Structural Engineering

The aquaculture net cage can provide the living space for fish in larger waves and stronger currents. However, if the fish escapes from the damaged of aquaculture net cage, the wild fish populations will be threated. In this paper, the dynamic model of the circular net was developed in steady current using lumped mass method. In order to validate the numerical model, the deformations of netting were compared with the physical model test and the numerical results by other authors. Then the dynamic result of flexible twine damaged could be obtained by numerical simulation analysis in current. The variety of netting deformation, the tension distribution of the circular net and the force of netting twine connected the floating collar were analyzed. The result show that the flexible twine damaged will lead to the local variable. This study is helpful for the predication of flexible twine damaged through measure the force distribution of floating collar.

Fabric-cast concrete involves casting concrete in forms made with flexible formwork. This provides the potential to produce forms that are both structurally efficient and architecturally exciting in a relatively inexpensive and practical manner. By careful shaping of the fabric it is possible to produce complex shapes that would otherwise be difficult and expensive to produce using conventional formwork systems. This book contains six essays that describe the collaboration between the Universities of Edinburgh and East London, together with the Centre for Architectural and Structural Technology (CAST) at the University of Manitoba, in their detailed and practical research into concrete casting and formwork. Richly illustrated with photographs and diagrams and containing new and innovative research this book offers the architect, engineer and student inspiration and technical guidance in this re-emerging material. Published (publisher's copy) Peer Reviewed

We make every effort to ensure the accuracy and quality of information when it is published. However, we can take no responsibility for the subsequent use of this information, nor for any errors or omissions that it may contain. RIBA Publishing is part of RIBA Enterprises Ltd www.ribaenterprises.com Fabric Formwork was published with the support of the Concrete Centre,

L’articolo presenta i principali risultati di esperimenti eseguiti su nodi trave-pilastro innovativi realizzati con struttura composta acciaio e calcestruzzo. Trattasi di cinque prove in cui altrettanti nodi a due vie in scala reale sono sottoposti a spostamenti pseudo-statici di tipo ciclico tali da indurre una condizione di sollecitazione di tipo sismico. Quattro nodi hanno le travi di tipologia mista acciaio e calcestruzzo ed un nodo e interamente in calcestruzzo armato normale per stabilire utili confronti. Per quanto riguarda i primi quattro, due nodi hanno i pilastri in c.a., un nodo e realizzato con pilastro con camicia di acciaio di sezione quadrata ed infine un nodo ha anche i pilastri in struttura reticolare mista. I risultati ottenuti sono analizzati criticamente e confrontati tra loro per poter trarre utili conclusioni sulla duttilita e sulla resistenza dei nodi innovativi nei confronti delle sollecitazioni di natura sismica.

The paper prosents an efficient numerical model for the inelastic response analysis of R/C panels under cyclic excitations. A plane stress 2d membrane model has been developed that accounts for the concrete and reinforcing steel interaction. The reinforcing bars are modeled as multiple smeared steel layers with an uniaxial stress-strain relation in the bar direction following the Menegotto-Pinto constitutive model with isotropic hardening. The concrete material model is based on damage mechanics with an efficient two parameter damage law. At this stage of the research the bond-slip between concrete and rebars is not taken into account. The new model is validated by comparison with several experimental results on reinforced concrete panels from the literature. The tests are carried out under quasi-static conditions. The accuracy of the model in reproducing the cyclic behavior of reinforced concrete panels with different reinforcement ratio and bar inclination is excellent.

The paper presents a set of 24 lab tests on 12 composite steel truss and concrete beams with inferior precast concrete base completed by second phase concrete cast. The experiments investigate the shear and flexural strengths of the beams with different depth, width and transverse reinforcement inclination. The beams failure modes are studied focusing on the crack patterns and on the interaction between concrete cast at different times. The obtained results are compared with theoretical evaluations of typical resisting mechanisms of steel-concrete composite and reinforced concrete structures using updated European and American design Standards. The main features of the composite steel truss and concrete beams are quantitatively and qualitatively discussed.

When performing the seismic risk assessment of new or existing buildings, the definition of compact indexes able to measure the damaging and safety level of structures is essential, also in view of the economic considerations on buildings rehabilitation. This paper proposes two series of indexes, named, respectively, Global Damage Indexes (GDIs), which are representative of the overall structure performance, and Section Damage Indexes (SDIs), which assess the conditions of reinforced concrete (RC) beam‐column sections. Such indexes are evaluated by means of an efficient numerical model able to perform nonlinear analyses of the RC frame, based on the continuum damage mechanics theory and fiber approach. An improvement of a two‐parameter damage model for concrete, developed by some of the authors, which guarantees a better correlation between the Local Damage Indexes (LDIs) and the material's mechanical characteristics, is also presented. For the reinforcement, a specific LDI, nam...

The anisotropy, plane action and operating time of revolving machinery depend on the performances that identify the signs of faults. Crack is one of the peaks unreliable and insecure faults that reduction working life of component or machine systems, thereby most important to impending injury to person if it is invisible. Crack or cracks existent in a machine or system brings a modification in the mass, damping, and stiffness of the rotor, and subsequently measureable changes seem in the modal things (natural frequencies, modal damping, and mode shapes). Many methods and models have been settled to detect a crack (or cracks) in stationary and rotating systems. Identification of cracks is usually visual inspection; techniques and models are based on vibration-based methods such as destructive method. Optical examination is a time overwhelming method and determining of mode shape as well as structural deflection is tough rather than calculating frequency. Finite Element Analysis of solid shaft such as slant cracked shaft at various rpm is done in this work. Healthy and slant cracked shaft is modeled and analyzed with numerical method. FFT analyzer is used to record the results of vibration, which are used to analyze the vibration characteristics of slant cracks. From the comparison of ANSYS & FFT results 23.03% maximum variations were saw for healthy Shaft & 8.36% to 26.96% increasing variation were saw for 45°to 60°O rientation for 100 mm Crack for Defected Shaft. The investigational results openly exhibit the ability of the recommended methodology for the credentials and position of cracks in fixed and revolving shafts.

This study has been undertaken to examine the feasibility analysis of Industrial waste unlike Foundry sand, Ferromanganese slag and Tyre Chips in Wet Mix Macadam (WMM) by partial replacement to the natural aggregates and stone dust used in WMM. Various mix designs were conducted using different proportions of the Industrial waste and aggregated mix together by partial replacement of industrial waste products to the natural aggregates especially fine aggregates and stone dust. Various laboratory tests i.e. Grain Size Analysis, Standard Proctor Test to determine the MDD and OMC of the mix, Permeability Test, California Bearing ration (CBR) were carried out to analyze the properties of the newly formulated mix in accordance with the conventional mix design of WMM. Further field applications and field results were conducted to analyze the practicability of the mix.

This research project explores the behaviour of laterally loaded piles in two different case studies with 3D FEM. A general understanding of the laterally loaded piles was reviewed with the insights of the behaviour of single pile or pile groups subjected to horizontal loading. This research project explores different method of analysis for laterally loaded piles and how 3D FEM could best be used as a reliable tool to predict the behaviour of the laterally loaded piles. The contribution to knowledge could be better understanding on the mechanism of laterally pile by using 3D FEM. A proper understanding of load transfer mechanism for pile is necessary for analysis and design. The natural of lateral loading can be divided into 'active' loading and 'passive loading' as suggested by Fleming . Reese & Van Impe [15] considered the active loading as 'timedependent or live loading' and passive loading as 'timeindependent or dead loading'. The active loading could be in the form of wind, wave, current, scour, ice, ship impact; and loads from other sources. Whereas, the passive loading, in the form of earth pressure, moving soil and thrusts from dead loading of structures is also noted. A study of several types of analysis method and the soil-structure interaction of laterally loaded pile would show the options and suitability for a practical method. Although many methods had been proposed by researchers to solve such problems, the reliability and uncertainties of such methods are open for discussion. Conventional analytical methods such as Broms' theory, Winkler approach, p-y method and Elasticity theory do require assumptions and empirical data to solve or provide some insights, which can be ambiguous in term of analysis. As such, the 3D FEM is a more reliable and easier tool to study behaviour of laterally loaded piles. The comparison of p-y method and finite element analyses was validated with a case study. The comparison of centrifuge model and finite element analyses was also validated with another case study. Literature review shows that many researchers [1, 4, 8, 9, 18] favour p-y method and they have proposed a lot of improvement or development to it. However, this method uses a p-y curve as an input to a finite difference program for solutions. In the past, the development of p-y curve is based on centrifuged or full-scale experimental data , and the formulation of p-y curve can be characterized under sand and clay. Recent papers from use finite element analysis to generate p-y curve for single pile and pile groups. Their process is rather tedious, but the advantage of p-y method can provide profile of deflection and bending moment of the laterally loaded pile as compared to other methods. But in other means, 3D FEM analysis can better provide better prediction with substantial number of parametric analyses.

Steel fly ash silos are critical components of industrial plants, particularly in the cement and power generation industries, where fly ash is stored for further use or disposal. Due to their height, large mass, and storage capacity, these structures are subjected to various forces, with seismic conditions being one of the most significant considerations for their stability. This paper explores the impact of seismic conditions on steel fly ash silos, focusing on design considerations and guidelines as per IS 1893:2024, which provides the criteria for seismic design of structures in India.

The objective of the study is to determine the flexural behavior of the built-up cold-formed steel (CFS) channel section strengthened with an oriented strand board (OSB) in the three-point bending experiment. CFS with a variety of shapes and grades is classified as a steel-based material and exposed to buckling failure when subjected to compression or flexural load. Thus, the CFS channel section with 100 mm of the web, 50 mm of the flange, 12 mm of the lip, and 1.55 mm of thickness has been selected. Then, the built-up CFS channel section is designed by filling with an OSB between the gap of each section. Channel, face-to-face built-up, and back-to-back built-up CFS sections are three types of tested specimens. From the result and discussion, the specimen with backto-back built-up CFS section is recognized to sustain the ultimate load with the highest value when compared with other specimens.

The high-rise building structure is prone to lateral forces, mainly due to the force generated by the earthquake. In calculating the multilevel building structure there are 2 ways, namely with Open Frame and Open Frame combination with shear wall. The shear wall is a wall that acts as a stiffener and is also a core wall for rigging entire buildings designed to withstand shear forces, lateral forces caused by earthquakes. so that the horizontal deformation (deflection) becomes small. The analysis used in this research is spectrum response analysis based on SNI 1726: 2012. This research has 3 model of set back building which will be reviewed, that is the model of set back building with special moment frame system, the model of backyard building with shear wall of each side and model of set back building with shear wall only on one side. All load inputs, stiffness and structural dimensions are the same, which differ only the special moment frame system model and the sliding wall placem...

An improved 4‐node quadrilateral assumed‐stress hybrid shell element with drilling degrees of freedom is presented. The formulation is based on Hellinger–Reissner variational principle and the shape functions are formulated directly for the 4‐node element. The element has 12 membrane degrees of freedom and 12 bending degrees of freedom. It has 9 independent stress parameters to describe the membrane stress resultant field and 13 independent stress parameters to describe the moment and transverse shear stress resultant field. The formulation encompasses linear stress, linear buckling and linear free vibration problems. The element is validated with standard test cases and is shown to be robust. Numerical results are presented for linear stress, buckling, and free vibration analyses.

While there has been significant research into the behavior of uplifting (or rocking) rigid structures under seismic loading, far less attention has been paid to the behavior of flexible structures allowed to uplift. Recently, however, Acikgoz and DeJong [1] have shown that these types of structures have unique dynamic characteristics that arise from the interaction of rocking motion with elastic vibration. An understanding of the behavior of uplifting flexible structures is required in order to fully benefit from the damage avoidance potential of allowing uplift. This is because building structures are invariably flexible with a finite fundamental frequency, and it is the desire of the structural designer that the structures themselves remain elastic, even while displaying non-linear behavior in a global sense. This paper is concerned with the behavior of flexible uplifting structures adapted with slip-friction devices. These devices act as hold-down connectors resisting overturning moment. They have a definite force threshold at which sliding will occur, and exhibit close to perfect elasto-plastic behavior. The ability of shear walls to avoid damage through the use of slip-friction connectors has been previously demonstrated by Loo et al. [2]. The modeling of the slip-friction connectors, using a combination of elements commonly available in finite element software packages, and their verification is discussed. Both single-degree-of-freedom (SDOF) and multi-degree-of-freedom (MDOF) flexible structures were modeled with a single plastic deformable hinge at their bases, and their behavior under various earthquake simulations investigated. These flexible structures (both SDOF and MDOF) were then affixed at their bases to a rigid platform, with slip-friction connectors implemented at the ends of the platform, and then subjected to the same earthquake simulations. It was found that the maximum drifts of structures with slipfriction connectors compared favorably with their equivalent structures with a single plastic deformable hinge. With a small amount of vertical load, residual drifts were also found to be small. The performance of MDOF structures with slip-friction connectors was somewhat superior to that of the SDOF structures, with maximum drifts and residual drifts smaller than that of comparable SDOF structures.

Investigations of the effects of strong vertical ground motions on structures have been gaining more attention in recent years. Many researchers have found that the assumptions in current design codes underestimate the significance of vertical excitations, especially in near-source earthquake events. Several numerical analyses have been conducted to investigate these effects. However, not many experimental works have been done. In this paper, a bridge model was excited simultaneously in the horizontal and vertical directions through a series of shake table tests. The bridge model was fixed to the base of the shake table. The seismic responses of the bridge structure in the longitudinal direction are discussed. It was found that the inclusion of vertical excitation can significantly increase the bending moment demand of the bridge deck and the development of axial force and plastic hinging in the bridge piers. However, the bending moment demand in the bridge piers have not been greatly affected by the vertical excitations.

The use of fragility curves in the design of bridges is becoming common these days. In this study, experimental data have been used to develop fragility curves for the potential of girder unseating of a three-segment bridge and a bridge-abutment system including the influence of spatially varying ground motions, pounding, and abutment movement. The ground excitations were simulated based on the design spectra for different soil conditions. The Newmarket Viaduct replacement bridge in Auckland was used as the prototype bridge. These fragility curves were also applied to the 2010 Darfield and 2011 Christchurch earthquakes. The study showed that for bridges with similar characteristics as the chosen prototype and with similar fundamental frequencies, pounding could increase the probability of girder unseating by up to 35% and 30% based on the AASHTO and NZTA seating length requirements, respectively. The assumption of uniform ground excitations in many design practices, such as the NZTA requirements, could potentially be disastrous as girders might have a very good chance of unseating (as much as 53% higher chances when considering spatial variation of ground motions) even when they are designed not to. In the case of superstructures with dissimilar frequencies, the assumption of fixed abutments could significantly overestimate the girder unseating potential when pounding was ignored and underestimate the chances when pounding was considered. Bridges subjected to spatially varying ground excitations simulated based on the New Zealand design spectra for soft soil conditions with weak correlation shows the highest chances of girders falling off, of up to 65% greater than for shallow soil excitations.

The gravity load will reduce the shear strength of a steel shear wall (SSW) under a wind load or an earthquake load. However, this effect is not considered in practice and may lead to potential danger. In this work, three assumed distributions of vertical stress due to the gravity load, i.e. 1) cosine distribution, 2) effective width model and 3) three-segment distribution, were considered. The stress throughout the inclined tensile strip, considering the effect of different vertical stress distributions, is determined using the Von Mises yield criterion. The shear strength is calculated by integrating the shear stress along the width. To evaluate the proposed approach with different vertical stress distributions a finite element model using the software LS-DYNA is developed. The results show that the three-segment distribution is able to describe the effect of gravity load of the SSWs of different aspect ratios and slenderness ratios, while that of the cosine distribution and the effective width model will underestimate the shear strength.

This paper focuses on the flexural performance of flax fibre reinforced polymer (FFRP) tubes confined coconut fibre reinforced concrete (CFRC) composites. In total, six 520 mm long cylindrical specimens with a mechanical bond between CFRC and FFRP tube were constructed. Two configurations were considered: 1). CFRC core confined by a single outer FFRP tube; 2). CFRC filled double FFRP tubes, and the inner tube was placed along the centre line of the cylinder beam. In the third point bending test, the maximum load, flexural deformation and outer tube strains in the longitudinal and hoop directions were measured. It was found that the double tube specimens possessed excellent flexural characteristics, in comparison to the single tube specimens.

Observations from past earthquake events indicate that skewed bridges are seismically vulnerable due to induced horizontal inplane rotations of the girder. To date, however, very limited experimental research has been done on the pounding behaviour of skewed bridges. In this study, shake table tests were performed on a single-frame bridge model with adjacent abutments subjected to uniform ground excitations. Bridges with different skew angles, i.e., 0 °, 30 °, and 45 °, were considered. e pounding behaviour was observed using a pair of pounding and measuring heads. e results reveal that poundings could indeed influence the responses of skewed bridges in the longitudinal and transverse directions differently and thus affect the development of the girder rotations. Ignoring pounding effects, the 30 °skewed bridges could experience more girder rotations than the 45 °skewed bridges. With pounding, the bridges with a large skew angle could suffer more opening girder displacements than straight bridges.

Early detection of tooth cracks is crucial for effective condition-based monitoring and decision making. The scope of this work was to bring more insight into the vibration behavior of spur gears in the presence of single and multiple simultaneous tooth cracks. The investigation was conducted in both time and frequency domains. A finite element analysis was performed to determine the variation in stiffness with respect to the angular position for different combinations of crack lengths. A simplified nonlinear lumped parameter model of a one-stage gearbox with six degrees of freedom was then developed to simulate the vibration response of faulty external spur gears. Four different multiple-crack scenarios were proposed and studied. The performances of various statistical fault detection indicators were considered and investigated. The simulation results obtained via MATLAB indicated that, as the severity of a single crack increases, the values of the time domain statistical indicator...

The earthquake attenuation behaviour is a critical part of seismic hazard modelling for regions of low and moderate seismicity. This paper presents a new approach for attenuation modelling, which does not involve the use of strong motion data, and is based on taking measurements of the shear wave velocity (SWV) in bedrock by a noninvasive technique to characterize the transmission of seismic waves. The developed filters are then applied to the generic source model for intraplate earthquakes for calculating the frequency content of seismic waves at the bedrock surface and was used as input to soil response analyses for the determination of site seismic hazard. Ground motion parameters and response spectra are then obtained from the stochastically simulated accelerograms to develop representative attenuation models for rock conditions. The described approach of obtaining a seismic attenuation relationship based on modelling the rock and soil crustal properties is not constrained to an...

Modeling of optimized flexible four bar mechanism considering joint clearances are developed at first. The dynamic analysis such as Moment, Torque, Energy and structural analysis such as Deformation, different mode of Stress are done by considering load in coupler point of optimized flexible four bar linkage. The deformation and stress are compared by considering different materials. Lagrange's equation is used to define the direction of the joint clearance. Differential evolution algorithm is used to optimize the length of links which reduce the gap between the desirable and actual path.

The experimental study of vibrating plates having simply-supported boundary conditions can be difficult to achieve due to the complexity of preventing translation, but allowing rotation along all boundaries simultaneously. Only a few methods have been proposed, but all are either time-consuming to set up and involve customization of the test rig for each plate or do not allow the plate to be reused for other purposes. The method described in this paper offers a low-cost, simple, accurate and non-destructive way of experimentally measuring the modal properties of thin, simply supported plates and can be used for quick validations of models and designs without modification for multiple trials and varying plate properties. The key attributes of this method include: An adjustable sliding support frame which can be made of a distinct material from the plate and which can accommodate variations in plate geometry and properties without modification. Removable flexible sealant applied in a v-groove on the supporting frame which can be easily used to fix and support the plate according to the simply-supported boundary conditions. A low-profile design, which can be used to accommodate most experimental testing methods for determining modal properties of vibrating plates.

Проведено прогнозирование уст алост ной долговечности сварных коробчатых конструкций. Результаты расчет а уст алост ной долговечности с использованием аналитической схемы, базирующейся на объемном методе, хорошо согласуются с соответствующими экспери ментальными данными.

Arms of excavators are often made from box-beams, welded of steel plates. This work considers the problem of fatigue and fracture of welded parts of the excavator arm. Necessary data for fatigue tests of arm box beams include chemical composition, microstructure of steel and welds, as well as their mechanical properties and fatigue behaviour.

In order to estimate the seismic demand by using the nonlinear static procedure, different approximate methods have been developed. One of the most useful methods is called displacement coefficient method (DCM), which is based on some modification factors. One of these coefficients denoted 1 C , concerns the inelastic deformation ratio and usually depends on either the yield-strength reduction factor or the ductility factor. In general the evaluation of the inelastic deformation ratio is based on the response of single degree of freedom (SDOF) systems, where the response of the structure is mainly controlled by the fundamental mode, knowing that the inelastic deformation ratio will not capture the contribution of higher modes in the overall structural response. A developed theoretical approach with the aim of estimating the inelastic deformation ratio for structures, considering contribution of higher modes of vibration, is introduced. In this assessment, the normalized yield strength coefficient (η) and the post-to-preyield stiffness ratio (α) are key factors. The results are compared to the uncoupled modal response history analysis (UMRHA) procedure and some existing formulations for a nine story building subjected to the El Centro 1940 ground motion. It appears that the new theoretical approach leads to enough accurate estimation of the inelastic deformation ratio compared to the UMRHA one.

Corrosion is one of the major causes of damage in offshore and onshore pipes. Based on the double circular arc (DCA) model and the average shear stress yield (ASSY) criterion for isotropic hardening materials, a new burst pressure equation for corroded pipes is developed in this paper. The ASSY criterion is a weighted average of the maximum shear stress and the octahedral shear stress and it is adopted to predict the burst pressure of the pipelines with corrosion defects. The accuracy of our predictive equations is validated respectively by both the ideal and corroded pipes. Firstly, the burst pressure equation of a corroded pipe is degraded into an ideal pipe's. Then we compare the calculated results with the full-scale experimental data. The calculated results are consistent with the experimental data for the ideal pipes. Again, we make a comparison of the predicted burst pressures of corroded pipes with the ones from the elastic-plastic finite element method (FEM) and the experiment. The calculated results show a good agreement with the numerical calculations and experimental data for the corroded pipes. Our research reveals that the corrosion defects can decrease the burst pressure for a pipe; the yield criterion and the strain hardening exponent are crucial to accurately capture the burst pressure. Our research is beneficial to evaluate the integrity of the corroded pipes.

The subject of the study the possibility of applying the finite element method to determine the bearing capacity of a damaged reinforced concrete structure and the subsequent selection of its reinforcement parameters with composite materials.<br><br>Research methodology – the studying of finite element models of the serviceable destroyed and restored structure and determination of design parameters of the structure before destruction, after the destruction, and after its strengthening.<br><br>The goal – identification of the possibility of further operation of the damaged structure using the finite element method, finding the most dangerous places in the construction, selection of parameters for its amplification.<br><br>Conclusion of the study – The proposed research method made it possible to more accurately and at a lower cost, identify the most dangerous areas in the damaged structure, and verify the effectiveness of the applied method of its ...

The subject of the study. The work investigated the deformative, strength, and cost parameters of concrete beams with various reinforcement types. The nature of the behavior under a load of beams reinforced with steel reinforcement and beams with basalt reinforcement of multiple diameters has been studied. A research methodology is the studying of finite element models of the reinforced concrete beam. The Drucker-Prager model was used to simulate concrete behavior. For steel reinforcement, a bilinear isotropic hardening model, a linear orthotropic model was used for composite reinforcement. The goal is to reveal the advantages and disadvantages of using basalt composite reinforcement in reinforced concrete. Conclusion of the study. The paper considers the behavior of four models of reinforced beams. In the first model, a control one, steel reinforcement, is used. In the second, the composite reinforcement diameter is equal to the diameter of the steel one. In the third model, the di...

талевої робочої арматури 3AE12 А400С контрольної серії БМ-1 на 2,78%, показали підвищення межі міцності балок на 3,51%; при гібридному армуванні розтягнутої зони згинальних бетонних елементів робочою склопластиковою арматурою 2AE14 АКС 800 і металевою AE12 А400С (серія БМС-7), з загальною площею, що перевищує площу металевої робочої арматури 3AE12 А400С контрольної серії БМ-1 на 10,85%, можна досягти підвищення межі міцності балок на 11,23%. В подальшому планується порівняти отримані експериментальні результати показників міцності дослідних балок з розрахунковими значеннями визначеними за діючою нормативною методикою. 1. Валовой О.І. Виготовлення будівельних конструкцій армованих металевою і склопластиковою арматурою з бетонів на відходах гірничо-збагачувальних комбінатів / О. І.

10. Тімченко Р. О. Обґрунтування вибору лінійної моделі регресії у плануванні експерименту для вирішення поставленого експериментального завдання / Р. О. Тимченко, Д. А. Крішко, Л. В. Кадол, В. О. Савенко // М істобудування та територіальне планування -К.: КНУБА, 2016. -Вип. 59 -С. 425-431. 11. Тимченко Р. А. Оптимизация конструктивного решения подпорной стены специального типа на основании линейной модели регрессии / Р. А. Тимченко., Д. А. Кришко, В. О. Савенко // Вісник КНУ. -Кривий Ріг: КНУ, 2016. -Вип. 41. -С. 54-58. 12. Тімченко Р. О. Застосування программ заснованих на методі скінченних елементів (М СЕ) для моделювання роботи системи «основа-інженерна споруда» / Р. О. Тімченко, Д. А. Крішко, В. О. Савенко // Строительство, материаловедение, машиностроение (сб. научн. трудов). -Д., ГВУЗ ПГАСА, 2016. -С. 143-148. 13. Особенности конструктивного решения массивной подпорной стенки для неблагоприятных территорий / Р. А Тимченко, Д. А. Кришко, О. В. Субота, О. С. Мокшина //Вісник КТУ. -Кривий Ріг: КТУ, 2007. -Вип. 16. -С. 136-139. Рукопис подано до редакції 19.03.17

The axle shaft wheel is the drive wheel shaft which functions to transmit power from the differential to the wheel. The rear wheels generally support heavier loads than the front wheels, consequently the wheel drive shaft construction is also relatively stronger. The method used was FEM with the help of ANSYS software. Based on the simulation results obtained the greatest stress value at Maximum principal stress is 365.02 Mpa. The results of crack analysis obtained J-Integral of 7,319 x 10 -7 and based on the SIFS value (K1) showed the crack intensity every 1 mm2 was 0.34317 Mpa. material safety factor was 1.51 which indicates that the material is in good category. Means the fracture of the rear axle shaft occurs because of other factors between caused by a momentary shock load that is large enough or defective due to the fabrication process.

Gempa bumi memiliki efek primer seperti kerusakan pada struktur bangunan, salah satu cara yang dapat dilakukan untuk memperkuat struktur bangunan dari gedung bertingkat dengan menambahkan pengaku pada struktur. Untuk mempertahankan mekanisme penahan lateral, sistem dinding geser maupun sambungan balok harus cukup kuat ketika beban terjadi. Dengan adanya beban yang bekerja maka akan terjadi tegangan dan regangan pada sebuah dinding geser. Dalam melakukan analisa tegangan-regangan dinding geser dilakukan dua model dinding geser yaitu free standing shear wall dan couple shear wall dengan menggunakan pemodelan finite element. Dalam pemodelan tersebut akan memasukan beban vertical dan beban lateral. Dari hasil pemodelan yang telah dilakukan diperoleh nilai tegangan dan regangan couple shear wall lebih besar dibandingkan free standing shear wall yaitu untuk tegangan 16680 kN/m2 dan untuk regangan 9,8x105. Sehingga dapat disimpulkan dari hubungan tegangan regangan bahwa couple shear wall l...

Outrigger structural systems are quite effective using the lateral loads on tall buildings, one of the main benefits of utilization outrigger is that it can reduce deformation and the danger of inter-story drift caused by lateral loads acting on the building. In this case, wind loads will be viewed as a lateral load because the wind load acting on tall buildings can also cause deformation of the building. The implementation of the outrigger system is viewed from different positions to see the deformation that occurs and the placement of the maximum location. The results of the analysis of wind loads reviewed on these buildings have proven that the use of outriggers in buildings can reduce displacement by 19.58%, and inter-storey drifts by 13.24%, which is applied in a position of ½ of the building height. The optimum location of the outrigger installation can also be determined by calculating the analysis of the maximum deflection that occurs on the 40th floor.

Flooding is a natural occurrence hazardous to people and properties and produces environmental and economic losses, especially in flood-prone areas. This study will be used to assess flood risk in the Bangko and Masjid watersheds. To analyze it, flood hazard mapping is arranged by slope, land cover, elevation, rainfall, buffer zone, and soil type, which is done with the help of a Geographic Information System (GIS), specifically QuantumGIS (QGIS). This system tool assesses each variable utilizing satellite spatial data and categorizes the vulnerability being very high, high, medium, low, and very low. Each map arrangement value is combined using an overlay value to determine the flood susceptibility. According to the mapping results, the Bangko and Masjid watersheds are highly vulnerable to flooding. Based on the results of the mapping, in the Bangko watershed 61% of the total area is vulnerable to flooding, and 20% has high to very high vulnerability, while in the Mosque watershed ...

Within the framework of a comprehensive research study of high strength concrete (HSC), the impact response of concrete plate specimens with variable strengths and different reinforcement was tested. The response of a structural concrete element under impact, involves the development of scabbing fragments at its back side, which reduces its effectiveness as a protective element. This well known phenomenon is expected to be more severe in HSC plates, because of the material relatively high brittleness. Consequently, various ways are examined in order to enhance the ductility of HSC elements. One possible direction is to use fibers or wire mesh reinforcement. The experimental study described herein utilized 40 x 40 cm concrete plate specimens, with variable thickness, strength, and reinforcement. By comparing the response of these plates to an impacting projectile, the effects of concrete strength and of the reinforcement were studied. The cylindrical steel projectile, weighed 118 gr, and had a conical nose with a 1.4 aspect ratio. The tests were conducted in a recently developed impact laboratory, where two gas guns were installed. In the current series of tests the projectile was accelerated by the release of compressed air to velocities of about 145 m/sec, measured by an electro-optical device. This paper describes the different levels of damage that were observed in the different specimens, focusing on the influence of the concrete strength and of the reinforcement, on the response.

This study focuses on a RC building with flat slabs that were designed according to current standards. A scenario of a slab with failed connections that is detached from its supporting columns and is falling downward is considered, and the impact results with the slab underneath are assessed. The suitability of the standards design criteria to provide safe design against impact loading is evaluated. It was found that larger span slabs experience heavier damage. Falling from a floor height and from a quarter floor height are analyzed and the damage results of these impacts are examined. At the lower impact velocity, the concrete slab surrounding the column undergoes major damage and shear deformations; In the case of a relatively short span slab, the rebars undergo large plastic deformations and almost reach the ultimate strain, such that a slightly higher impact velocity would cause rebars fracture and total failure of the slab-column connection. In the case of high impact velocity, the concrete in the slab around the column is fully crashed and the longitudinal and the bent up rebars are ruptured. The yield of the rebars occurs within a few milliseconds. During this extremely short time the impacted slab hardly starts developing its downward displacement. The impacted slab responds like a rigid body with severe damage concentration at the slab-column connection region. Different parameters affecting the slabs dynamic response are examined, and new insight is gained on the complex impact response of flat RC slabs. This study finds that the current design standards that are based on static loading considerations do not provide resilience to flat slab connections that are subjected to impact loading and therefore cannot prevent a progressive collapse scenario.

Cracking is an inherent characteristic of a reinforced-concrete (RC) element subjected to tension or bending. The crack width growth with loading depends on the rebar-concrete bond behavior. RC bridges are designed under strict requirements to ensure their proper long lifetime performance. Limiting the crack widths improves the performance and safety of bridges that are exposed to harsh climatic and environmental effects and enhances bridge service life-cycle expectancy. This paper presents an extended one-dimensional formulation for analyzing RC elements subjected to tensile loads and solves the one-dimensional tension stiffening problem. The extended bond-slip model analyses the entire range of loading, following cracks growth up to their maximum allowed width, employing a bi-linear bond-slip relationship. The analytical solution refers to the early loading stage where the first bond-slip segment governs the entire element and a closed form solution is obtained, followed by the higher loading stage where two different bond-slip relationships govern two complementary segments of the element. Analytical expressions for the stresses, strains, and displacements in concrete, steel, and interface are developed. Cracking is followed until rebar yielding. Validation of the model with available test results shows good agreement that is superior to the commonly used linear bond-slip model.

A parameter analysis is performed on an analytical penetration model which has been recently developed. Figures are plotted to show how the disturbed zone size, parameters of displacement and stress fields and dynamic section pressure are dependent on soil compressibility, shear strength and mass density. Main results are presented and discussed.

RC flat slabs supported by an array of columns subjected to the action of impulsive pressure were investigated. The slabs were designed for static loads according to current standards. The dynamic responses of 4 × 4-and 8 × 8-column-supported slabs were similar, as were damage and failure. A simplified model consisting of a tributary area and a central column yielded similar results, demonstrating the accuracy of the simplified model and its reliability. These analyses exhibited modes of damage and failure characterized by large shear distortions in the slab-column connection zone. The rest of the span remained undamaged and in a horizontal position. In all analyses, the slab concrete around the column was fully damaged. The rebars failed within a limited zone at the slab-column connections. The early failure of integrity reinforcement indicated that it could not fulfill its duty; thus, a subsequent progressive collapse scenario was inevitable. All bent-up rebars failed, and their contribution to shear resistance was doubtful. The static analysis was entirely different from the dynamic failure mode. Impulsive loading damage and failure were similar to those in the case of slab-on-slab impact; in both cases, the slab underwent large displacement and severe damage in the narrow slab-column zone, whereas the rest of the slab remained almost completely flat and undamaged.

This paper presents results of the first stage of an experimental research program on the pounding response of adjacent concrete structures during earthquake. It shows experimental results for longitudinal impact of concrete rods. The impact of concrete to concrete surfaces of the rods was studied and the coefficient of restitution was experimentally determined. Acceleration time histories were recorded and characteristics of the impact pulse was determined. The study was extended to include filling materials that had been placed in the joint between the impacting concrete surfaces to study their effect on the impact.

The elasto-plastic theory of a shallow two bar truss is developed. The behavior of this structural system under tension loading or compression loading is formulated, as well as for reversal loading, where the structure undergoes loading, unloading and reloading. The simple straightforward expressions enable one to correlate the external work to the central displacement and follow the elasto-plastic stresses and strains in the bars along the loading history.

Crack width is a major performance criterion in reinforced-concrete structures, in general, and is of utmost importance in ensuring bridge performance, in particular. A reliable theory-based method is required to assess crack widths and gain insight into their dependence on material, geometry, and loading parameters. A new, exact analytical method is proposed for a one-dimensional reinforced concrete element based on equilibrium, constitutive, and kinematic relationships, accounting for the geometrical and material behavior of the concrete and reinforcement. A linear interfacial bond stress slip is assumed to represents the small slips associated with the limited allowed crack width. Closed-form expressions have been developed and a wealth of information can be calculated immediately, such as the cracking load levels, the crack width dependence on the load level, the expected number of cracks, and the cracks spacing. The entire nonlinear force-displacement relationship of a cracked reinforced-concrete element may be depicted, demonstrating the tensionstiffening behavior that depends on the variations in the crack width throughout the loading history. Comparisons of the model with experimental data demonstrate very good agreement.

Nesse trabalho apresenta-se um estudo comparativo entre os sistemas de estabilizações verticais em pórticos rígidos e os sistemas em treliças em `K' e em `X'. A eficiência estrutural é analisada através do relacionamento entre o número de pavimentos com os deslocamentos horizontais, esforços solicitantes e os perfis adotados no dimensionamento dos modelos. Nos sistemas rígidos, os esforços solicitantes e os deslocamentos horizontais são maiores do que nos sistemas contraventados. Nesse caso, leva-se a estruturas mais pesadas e, portanto, menos econômicas. A partir de 24 pavimentos, para se garantirem deslocamentos aceitáveis nos modelos rígidos, a rigidez necessária do sistema fica impraticável. Usaram-se as teorias linear e não-linear (Efeito P-delta) para análise comparativa dos modelos adotados. Nesse contexto, verificou-se que a análise não-linear é fundamental para os modelos com maior número de pavimentos, pois proporciona resultados de esforços e deslocamentos mais co...

A welded steel moment-frame building is used to assess performancebased engineering guidelines. The full-scale four-story building was shaken to collapse on the E-Defense shake table in Japan. The collapse mode was a side-sway mechanism in the first story, which occurred in spite of a strongcolumn and weak-beam design. Computer analyses were conducted to simulate the building response during the experiment. The building was then evaluated using the Seismic Rehabilitation of Existing Buildings (ASCE-41) and Seismic Evaluation and Upgrade Criteria for Existing Welded Steel for the collapse prevention performance level via linear and nonlinear procedures. The guidelines had mixed results regarding the characterization of collapse, and no single approach was superior. They mostly erred on the safe side by predicting collapse at shaking intensities less than that in the experiment. Recommendations are made for guideline improvements.