail or in a notes column.
Fig. 3.17 Modern timber frame — substructure detail.
Fig. 3.20 Hold down strap from timber frame to top of foundation.
Fig. 3.19 Modern timber frame — intermediate floor junction detail.
Fig. 3.22 Just two of many types of wall tie suitable for timber frame cladding. Fig. 3.21 Weep as a ventilator at the wallhead.
Fig. 3.23 Vertical fire stopping at corners of a building. The details you don’t see are often more im- portant than the ones you do. The wall panels we have looked at earlier were all fire stopped horizontally to reduce the spread of fire up the cavity between panel and cladding. However, there is a need to fire stop vertically to reduce the spread of fire horizontally. This is done at corners; Figure 3.23 gives a detail while Fig- ure 3.24 shows a photograph. What is not im- mediately apparent in the photograph is that the horizontal fire stop is there but shows only as a bump under the breather paper — just be- low the scaffold boards. Now why didn’t the builder put up the corner ones as well, then put on the building paper? Well, the panels come with the paper already fixed in place and so when the paper from the upper panels was dropped, it covered the fire stop. Then they came along and fixed the corner fire stops.
Fig. 3.24 Vertical and horizontal fire stopping.
Fig. 3.25 A ring beam and joisted base ready for panel erection. Figure 3.25 is a photograph of a ground floor built on a block substructure and ready to have wall panels erected on it. The wall plate with the ring beam and the sole plate dou- bler are all there round the outside. Then there are sleeper joists with solid strutting across the mid span of the joists. What is not terri- bly clear is the two sleeper walls with wall plates supporting the joists at their mid third points.
Fig. 3.27 Intermediate floor/panel junction over a window opening.
Fig. 3.26 Panels erected on a base.
Fig. 3.31 General partition details.
Fig. 3.33 Partition base in sandwich floor construc- tion.
Fig. 3.32 Acoustic partition.
Fig. 3.34 Expansion joints — a selection of details.
Fig. 3.36 A mastic sealed joint in a complex wall of reconstructed stone and rendered blockwork. Fig. 3.35 A proprietary joint of plastic in a rendered finish block wall.
Fig. 3.38 Proprietary expansion joint cover.
Fig. 3.37 Faulty joint being built in the block cladding of a timber frame house.
Fig. 4.1 Alignment of joists, span and wall rest. It may seem obvious, especially after look- ing at ground floor construction in timber, but it has to be stated that all joists are built in with the long dimension of the cross-section in the vertical plane, as shown in Figure 4.1. The reader can test the effect of using a supporting timber on ‘edge’ or on ‘flat’ by placing a ruler across the gap between two books and press- ing down at the middle of the span. The ruler is much stiffer when it is on edge but is prone to buckle sideways. This is due to the very small width/span ratio. Joists of course are restrained at each end and in short spans do not buckle because the ratio is much higher. In long spans we can employ techniques such as strutting to prevent buckling. The various al- ternative forms of strutting are discussed later in this chapter.
Fig. 4.3 Heavy gauge joist hangers supporting upper floor joists. oe <_ eee ee ene RN In modern timber frame construction, the upper floor joists are supported by the wall
Fig. 4.34 Traditional sound proofing.
Fig. 4.5 Upper floor joists in timber frame construc- tion (2). photograph the joists are seen resting on top of the timber frame panels; the ring beam can be clearly seen, as can the dwangs or noggings for the edge of the sheet flooring material. The timber frame panel shows a double top runner at the left-hand side but uses a steel channel section to provide support over an opening under the remaining joists. See Chap- ter 5, Openings in Masonry Walls, where the use of metal sections in timber frame construc- tion is discussed in more detail.
Fig. 4.4 Upper floor joists in timber frame construc- tion (1). ee OE SEE eee eee Figure 4.5 is the closest it was possible to get to Figure 4.4 for comparative purposes. In the
When spans start to exceed this range it is time to think of alternative ways to sup- port the joists — in other words to break the span into two or more manageable propor- tions. The best options are to have a load- bearing partition under the joists or provide a beam of some kind. This can be done by mak- ing use of partitions on the lower storey as loadbearing partitions, as shown in Figure 4.7. The partition has a door opening spanned by a timber lintel supported on cripple studs with doubled top runners supporting the first floor joists. Note the joists do not fall directly above the studs as these timbers are at different cen- tres, but the top runner of the partition is a double layer of timber. Breaking the span of joists can also be achieved by:
Fig. 4.7 Upper floor joists supported by a partition (2).
Fig. 4.8 Flitched beam from the 1970s.
Fig. 4.10 Flitched beam detail with minimal steel content.
Fig. 4.12 Centres of joists in relation to wall and ‘last space’ and last wall.
Joist spacing uneven or greater than required for sheet finish Fig. 4.13 Brandering.
Fig. 4.15 Solid strutting and steel and timber herringbone strutting. The spans of upper floor joists are inevitably longer than ground floor joists, and, with the Figure 4.15 is a detail of solid and herring- bone strutting in steel and timber, and Fig- ure 4.16 is a photograph of a mock-up of the galvanised steel strutting. Note that the joists
Fig. 4.14 Cheek pieces.
Fig. 4.16 Galvanised steel herringbone strutting.
Fig. 4.18 Timber herringbone strutting.
Fig. 4.17 Solid timber strutting.
Fig. 4.19 Common joists, trimmers and trimming joists.
Fig. 4.20 Key to Figure 4.19.
Fig. 4.22 Bridling joists around large pipes.
Fig. 4.24 Clay flue liner. Masonry flues must now include a liner which is generally made of fired clay; a typi- cal example is shown in Figure 4.24. The liner is made in lengths of around 450 mm and the joints are joggled. Note that the joggle can be built upside down, which would allow any tars from the fuel being burned which con- dense on the cooler wall of the liner to run out of the joint, thus staining the surrounding surfaces. Figure 4.25 shows a flue through a floor and top of chimney breast, with the joint in the liner laid correctly.
Fig. 4.23 Schematic of flues passing through floor.
Fig. 4.25 Flue passing through floor at top of chimney breast. When framing up openings in floors with larger joists, the trimmer and trimmer joist joint is usually a tusk tenoned joint (see Appendix C). Housed joints are used for joists to trimmer junctions. Modern domestic
Fig. 4.26 Proprietary flue system support and sealing plates. construction frequently uses pressed steel hangers for all joints. Figure 4.27 shows joists fixed to a trimmer with pressed steel hangers. Note that these hangers are of thin galvanised steel sheet; that many small galvanised nails are used to fix them; and that the top of the hanger is bent flat over the top of the joist and nailed down. The latter can be seen on some of the earlier photographs.
Fig. 4.29 Light pressed steel hanger for joining joists. Alternative materials for joisting
Fig. 4.28 Heavy gauge hanger for fixing joists to masonry. Fig. 4.27 Floor joists fixed to trimmer with pressed steel hangers.
Fig. 4.30 Posijoists. Another lattice style joist is made by a com- pany called Metsec. The strength is from the all steel construction, the top and bottom chords being made from pressed steel chan- nels and the lattice from a continuous length of steel tube bent and welded between the channels. To make the joist ‘joiner friendly’, timber inserts are crimped into the steel chan- nels, providing a fixing for both floor boarding and ceiling boarding.
Fig. 4.31 All timber, man-made joists. For more information try the website http:/ /www.metsec.co.uk/metsec/en
Fig. 4.32 Upper floor supported with Finnjoists. joist. The straight webbed joist can use a heav- ier material for the web and it is frequently a type known as OSB - oriented strand board — in thicknesses from 11 upwards. There is a proprietary system marketed under the name Finnjoist which uses OSB for the web, but in- stead of solid timber for the flanges, it uses laminated timber.
Fig. 4.33 OSB sheet. Because the wavy webbed joist requires a more flexible web material, plywood or even hardboard is used. If you doubt the strength of hardboard you really must revise your think- ing. As part of any stressed panel construc- tion even 3 thick hardboard can be incredibly
Fig. 4.35 Sound and fireproofing 1960s style. Figure 4.35 shows a detail from the 1960s - a floor with sound and fire proofing as used
Fig. 4.36 Fireproofing an RSJ spine beam.
Fig. 4.37 Up-to-date sound and fireproofing of an upper floor.
Fig. 4.39 Restraining straps. The joists in this particular building are reg- ularised out of 250 sawn timbers so the dwang should be at least 125 deep. It shows around 50 x 50. What is not shown in the photograph is the packing between the wall and the first joist. This was a plain square section timber. Wedging would have been better. This was
Fig. 4.38 Detail of support from floor of masonry walls (1).
Fig. 4.43 Match board fixing clip. In every instance the finish mentioned has been plasterboard. Plasterboard is not just available in one form, but in a variety of sizes, thicknesses, configurations, composi- tions, finishes and a host of sensible combi- nations of these. Much of that information is summarised in Appendix H, Gypsum wall board, or can be readily obtained from the websites quoted there.
Fig. 4.40 Detail of support from floor of masonry walls (2).
Fig. 4.41 Detail of support from floor of masonry walls (3).
Fig. 5.2 Saving over in brickwork at ducts, pipes and ventilators.
Fig. 5.5 Pre-1970s jamb detail, rendered external finish.
Fig. 5.3 Terminology associated with openings in walls. the DPC at jambs and head was never quite satisfactory.
Fig. 5.4 Pre-1970s sill and head details, rendered ex- ternal finish.
Fig. 5.6 Pre-1970s sill, jamb and head details, facing brick external finish.
Fig. 5.8 Photograph of 1990s head, sill and mullion in artificial stone.
Fig. 5.10 Steel lintel at inner leaf of opening. Figure 5.1lisa photograph of a cavity clo- sure in blockwork. Note how a cut block closes It is important to note that frames for win- dows or doors are only fastened to the walls through the jambs and that in the traditional methods this fastening went into the masonry, closing the cavity.
Fig. 5.7 Photograph of 1990s sill and jamb.
Fig. 5.9 Detail of mullion-sill junction.
Fig. 5.12 Window frame cramp.
Fig. 5.11 Detail of checked jamb. the cavity and bonds into the inner leaf in al- ternate courses, and that a cut of blockwork is used for the intermediate courses, all bedded up solid in mortar and with a vertical strip of DPC between closure and the outer leaf. Compare these photographs with Figure 5.4, the general sections.
Fig. 5.13 Eliminating cold bridging at sill and head.
Fig. 5.14 Alternative jamb arrangements and cavity closure to eliminate cold bridging. ihe figures which follow show variations on the finishing of various parts of open- ings incorporating different materials and
inner lintel here is rectangular and that a DPC is dressed over it and down over the angle to project beyond the angle iron. DPC projection is necessary in all the details where it is shown to provide a good drip and prevent water be- ing drawn under the lintel and so coming in contact with the frame. Mastic pointing is used at the head of the frame.
Fig. 5.16 Pressed steel lintel (2). some manufacturers do not recommend one. Figure 5.16 shows an IG lintel, available in gal- vanised steel and stainless steel. Sealing the window frame and foam filling etc. is all the same as the earlier lintels. Figure 5.17 shows a very old form of lintelling when using a facing brick outer leaf: the mild steel angle iron. Gal- vanised angles are more readily available and are to be preferred to plain steel. Note that the Fig. 5.17 Angle iron lintel.
Fig. 5.15 Pressed steel inner lintel (1).
Before leaving lintels the term ‘bellcast’ re- quires expansion. It is obvious how this pro- jection of a roughcast or rendered finish got its name. It is not formed directly by applying the mortar in that shape; that would not be possible. Instead, early craftsmen fixed a tem- porary batten to the masonry background and worked to the thickness of that batten. Mod- ern practice uses either a galvanised steel bead ora plastic bead, which is fixed to the wall and the render brought to that. Figure 5.19 shows a typical section and its application, while Fig- ure 5.20 is a photograph of three galvanised beads, from the left:
Fig. 5.20 Photograph of bellcast bead and corner bead. Fig. 5.19 Bellcast bead.
Fig. 5.21 Proprietary cavity closure at head and jambs. metal and is made by slitting the metal sheet and then pulling it apart.
Fig. 5.23 Proprietary cavity closure at sill. Tiles, both plain roofing of clay or concrete and quarry floor tiles, make good sills as they are made to prevent the entry of water. The detail is illustrated in Figure 5.25. They must, however, be laid in a minimum of two courses with the bond broken and in a strong mor- tar, mix 1:5 or even 1:4. Any DPC must be brought down at least one, preferably two, brick courses below.
Fig. 5.24 Alternative sill in PCC.
detail is shown in Figure 5.29 and a photo- graph in Figure 5.30. with the reveal finished in the same way as the wall. Note that the second arrangement re- duces the amount of timber used for the door frame and the stop facing; there are no plinth blocks to make and fix and no architrave; there are + round beads; and plaster and skirting
Fig. 5.29 Threshold (2). have to return into the reveal from the wall face. This detail is more economical than the first arrangement.
Fig. 5.30 Photograph of threshold (2).
confused with a threshold bar), a plain tim- ber section, usually hardwood. This may be only the width of the door (irrespective of the actual frame width) or the width of the frame. From a purely practical point of view, a full width plate is best as any floor covering fitted to the threshold plate does not incur excessive waste. Indeed, the occupant may be forced to purchase the next width up in floor covering because of the door ‘recess’.
Fig. 5.31 Partition lintels. Frames f for doors in partitions will normally include a timber threshold plate (not to be
Fig. 5.33 Timber frame wall schematic. a source of potential trouble as the building ages.
Fig. 5.35 Pipes and ducts through timber frame wall (1).
Plastic sleeve < 50 diameter and light metal or plastic duct > 50 Fig. 5.36 Pipes and ducts through timber frame wall (2).
Fig. 5.38 Pipes and ducts through timber frame wall (4).
Fig. 5.37 Pipes and ducts through timber frame wall (3).
Fig. 5.39 Window opening in early timber frame constructioin.
Fig. 5.40 Elevation of early timber panel at window opening. Figure 5.41 shows a more modern approach to timber frame panels. This is a photograph of
Fig. 5.44 Flitched beam over large opening. at 600 centres and so the joists are put in at 600 centres and have to be much deeper. A further complication is the need to keep ceil- ing heights down. If wooden lintelling is used for wide openings, the top of the glass in the window would be much too low. This can be
Fig. 5.42 Rolled steel channel as lintel in timber panel.
Fig. 5.41 Modern timber panel at window opening.
Fig. 5.43 Detail of rolled steel channel as lintel in tim- ber panel.
port the large squad of carpenters required,
Prefabrication
Fig. 6.3 Stick built roof timbers.
Fig. 6.4 Pitched roof shapes and types. pression and so much stronger timbers have Figure 6.4 shows some layouts of these tim- bers in (1) in the above list for various forms of roof. For the same timber sizes, roof C is a larger span version of A, while B, the col- lared roof, is common on old properties and farm buildings but is not as strong as roof A. The provision of a tie in roofs A and C pre- vents the rafter ends at the wall head pushing outwards and pushing the wall over. While a collar can also do this, the lower half of the rafters are put into bending as well as com- pression and so much stronger timbers have
Fig. 6.5 Purlined roof. to be employed for the same span of roof. D is the form of C with a steeper pitch and the possibility of having attic rooms. With the steeper pitch, lighter section rafters, collars and hangers can be used but the ties now dou- ble up as floor joists and so must be heavier and possibly even supported at mid span by a beam or partition. Roof D also shows a de- vice from the early roofs, the sprocket or bell- cast piece. These were separate short lengths of timber attached at the eaves and forming part of the eaves projection. The pitch angle on them was usually less than the main roof, which slowed the run-off of water from the slate or tile into the gutter.
Fig. 6.6 Trusses and purlins. It is possible to do without trusses if the length between the gables is not too long, by using trussed purlins or I beam purlins or box beam purlins. Figure 6.8 shows sections through these, together with the position be- tween the gables that they would take. Note that there will still be a wall plate on top of the wall for all the rafter feet, and a ridge where the pairs of rafters join. A plywood I beam with a depth of approximately 900 and with four 100 x 50 SC3 timbers as flanges, was ca- pable of supporting a tiled roof over a span of 4000. These beams can all be made on site, the fastening being either bolts and connectors
Fig. 6.9 Queen post and mansard trusses.
Fig. 6.8 Trussed, I beam and box beam purlins.
The common rafters are fixed in position starting with a rafter near one gable and at regular centres to the other end of the roof, ignoring the truss positions Purlins and ridge board in position. Both can be joined at the bearing point on the truss with scarfed joints Fig. 6.7 Trusses within the roof outline.
Fig. 6.10 Hammer beam and Belfast trusses.
Fig. 6.11 TRADA trusses.
Fig. 6.13 Gang nail plate.
Fig. 6.12 Gang nail plate schematic.
Fig. 6.16 Trussed rafters secured to wall plate.
Fig. 8.23 Knobs and levers. Materials include cast iron, brasses, stain- less steel, wrought iron, aluminium, plastics, wood and porcelain. Finishes include enam- els or japanning (applied to cast iron and wrought iron), BMA (bronze metal antique — applied to brass ironmongery), SAA (satin an- odised aluminium) and plain old-fashioned polishing and lacquering (applied to brass ironmongery).
Fig. 8.22 Threshold / weather bar schematic.
Fig. 6.15 Wall plate secured to wall head. Figure 6.14 is a photograph of some newly erected trussed rafters on a two-storey house. They are spaced out at 600 centres and are set on and fixed to a wall plate bedded and fastened down to the inner leaf at the wall head. Figure 6.15 shows the wall plate bed- ded down and two of the straps which hold it down can be seen on top of the plate. In Fig- ure 6.14 the ends of these straps can be seen
Fig. 6.14 Trussed rafter roof.
Fig. 6.17 View down centre of trussed rafters. Figure 6.18 illustrates the Fink layout and a few other common arrangements. More are shown in Figure 6.19, including the mansard truss and the attic truss. The term panel in relation to these truss shapes refers to the un- supported length of rafter in each. The first, Fink truss is of four panels — each rafter is sup- ported by the struts at the centre of its length, dividing each rafter into two, therefore four panels.
Fig. 6.19 Various truss shapes (2). Fig. 6.18 Various truss shapes (1).
Fig. 6.20 Wall to roof stability (1).
Fig. 6.22 Roof ladders.
Fig. 6.21 Wall to roof stability (2).
Fig. 6.24 Eaves detail.
Fig. 6.23 Roof ladder details.
Fig. 6.25 Eaves and verge junction.
Fig. 6.27 Roof bracings schematic.
Fig. 6.26 Horizontal brace to gable panel detail.
Fig. 6.28 Breathable plastic underslating felts.
Fig. 6.30 Flat roof — options for insulation and venti- lation.
Fig. 6.32 Roof with traditional sarking boards.
Fig. 6.33 Stick built roof (2). Temporary bracing was fixed inside the rafters, and sarking boards were nailed to the overall roof surface which was finally cov- ered with underslating felt and concrete in- terlocking tiles. The photograph of the roof with the sarking shows some boards missing. These were put in place as the boarding went on but they were not nailed into place. Once two more boards had been nailed above them these boards were taken out and nailed tem- porarily to the boards below. This gap gave a foothold for the carpenters to step up and complete more of the boarding. Once the last
Fig. 6.31 Stick built roof (1).
Fig. 6.34 Stick built roof (3). Fig. 6.36 Pole plate (1).
Fig. 6.35 Corbel at eaves verge junction. Fig. 6.37 Pole plate (2). Figure 6.35 is not about the roof so much. It is, after all, a trussed rafter roof, which has been shown earlier. It is more about the wall which sticks out at you in the centre of the
Fig. 6.39 Warm and cold pitched roofs. Pitched roofs can also be built as warm or cold roofs. Figure 6.39 shows schematics for both warm and cold roofs. Cold roof A not the case in a roof where the structure is predominantly of wood and wood products. The ideal must be to keep the wood prod- ucts on the warm side of the insulation and to keep them protected from moisture com- ing through the ceiling finish by placement of a VCL immediately behind the ceiling finish. There has to be a void to carry ventilating air in and moisture laden air out, and whether the roof is a cold roof or a warm roof will deter- mine where that void will be. Looking back at Figure 6.30, situation B is a cold roof so the void is to the outside of the insulating layer. Situations D and E show warm roofs and the void is to the inside of the insulating layer. No matter what else happens in the construction of these roofs, the Regulations require a mini- mum 50 deep gap between the insulation and the deck or ceiling. See ig 1 1 1 ev.
Fig. 6.38 Roof details — corbel and pole plates. a key between the rafter feet and the ends of the tie and prevents the rafter feet sliding off.
Fig. 6.40 Preformed plastic foam insulation for a warm roof.
Fig. 7.1 Houses ready for roof tiles.
Fig. 7.3 Double lap roof unit — showing lap with al- ternate courses.
Fig. 7.2 Double lap roof unit — method of setting out.
Fig. 7.4 Eaves tile ‘cocking up’. ness, it is also unsightly and we will return to this aspect when we examine single lap fixing.
Fig. 7.6 Underside of an interlocking tile. Figure 7.7 is a schematic view of the ridges and rebate on the side of these tiles. This is what stops the water passing down between the tiles onto the surface below. shows the tile top at the top. One feature can be seen that is common to all man-made tiles — nibs which hook over the tile batten and prevent the tile sliding down the roof. There are ridges running horizontally across the back of the tile. These are water stops and prevent water being blown up under the tile from the surface of the one below.
Fig. 7.5 Interlocking tiles on battens and counter battens.
Fig. 7.7 Schematic of side interlocking joint. but a reasonable guide would be to nail the first three courses at the eaves, the last three courses at the ridge and three tiles in at every verge or abutment. In addition, every third or fourth course has to be nailed for its com- plete length. It used to be normal for all tiles supplied to have two nail holes preformed in their head. Many tiles are now made without holes as the manufacturers wish to have their tiles fixed with their own patent clips. See the manufacturers’ websites.
Fig. 7.8 Spanish and Roman over and under tiles. These are frequently called over and under tiles due to the shapes used and the manner of laying them. The shapes are illustrated in Figure 7.8.
the outriggers and in a groove in the back of the barge board — sometimes referred to as a berge board. A further timber plate is cut to fit the underside of the projection of the roof- ing tiles — called scribing — and then nailed to the barge board with a mastic fillet on top. As it is fixed in position, the roofing membrane should be brought out and stuck between the plate and the tiles. verge; the idea of bedding the verge in cement mortar is not really feasible. It was generally only done when the projection was about 75 to 100 and an undercloak of asbestos cement sheet or of plain tiles was bedded on top of the masonry and then the roof tiles bedded on top of that. Here there is a wide projection supported on short lengths of timber — outrig- gers — nailed to the side of the first/last rafter. There is a soffit plate and barge board, the equivalent of the eaves fascia. The soffit plate is fixed to a batten nailed to the underside of
Tiles, battens, counterbattens and roofing membrane as Figure 7.9
Fig. 7.12 Verge tiled.
Fig. 7.13 Abutment detail.
Fig. 7.11 Verge detail.
preserve the timber in the joint from rotting. The lead paint dried out fairly rapidly and the timber still rotted. Doors with bare joints allow the wood to swell and generally give a watertight joint — and still rot. Timber can now be treated to prevent rot but the timber will still take up moisture and swell to keep joints tight.
Note that the position of the brace deter- mines which is the lock stile and which the hinge stile. For a door of the opposite hand, the brace must be fitted the other way round. Most types of lock or latch can be fitted to this door but the mortice and tenoned joint of the lock rail should be avoided when fitting any lock or latch, but particularly mortice locks. offer little security and can only be used as pass doors’. Solid cores make the heaviest doors, which do offer security and are used for external doors if the glues used are weath- erproof.
Fig. 8.3 Flush panel door.
Note: Panels do not extend to bottom of groove. This allows panel to expand/contract independently of the frame
Fig. 8.6 Pressed hardboard mock panel doors.
Fig. 8.7 15 pane glazed door. The astragals are made with double ovolo mouldings and double rebates as shown. The ends of the astragals are reduced to rectangu- lar section tenons and let into mortices cut into the stiles and rails. The mouldings on the as- tragals match those on the stiles and rails and these are mitred at the morticed and tenoned joints. Junctions of astragals are generally half checked, with the mouldings mitred. T7. ~—. gy ww et. fg a:
Fig. 8.8 Door frame construction. Door frames rebated to provide a stop for the door are generally associated with good quality work but are more frequently used for external doors where the frame is fixed according to English practice. wall finish and the complete door frame. - Figure 8.9 illustrates the use of a full width casing and stop at an internal door, while Fig- ure 8.10 is a photograph of the opposite side of that door with a more decorative architrave which covers the joint of the frame with the wall finish and the complete door frame.
Fig. 8.10 A hung door.
Fig. 8.11 Fixing door frame using plugs or billgates.
Bottom hinge with whole of hinge pin exposed
Fig. 8.13 Over-rebated door in frame. and frame. Gaps between door and threshold should however be kept down to 3. Smoke seals might have to be fitted in the bottom edge of the door.
Glazing So far the discussion has centred on doors and door frames, but the Standard goes on to dis- cuss glazed portions of the door and glazed sidelights and so on — the whole thing be- coming quite complex. In summary, glazing in a fire door needs a lot of care and attention. When a hole is cut into a door the core is ex- posed and this core edge requires protection from the effects of fire. Also, core materials do not often give ideal conditions for mechani- cal fixing — nails and screws — so that bead style solutions to fixing glass in an opening are doomed to fail. There are proprietary systems of high resistance rated materials which can be used to hold glass in such openings, and they
Fig. 8.16 More hinges.
Fig. 8.17 Some locks and latches.
Fig. 8.18 An old rim lock.
Fig. 8.19 The escutcheon plate for the lock in Figure 8.18.
Fig. 8.20 Tower and slip bolts.
Fig. 9.1 Typical layouts of fixed and opening sashes for casement windows.
Fig. 9.3 Ordinary and deep rebates in casement sashes.
Section through jambs and mullion of window Fig. 9.2 Typical casement window sections.
Fig. 9.4 Brush, wipe and compression seals.
Fig. 9.6 Building in a casement window.
Fig. 9.9 Finger joints in a casement. The sections of all the members of a casement have been shown in the figures above, but what has not been covered is how they are joined together. Many casements in the past have had all the joints carried out as mor- tice and tenon joints with the rounded and splayed edges mitred. With modern machin- ery cutting mating faces and the joints them- selves, variations of the finger joint are now commonplace and gluing is the favoured ‘fas- tener’. Figure 9.9 shows a typical joint of two casement sections. The joint of jambs to sill of the frame can be plain housings, glued and nailed from the back, or they can be finger jointed but the sill is not cut to its full depth.
Fig. 9.7 Wedging in a window.
Fig. 9.8 Plugging in and framing anchors. Joining the frame and casement members The sections of all the members of a casement
Fig. 9.11 Casement sill and frame stile joint.
Fig. 9.12 Casement head and frame stile joint.
Fig. 9.10 Typical casement window.
Fig. 9.13 Mullion and frame sill joint.
Fig. 9.14 Casement joint. right-hand side of the mullion is a soft plas- tic setting block for the double glazed units which will be used. Finally, Figure 9.14 is a pic- ture of the corner of the casement showing a very deep rebate, and it is on the outside. The whole window was set up for glazing with a sealed unit in beads from the outside. The householder will get a window which has the security value of a sealed double glazed unit completely negated by having it glazed from the outside.
Fig. 9.15 Schematic of sashes in sash and case win- dow.
Fig. 9.16 Outline of case head and stiles.
Fig. 9.17 Outline of case sill and sash sill in relation to masonry.
Fig. 9.18 Detail of case head and stile in splayed, checked reveal.
Fig. 9.19 Alternative sill build ups.
Fig. 9.20 Duplex hinges and operating schematic.
Fixing of the balance to the sash is done with a metal bracket which allows the balance to be released and refastened to the sash easily and effectively. The balances are manufac- tured with a range of spring strengths which accommodate all but the largest sashes. The critical factor in many instances is the use of double or triple glazing.
Fig. 9.22 Spring balances. The balance has a hole for an ordinary wood screw fixing to the stile, and the spiral has a
Fig. 9.24 General view of sash and case window.
Fig. 9.23 Hinge down sashes with spring balances.
Fig. 9.25 Sash pulleys and cord grip.
Fig. 9.27 Pocket in stile open.
Fig. 9.26 Batten rod screws. taken from inside a more modern window and shows two pulleys in the case backplate. The left-hand cord runs through a cord grip which allows the user to pull the cord and raise the sash weight, allowing the sash to be released from the cords. Figure 9.26 shows the batten rod removed, and the captive screws which hold it in position can be clearly seen in the rod and the plate they screw into in the back- plate. The parting bead is still in position. Fig- ure 9.27 shows the parting bead removed and the pocket — the access plate to the weights — which is cut into the backplate. Note how the pocket cover is cut in the groove for the parting bead. When the parting bead is fit- ted, this together with the lower sash keeps the cover in place. Maintenance work can be carried out such as replacing cords, adding make-weights, shortening off stretched cords, etc. Figure 9.28 is a picture of the joint of the sash stile and sash sill. The joint is a mortice and tenon joint with a dowel, which can be seen proud of the face under the paint. Fig- ure 9.29 is the same joint viewed from the side, and the end of the tenon can be seen with the wedges either side to hold it firmly in place. Figure 9.30 is the joint of sash stile to meeting
Fig. 9.28 Sash sill to stile junction (1).
Fig. 9.29 Sash sill to stile junction (2).
Fig. 9.30 Meeting rail to stile junction.
Fig. 9.31 Rebate nomenclature in glazing.
Fig. 9.32 Glazing in compound.
Fig. 10.1 Illustration of some definitions associated with stairs. Landings
Fig. 10.2 Flights and landings. Landings may be quarter landings or half landings (see Figure 10.2). The Regulations only allow 16 steps maximum in any flight. Should a stair be in excess of 16 steps, it must be broken into two or more flights with run- ning landings in between. The length of a run- ning landing must be at least the same as the width of the flight.
Fig. 10.3 Open cut string stair being installed. Stairs may be built into the staircase in such a way that the strings may touch the walls on both sides, on one side, or be completely unattached. Strings against the wall are called wall strings; strings not touching the wall are free-standing strings. Wall strings can be at- tached to the wall over their length and so can be manufactured from thinner timber. Free standing strings can be shaped so that the end of each step projects over the string. Such strings are termed open cut strings and they can be done in many different ornamental styles. Figure 10.3 is a photograph of an open cut string stair being fixed into position. Note the projection of the tread over the string and the curved plate mitred to the riser. See also Figure 10.4.
Fig. 10.4 Open cut string details. Balustrades With a free-standing string a rail is required to ensure the safety of the users. This is called a balustrade and comprises a handrail supported on balusters, all exposed and fre- quently elaborately turned on a lathe. Alter- natively, a frame may be erected on the string and panels placed in the frame, or itis boarded over with sheet material, matchboarding, etc.
Fig. 10.5 Balustrade, newels, total rise and total going.
Fig. 10.6 Balustrade detail, newel fixing detail. Two more measurements are the going and the rise, both of individual steps and of the complete flight, the latter being frequently
Fig. 10.8 Ends of stair stringers. long wedges are driven into the remainder of the groove, which forces the tread and riser of each step in turn to close up to the upper edge of the groove, and also puts the glue line under pressure. This is all done with the stair in the position shown in the photograph.
Fig. 10.7 Step to stringer joint. On Figure 10.7 the joint of steps to stringer is illustrated. Remember that a step comprises a tread and the riser immediately below it, glued and screwed together with triangular blockings. One can see the groove which has been cut in the inside face of the string and into which each step is placed — with glue. Once all the steps are in place they are joined together by nailing the riser of the step to the back of the tread below — with more glue. Then
Fig. 10.9 Winders and rough carriage.
Holes are not allowed in mutual walls such as we are considering here. This of course includes the incidental formation of holes due to incomplete bedding of masonry. Beds and perpends must be fully filled. Holes and cracks may also form when building materi- als or components shrink and crack. Where there is a danger that this might happen, the use of a flexible filling compound might be considered appropriate, and where the detail is combined with a need for fire resistance, in- tumescent compounds would be even better. Fire resistance
Fig. 12.1 Compression fitting on copper and poly- butylene piping. The non-manipulative compression fittings used on plastics waste pipe (they can also be used on copper pipe of appropriate diameter) follow the same general design principles but without the need to withstand more than a modest pressure. The wedge-shaped section design of the sealing ring is only about ob- taining a seal and a modest grip on the pipe. A liner is not required as the plastics of the pipe is generally quite rigid.
Fig. 12.2 Compression fitting on waste disposal pipe.
Fig. 12.5 Push fit fittings for hot and cold supply pipework.
Fig. 12.4 Push fit fitting for waste disposal pipe. The second type of joint has a sealing ring squeezed between the pipe and the fitting, but also a grab ring which resists any tendency for the joint to pull apart. There is no such tendency with disposal pipework but there is with any pressurised system such as hot and cold water supply and central heating. Push fit joints are not used for gas supply pipework.
Fig. 12.3 Capillary fitting joining two lengths of pipe.
Fig. 12.6 Solvent weld fitting for disposal piping.
Fig. 12.9 Selection of bends, elbows, straight cou- plings and Ts all with compression joints.
Fig. 12.7 Female iron to copper fitting connection.
Fig. 12.8 Male iron to copper connection with a back nut.
Fig. 12.10 Selection of straight and bent capillary cou- plings and Ts.
Fig. 12.12 Selection of push fit couplings for hot and cold water pipework.
Fig. 12.13 Selection of compression couplings for disposal pipework.
Fig. 12.11 Selection of bent and straight connections, all with compression joints. rigure 12.10 SNOWS a selection OF COMpres- sion couplings for disposal pipework. From the left and clockwise there is an elbow, a
Fig. 12.14 Selection of solvent weld couplings for disposal pipework. www.hepworthplumbing.co.uk www.polypipe.com/bp www peglerhattersley.com
Fig. 12.18 A pair of float valves.
Fig. 12.19 Exploded version of the Portsmouth pat- tern valve.
Fig. 12.17 A plug cock with compression tails for copper. Figure 12.19 shows an exploded version of the Portsmouth pattern valve. Across the bot- tom is the lever arm with the float and at the other end the hole for the pivot pin and the ear- like appendages which engage in a groove in the plunger. Above, from left to right, a pair of back nuts and a washer to secure the valve in the tank or cistern; the male iron spigot with the nut which attaches it to the valve body; the valve body with the nozzle and the hole for the pivot pin; below the body, the pivot pin — a brass split pin; the plunger which has a soft washer in the end and a groove along the side for the ears on the lever arm; a cap to keep the plunger in the body. What cannot be
Fig. 12.16 Selection of valves.
Fig. 12.21 Schematic of the cold water supply pipework.
Fig. 12.20 Identification of the appliances and equip- ment to be connected up. through a tee piece at the bottom of the cylin- der, the branch being a male iron spigot (tees like this are often referred to as boiler tees as that is where they were most commonly fit- ted). This branch is connected to the cylinder, and the other end of the tee connects to a scour valve (usually a plug cock) with a pipe go- ing to the outside of the building. Opening the scour valve empties the hot water system completely above the level of the scour valve. If the valve on the cold feed is left open, the cold water cistern is emptied.
Fig. 12.22 Schematic of the hot water supply pipework.
Fig. 12.23 Soil, waste and ventilation pipework. Figure 12.23 shows a schematic for the appli- ances already piped up for water supply. Note
Fig. 12.25 Cast iron toby cover in the street.
Fig. 12.26 Cold water storage cistern and linked cisterns. Hot water storage cylinders have been made from galvanised steel and from polypropy- lene but by far the most common material is copper. HW cylinders are made in capacities from around 90 to 500 litres, and their shape
Fig. 12.28 An indirect HW storage cylinder with fac- tory applied insulation.
Fig. 12.27 A direct HW storage cylinder connected to a back boiler.
Fig. 12.30 A single feed, indirect, HW storage cylinder.
Fig. 12.29 A double feed, indirect, HW storage cylinder.
Fig. 12.32 A pressurised central heating system — gas or liquid fuelled.
Fig. 12.33 The pressure vessel and valve arrange- ments of a pressurised central heating system.
Fig. 12.31 An open vented central heating system — gas or liquid fuelled.
Note: The mains water pipe is used to fill the heating system but cannot be permanently connected to the system in case contamination of the water supply takes place. Flexible hose is used for filling and topping up but must be disconnected and the caps replaced on the pipe ends. The one-way valve prevents boiler water flowing back into mains if pressure is less in the main
Fig. 12.35 A typical emitter. They are common as kitchen heaters where they are designed to sit behind the kicking board under fitted kitchen units. At the tem- peratures at which radiators operate there is not a lot of radiant heat available. One has to be within 600 of the panel to feel anything in most installations, and where there are chil- dren or old people the water temperature from the boiler has to be kept low enough to avoid burning vulnerable people should they touch the emitter surface. Figure 12.35 shows a typ- ical emitter and Figure 12.36 shows a typical thermostatic radiator valve (TRV).
Fig. 12.36 A thermostatic radiator value (TRV). The term ‘appliances’ covers things such as sinks, wash hand basins, baths, showers and
Fig. 12.38 Low level flushing cistern and WC.
Fig. 12.37 Ware to pipe connectors.
Fig. 12.39 Close coupled flushing cistern and WC.
Fig. 12.41 The single stack system with an additional WC on an extended side branch.
Fig. 12.40 An instant shower.
Fig. 12.44 SVP pipe fittings — a bend and a pipe with blank bosses.
Fig. 12.45 SVP pipe fittings — push fit bend with syn- thetic rubber seal.
Fig. 12.43 SVP pipe fittings — an access pipe.
Fig. 12.42 SVP pipe fittings — a pair of branches, one at 137.5° and one at 92.5° with blank bosses.
Fig. 12.47 Durgo valve. Note that there is a maximum length of
Fig. 12.46 Basic trap shapes. ala da sUdleiit UlOuUsT dp. WCs should be sited as close to the soil stack as possible, reducing the length of the branch pipework to a minimum. Should the branch exceed approximately 1200, then some means of ventilating the branch has to be fitted. An expensive solution would be to erect another stack, but apart from the expense it might not be possible to accommodate another stack. The solution is to carry the branch pipework past the WC and turn it up the wall next to the WC. The top of this pipework has to be higher than the top of any other appliance connected to the branch — frequently a WHB in the same compartment. Then cap the pipe off with an air admittance valve, sometimes referred to by its original trade name, Durgo valve. It is illustrated in Figure 12.47, which shows a gen- eral view as fitted to the top of the SVP, and the view into the bottom, which doesn’t show alot but merely indicates that there is more to the thing than just a fancy dome! In fact there is a fairly delicate valve mechanism which opens and closes in the flow of air in and out of the SVP. —— -_ we
Fig. 12.48 Schematic of disposal pipe connections to an SVP in domestic premises. Figure 12.48 illustrates other important points regarding the junction with the SWVP.
Fig. 12.50 Plumber’s first fixings. Fig. 12.49 Shock absorber loop on rising main.
Fig. 13.1 Diagram of sine curve and power genera- tion.
Fig. C.14 Plunge router — schematic. The router, illustrated in Figure C.14, was origi- nally conceived as a portable tool (passing over
Fig. 13.2 Single phase cut-out and meter in cupboard. Figure 13.2 is a photograph of a typical sin- gle phase cut-out and meter cupboard. There are many different patterns of cut-out and meter. The photograph is fairly self explana- tory. The cupboard, a lidded box, is made of glass fibre and has a piece of 25 particle board fitted in the back onto which the equipment is
Fig. 13.4 Schematic of consumer control unit.
Fig. 13.3 Cables.
Fig. 13.5 Consumer control unit. Personal protection is provided by the inclu- sion of an RCCB or ELCB in the CCU. The de- vices used to protect sub-circuits are of three kinds:
Fig. 13.6 Fuses and a miniature circuit breaker.
Fig. 13.7 Steel back box and plastic conduit connec- tions.
Fig. 13.8 Plastic dry lining boxes and cable clips.
Fig. 13.9 Earthing clamps on pipework. Final fix
Fig. 13.10 Earthing clip on radiator. Once the first rough is completed, the elec- trician must wait for wall, floor and ceiling finishes to be applied right up to the painting and decoration. When that is at least under way the electrician can return and fit the light switches, socket outlets, etc. to the back boxes or dry lining boxes, the ceiling roses for lights, etc. and make the electrical connections in each. The CCU is also mounted in a cupboard where the tails come through the wall from the meter, and all the connections are made in that. All the earth cabling from around the house must also be connected to an earthing terminal and this connected to the earthing terminal on the supply company’s cut-out.
Fig. 13.11 Schematic of a residual current circuit breaker.
Fig. 13.13 Socket outlets, plug top and cable outlet. Flexible cord is different from the cable used to wire up the sub-circuits, and it is principally the cores which make that difference. Insula- tion is PVC just like the sub-circuit cable, but it may be flat or round and there may or may not be an earth core. Line and neutral cores are insulated brown and blue normally and the earth is always green/yellow. The cores are formed by twisted copper wires, anything from 19 strands upwards being used. The
Fig. 13.12 Light switches. Figure 13.12 shows switch plates and a ceil- ing lighting pendant. On the left are three
Fig. 13.14 Electrician’s roughs — cable coming to- gether at the point where the CCU will be sited.
Fig. A A completed site plan with details of the placement of buildings and finished floor levels.
Fig. A.2 A 1:500 site plan prepared for a small area of approximately 0.903 hectares.
Fig. A.4 Part of the accommodation plan of Old Grange Farm to a scale of 1:50.
Fig. A.5 Part of a section through the redeveloped Old Grange Farm to a scale of 1:20.
Fig. A.6 Part of a sheet of details showing wall, ground floor and underfloor construction with intermediate support to the floor.
Fig. B.2 Typical dumpy level and staff.
Fig. B.4 Schematic of dumpy level in use.
Fig. B.10 The target. The instrument can also be used to assist in the setting of objects to a given height in the land- scape. Refer to Figure B.7. The process com- mences with setting the telescope level and
Fig. B.9 The peg and the nail under the EPDM instrument. Fig. B.£8 An EPDM instrument on its tripod and in close-up.
Fig. B.7 Setting to a ‘level’.
Fig. C.3 Log, quarter sawn.
Fig. C.2 Logs, alternative sawings. Lengths and cross-sections available obvi- ously depend on the availability of suitable trees for conversion. As the larger trees are felled or become the subject of conservation, longer lengths and wider and thicker timbers become scarce and more expensive. Timbers over 6.00 metres long are more expensive, as are tim- bers with one side over 200 mm wide. Combine
Fig. C.1 Log, slab sawn.
Fig. C.4 Schematic of planing and thicknessing ma- chine.
Fig. C.5 Schematic of four sider machine.
Fig. C.6 Distortion of timber sawn from various parts of a log. Figure C.6 shows the distortion of timber when cut from various parts of the log and in
Fig. C.8 Defects caused by seasoning.
Fig. C.10 Schematic of preservative treatment pres- sure cylinder.
Fig. C.9 Demonstration of air entrapment in cells. No matter how far down or how hard the jar is pushed into the liquid, the air trapped will never be displaced. The cells in timber are ina similar state. As the outer cells fill, the inner cells containing air are merely pressurised.
Fig. C.11 Char ona solid timber beam.
Fig. C.12 Portable circular saw — schematic.
Fig. C.15 Selection of router cutters. timber) but it can be adapted to fit into fixed mounts (the timber is passed over or under the tool). A wide variety of cutter shapes is avail- able and some are shown in Figure C.15. The most common is the straight fluted cutter which can cut rebates, grooves and shape timber and board by following a template.
The router
Fig. C.17 A groove. Cutting a rectilinear cross-sectioned piece of tim- ber from the body of a plank or board and
Fig. C.18 A trenching.
Fig. C.21 A mortice. Anything less than half the thickness or width of the timber is a notching; cutting away half the timber is a halving; cutting more than half the timber is never done. Notching or halving are done with multiple passes of a power saw or router, or multiple saw cuts and hand chiseling, on wrot and sawn timbers.
Fig. C.20 Notching or halving.
are shown in the later illustrations on mortice and tenoned joints. It is most common on wrot timber and is done using multiple passes of a fixed saw or router, or a purpose-built machine.
Fig. C.25 A dovetail. matching splayed slot or groove. There are many variants from single dovetails to multiple dove- tails, used in furniture and cabinet making. It used to be cut by hand but is now done using a special jig and a router. It is most common in wtrot timbers.
Fig. C.27 A half checked or halved joint. The timbers can be joined to give:
In carpentry work the timbers are nailed but in joinery work will be pinned and glued or glued and screwed from the hidden face.
Fig. C.29 A finger joint (2).
This is used to join wider timbers or sheet mater- ials at right angles. The extra width allows the edge of the joint to show a plain ‘butt’ joint while
Fig. C.33 Shouldered morticed and tenoned joint. This variation of the mé&t joint is used for the bottom and mid rails of bound lining doors — see Chapter 8 on Doors. The illustration shows the bottom rail with the tenon cut, the stile with
Fig. C.32 Plain morticed and tenoned joint.
Fig. C.31 A shouldered housing.
Fig. C.34 Barefaced morticed and tenoned joint.
Fig. C.35 Blind morticed and tenoned joint with fox- tail wedges (1). This variation is used to join the rails to the stiles of a door in high quality work. The mortices are ‘blind’, i.e. they do not show on the exposed edges of the doors stiles. Note that the tenon is
Fig. C.36 Blind morticed and tenoned joint with fox- tail wedges (2).
Fig. C.37 Tusk tenoned joint.
Fig. C.39 Toe joint.
Fig. C.38 Draw boring morticed and tenoned joints. Draw boring morticed and tenoned joints (Figure C.38)
Fig. C.43 Single and double notchings. Fig. C.42 Scarf joints — variations (2).
Scarf joint variations (1) (Figure C.41)
Fig. C.45 Dovetailing. Dovetailing is more common in cabinet work and the illustration is of a dovetailed joint for
Fig. C.46 Sheet metal connectors.
Fig. C.47 Stress grading machine — schematic. There are at least three companies offer- ing these machines in the UK market. All are
Fig. C.49 Traditional flooring board machined from solid timber. Manufactured board materials are now widely used for flooring over joists or battens and also for providing floating floors over insula- tion where the sheets are glued together. Ply- wood was one of the first materials to be givena
Fig. C.48 Stress grading marks. Building Regulations now include load/ span tables for structural timbers such as joists, roof timbers and structural partitions, so that to comply with these regulations the designer has only to match the expected load with the pro- posed span and select the appropriate timber size at a given grade.
Fig. C.50 Corner of a sheet of flooring grade particle board.
Fig. C.51 Four nails in width across a joist or batten.
Fig. C.53 Tongue and groove forms and secret nailing of flooring boards. as showing how secret nailing of tongued and grooved floor boards is carried out. The nails mentioned are illustrated in Appendix G.
Fig. C.52 Laying t&g all round particle board. LH end of the sheet fits into the space C1. It has a groove on the LH end which fits over the tongue on the RH end of the first FS. On plan B, the bit left from cutting C1 from a full sheet is placed on the LH side of the room (C2). The cut end is to the wall and the grooved end is ready to receive the next sheet, which is marked as a full sheet but might be a fraction less. If so, the narrow strip cut-off is discarded. On plan C, the laying continues with an FS laid on the LH end of the floor boards already laid, and a cut C1 is put in next, cut end to the wall on the right. C2 from that cutting is then cut down in width — scribed — but only the tongued edge should be removed as we need the groove to fit over the edge of the previous tongues. Finally, a full sheet is scribed to the wall and laid with the grooved edge over the previous tongues. Quite simple and logical once you work it out. 1 141 1 aa 1
Fig. D.1 Grading of aggregate.
Fig. D.2 Reinforcement bar shapes.
Fig. D.6 No-fines concrete — typical substructure detail.
Fig. F1 Shoring strutting and waling using timbers.
Fig. F2 Timber and steel sheet piling for earthwork support.
Fig. F.3 Steel trench support.
Fig. G.3 Copper boat nails 35, 50 and 100 long. Note the square shank and whatis termed a rose head. Used for fixing weather boarding etc. in exposed, aggressive situations — near the sea etc.
Fig. G.1 Nails. Top left, starting with 150 and 125 wire nails down to 25 wire nails; to the bottom of that group, a few ‘improved nails’, and to the left of that are two groups of oval and round brads. On the right, a few aluminium slate nails and galvanised felt nails, then two improved nails called drive screws. The latter are used to fix down corrugated metal sheet to timber. Below them, a range of wire nails which have all been galvanised.
Fig. G.2 Cut nails. At the top are a 125 and two 150 stainless steel cut nails; bottom right, plain steel cut nails and, bottom left, some flooring brads.
Fig. G.5 Collated nails for an electrically powered or pneumatic nailer. Both sets of nails are 75 mm long; one set is sherardised and each has a ring barb shank, and the other set is zinc plated and they have square twisted shanks.
Fig. G.6 A selection of screw nails for timber
Fig. G.4 Improved nails—on the right the long nail has a square twisted shank and on the left are two groups of nails with ring barb shanks; the smaller nails are of plain steel and the larger are of phosphor bronze.
Fig. G.7 Cutters/bits for, left to right: a counter- sink; countersink and clearance hole; and countersink, clearance hole and pilot hole.
Fig. G.8 Plug cutter and plugs through various stages of pelletting over.
Fig. G.9 Bolts and coach screws. Top left, four coach screws, galvanised and black iron; below them, five coach bolts; on the right, a selection of hex bolts and a single nyloc nut. One screw which is used for heavy work is the coach screw (Figure G.9). The shank is tapered and the bottom two-thirds have a tapered thread with a relatively sharp point, but the head is either square or occasionally hexagonal, both
Fig. G.10 Bulldog timber connector. The truss had to be made in a jig, and it was not uncommon in the 1950s to see a rough shel- ter built on a site and under it the carpenters cutting out and laying timbers in a jig, boring holes through them all and then fitting connec- tors in place over a high tensile steel nut and bolt with several large, well greased washers fitted. A long-handled ring spanner was used to tighten up, the teeth on the Bulldog connector or the ring on the shear connector biting into the timbers. If there were too many layers, the bolt had to be put into only a few at a time, and then more timbers and connectors added until the whole
Fig. G.11 Some nails for masonry and the hand tool for masonry nails.
Fig. G.12 Hilti gun, cartridges and nails. and cartridge are loaded into the gun, and the nose of the barrel is depressed against the tim- ber. This releases the safety catch and the trigger can be pulled. The cartridge fires and the nail is driven into the timber and the background. A range of cartridges is available which allows backgrounds of different types and densities to be penetrated. It is possible to nail timbers to the flanges of steel joist and beams. A Hilti gun, car- tridges and nails features in the photograph in Figure G.12.
Fig. G.14 Fibre, plastic and amorphous plugging for fixing screw nails. The preformed soft material fastenings were first introduced by the original Rawlplug Co, now Artex-Rawlplug, and were simple tubes of
Fig. G.15 On the left are two bolts, one with a hex head and the longer one with a Torx head. These are designed to be screwed into concrete requiring a pre- cisely drilled and clean pilot hole. On the right are im- proved shank bronze nails, again used to fix weather boarding etc. in aggressive situations such as near the sea.
Fig. G.16 Rawlbolts — schematic.
Fig. G.18 Spring toggle and expanding fasteners for blind fixing in hollow sections or panels.
Fig. G.17 Rawlbolts M6 and M12 in bolt projecting and loose bolt types.
Fig. G.19 Spring and gravity toggle fasteners — schematic. Fixing back to a hollow background is another area where inventive minds have run riot. All the fixings manufactured depend on having a device which expands behind the skin or panel to which you are fastening — except one, which is the gravity toggle. This goes through the hole all aligned, then gravity takes over and part of it falls over and can be drawn up tight against the back of the panel. Figures G.18, G19 and G.20 show all this. Frame fixings (Figures G.21 and G.22) were spe- cially developed to make the fixing of door and window frames into openings in masonry walls easier than with the traditional plug or dook. To use them, the frame has a clearance hole drilled for each fixing. Then a masonry drill is used through the clearance hole to drill correspond- ing holes in the masonry reveals. To do this
Fig. G.22 Frame fixings — the large one on the right is 150 long. Next to it is the drive screw which is used. Note the shape of the thread.
Fig. G.20 Rawlnuts and plastic mushroom fasteners — schematic.
Fig. G.21 Frame fixings — schematic. These devices are widely used in the indus- try but there appears to be little advantage over the traditional plug or dook. The plug or dook can be cut from waste timber, and waste from
Fig. G.23 A chemical anchor schematic. A more up-to-date system uses a mastic gun and a cartridge of one par resin to fill the hole into which the anchor is set.
Fig. G.24 Skeleton gun for injecting compounds into holes, grooves or recesses in construction work.
Fig. H.2 Taping and jointing board joints. Alternatively, fixing can be with screw nails — dry lining screws — which are made of hardened steel and have a specially shaped head with a Phillips or Pozidriv slot, a thread which has a fast
Fig. H.3 Dry lining screw, nail and screwdriver bit. For small jobs, hammering in nails with a joiner’s hammer is not too tedious but to speed up the process and reduce the physical effort fixing with screws is extremely good. Battery powered tools have changed attitudes in the in- dustry, and the use of collated dry lining screws in a portable tool makes fixing large sheets of
Fig. H.1 Double plasterboard layer with board joints staggered.
Fig. H.4 Dry lining screws and driver bit.
Fig. 1.3 Laying and overlapping of DPC and DPM.
Fig. 1.4 Brick and tile DPCs to scale.
Fig. 1.2 Placement and thickness of DPC and DPM in a detail drawing.
Fig. 1.5 Polythene DPM.
Fig. 1.8 Weep opened up to show the baffles and water channels.
Fig. 1.7 A proprietary plastic weep.
Fig. I.6 Schematic of a weep formed at ground level in a masonry wall.
Fig. 1.9 Ventilators and liners made in terracotta.
Fig. 1.10 Closing all four sides of vent opening with cuttings of roofing slate. One of the many gadgets made for the indus- try is a telescopic liner for underfloor ventilators. They can be used to duct air across and up or down a cavity where there is a non-conventional arrangement of ground and floor levels. For ex- ample, a hung floor might be built which is
Fig. 1.13 A similar liner built into a cavity wall in the wrong place.
Fig. 1.11 Telescopic liner for under floor ventilators.
Fig. 1.12 Terracotta liner built into a blockwork sub- structure wall.
Fig.1.15 Typical house plan with the position of vents.
Fig. 1.14 A typical vent in a cavity wall with a 100 thick outer leaf of artificial stone.
Fig. 1.16 A house with part of the floor of solid con- crete on upfill construction.
Fig. I.18 A house with a small area of hung floor - adequate ventilation.
Fig. 1.17 A house with a small area of hung floor — inadequate ventilation.
Fig. J.1. Architectural drawing symbols (1). As one would expect, the drawing of archi- tectural details requires a common methodo- logy for the representation of building materials
While DPCs and DPMs are always shown to an exaggerated scale, the problem also arises with membranes. Where plastic, paper
Why should we be starting a book on building construction with a discussion of bricks and blocks? Quite simply because bricks are one of the major construction materials instantly as- sociated with construction in the mind of the novice or lay person, but more importantly because the sizes chosen for the manufacture of bricks and blocks affect practically every- thing in a building except the thickness of the coats of paint or the coats of plaster. This will be discussed in more detail as we proceed. Masonry Construction in Bricks and Blocks
Table 1.1 Brick types by end use —- compressive strength and water absorption.
Table 1.2 Mortars for clay bricks and concrete blocks. Adding lime to the mix
Table 3.1 Mortar mixes suitable for external rendering of masonry walls. a year or two while EVA is fully waterproof and should last the life of the render. EVA can be purchased as a powder or a liq- uid. Recent research has shown that liquid EVA blocks most of the pores, thus helping to retain water within the wall rather than let- ting the wall ‘breathe’. Powdered EVA is more successful. It does not block the pores but lines them, thus repelling solid water trying to en- ter while retaining a fully open surface for evaporation.
Table 6.1 Roof angles and rise in horizontal distance in millimetres. horizontally. That ratio of vertical height to horizontal distance is better known as the nat- ural tangent of the included angle, i.e. be- tween the slope and the horizontal. The natu- ral tangents for the whole degree angles from 1 to 10 are listed in Table 6.1, together with the flat roof slope to give the reader some instant appreciation of what these slopes are really like.
Table 7.1 Tiles and slates — materials, fixing and laying method.
Table 8.1 Comparative costing of wall and window.
Table 12.1 Materials used for pipe. *When used for central heating pipework, ordinary plastics pipe will allow oxygen to diffuse in through the pipe wall. A special grade of pipe is manufactured with an oxygen barrier in the wall of the pipe.
Table 12.2 Valves and cocks, nomenclature. or elbow or even a T. Valves can also be ob- tained with flanges for fixing to some type of background. Depending on the manufacturer, brass and DZR versions of the valves are made, and there can be one or both ends with male or fe- male threads. So one could have one end for copper and one male or female end, or both male ends or both female ends. To the best of the author’s knowledge no-one has made a valve with one male and one female end. Hav- ing valves with single male or female ends means that a connection can be made to an ap- pliance and then the pipe connected directly to the valve. i amare 1 1 ell a | ye
*A pipe sleeve is a cutting of pipe built into a masonry wall through which a service pipe is passed. It protects the service pipe and allows it to expand and contract or move lengthwise in the sleeve without damage to itself or the wall. It always bridges cavities in walls and so prevents pipe contents from spilling into the cavity in the event of a leak. A pipe sleeve is mandatory for gas service pipes passing through a cavity or any other walls. There should neve be any pipe joints secreted in a pipe sleeve. Table 12.3 Service and pipe used.
Table 12.4 Disposal pipe sizes, trap seals and maximum branch lengths.
“Depending on the total rating of the appliances or whether it is only an oven, and a gas hob has been fitted. “This would only allow the fitting of a light and a double socket outlet in the garage. 'This would allow a lighting circuit with several lights and a ring main with several socket outlets to be installed. Table 13.1 Circuits and cables.
Table B.1 Noting the readings in a level book
Table E.1 Thickness of screed by method of laying and type of material.
Table I.1 Class and description of each type of bitumen DPX from Table 1 of BS 6398 Table 2 of BS 6398 lists suitable locations for the use of these DPCs, with the recommendations based on the following: Table 2 of BS 6398 lists suitable locations for the use of these DPCs, with the recommendations based on the following: with a layer of concrete. This will be under the timber hung ground floor of the house.
Table A Common cross-sections with availability and relative cost. machining of the opposite faces, generally with rotary knives, to bring the surfaces to a smooth, even finish and the timbers to the same overall dimensions. The surfaces will only require sanding before a decorative finish is applied — paint, varnish, stain, etc. This reduction in overall size is controlled within the limits set out in Table C and de- pends on the end use of the timber and the ba- sic sawn dimensions. The reductions vary from 4 to 13 mm and are inclusive of any ‘re-sawing’
Table B Common lengths showing availability and effect on cost.
Table C Maximum permitted reductions from basic sawn sizes to finished sizes by planing two opposing faces (mm).
descriptionView Paperarrow_downwardDownload
Maintenance des équipements hydrauliques
by Joël Mètogbé Zinsalo, ing., Ph.D.
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Introduction to Directional and Horizontal Drilling - Jim Short
by Jessica Silva Angulo
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Structural Wood Design A Practice-Oriented Approach Using the ASD Method, 0470056789
by Bianca Stan
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CONCEPTION, ETUDE ET DIMENSIONNEMENT DE LA TOUR JW MARRIOTT CASABLANCA MARINA
by Mohamed FELLAH

2018

This report presents the work I did as part of my graduation project. It consists of designing, studying and dimensioning the JW Marriott Tower in Casablanca Marina. Being one of the largest cities in Africa, Casablanca plans to develop... more
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An Overview on Evolution of Mobile Wireless Communication Networks: 1G-6G
by International Journal IJRITCC
There has been a huge advancement in mobile wireless communication since the last few decades. This advancement consist of several generations and is still going on. The journey of mobile wireless communication began with 1G followed by... more
GSM(Global System for Mobile Communication) is the most widely used 2G mobile standard.2G was commercially launched on GSM _ standard in Finland, in 1991.GSM technology was the first one to support international roaming. This enabled the mobile subscribers to use their mobile phone connections in different countries of the world with better quality and capacity. The GSM technology was continuously improved to provide better services which led to development of advanced
2 gee ee 2 eee ee a i a a oe The third generation wireless mobile communication system was introduced in 2000.The goal of 3G systems was to offer increased data rates from 144kbps to384kbps in wide coverage areas and 2Mbps in local coverage areas.3G offers advanced services to the users as compared to 1G and 2G.Along with voice communication it includes data services, access to TV/videos, Web browsing, e-mail, video conferencing, paging, fax and navigational maps. It has a bandwidth of 15-20MHz used for high speed internet, video chatting, etc. A 3G mobile system was defined by an organization called 3rd Generation Partnership Project(3G PP) which fulfils the IMT-2000 standards. It was called as UMTS(Universal Mobile Telecommunication System) in Europe, which is TSI driven.IMT2000 is the TU-T name for the third generation system, while CDMA 2000 is the name of American 3G variant. Also the MT2000 has accepted a new 3G standard from China, ie TD-SCDMA.WCDMA is the air-interface technology for UMTS. The first commercial 3G network was launched by TT Do co mo in Japan, in 2001. systems called as 2.5 Generation(2.5G) systems.2.5G lies between 2G and 3G technologies. In addition with circuit switched domain of 2G system, 2.5G implements a packet switched domain, and provides a data rate of 144kbps.2G used technologies such as General Packet Radio Service(GPRS) and EDGE(Enhanced Data rates in GSM Environment).GPRS provides packet switching protocols, short setup time for ISP connections and the possibility to charge the subscriber according to the amount of data sent rather than connection time. GPRS supports flexible data transmission rates and provides continuous connection with the network. GPRS is the significant step towards 3G.
Figure 5. 4G Network Architecture
nternational Journal on Recent and Innovation Trends in Computing and Communic folume: 3 Issue: 5 TABLE I. OSI layers in the 5G Mobile Terminal Design
In 5G network, the Physical and Data Link layer defines the 9G wireless technology indicating it as an Open Wireless Architecture(OW A).The 5G technology also maintain virtual multi-wireless network. To perform this the Network layer is sub-divided into two layers; upper network layer for mobile terminal and lower network layer for interface. Here all the routing will be based on IP addresses which would be different in each IP network worldwide. In 5G technology the higher bit rate loss is overcome by using Open Transport Protocol(OTP).The OTP is supported by Transport and Session layer. The application layer is for quality of service management over various types of networks. Features Figure 6. 5G Mobile Network Architecture
TABLE II: Comparison of all Generations
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RESISTENCIA DE MATERIALES
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IRC SP 013: Guidelines for the Design of Small Bridges and Culverts
by Champa Majumder
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Structural Elements for Architects and Builders: Design of columns, beams, and tension elements in wood, steel, and reinforced concrete
by Helton Celi
Butterworth -Heinemann is an imprint of Elsevier
Geometry factor parameters for Example 9.4
values of which are central to the most fundamental questions of structural engi- neering: Is it strong enough? Is it safe?
Framing plan showing tributary areas for beams, girders, and columns
Distributed load on a floor carried by two columns
column, having no effect on Beam B. Unlike Beam A, the floor loads are transferred to Beam B at two points: each concentrated load corresponds to a tributary area of 17.5 X 10 = 175 ft?; therefore, the two loads each have a magnitude of 100 X 175 = 17,500Ib = 17.5kips. The load diagram for Beam B is shown in Figure 1.7b.
Framing plan showing tributary areas for columns (one floor only)
additional weight of cladding and the possibility of resisting wind and earthquake forces through rigid connections to the spandrel girders. Column D supports a tributary area of 35 X 20 = 700ft? so that the load trans- ferred to Column D from the floor above is 100 700 = 70,000Ib = 70kips, assum- ing that the floor above has the same shape and loads as the floor shown. But every floor and roof above also transfers a load to Column D. Obviously, columns at the bottom of buildings support more weight than columns at the top of buildings, since all the tributary areas of the floors and roof above are assigned to them. As an example, if there are nine floors and one roof above Column D, all with the same distributed load and tributary area, then the total load on Column D would be, not 70k, but 9 + 1) X 70 = 700kips. In practice, the entire load as previously calculated is not assigned to columns or to other structural elements with large total tributary areas. This is because it is
Examples of plane structures: simply supported beam, three-hinged arch, and rigid (moment- resisting) frame
Abstract symbols for reactions, including (a) hinge or pin-end, (b) roller, (c) fixed, and (d) free end For any plane, rigid-body structure (just “structure” or “structural element” from now on) subjected to various loads, the three equations of equilibrium provide the mathematical basis for determining values for up to three unknown forces and moments—the reactions of the structure to the loads. Structural elements of this type are statically determinate because the magnitudes of the unknown reactions can be determined using only the equations of static equilibrium.
Load diagram for simply supported beam for Example 1.1 showing (a) constraint symbols and (b) unknown forces replacing constraint symbols, and resultant corresponding to distributed load
Vertical component of cable force for Example 1.3 is found (a) just to the left of the external load at point C and (b) just to the right of the load Sag point occurs where the vertical component of internal cable forces changes direction (sign) for Example 1.3
Vertical component of cable force for Example 1.3 is found (a) just to the left of the external load at point D and (b) just to the right of the load
Free-body diagram cut at the sag point for Example 1.3
Internal forces and moments 1 Internal shear and axial forces and internal bending moment
Free-body diagram for Example 1.4 (a) cut just to the left of the external load at point C; and (b) just to the right of the load
Internal forces and moments | Free-body diagram for Example 1.4 (a) cut just to the left of the external load at point D and (b) just to the right of the load
Load, shear, and moment diagrams for Example 1.4 “Fy = 5 — 5 — 5 — Vg = 0, from which the internal shear force Vg = —5kips (downward which is equivalent to 5kips (upward).
Relationship between value of shear diagram and slope of moment diagram Load and shear diagrams for Example 1.5
Shear diagram for Example 1.5, showing distance from reaction at point A to the point where the shear diagram crosses the baseline, going from positive to negative value
Load, shear, and moment diagrams for Example 1.5, using load diagram “areas” to find shear values, and shear diagram “areas” to find moment values
Loading diagram for, and geometry of, truss for Example 1.6
Deflection diagrams for the two components of the structure shown in Figure 1.46: (a) a simply supported beam with a concentrated load, P;, and (b) a tension hanger with load P> Load diagram for a simply supported beam with an added hanger at midspan as shown in Figure 1.47, where A, and A, are the deflections of the beam and hanger, respectively; P; and P, are the loads assumed to act separately on the beam and hanger; and S$, and S> are deflection constants that include the length or span of the elements as well as their stiffness (.e., their resistance to deformation). These deflections, calculated separately for the beam and hanger, must actually ee er ee a a i i a a |
Dimensions of an |-shaped section oriented about its y-axis, for the calculation of moment of inertia Moments of inertia for circular rings (Figure 1.48d) are determined as before: by subtracting the moment of inertia of the smaller from that of the larger circle. For the L-shaped section, however, it is not possible to simply subtract the smaller rec- tangles from the larger, as was done when computing the moment of inertia about the x-axis, since the centroids of the various parts being subtracted do not coincide. Instead, one must add the three moments of inertia of the two flanges and web, as shown in Figure 1.49, each taken about the y-axis:
FIGURE 2.4 “Influence areas” for beams and columns
There are a few obvious exceptions to the rules governing live load reductions, most importantly for structural elements supporting large areas that are expected to be fully loaded. In such cases (e.g., in places of public assembly or in garages), no live load reduction is allowed. Additionally, reductions are restricted for one- and two-way slabs since the failure mode of such slabs is not directly a function of tribu- tary area, but rather corresponds more closely to any given “strip” within which reinforcing bars are placed. These are minimum values for live loads: other than exposing oneself to the potential wrath of developers, owners, project managers, and contractors, nothing prevents a designer from using larger, or unreduced, val- ues if warranted by the particular conditions of the project.
Snow load diagram showing (a) distributed snow load and (b) snow load on a typical rafter, for Example 2.3
Historic values for wind loads, based on 1969-1981 New York City Building Codes
Wind pressure on buildings
Distribution of wind pressure on windward and leeward surfaces for Example 2.4
Typical distribution of equivalent seismic story forces on a building of larger “component and cladding” loads in wind design: because the actual distribu- tion of seismic forces is nonuniform, complex, and constantly changing, the average force expected to act upon the entire lateral-force-resisting structural system is less than the maximum force expected to occur at any one level or upon any one build- ing element.
Schematic section through building, showing story heights, for Example 2.5 Find the distribution of seismic story loads on a five-story office building located in Los Angeles, away from the ocean. Plan dimensions are 60ft x 80ft; assume that an “effective seismic weight” of 75 psf can be used for all story levels (primarily due to the dead load). The structure is a Steel special moment-resisting frame and is built upon dense soil. The typical building sec- tion is shown in Figure 2.17.
56 CHAPTER 3 Material properties can be custom fabricated in an unlimited variety of sizes and geometries. A typi- cal LVL cross section is shown in Figure 3.3.
as they simultaneously compress the areas that cooled first. The typical pattern of residual stresses within a wide-flange cross section is shown in Figure 3.6. Residual stresses have an impact on the inelastic buckling of steel columns, since partial yielding of the cross section occurs at a lower compressive stress than would be the case if the residual compressive stresses “locked” into the column were not present.
Cross section of a typical steel wide-flange (W) section Wide-flange shapes are commonly used for both beams and columns within steel- framed structures. They are designated by a capital W, followed by the cross sec- tion’s nominal depth and weight (ib) per linear foot. For example, a W14 X 38 has a nominal depth of 14in. and weighs 381b per linear foot (see Figure 4.1). Unlike stan- dard (S) “I-beam” sections, whose flange surfaces are not parallel—the inner surface slopes about 16% relative to the outer surface—wide-flange (W) sections have parallel flange surfaces, making it somewhat easier to make connections to other structural elements. Wide-flange sections are manufactured in groups with a common set of inner rollers. Within each of these groups, the dimensions and properties are varied
Penetration of lag screw into main member, for Example 9.5
(a) Framing plan and (b) section for Example 5.1
Illustrations of (a) tension element and (b) free-body diagram cut at any cross section with area, / by its thickness, ¢. This net width is found by subtracting from the gross width, W, the sum of hole diameters, d,,, and then adding spacing-gage terms, s?/(4 2), for each diagonal line in the failure surface. In these calculations, s is the spacing between bolt centerlines parallel to the direction of load, and g is the “gage,” or spacing between bolt centerlines perpendicular to the direction of load. weet dhe » @
—_— NE EE EE EO Where all parts G.e., flanges, webs, etc.) of a cross section are connected, and the so-called shear lag effect described earlier cannot occur, the coefficient U is taken as 1.0, and the effective net area equals the net area, just as in timber design. For short connection fittings like splice plates and gusset plates, U is also taken as 1.0, but A, = A, cannot exceed 0.85 times the gross area. These short connecting elements may have an effective width less than their actual width to account for the shear lag effect, based on what is known as the “Whitmore section,” shown in Figure 6.8. For a length, Z, of the fastener group measured in the direction of load, and a distance, W, between the outer rows of bolts or welds, the effective width is
computed by extending a 30° line out from both sides of the fastener group; it can be seen that the effective width, /,,, is equal to 2Ztan 30° + W. Finally, the lengths of tension members, other than rods and cables, are limited to a slenderness ratio—defined as the ratio of effective length to least radius of gyra- tion—of 300, to prevent excessive vibrations and protect against damage during transportation and erection. The radius of gyration, a property of the cross section, is equal to (1/A)°*, where I is the moment of inertia and A is the cross-sectional area of the element.
Truss elevation, connection detail at gusset plate, and sections through gross and net area for Example 6.4 100 CHAPTER 6 Tension elements
Definition of net area for pin-connected plates
Increase of bending moment in a column due to load-induced deflection
(1707-1783) figured out was that these deflections increase rapidly in the vicinity of a particular Ccritical”) load, at which point the column is assumed to fail, and that the value of this load is independent of the initial eccentricity. In other words, even with the smallest imaginable deviation from axiality, a column is assumed to buckle at some critical load. Since no perfectly axial columns (or loads) can exist, all columns behaving elastically are assumed to buckle at the critical buckling stress derived by Euler:
The strength of wood and steel columns is limited in two ways: either they will crush at their maximum compressive stress, or they will buckle at some criti- cal stress that is different from, and independent of, their strength in compression. Euler’s equation for critical buckling stress works well for slender columns but gives increasingly inaccurate results as the slenderness of columns decreases and the effects of crushing begin to interact with the idealized conditions from which Euler’s equation was derived. Figure 7.3 shows schematically the relationship among Euler critical buckling stress, crushing strength, and test results for columns with dif. ferent slenderness ratios. It can be seen that only for slender columns can the Euler curve be used as a basis for design.
Framing plan and building section for Example 7.2
Allowable axial column load plotted against unbraced length Inelastic and elastic critical stress curves for column buckling
Framing plan and building section for Example 7.4 Problem solution 1. Find total column load:
Reinforced concrete 1]
Nominal stresses at failure of axially loaded reinforced concrete column
Column cross section for Example 7.5 Solution overview
Comparison of “positive” and “negative” bending in (a) a simply supported beam anc (b) a cantilevered beam be seen from Figure 8.4a, a counterclockwise moment on the right side of a free- body diagram is equivalent to a distribution of bending stress with compression on the top and tension on the bottom of the beam: “positive” bending (and “positive” bending moment). Figure 8.4b shows a free-body diagram cut through a cantilever beam with “negative” bending—that is, tension on the top and compression on the bottom corresponding to a clockwise moment as shown. The reversing curvature of a continuous beam, such as that shown in Figure 8.3, corresponds precisely to a reversal in the sign of the bending moment. As shown in Figure 8.5, points of inflec- tion (points where the curvature changes) always occur at points of zero moment. Bending stresses within these beams can be computed if we assume that the stretching and shortening that take place at any cross section are linear; that is,
Elongation, strain, and stress diagrams for a linear, elastic material Shortening and stretching (compression and tension) at a typical beam cross section FIGURE 8.6
Elongation, strain, and stress diagrams for an elastic-plastic material such as steel showing (a) elongation and shortening of the actual material, (b) strain diagrams, (c) stress diagram at the point where the outer fiber has just yielded, (d) stress diagram corresponding to strain just beyond the elastic limit, (e) stress diagram corresponding to continued strain beyond the elastic limit, (f) stress diagram corresponding to the plastic moment (where the entire cross section has yielded), and (g) stress-strain diagram As an example of how the stress-emoment relationship is computed using the allow- able stress design method, consider a free-body diagram cut from a rectangular cross section of width, b, and height, 4 (assuming a linear stress-strain relationship resulting in a linear stress diagram), as shown in Figure 8.9a. From the requirements of horizontal equilibrium, the total compressive force, C, must equal the total ten- sion force, 7. For this to occur, the neutral axis must be at the center of the beam, and the maximum compressive stress must equal the maximum tension stress. Any other linear distribution of stresses would be inconsistent with these requirements
Reduction of shear force, Vinay, in the vicinity of the beam’s reaction (support) Distribution of shear stress on a rectangular cross section
Comparison of actual and assumed maximum shear stress, Tmax, for a steel wide-flange beam istribution of shear stress on a flanged cross section, and calculation of maximum shear stress, Ta
Framing plan for Example 8.4
Being able to resist the full plastic moment represents an extra margin of safety: if a beam can develop this plastic moment without buckling, the maximum available bending moment of M,/Q is used, as shown in Equation 8.12. In addition to lateral- torsional buckling (Figure 8.23a), various types of local flange and web buckling must also be prevented from occurring before the plastic moment is reached (Figure 8.236). Local buckling is prevented by limiting the ratio of flange width to flange thickness, as well as web width to web thickness. Sections proportioned so that local buckling will not occur are called compact sections; these sections must be used to qualify for the full available moment of M,/Q. As it turns out, all but one of the wide-flange shapes listed in Table A-4.3 is a compact section when made from A36 steel (the exception being W6 X 15). For 50-ksi steel, all but 10 (W6 X 8.5, W6 X 9, W6 X 15, W8 X 10, W8 X 31, W10 X 12, W12 X 65, W14 X 90, W14 X 99, and W21 X 48) are compact. Ear cectinne that are crnmnact and laterally Ararcred Roiatinn 219 annliee and the
Influence of lateral-torsional buckling and flange slenderness on available moment: three zones are defined for (a) lateral torsional buckling, with the boundaries established by the unbraced length, L, (the greatest unbraced length where the section can reach a plastic moment without lateral torsional buckling) and L, (the greatest unbraced length where the section will buckle inelastically before reaching the plastic moment); and for (b) flange slenderness, with the boundaries established by the ratio of half the flange width to flange thickness, \ = b;/(2t), set equal to d, (the greatest flange slenderness where the section can reach a plastic moment without local flange buckling) and \, (the greatest flange slenderness where the flange will buckle locally in an inelastic manner before reaching the plastic moment)
Selection of W21 x 44 beam based on available moment graphs (Table A-8.5) for Example 8.6
Relationship of bending moment and position of tension steel reinforcement
SLCCI All CONCTCUC (SCC PISUre /.7). The strength, or capacity, of a reinforced concrete beam can be determined by considering the equilibrium of tensile and compressive forces at any cross section. Failure of the beam occurs either with crushing of the concrete within the compres- sion region; or yielding of the tension steel, followed by compressive crushing of the concrete. Since tension yielding is the preferred mode of failure—compressive crushing of the concrete would be sudden and catastrophic, whereas yielding of the steel provides warning signs of collapse—concrete beams are often deliberately under-reinforced to guarantee that, in the case of failure, the steel reinforcing bars begin to yield before the concrete in the compressive zone crushes. At the point of failure, the stresses in a reinforced concrete cross section are as ‘* = ‘amaligh za. ac 6 - Fe .. 7 a oe ee aa
Comparison of (a) actual stresses in reinforced concrete beam with (b) equivalent rectangular (“Whitney”) stress block
The maximum steel ratio (P,4.), Whether derived from the lowest permissible steel strain of 0.004 or the simpler value of 0.005, sets an upper limit to the amount of steel in a reinforced concrete beam where failure, should it occur, is initiated by yielding of the tensile reinforcement. By comparing the stress and strain diagrams of the balanced condition (Figure 8.40) with the condition where the steel strain at failure is 0.005, it can be shown that the steel ratio corresponding to a steel strain of 0.005 is Pmax = 0.63375 pp). For beams, a lower limit for the steel ratio (~,,;,) is also prudent and is set at 200/f, for concrete strengths in the 3000- to 4000-psi range and 3¢(f, Diy for 5000-psi or higher concrete (where //, and Jy are in psi units). A minimum s/ab steel ratio is set at 0.0018, consistent with slab requirements for minimum temperature and shrinkage reinforcement perpendicular to the direction of span. These lower bounds protect against a type of sudden failure that might oth- erwise occur in very lightly reinforced beams if the redistribution of stresses brought about by the initial cracking of concrete in the tension zone exceeds the capacity of the “cracked” cross section assumed in the calculation of steel area. Typical mini- mum and maximum values for the steel ratio, p, are shown in Table A-8.8. There is a subtle, but important, important difference between positive-moment T-beam design (with effective “flange” width, b, and web or stem width, D,,) and rectangular beam design (with constant width, b): the minimum steel ratio, Py,;,, is much lower for the T-beam when expressed in terms of width, b. This is because Pmin, derived from a consideration of the beam’s moment capacity before tensile een ew ldetan ee nn fLthke nn new nreantn tn AnLar ne San trretennn no eben Le pe we he wert dah fae thn ernentna
The rigorous calculation of reinforced concrete beam or slab deflection is compli- cated by the difficulty of determining the stiffness, ET, of such bending elements that would be required in any deflection equation: in particular, the moment of inertia of a cracked section (cracked in the tension zone) containing two very different types of materials (steel and concrete) is complex and uncertain. While such procedures exist, we can control deflection—for preliminary design—by establishing minimum thicknesses for beam and slab elements based on their clear span, as shown in Table A-8.2. For example, the minimum thickness for a continuous reinforced concrete
Alternate bar selection for Example 8.9
Bar selection options for negative moment in T-beam for Example 8.10
Cross section, load, and shear diagrams for Example 8.10
Examples of (a) single shear and (b) double shear. “S” indicates side member; “M” indicates main member
Mode | behavior of fastener in single shear, showing (a) pattern of forces on fastener and (b) corresponding critical stresses on wood member
Simple single-shear model with two equal and opposite forces, but rotational equilibrium unaccounted for (a) forces acting on wood members and (b) forces acting on dowel-type fastene!
Tee ene ne eee een nn neg een OE OEE I EE OI EEE IEEE IA EES The general strategy for designing wood connections is to first find the capacity of a single fastener, using one of the strategies discussed (.e., using yield limit equa- tions or various tabular design aids), and then to multiply that capacity by the num- ber of fasteners comprising the connection. As already suggested, this total capacity for multiple fasteners is explicitly modified using the group action adjustment fac- tor C,; the other adjustments—C>p, Cy, and C,—can be applied to either the entire connection or just a single fastener, but should only be applied once each per con- nection. A temperature factor, C,, should be applied to wood elements subjected to sustained high temperatures: see Table A- 2. 9. ee ee ee re. ee ee: eT ee | a Se
Single-shear bolted connection with multiple fasteners for Example 9.2
all the members, the loading direction is parallel to grain, so the minimum edge distance aE NN DN re) PE End distance: Adjustment criteria for end distance appear in Table A-9.7, part C. For all tl members, the loading direction is parallel to grain. Where the fasteners are bearing towa the member end (in “tension”) and where the wood is softwood, the minimum end distan for full value (i.e., for Cy = 1.0) is 7D = 7(0.5) = 3.5in. For the primary members, the actt end distance of 3.5in. is no less than this, so the geometry factor is Ca, = 1.0. Howev for the connecting member, shown to the right in Figure 9.13, the actual distance of 21 is between the absolute minimum (3.5D = 1.75in.) and the required distance for full val (7D = 3.5in.); therefore, the geometry factor is taken as the actual end distance divided the minimum distance for full value, or Ca = 2/3.5 = 0.571. Edge distance: Adjustment criteria for edge distance appear in Table A-9.7, part D. F all the members. the loading direction is parallel to grain. so the minimum edge distan
End distance: Adjustment criteria for end distance appear in Table A-9.7, part C. For all the members, the loading direction is parallel to grain. Where the fasteners are bearing toward the member end (i.e., in “tension” and for softwood) the minimum end distance fo! full value (i.e., for Cy = 1.0) is 7D = 7(0.5) = 3.5in. For the main members, the actual end distance of 3.5in. is no less than this, so the geometry factor is C, = 1.0. However, for the connecting member, shown to the right in Figure 9.15, the actual distance of 2in. is between the absolute minimum (3.5D = 1.75in.) and the required distance for full value (7D = 3.5in.); therefore, the geometry factor is taken as the actual end distance divided by the minimum distance for full value, or Cy = 2/3.5 = 0.571. Fdoe distance: Adiustment criteria for edge distance annear in Table A-9 7. nart D For
Geometry factor parameters for Example 9.5
Single-shear nailed connection for Example 9.6
Double-shear bolted connection with multiple fasteners and steel side plates for Example 9.7 (same as Figure 9.16 for Example 9.4)
Geometry factor parameters for Example 9.7 (same as Figure 9.17 for Example 9.4)
Bearing of post on beam: the direction of grain is indicated by the parallel lines on each surface
Connection of W8 X 24 tension element using two lines per flange of high-strength bolts for Example 9.10
Fillet weld terminations In certain cases, fillet welds must be terminated before reaching the edge of the steel elements they are connecting in order to prevent damage (notching, gouging) of the element’s edge. Figure 9.33a illustrates a condition where the fillet weld at the underside of a plate (Shown as a dotted line) must be interrupted at the cor- ners before turning 90° and being deposited on the opposite side of the same plate.
Connector plate capacity for Example 9.11 using (a) transverse welds and (b) longitudinal welds Find the capacities of the 6-in.-wide, ‘-in.-thick plates shown in Figure 9.34, welded to (1) a wide-flange shape with transverse welds and (2) an 8-in.-deep channel shape with longi- tudinal welds. In each case, assume that the plates are fabricated from A36 steel and that the weld size is ¥in. Use an E7Oxx electrode with F,, = 7Oksi.
Extension of rebar in tension zone of reinforced concrete element
In Equation 9.6, J, is the development length for tension Gn.); Sy is the yiel« stress of the steel reinforcement (psi); f/ is the compressive strength of the con crete (psi); w, is a coefficient equal to 1.0, except when there is at least 12in. o freshly cast concrete below the steel bars, in which case w, = 1.3 (accounting fo: the negative impact on the bond between steel and concrete caused by rising ai and water within a large mass of freshly cast concrete); and d, is the reinforcins bar diameter Gin.). Where the minimum conditions for spacing and stirrups (or ties described here are not met, the development length must be increased by a factor o 1.5. Where the bar size is smaller than No. 7, the development length is multipliec by 0.8. In no case may the development length be less than 12in. Typical values fo: development length are tabulated in Table A-9.22 for common bar sizes. Development length is influenced primarily by three factors: assuming adequate
Required rebar development length for Example 9.14
PVULO 1Ul fF GI ity 1. When using Table A-2.5, Parts C, D, and E, the roof height, h, is measured to the mean roof elevation, except for roof angles less than or equal to 10°, in which case h is measured to the eave, as indicated by the dotted line. 1. The low hazard factor may be reduced to 0.77 in hurricane-prone regions with wind speed, V > 100 mph.
B. Minimum width (in.) for tied columns?
1. Rebars in the United States were traditionally designated by the nominal diameter (in.) divided by 8. Rebars are no longer marked using this designation. 2. Rebars are currently designated (and marked) by the approximate number of millimeters in their diameter. 3. These minimum dimensions assume 1-in. maximum aggregate; 142-in. cover (measured from outside face of rebar or spiral to face of concrete); and ¥%-in.-diameter stirrups, ties, or spiral. Minimum widths or diameters are typically rounded up to nearest inch, or to the nearest even inch. The amount of column steel is also limited by required reinforcement ratio, pg, between 0.01 and 0.08. Table A-4.11 (Continued)
Table A-7.1 Effective length coefficient, kK, for wood and steel columns Note: 1. Use 2.0 for steel columns; 2.4 for wood columns.
Table A-8.5 Available moment for A992 wide-flange (W) shapes!2 A. Available moments from O to 100 ft-kips
C. Available moments from 200 to 400ft-kips
E. Available moments from 600 to 1000ft-kips
F. Available moments from 1000 to 2000 ft-kips
Table A-8.5 (Continued) 1. Values are based on the conservative assumption that the “lateral-torsional buckling modifier,” C, = 1.0. This conservative value of Cy = 1.0 is quite close to the actual value for simply supported beams with equally spaced point loads of equal weight, where the beam is braced at those points only, except for the special case of a single point load at midspan, in which case Cy = 1.364. Actual values for Cy can be found for each unbraced beam segment by calculating the bending moments at the quarter-points along each segment (Ma, Mp, and Mo, with Mg being the moment at the midpoint of the segment), as well as the maximum moment, Mmax Within each segment, and then inserting these values into Equation 8.13, reproduced as follows: 12.5M se max > We
Table A-8.7 Moment values for continuous reinforced concrete beams and slabs! distributed design loads, w,, and clear span, |,, when the following conditions are met: a. Lengths of adjacent spans do not differ by more than 20%. b. The unfactored live load is less than or equal to three times the unfactored dead load. 2. The negative moment (at the face of support) can be taken as w,I,2/12 for slabs with clear spans no greater than 10ft and for beams framing into relatively stiff columns (specifically, the sum of column stiffness divided by the sum of beam stiffness at each end of the beam must be greater than 8). Stiffness is the product of modulus of elasticity and moment of inertia, neither of which are straightforward quantities for structural elements consisting of two materials bonded together. For normal-weight concrete, the modulus of elasticity, E, (psi), may be taken as 57,000(f! °°), where the cylinder strength of concrete, ff , is in psi units. The calculation of moment of inertia is left to the designer, with the American Concrete Institute (ACI) permitting “any set of reasonable assumptions.” One suggestion is to use gross E,/ values for both beams and columns: where E, is the same for all members, a typical joint with columns and beams at all four orthogonal points, and constant width for column and beam sections, would qualify for the w,|,°/12 negative beam moment only when the column thickness at that joint becomes more than twice the beam thickness.
Table A-9.2 Selected common wire nail dimensions 1. The designation for nails once had some relation to the cost of 100 nails; it now refers only to the nail’s size. The letter “d” in the designation refers to the pennyweight of the nails and is said to be derived from the biblical use of denarius (hence “d”) as the historical equivalent of the modern penny (hence “pennyweight”). We continue to use the abbreviation “d” to stand for “penny” and we say “10-penny nail” when reading “10d nail.”
Table A-9.3 Penetration and dowel bearing length! £. FIG GOWE! VCaHMS ICHSU WT IC Fidlll THICTIIOCl, God Hl YiCiC HiT CalCulaliGHlo, Hlay OC GHICICrit HOTT the penetration as defined earlier: for lag screws, the dowel bearing length in the main member equals the penetration (which excludes the tapered tip); however, for nailed connections, the dowel bearing length in the main member includes the tapered tip where p > 10D, but otherwise excludes the tapered tip (the length of which can be approximated as 2D). 2. For lag screws where the penetration, p, falls between the two values shown in the table, the lateral design value, Z, is multiplied by p(8D). Therefore, where the penetration equals the absolute minimum value of 4D, the lateral design value is taken as one half the tabular (or computed) value of Z. 3. For nails where the penetration, p, falls between the two values shown in the table, the lateral design value, Z, is multiplied by pX10D). Therefore, where the penetration equals the absolute minimum value of 6D, the lateral design value is taken as 0.6 times the tabular (or computed) value of Z. 4. For bolts, “penetration” is always, by definition, 100% through both the main member and side member(s) so there is no need to calculate its effect on the lateral design value, Z.
Table A-9.8 Toe-nail adjustment factor, C;,, for nails? 1. Toe-nailing values are based on two assumptions: That the nail is driven at an angle of approximately 30° to the face of the side member. That the nail insertion point is one-third of the nail length (I,/3) above the end of the side membe!
A. Designation for double-shear lateral design values according to direction of grain?
A. Designation for single-shear lateral design values according to direction of grain?
Schematic section through building for Example 2.4
A. Basic volumetric weights in pounds per cubic foot (pcf)
Tables for Chapter 2 (loads) 2
Table A-2.3 Environmental loads! 1. Approximate values taken from snow, wind, and seismic maps. 2. S, and S; are, respectively, the maximum considered earthquake ground motions of 0.2-second (short) and 1-second (long) spectral response acceleration (5% of critical damping) for site class B, measured as a fraction of the acceleration due to gravity. T, is the so-called long-period transition period (in seconds). 3. Los Angeles regions adjacent to the ocean have a value of T, = 8.
Table A-2.4 Snow load Importance factor, /;
fe Ee 1. L and B are the plan dimensions of the rectangular building, with B being the dimension of the windward and leeward walls, and L the dimension of the sidewalls. See Table A-2.5, Part H, for graphic explanation of building geometry parameters.
B. External pressure coefficient for walls, on
D. External pressure coefficient on leeward slope of roof, C,, for wind direction normal to ridge. Notes for Part D: 1. The height h is measured to the eave for roof angles equal to 10°, otherwise, h is the mean roof height above grade; L is the horizontal length of the building parallel to the wind direction. See Table A-2.5, Part H, fo! graphic explanation of building geometry parameters. 2. For roof angles less than 10°, the roof is considered to be flat, and no leeward pressures are computed. Instead, use the values in Table A.2.4, Part C, for the entire roof. 3. Interpolation is permitted between values. 4. Negative numbers indicate “suction,” that is, forces acting away from the building surface; positive numbers indicate forces “pushing” against the building surface.
E. External pressure coefficient on roof, Cp, for wind direction parallel to ridge, for all roof angles!2:3.4.
E. Fundamental period of vibration, T (seconds)—approximate value, and exponent, k
H. Seismic response coefficient, 'C, NOLES TOF Fart 7: 1. Values for S; and T, for selected cities can be found in Table A-2.3; values for Spgs and Sp; are found in Table A-2.6, Part C; values for R are found in Table A-2.6, Part D; approximate values for T are found in Table A-2.6, Part E; and values for I¢ are found in Table A-2.6, Part F. 2. Use the “provisional” value for C; when it falls between the lower and upper limits; otherwise, use the lower limit (when the provisional value is below the lower limit) or the upper limit (when the provisional value is above the upper limit). Table A-2.6 (Continued)
A. Dimension lumber (2 to 4 in. thick)
B. Beams and stringers*
Size factor, C- = 1.0 for tension stress, except for the following sizes of dimension lumber:
Load duration factor, Cp, is as follows: Tables for Chapter 3 (material properties)
D. Glued laminated softwood timber
Load duration factor, Cp, is as follows: 270 APPENDIX 3 Tables for Chapter 3 (material properties)
The column stability factor, Cp, is as follows:
E. Glued laminated softwood timber bent about y-axis (loaded parallel to wide face of laminations)
(2) For glulam:
C. Glued laminated softwood timber bent about x-axis (loaded perpendicular to wide face of laminations) A. Dimension lumber (2 to 4 in. thick)
D. Glued laminated softwood timber bent about y-axis (loaded parallel to wide face of laminations)
Table A-3.12 Steel properties!
Table A-3.13 Steel allowable stresses and available strengths
Table A-4.1 (Continued)
Table A-4.2 Dimensions of typical glulam posts and beams 1. Western Species (WS) consists of numerous species groups, not all of which are produced in the westerr United States, including Alaska Cedar (AC), Douglas Fir-Larch (DF) and Douglas Fir South (DFS), Eastern Spruce (ES), Hem-Fir (HF), Softwood Species (SW), and Spruce Pine Fir (SPF).
Table A-4.3 (Continued)
Table A-4.3 (Continued)
Table A-4.3 (Continued)
Table A-4.3 (Continued)
Table A-4.3 (Continued) IVOULCS. 1. Section not compact for steel with Fy = 36ksi or Fy = 50ksi. 2. Section compact for steel with Fy = 36ksi, but not compact for steel with Fy = 50ksi. 3. Section webs do not meet slenderness criteria for shear for which the allowable stress can be taken as F, = 0.4F,; instead, use a reduced allowable shear stress, Fy = 0.36Fy.
Table A-4.4 (Continued)
Table A-4.5 (Continued)
Table A-4.10 Steel reinforcement—rebar—areas (in?) for groups of bars 1. Rebars in the United States were traditionally designated by the nominal diameter (in.) multiplied by 8 Rebars are no longer marked using this designation (see Note 2). 2. Rebars are currently marked by the approximate number of millimeters in their diameter, although designation by nominal diameter (in.) multiplied by 8 is still widely used in the United States.
Table A-5.2 Reinforced concrete strength reduction factors, @ and a
PYULE. 1. Slenderness ratio, KL/r > 200, for this effective length.
Table A-7.5 Allowable stresses for A500 Grade B HSS round columns (Fy = 42 ksi)
A. Deflection coefficient, C, for maximum deflection,” A (in.), where A = CPL3/(El,)
Table A-8.4 Plastic section modulus (Z,) values: lightest laterally braced steel compact shapes for bending, Fy = 50ksi
Table A-8.6 “Shear” equations for reinforced concrete beams!
able A-8.8 Limits on steel ratio for “tension-controlled” reinforced concrete beams!
Table A-9.1 Selected lag screw (lag bolt) dimensions
Table A-9.4 Duration of load adjustment factor, Cp, for wood connectors! Table A-9.5 Wet service adjustment factor, Cy, for wood connectors! 348 APPENDIX 9 Tables for Chapter 9 (connections)
Table A-9.6 (Continued)
B. Spacing (in.) between rows of fasteners?.°
Table A-9.9 Temperature factor, C;, for wood fasteners
C. 3¥%-in. main member thickness
D. 5%-in. main member thickness 1. Member thickness is measured parallel to the axis of the fastener. 2. Designations for lateral design values are as illustrated: (a) Z,,, for both members with direction of grain parallel to load, (b) Z..per for side member with grain perpendicular to load and main member with grain parallel to load, and (C) Zp-per for main member with grain perpendicular to load and side member with grain parallel to load. A fourth possibility, with both members having grain perpendicular to the direction of load, is rarely encountered and not included here. The official designations also shown beneath the illustrations contain “parallel” and “perpendicular” symbols instead of the abbreviations, “par” and “per,” used in these tables and text.
1. Member thickness is measured parallel to the axis of the fastener. 2. Designations for lateral design values are as illustrated: (a) Z,,, for all members with direction of grain parallel to load, (b) Z..per for side members with grain perpendicular to load and main member with grain parallel to load, and (C) Zm.per for main member with grain perpendicular to load and side members with grain parallel to load. A fourth possibility, with all members having grain perpendicular to the direction of load, is rarely encountered and not included here. The official designations also shown beneath the illustrations contain “parallel” and “perpendicular” symbols instead of the abbreviations, “par” and “per,” used in these tables and text.
1. Member thickness is measured parallel to the axis of the fastener. 2. Designations for lateral design values are as illustrated: (a) Zp, for main member with direction of grain parallel to load and (b) Zper for main member with grain perpendicular to load. The official designations also shown beneath the illustrations contain “parallel” and “perpendicular” symbols instead of the abbreviations “par” and “per,” used in these tables and text.
1. Member thickness is measured parallel to the axis of the fastener. 2. Designations for lateral design values are as illustrated: (a) Zp2, for all members with direction of grain parallel to load, (b) Z..per for side members with grain perpendicular to load and main member with grain parallel to load, and (Cc) Zm-per for main member with grain perpendicular to load and side members with grain parallel to load. A fourth possibility, with all members having grain perpendicular to the direction of load, is rarely encountered and not included here. The official designations also shown beneath the illustrations contain “parallel” and “perpendicular” symbols instead of the abbreviations, “par” and “per,” used in these tables and text. 3. Tabular values are based on full value minimum penetration, p, into main member. For penetration into main member between 4D and 8D, multiply tabular values by p/((8D). 4. The reduced body diameter, D,, is used in yield limit calculations for these lag screw lateral design values, except in the calculation of the dowel bearing strength for loading perpendicular to grain, Fe.perp, in which case the nominal diameter, D, is used.
A. %-in. side member thickness Table A-9.14 Lateral design value, Z (Ib) for common nails: single-shear connections,
Pee 1. Member thickness is measured parallel to the axis of the fastener. 2. Where values are not indicated, nail penetration into main member does not satisfy minimum requirements. Otherwise, except as indicated in Note 3, it is assumed that the minimum penetration of the nail into the main member is equal to 10D (see Table A-9.3 for notes on penetration). 3. These values include a reduction for penetration into main member because the penetration falls below the minimum for full value. The dowel bearing length in the main member, I;n, used in the calculation of these lateral design values does not include the length of the tapered tip, for the same reason (see Table A-9.2 for nail dimensions).
Table A-9.16 Withdrawal design value, W, per inch of penetration (Ib) for lag screws!2
Table A-9.17 Withdrawal design value, W, per inch of penetration (Ib) for nails!
A. Bearing-type connections! B. Slip-critical connections (based on strength rather than serviceability)?
frets. 1. Capacities are tabulated for single-shear connections, with bolt threads excluded from all shear planes (condition X). For double shear, multiply values by 2; for threads included within shear planes (condition N), multiply values by 0.8. For double shear and threads included, multiply by 2 X 0.8 = 1.6. 2. Slip-critical capacities are based on standard holes and single-shear. For double shear, multiply values by 2. Slip-critical bolts must also satisfy bearing capacity values in Table A-9.19.
Table A-9.19 Bearing capacity, or available strength, for a high-strength bolt bearing on material lin. thick, with clear spacing between bolts (or edge) > 2in. (kips)! 1. Capacity (available strength) is tabulated assuming that the bolt hole clear spacing (or clear spacing between bolt hole and material edge) in direction of force is no less than 2in. For clear spacing less than 2in., multiply capacity by L./2, where L, is the actual clear spacing (in.). For cases where the small deformations associated with bolt bearing, at ordinary service loads, are considered to be a design issue, multiply capacity by 0.8. Where the thickness, t, of the material is other than 1in., multiply the capacity by the thickness, t (in.). These multiplications are cumulative so that, for example, the capacity of a material with t = % in., clear spacing between bolts of 1.75in., and consideration of bearing deformations, would be equal to the tabular value multiplied by (%)(:’4)(0.8) = (tabular value X 0.4375). Table A-9.19 Bearing capacity, or available strength, for a high-strength bolt bearing on 370 APPENDIX 9 Tables for Chapter 9 (connections)
A. Minimum bolt spacing (in.) B. Minimum edge distance (in.)!
Table A-9.22 Development length in inches, /,, for deformed bars in tension, uncoated, normal-weight concrete, with adequate spacing and/or stirrups}:2:3:4:
Notes: Table A-9.24 Development length in inches, /c, for deformed bars in compression!2:34 1. Values may be multiplied by 0.75 where adequately confined by a spiral or ties (specifically, with a minimum 44-in. spiral at no more than a 4-in. pitch or with No. 4 ties spaced at no more than 4in. on center). 2. Values may be multiplied by the ratio of required steel bar area to provided steel bar area, except in cases where the anchorage is required to reach the yield stress, fy, or in certain high-risk seismic zones. 3. All of the modifications mentioned in Notes 1 and 2 are cumulative; that is, a value may be multiplied by one or more of the applicable modification factors. 4. In any case, the development length for compression, Ij, cannot be less than 8in.
Table A-10.2 Conversions from SI (international system) to inch-pound units
Table A-10.3 Conversions from inch-pound to SI (international system) units
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