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According to modern seismic codes, in certain cases, the vertical component of the ground motion has to be taken into account. However, no specific instructions concerning the structural modelling—and especially the modelling of vertical masses—are provided. The objective of the present paper is the evaluation of alternative structural models of reinforced concrete slabs under vertical seismic excitation. For this purpose, a series of single-storey buildings were analysed by means of linear and nonlinear time-history analysis and the values of representative response quantities were calculated. The influence of several parameters such as the dimensions and the shape of the slabs, the existence of openings, the distribution of the vertical load, the type of the seismic excitations and the analysis method was investigated. The whole evaluation study led to the derivation of useful conclusions.

Storage racks are nonstructural components mainly designed to support the vertical load of goods. During strong external loads such as an earthquake, which acts in the lateral direction of the racks, stored goods become structurally vulnerable. To identify and reinforce the vulnerable parts of storage racks and improve their seismic performance, we developed a viscoelastic damper system with a capacity designed for storage racks. First, we performed an experiment to analyze the behavioral characteristics of a pallet rack — a representative storage rack used for large goods — under vibration. Based on the results of the experiment, we chose the members of storage racks that were vulnerable to vibration. For the proper seismic reinforcement of vulnerable members, we developed a viscoelastic damping system for storage racks by calculating the structural shear force on each floor of the rack and the capacity of the damper to distribute the shear force. First, three viscoelastic dampers of different capacities were fabricated using a viscoelastic material and subjected to cyclic loading tests to evaluate their mechanical performance. We determined the position on which the damper should be placed to improve the rack’s seismic performance by considering the shear force on each floor of the storage rack and its operational characteristics. Finally, we conducted a shaking table test to verify the new viscoelastic damper system. The system improves the seismic performance of storage racks by controlling their elastic and permanent deformations.

In this study, the lateral resistances of mass timber shear walls were investigated for seismic design. The lateral resistances were predicted by kinematic models with mechanical properties of connectors, and compared with experimental data. Four out of 7 shear wall specimens consisted of a single Ply-lam panel and withdrawal-type connectors. Three out of 7 shear wall specimens consisted of two panels made by dividing a single panel in half. The divided panels were connected by 2 or 4 connectors like a single panel before being divided. The applied vertical load was 0, 24, or 120 kN, and the number of connectors for connecting the Ply-lam wall-to-floor was 2 or 4. As a result, the tested data were 6.3 to 52.7% higher than the predicted value by kinematic models, and it means that the lateral resistance can be designed by the behavior of the connector, and the prediction will be safe. The effects of wall-to-wall connectors, wall-to-floor connectors and vertical loads on the shear wall were analyzed with the experimental data.

This study is in the characteristics of a case study. In this study, damage analysis has been made to the Golyazi Apartments Block A building and the causes of the damages were investigated. The building is located in Konya/Turkey. It has some damaged vertical load bearing elements as a result of various effects. The damage was first detected by the residents in September 2018. Creep and axial load analyzes were carried out in the building through ETABS and ANSYS structural analysis programs and crack/damage checks were made analytically for the existing damage situation and for new damages that might occur. At the end of the study, it has been observed in some of the columns in the humid basement of the building that load bearing capacities were exceeded due to creep, axial compressive loads and corrosion effects and severe damages occurred. In addition, ANSYS analysis results coincide with existing building damage. Although no damage occurred in some of the columns of the structure, damage was observed in the same columns in the ANSYS model. This situation might predict the future damage in the building that can happen. Finally, some measures that can be taken as a result of the identified damage situation are presented.

For a laterally loaded pile with its head keyed into the cap, pile head actually rotates in spite of the restraint of the cap. Being aware of this fact, some parameters were put forward to represent the degree of rotational restraint at pile top, and many calculation methods of lateral pile responses were then developed. However, the presented solutions are only for piles under pure lateral loads. In fact, they are usually under the vertical loads simultaneously, caused by the weights of themselves and superstructures. Besides, the slight initial inclination of pile shaft is inevitable in engineering. Some researchers raised solutions of lateral responses of the slightly inclined single pile under combined vertical and lateral loads, but the partially fixed-head condition and the elastoplasticity of soil were not considered. In this study, elastoplastic semi-analytical solutions of lateral responses of the slightly inclined single pile under combined vertical and lateral loads were deduced, in which the rotational restraint coefficient was used to represent the degree of rotational restraint at pile top, and the three-parameter model of the coefficient of subgrade reaction was employed. The computer program was developed thereafter. The effectiveness and advantage of the obtained solutions were validated by the comparison among existing solutions, presented solutions and model test results. Sensitivity analysis was carried out for parameters such as the initial inclination angle of pile shaft, the rotational restraint coefficient, and the vertical load. Eventually, effects of each parameter on lateral pile responses were presented and discussed.

In lunar exploration, flexible metal wheels are designed because the pneumatic tires and rigid wheels are not suitable for crewed lunar rovers. However, the load capacity of the existing flexible metal wheels cannot meet the requirements of heavy load. In this work, an innovative flexible metal wheel consisting of a single rim and twin carcasses was proposed. Firstly, the design method and the detailed structure of this wheel was described. In order to analyze its mechanical performance under different heavy loads, Finite Element Method simulations were conducted based on lunar environment. By vertical load simulation, sheet thickness (1.5 mm) was determined considering elasticity and stiffness. By tangential force and side force simulation, the maximum stresses were respectively obtained as 715.5 MPa and 433.2 MPa, which were less than the yield strength of the spring steel, thus no plastic deformation would occur. Impact simulation showed that the maximum stress of the flexible wheel on the rigid ground exceeded the yield strength of the spring steel, resulting in plastic deformation, while the maximum stress on the soft ground was less than the yield strength and no plastic deformation occurred. Based on these simulations, the flexible metal wheel was fabricated and tested to verify its strength, stiffness, and impact resistance. The wheel exhibited excellent load capacity and elasticity. Finally, the relationship between the test and simulation was analyzed. It is believed that the structure and design process of this new flexible metal wheel are valuable for the subsequent development of heavy flexible metal wheel.

Seismic damage of spatial structures of rectangular plan with RC substructures was observed in several earthquakes, especially in the RC substructures. In order to reduce the seismic damage potential, a new structural configuration of spatial structure of rectangular plan is proposed, the substructures of which are composed of the steel substructure and the RC substructure. The latter only bears the vertical load of roof by the arrangement of horizontal sliding bearings between the roof and the RC substructure. The pushover analyses are performed on a steel braced frame and an RC frame with similar lateral stiffness, and the results show that the lateral capacity of the steel structure is much larger than those of the RC structures. A spatial structure of rectangular plan with two different substructures is designed according to Chinese structural designing codes. Seismic time history analyses are carried out for the spatial structure under five ground motions. The results show that the damage mainly concentrates on the substructures, and the seismic performance of the structure with steel and RC substructures is much better than that of the structure with RC substructures.

The paper presents selected results of tests of full-scale masonry walls linearly supported on a deflecting beam. The walls with thin bed joints and unfilled head joints were 4.55 m long and 2.45 m high, and were made of group 1 calcium silicate masonry units. The tests included walls with and without openings. The tests were carried out in a specially designated and constructed test stand, which allowed simultaneous vertical load on the upper edge of the wall and vertical deflection of the beam supporting this wall. During the test, measurements of mutual displacements of six points on the wall surface were carried out. On both faces of masonry specimens, the changes of the length of the measuring bases connecting these six points were recorded. Walls without openings were detached from the central part of the supporting beam at a deflection not exceeding 2 mm. Walls with one door opening also cracked at an early stage of tests. In this case, a detachment from the supporting beam and cracking at the ends of the lintel occurred because of the rotation of the pillars connected by the lintel above the opening. In walls with two door openings, first cracks were formed at the ends of lintels due to the rotation of pillars with a small deflection of the supporting beam, less than 3 mm. Whereas, in walls with door and window openings, first cracks occurred under the window and at the end of the lintel in the outer pillar of the wall.

Thermal behaviors significantly affect the contact stiffness and position accuracy of the rolling linear guide, which worsen the performance of the precision machinery. In this paper, based on the modified lumped capacitance method (MLCM) and finite element method (FEM), a thermal model of rolling linear guides has been formulated in terms of the geometric parameters, friction, gyroscopic moment, and loading conditions. Experimental results show that the thermal model can well predict the real-time temperature variation under different working conditions. Further analysis shows that, the applied vertical load, carriage velocity, and toque load significantly influence the temperature variation of linear guides, while the influence of the torque load on temperature variation decreases with increasing vertical load levels. Besides, the reasons of the steady-state temperature variation considering the load distribution model are also discussed.

La primera parte de esta investigación presenta un modelo optimizado para cabezales o zapatas rectangulares apoyadas sobre un grupo de pilotes para obtener la superficie mínima en planta (área óptima) que soporta una carga axial y dos momentos sobre el eje X y Y debido a una columna. La presente investigación muestra el diseño óptimo (costo mínimo)para cabezales. Este modelo considera que los cabezales son perfectamente rígidos y los pilotes están articulados en la unión de los cabezales con los pilotes y, por lo tanto, los pilotes transmiten solamente carga vertical. La metodología normalmente utilizada para obtener el diseño de los cabezales considera que todos los pilotes transmiten la misma carga vertical; esto funciona únicamente cuando la columna transmite carga axial y no momentos. Además, cinco tipos de cabezales apoyadas sobre un grupo formado por dos, tres, cuatro, cinco y seis pilotes se muestran para demostrar la precisión del modelo presentado en este documento

Bridge damage often occurs, as a result of damage to the bridge causing financial aspects losses and can also cause fatalities. The causes of the damage various factor, one of which is the bridge structure experiencing fatigue. This fatigue caused the strength of the structure of the bridge to decrease. Bridge damage due to a decrease in the strength of this bridge structure can impact the bridge to collapse. To minimize bridge damage due to a decrease in the strength of the structure of the bridge there is a need for bridge maintenance and to make it easier in terms of maintenance it is necessary to know the pattern of collapse of the existing bridge. In the analysis of this collapse pattern, a waren type steel continous bridge will be modeled with a span length of 120 meters. This analysis is carried out by giving a static vertical load at a reference point on the bridge frame, where the load is increased by multiplying until the structure is demage. The results of the study show that in the waren type continuous steel truss bridge failure occurs at the final portal diagonal element in the 2 middle positions. Based on FEMA 356 displacement target, the level of structural performance shows the bridge model under IO conditions and based on SNI 2833-2008, the actual ductility that occurs has met the requirements.

This paper compared two approaches used to analyze a modular pedestrian pavement made of hexagonal basalt pavers. In presence of occasional heavy traffic roads, the pavement should be verified using methods currently used for road pavements. Different loading conditions were examined varying the geometry of the blocks, and the magnitude of the vertical load. In all cases, the results obtained from the analytical theory of Westergaard were higher than those obtained from a finite element model (FEM). Therefore, a parametric study was performed in order to use the analytical method as an alternative to the costly FEM approach. The results of comparison gave a correction factor, valid for hexagonal pavers: it permits to analytically estimate with good approximation the stresses induced by heavy loads applied to natural stone blocks.

Cold-formed steel (CFS) composite exterior walls are made of cold-formed, thin-walled steel lipped channel studs with board linings on both sides. There are limited data on the structural and thermal performance of CFS composite exterior walls under fire conditions, especially from simulation analysis, in contrast with the data available for interior walls. Therefore, a new simplified model was proposed in this paper to accurately simulate exterior walls exposed to fire on one side; in this model, spring elements were applied to provide out-of-plane constraints different from the constraints of the simplified model for interior walls previously proposed. A discussion of the numerical simulation results of studs with different parameters, including temperature-rise curves, vertical load ratios, screw spacings, steel grades and cross-sectional sizes, was conducted to determine the range of the spring stiffness. Finally, the developed model was validated using the fire test results of two CFS exterior walls, where one had an external panel made of oriented strand boards and the other had an external panel made of autoclaved lightweight concrete boards.

Layered and jointed rock masses are common in underground environments. Honest stability analysis of such rock masses requires the application of discrete element methods, since other methods of analysis are either continuous by nature (FEM), or limited to two block interaction (Voussoir model). In this paper the stability of jointed rock layers is studied using DDA. Two different configurations are studied: 1) single layer-immediate roof; 2) multi-layered roof. The influence of joint spacing and shear strength is inves- tigated and different failure modes are discussed; the kinematics and evolution of deformation are studied in depth. For a single layer configuration it is shown that stable arching is achieved when the shear resistance along joints is sufficient to inhibit inter-block shear and to induce block rotation at the abutments. For a multi- layered configuration it is found that the transition from unstable multi-layer deflection due to vertical load transfer, to stable arching is marked by reduction of differential deflections and homogenization of displace- ment within the stack of layers. The numeric solution is compared with the semi-analytical Voussoir solution, which for the given rock mass structure and mechanical properties, is found to be un-conservative.

This paper presents an experimental assessment into the behaviour of fire-exposed reinforced concrete (RC) beam–column joints with different reinforcement anchorage details subjected to exterior column removal. The thermal response of the RC joint specimens is firstly described, including the development of the temperature fields and the horizontal restraint forces throughout the fire tests as well as the cooling-induced cracking patterns. Subsequently, within the following displacement-controlled push-down tests, the vertical load and horizontal reactions are also monitored. The mechanical behaviour of the test specimens is discussed in detail and a full account of the observed failure modes is provided. Particular attention is given to comparing the experimental axial-moment strength interaction curves with theoretical predictions in order to examine the underlying behavioural mechanisms, with emphasis on the influence of the fire conditions as well as varying anchorages details. Overall, this study provides not only reliable data for the validation and calibration of future numerical and analytical studies, but also forms the basis for practical design of fire-exposed RC frame structures against progressive collapse.

Made available in DSpace on 2019-10-03T17:31:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-08-01. Added 1 bitstream(s) on 2019-10-04T16:20:51Z : No. of bitstreams: 1 S1983-41952019000400884.pdf: 2851790 bytes, checksum: ebaa6507d00b6e0104e34d8fb682dfdf (MD5) Resumo Vigas são submetidas à flexão e cisalhamento, sendo esse último esforço o tema desta pesquisa. O objetivo deste trabalho é analisar especificações para dimensionamento ao esforço cortante de vigas de alvenaria estrutural em blocos de concreto, a partir de extensa avaliação da literatura e de ensaios experimentais aqui relatados. A partir desse escopo, são sugeridas especificações para revisão da normalização brasileira. Na parte teórica, foram considerados trabalhos anteriores tanto nacionais quanto internacionais e as prescrições das normas brasileiras NBR15691-1/2011 e NBR 6118/2014, além da norte-americana, australiana, canadense e europeia, TMS 402/2016, AS3700/2001, CSA S304/2014 e EuroCode 6.1/2001, respectivamente. Com intuito de analisar e validar as especificações da literatura foi realizado um programa experimental de análise de dez vigas de alvenaria com blocos de concreto submetidos principalmente ao esforço cortante. Foram consideradas vigas de duas fiadas, três posições da carga vertical, variando a/d, e duas taxas de armadura transversal. Na análise dos ensaios verificaram-se semelhanças no comportamento último das vigas de alvenaria armada com a teoria proveniente das vigas de concreto armado, com algumas particularidades de fissuração na região das juntas de argamassa. Além disso, as especificações estabelecidas pela norma brasileira e europeia levaram a resultados consideravelmente maiores do que os resultados experimentais, enquanto que os presentes nas normas TMS 402/2016, AS3700/2001, CSA S304/2014 e NBR6118/2014 levam a resultados próximos aos obtidos experimentalmente. Como conclusão pode-se destacar que o padrão de ruptura é semelhante ao esperado para vigas de concreto armado, as fissuras foram condicionadas pela posição do ponto de aplicação do carregamento e pelas juntas de argamassa, o aumento da taxa de armadura transversal levou ao aumento da força cortante de ruptura. Os resultados indicam não ser consistente a consideração de aumento aparente da resistência ao cisalhamento pela relação M ⁄ (V∙d). Eliminando-se essa recomendação, considerando a resistência da alvenaria igual a 0,35 Mpa, limitando a tensão nos estribos a 0,90 de fyk e considerando a contribuição da armadura longitudinal, foi possível estimar o valor de cortante na ruptura de cada viga entre 73% a 106% dos valores verificados nos ensaios. Abstract Beams are subject a flexure and shear, with the last as the theme of this research. The purpose of this paper is to analyze specifications for the shear design of concrete block structural masonry beams, based on an extensive literature review and experimental tests here reported. From this scope, specifications for revision of Brazilian standardization are suggested. In the theoretical part, literature review from both national and international researchers were considered and the specifications of Brazilian standards, in addition to North American, Australian, Canadian and European, ABNT NBR 15961-1/2011, ABNT NBR 6118/2014TMS 402/2016, AS3700/2001, CSA S304/2014 and EuroCode6.1/2001, respectively. To analyze and validate the specifications of the literature, an experimental program was carried out assessing ten concrete block masonry beams results tested mainly to shear loads. Two-course high beams with three vertical load positions (position a/d) and two transverse reinforcement rates were tested. The specifications from the Brazilian and European standards led to considerably higher results than the experimental results, while those presented in the standards TMS 402/2016, AS3700/2001, CSA S304/2014 and NBR6118/2014 lead to results close to those obtained experimentally. As a conclusion, it can be noted that the rupture pattern is similar to that expected for reinforced concrete beams, the cracks were conditioned by the position of the loading point and by the mortar joints positions, the increase in the transverse reinforcement ratio led to an increase in the shear force. Results indicate that the consideration of apparent increase in shear strength by the ratio M ⁄ (V∙d) is not consistent. Eliminating this recommendation, considering the masonry shear strength equal to 0.35 MPa, limiting the stirrups tension to 0.90 of fyk and considering the contribution of the longitudinal reinforcement, it was possible to estimate the shear value at the rupture of each beam between 73% to 106% of the values verified in the tests. Universidade Federal de São Carlos Departamento de Engenharia Civil Universidade Estadual Paulista Departamento de Engenharia Civil Universidade Estadual Paulista Departamento de Engenharia Civil

This research aimed to develop the 3D finite element model of non-pneumatic tire (NPT) for designing the proper radial spoke. The NPT was cut using waterjet cutting technique to prepare the appropriate test specimens. The hyperelastic constitutive models were used to model the deformation behavior of these NPT components. The rebar elements were used to model steel belt layers of the non-pneumatic tire, while the tying equation was used to tie the degree of freedom between belt layers and rubber elements. The NPT model was assigned to contact the rigid surface at the load of 14, 16, 18, 20 and 22 kN. The deformation analysis result of NPT model was compared with the physical experiment which obtained the average error of 9.29 %. The vertical stiffness of the NPT model was 810.66 N/mm; therefore the error was 6.81 % when it was compared to the experimental result. The validated NPT model was then used to search for the proper spoke thickness. The spoke thickness of 5 mm was found to be the proper thickness which given the identical vertical stiffness as the pneumatic tire.

Research on soil-wheel interaction is essential in studies of motion resistance of narrow wheels of agricultural machines. The aim of this research was to study the effects of soil moisture content and tyre inflation pressure on motion resistance of narrow wheels using a locally developed single wheel test rig. A single wheel Test Rig facility was developed at Federal University of Technology, Akure. It consists of a soil bin, carriage, single narrow wheel tester, trolley and drive system. An existing indoor soil bin facility was equipped with a soil bin which dimension was 9.76 m length x 1.98 m width x 0.92 m high. The single-wheel test facility was utilized to investigate the effect of tyre inflation pressure and vertical load on motion resistance of wheel. Two narrow wheels of 90/10-10 in width, IRC MB90 tyre were used as the test wheels on clay soil and were separately installed on a carriage that traversed the length of soil bin. Two inflation pressures of 274 kPa and 380 kPa and four levels of vertical load applied on wheel (i.e. 15, 20, 30, and 40 kg) were examined at two different soil moisture conditions (bulk density of 1.58 g/cm3 and 1.55 g/cm3, soil moisture content of 8% and 10% dry basis and soil penetration resistance of 1.02 MPa and 1.5 MPa). Exponential regression was obtained for the two wheels to check for linearity at different moisture content, R2 value for test wheel 1 with inflation pressure of 270 kPa at 8% moisture content was 0.9974 while that of inflation pressure of 380 kPa at 10% moisture content was 0.9952; also for test wheel two (2) R2 value was 0.9977 and 0.9914 at moisture content of 8% and 10% respectively, this shows for test wheel 1 with inflation pressure of 270 kPa at 8% moisture content showed more motion resistance compared to motion resistance of test wheel 1 at inflation pressure of 380 kPa and 10% moisture content, while for test wheel 2 with inflation pressure of 270 kPa showed low motion resistance at 8% motion content. The effect of different inflation pressures and vertical loads on the motion resistance of the narrow wheels has been investigated under different moisture content (8% and 10%). The contact area for all tests was in the range of 309-330 cm2, average contact pressure increased nearly linearly with increase in vertical load and increase in inflation pressure The research provides data that are relevant in the study of soil-wheel interaction.

To ensure ductile behavior of light frame timber wall elements in the context of capacity design it is indispensable to design non-ductile parts and connections with considerable overstrength. The determination of overstrength values based on reliability methods enables to address different target failure probabilities. A two-step procedure is proposed. First a sensitivity analysis is carried out on 972 wall configurations. Within the configuration the nail diameter, the nail spacing, the sheathing material, the thickness of the sheathing, the arrangement of the sheathing, the length of the wall elements and the vertical load is varied to assess the influence of the varied parameters. Within the sensitivity analysis the overstrength values that ensure the target failure probability P f = 0.04 within the range of P f = 0.023 to P f = 0.067 are determined using first-order reliability methods. The sensitivity analysis shows that the determination of overstrength values for different parameter configurations seems not to be necessary. For the second step the wall configurations that lead to the greatest overstrength values according to first-order reliability methods are identified. For these wall configurations the failure probability is determined using Monte-Carlo-Methods. The failure probability is determined using overstrength values within the range of γ R d = 1.0 to γ R d = 2.6 and minimum dimensions for the main load carrying parts of a timber frame wall element. The overstrength values that leads to an exact failure probability of P f = 0.067 for the wall configurations are determined. The overstrength values determined on the selected wall configurations are used to calculate the failure probability for all 972 wall configurations using Monte-Carlo-Methods. Finally, overstrength values are proposed to achieve ductile failure for all considered wall configurations for a certain level of probability.

The need to cut construction cost of residential and public buildings and provide them with a free and transformable planning structure during their operation cause interest in building wall systems with a large step of bearing walls. In order to reduce labor inputs and increase rate of construction in such building load-bearing system it is also necessary to maximize the use of large-sized prefabricated products and minimize consumption of in-situ concrete. In this case prefabricated products should be substituted according to the conditions of local (regional) construction industry base and volume of in-situ concrete must be sufficient to ensure a complete redistribution of internal forces between elements of the bearing system under load. As for the described bearing wall system of a multi-storey building the paper presents a flat precast solid floor formed by hollow-core slabs and monolithic crossbars supported by load-bearing walls. The hollow-core slabs supported at the ends on cast-in-place crossbars in the planes of bearing walls are arranged in dense groups between cast-in-place braced cross-beams. Dense contacts between overlapping elements are fixed by internal bonds. New data on distribution of forces in floor elements under the action of a vertical load have been obtained on the basis of full-scale tests and existing theoretical assumptions. It has been established that due to this load reactive thrust forces ensuring an operation of every hollow-core slab group in the floor as an effective solid plate supported along the contour have been originated in the floor plane along two main axes. Calculation of the reactive thrust forces makes it possible more accurately to assess a load-bearing capacity and rigidity of the precast solid floor and to increase a step of bearing walls up to 8 m and more while having hollow-core slabs with a thickness of 220 mm.

The aim of this research is to assess the validity of Detailed Micro-Modeling (DMM) as a numerical model for masonry analysis. To achieve this aim, a set of load-displacement curves obtained based on both numerical simulation and experimental results of clay masonry prisms loaded by a vertical load. The finite element method was implemented in DMM for analysis of the experimental clay masonry prism. The finite element software ABAQUS with implicit solver was used to model and analyze the clay masonry prism subjected to a vertical load. The load-displacement relationship of numerical model was found in good agreement with those drawn from experimental results. Evidence shows that load-displacement curvefound from the finite element model has almost the same shape and pattern of the experimental one. The curves in both situations become more and more resembling as the load increasing till they reach failure.

High-performance fiber-reinforced cementitious composite (HPFRCC) has potential to greatly improve the fire resistance and seismic behavior of concrete structures. This paper reports an experimental investigation on post-fire seismic behavior of two-bay two-story frames with HPFRCC joints. Four reinforced concrete frames were fabricated; three of them were tested in compartment fire for 60 min. The fire was regulated following ISO-834 temperature curve. Two different fire scenarios (one- and two-bay fire) were investigated. Two frames were made of monotonic conventional concrete; the other two frames had HPFRCC joints. Each frame was tested under a constant vertical load and a pseudo-static cyclic horizontal load with increased magnitude until the frame failed. The effects of the HPFRCC and fire scenarios on the failure mechanism, hysteretic loops, envelope curve, stiffness degradation, and energy dissipation of the frames were evaluated. The experimental results revealed that the fire exposure reduced the load capacity and deformability of the frames. In the two-bay fire scenario, the use of HPFRCC joints increased the post-fire load capacity by 11%, ultimate deformation by 6%, initial stiffness by 30%, and energy dissipation by 21%. The cyclic behavior of the frame in one-bay fire was better than that in two-bay fire. The frames with HPFRCC joints demonstrated better cyclic behaviors than the virgin reinforced concrete frame.

The critical properties of laminated rubber bearings including the effect of eccentric vertical loading are investigated in this article. The critical load, horizontal critical displacement, and vertical displacement of the laminated rubber bearing including an initial eccentric vertical loading are compared with those of the laminated rubber bearing under axial vertical loading. The comparison results show that the critical load and the horizontal critical displacement decrease with the increase in the eccentricity of the vertical loading when the laminated rubber bearing moves into the side where the vertical load acts (“ positive side”), whereas they increase in the opposite side (“ negative side”). The vertical displacement in the “ positive side” increases with the increase in the eccentricity of the vertical loading, whereas that in the “ negative side” decreases. Moreover, the vertical displacement of the laminated rubber bearing in the “ positive side” is larger than that in the “ negative side.”

Vertical load characteristics used in laboratory repeated load triaxial tests (RLTT) have a significant impact on evaluating unbound granular materials (UGMs) for the flexible road pavements. Many studies and standard testing protocols suggest a diverse range of these characteristics (i.e. stress magnitude, pulse shape type, loading period and rest period). Several studies have been conducted to identify the factors that affect the permanent deformation (PD) and resilient modulus (Mr) of UGMs. However, the effect of the pulse shape types has not yet been investigated. The aim of this study is to experimentally investigate the effect of vertical stress pulse shape type on the PD and Mr behaviour of the UGMs using RLTT. For further assessment, a parametric analysis was also conducted using eight existing PD and Mr constitutive models. Three typical vertical stress pulse shape types were investigated, namely trapezoidal, haversine and triangular, as suggested by several international testing protocols. The results show that tested UGMs, using trapezoidal stress pulse, produced higher PD and lower Mr than haversine and triangular pulses under controlled experimental conditions. As the loading span of the pulse increased, the amount of PD also increased, and Mr decreased. Some of the regression parameters of the investigated constitutive models for both PD and Mr showed correlations with the type of applied stress pulses. Moreover, it was found that the PD and Mr models were material dependent, as a better statistical fit was achieved for the granite than the basalt samples. It is recommended to take extra precautions while adopting a particular type of vertical stress pulse shape as the results may vary widely.

After a fire, underground concrete structures, specifically in subway stations, are often repaired and reused rather than demolished. The mechanical performances of a structure after being exposed to fire require intensive evaluation before a station is reopened. This paper describes the mechanical behavior of a post-fire subway station structure by means of a structural test. A large-scale slab-column/wall structure was exposed to fire. After one of the columns damaged by fire was repaired, a combination of constant vertical load and cyclic lateral load was applied on the repaired structure. A cyclic pushover test was carried out to discover the mechanical behavior of the post-fire structure under soil pressures and service loads. Damage was accumulated as cyclic loadings increased until the structure failed due to shear crushing of the repaired column. The hysteretic loops of the entire structure were thin, indicating that fire exposure decreased the energy dissipation. Results show that the fire caused substantial damage to the structure, resulting in reduced load bearing capacity, deformation capacity, and seismic resistance.

Cold-formed steel-framed walls lined with appropriate sheathing materials are increasingly being used as vertical load bearing systems due to their many benefits. Despite this widespread use, attempts at improving their structural efficiency using either optimised studs or novel sheathing elements have been scarce. Arguably, the sustained use of lipped channel studs and conventional sheathing materials have long forestalled such improvements. Firstly, this study provides experimental evidence on the superior characteristics of the web-stiffened studs, developed specifically for load bearing steel-framed wall applications, and their ability to utilise sheathing restraints to achieve higher axial compression strengths. Secondly, it shows that the use of steel sheathing, either in isolation or together with gypsum plasterboards, significantly increases the strength of the web-stiffened stud. Thirdly, single plasterboard web-stiffened stud walls are found to be highly efficient due to the monolithic nature of the sheathing that leads to greater degrees of composite action between the studs and the sheathing. Finally, it presents a spring based analytical model capable of estimating the failure loads of sheathed web-stiffened studs conveniently. The model particularly focuses on the out-of-plane restraints provided by the sheathing, the contribution of which to the overall strength of the wall has traditionally been considered trivial, but is shown to be substantial in the case of web-stiffened studs. Using the improvements proposed, high capacity steel-framed load bearing walls can be developed with significant material and cost savings.

Influence of vertical load on the adhesion coefficient of automobile wheel in the braking mode on the basis of experimental researches is analyzed. Research results of different authors concerning the degree of the influence of various factors on the adhesion coefficient are presented. It is known that the fundamental basis of vehicle active safety is its braking properties, and the nature of braking depends on the interaction of motorcar tires with road surfaces. Such interaction in the theory of a car is usually described by the adhesion coefficient, which can be implemented both in the longitudinal and transverse directions relative to the rotation area of the vehicle wheels. Experimental researches on rolling car wheel of locking border have demonstrated that a high change of filling speed of the brake chamber does not contribute to increasing the braking efficiency and consequently, the work of the modulator in the mode of intensive filling of brake chamber makes no sense. Vice versa, as experimental researches have demonstrated, the reduction of filling rate of the brake chamber increases the efficiency of braking, although at the initial moment of time, due to the low braking torque, the efficiency is slightly underestimated. Considering the inconsistency of the adhesion coefficient in automotive practice will allow modeling dynamics of vehicle inhibition with automatic regulation systems at a higher level and with greater reliability. Increasing the vehicle mass leads to a decrease in the coupling properties of its tires and consequently to reduce the amount of deceleration, reducing its mass, vice versa increases the coupling properties between the tire and support surface, which positively affects the performance of the vehicle braking (its slowing increases).

Three different types of joints with long bolts were designed and tested in the scenario of column loss. The performance of different joints including flush endplate, extended endplate and stiffened angle under column removal was studied in detail. The investigation was focused on failure modes, formation and developing of catenary action and deformation capacity. The equivalent dynamic response of different joints would also be assessed. The results show that the match of plate thickness and bolt diameter plays an important role in the performance of joint. Relatively thinner plate would help the formation of catenary action. The configuration of flush endplate is more beneficial for the formation of catenary action than extended endplate. By using different connection configuration, the performance of flexural action in joint would affect the contribution of catenary action. The acceptance criteria in DoD and GSA are suitable to assess the rotation related to the first load drop of joints whilst those in FEMA350 is suitable for assess the rotation related to maximum load which represents the anti-collapse behavior of joint. The dynamic amplification coefficient (DAC) suggested by DoD is appropriate if the joint carry vertical load mainly by flexural action. With the influence of catenary action, the DAC would be larger than the values suggested by DoD.

The bearing response of pile foundations for cross-sea bridge subjected to lateral loading is investigated through threedimensional finite element numerical analyses. In the analyses, non-linear behavior of concrete is simulated using smeared cracking model, and the strain-stress relationship of rebar is modeled through perfectly elasto-plastic model obeying Mises yield criterion. The finite element model is validated against published lateral static loading test in situ. The effect of reinforcement ratio of reinforced concrete and vertical load level is explored on the displacement of pile head and lateral capacity of pile. The results show that for the pile with low reinforcement ratio, the allowable lateral capacity is controlled by concrete cracking, however the allowable lateral capacity is controlled by the displacement of pile head with high reinforcement ratio. The vertical load applied on the pile head may reduce its displacement but increase simultaneously the maximum moment in the pile body. Therefore, the optimum vertical load level is 0.4~0.6 times of the vertical ultimate load of a single pile.

The objective of this study is to identify the behavior of the car suspension components subjected to road surface contours. Strain signals were measured by installing a strain gauge at the critical area of the coil spring and lower arm. The car was driven on a flat and rough road surface with speeds of 30–40 km/h and 10–20 km/h, respectively. According to the fatigue life assessments based on the strain-life approach, it was found that when the car was driven on the rough road, the components received higher stresses, contributing to a shorter fatigue life. The fatigue life of the coil spring when being driven on the rough road was 1,248 cycles to failure, which was more than 14 times shorter when being driven on the flat road, with 19,060 cycles to failure. Meanwhile the fatigue life of the lower arm being driven on the rough surface was 3,580 cycles to failure, which was almost 3,328 times shorter when being driven on the flat road, with 11,914,000 cycles to failure. The useful life of the coil spring was more than 625 times lower than the lower arm when driven on the flat road, whereas when driven on the rough road, the useful life of the coil spring was almost 3 times lower than the lower arm. In conclusion, the coil spring will fail more than 2 times faster than the lower arm. This is because the contour of the road surfaces provide a vertical load, directly working the coil spring which reduces the load vertically, while the lower arm functions to hold the load when turning., Fatigue; Strain; Stress; Vibration; Life.

This work examined the behavior of a RC beam on a soil foundation subject to concentrated vertical loads and bending moment in both the elastic and the plastic phases. Some of the simplifie...

Over the last 50 years, research has mainly focused on characterizing the In-Plane behaviour of unreinforced masonry infill walls. Recently, the focus of research has been addressed to understanding Out-of-Plane behaviour, also from the experimental point of view. However, in the experimental campaigns, there is high variability in the geometrical and mechanical properties of URM infill walls and also in the application of Out-of-Plane loads. Therefore, it is important to outline and critically evaluate the major findings obtained by experimental studies and identify research gaps to better understand the differences and the affinity of apparently equivalent tests. In this paper, the extensive literature regarding the Out-of-Plane tests on infill walls has been reviewed with a detailed comparison of the experimental results based on different influencing parameters (slenderness ratio, aspect ratio, boundary conditions, openings, vertical load. In-Plane damage, strength of masonry and plaster, frame stiffness). Based on the study, the main areas that demand further experimental campaigns have been identified and recommended.

In this study, the response of brick masonry specimen subjected to vertical load is analytically calculated using existing formulas and numerically investigated using a popular software ABAQUS. The brick masonry specimen is a small part of the old building which was constructed with brick masonry was taken for analytical and numerical investigation purpose. It consists of three layers of brick and two layers of mortar. The height, width and thickness of the specimen is 245 mm, 220 mm, and 100 mm respectively. Macro and micro model of the specimen was developed using ABAQUS software. The material model used is elastic plastic model C3D8R. Vertical load from 0 to 30.0 kN at interval of 3.0 kN was applied on the specimen. It is very difficult to study the behaviour of brick and mortar together and separately of brick masonry considering the effect of continuity of materials at the joints between brick and mortar. To study the behaviour, macro and micro models are developed and tested upto design load. From the macro and micro models, deflections and strains of brick and mortar upto design load were predicted and these values were compared with analytical calculations. It was found from the investigation, that the increase in strains and deflections are almost proportional to the applied loads.

For civil engineers, the determination of ring footing bearing capacity subject to the combination of inclined and eccentric loading is a great topic of interest. In this paper, a novel approach is proposed to predict the behavior of ring footing subject to combinations of inclined and eccentric loading using the failure envelope approach, which can explain shallow footings behavior. Load eccentricity, inclination angle, and diameter ratio for ring footings are the most effective parameters on the failure envelope. In this regard, a series of experiments were conducted to investigate the behavior of ring footing subject to a possible form of eccentrically inclined loading. Three values of diameter ratio were considered, including n = 0.2, 0.4, and 0.6, along with a circular footing (n = 0). According to the test results, the conical 3D failure envelope and its equation were developed for each type of footing model. With constant vertical load the failure envelopes show that when the eccentricity is increased, the possible inclination angle is decreased. Also, by increasing the vertical loading, the possible eccentricity and inclination angle is decreased. Based on the observations, and obtained failure envelopes for different diameter ratios, when a ring footing is subject to combined eccentric inclined loading, n=0.4 is optimum. In the following, by using the failure envelope, the concepts of critical eccentricity and critical inclination angle were defined in a way that is suitable for studying the stability of ring footings in the V-H-M/B space.

Peak tibial accelerations during running are of interest because of their correlation with vertical ground reaction force load rates and association with running injury. Previous work has demonstrated systematically lower accelerations measured with a bone- compared to skin-mounted accelerometer. However, no studies have assessed the effects of more or less secure attachment methods for skin mounted sensors. Our purpose was to compare two methods of attaching a skin mounted sensor on mean tibial accelerations, stride-to-stride variability, and correlations with vertical load rates. 18 injury-free runners were recruited as participants. An inertial measurement unit, containing a tri-axial accelerometer, was used to record tibial accelerations while participants ran at a self-selected speed on an instrumented treadmill to collect ground reaction forces. The two attachment methods for securing the sensor to the skin were a manufacturer-provided strap (strap condition) and a combination of tape and elastic wraps (wrap condition). Mean vertical accelerations were significantly lower in the wrap condition (p = 0.02, d = 0.57). No differences were detected in resultant accelerations, vertical loading rates, or stride-to-stride variability. Correlations between tibial accelerations and vertical loading rates were strong (r = 0.79–0.91) and similar between conditions. These results provide two key findings of evidence. Evidenced by systematically lower vertical accelerations, a more secure attachment method may be necessary for capturing the most representative measure of tibial accelerations during running. However, a less secure method (i.e. the strap) is sufficient for capturing tibial accelerations as a surrogate for impact loading forces.

Este documento muestra un modelo optimizado para cabezales o zapatas rectangulares apoyadas sobre un grupo de pilotes, con el fin de obtener el área de la superficie mínima en planta que soporta una carga axial y dos momentos en dirección del eje X y Y debido a una columna. Este modelo asume que los cabezales son perfectamente rígidos y los pilotes están articulados en la unión de los cabezales con los pilotes y, por lo tanto, los pilotes transmiten solamente carga vertical. La metodología normalmente utilizada para obtener el área de la superficie en planta de los cabezales se propone de acuerdo con la distribución de los pilotes, tomando en cuenta las especificaciones marcadas por los códigos de construcción. También, cinco tipos de cabezales apoyadas sobre un grupo formado por dos, tres, cuatro, cinco y seis pilotes se muestran para demostrar la exactitud del modelo presentado en este documento.

A simulation model including the cumulative damage caused by structural residual deformation before vertical and longitudinal loading during the ROPS test of the mining truck is established based on the material elastic-plastic mechanics theory and nonlinear finite element analysis method. The finite element model is calculated and analyzed according to the loading requirements of GB/T 17922-2004, and the lateral load displacement curve, the lateral energy absorption displacement curve, the vertical load displacement curve and the longitudinal load displacement curve of the mining truck are obtained. The simulation results are verified by tests, which show that the simulation curves are consistent with the test curves under each working condition. The simulation method is feasible and practical.

Steel grandstands are structures that are frequently used during sport games and many other non-sporting events, such as festivals, music concerts, or even politicians rallies, with participation of a large number of attendees. Unfortunately, the presence of unexpected excessive dynamic loads due to unpredictable behaviour of spectators (e.g. synchronized harmonic jumping or swaying) may lead to serious structural damage or even total collapse of a structure, and such cases were observed in the past. Given that, steel grandstands should be designed so as to withstand the unexpected dynamic loads leading to damage and, therefore, ensure maximum safety for all participants. Building codes, however, apply different approaches. According to the Polish Standard, an additional horizontal load equal to 6% of the total vertical load acting on a grandstand has to be considered at the design stage. The British Standard, on the other hand, specifies a higher value of horizontal load, i.e. 10% of the total vertical load that should be taken into account. Therefore, the aim of the present paper is to conduct a dynamic numerical investigation focused on the response of a steel temporary grandstand subjected to human-induced vibrations due to jumping with two different values of horizontal load (6% and 10% of the total vertical load) as well as for two different bracing elements (typical tubular member and polymer damper). The results of the study clearly show that the response of a temporary steel scaffolding grandstand equipped with two different bracing elements taking into account two different approaches is substantially different.

Conventional analysis of building frames will be made by assuming the bases to be rigid or hinged, whereas buildings rest on soil which allows the bases to displace and rotate. This paper presents the results of static vertical load tests carried out on model building frame supported on pile groups embedded in sand. The experimental results of displacements due to the applied loads on the experimental model have been modeled mathematically, and relevant equations have been developed. The developed equations show very good correlation coefficient which implies that the equations developed can be used to get output obtained from the experiment with fairly well with that of experiments. The present research is an attempt to model the experimental results of various displacements, viz. lateral, vertical, and rotational displacements in case of a building frame resting on group of piles embedded in sand. The developed equations can be utilized as a means to replace the experiment conducted in the laboratory with that of mathematical equations within the limitation of experimental inputs.

The large number of existing masonry bridges still in service in the world roadway and railway networks requires that transportation system managers carry out ordinary and extraordinary maintenance. In many of these networks, the need for increasing the speed and/or weight of the traffic loads also entails the design of strengthening interventions aimed at enhancing the load-carrying capacity of masonry bridges. Among the available techniques for the strengthening of these structures, the use of fiber reinforced cementitious matrix (FRCM) composites has gained popularity due to their advantages with respect to more traditional techniques. More recently, the use of steel fiber reinforced mortars (SFRM), has also been investigated for the strengthening of masonry bridges, with promising results. In this paper, a limit analysis for assessing the vertical load-carrying capacity of single-span bridges strengthened with FRCM or SFRM, applied at the intrados, is described, and calibrated using available experimental results. The document highlights the variables that should be considered in such procedure and also discusses the similarities and differences between the two strengthening techniques. A subsequent parametrical analysis shows that both techniques produce comparable increments in the load carrying capacity of the masonry bridges when compared to unstrengthened conditions. In addition, it was seen that if the finite friction between blocks is not considered when performing the limit analysis of masonry bridges, the ultimate load capacity of the arches can be overestimated as the failure mode can be attained due to shear sliding of the masonry blocks, a hinge mechanism or a combination of both.

Analysis was performed of the effect on the bearing capacity of the ground base supporting a vertical load from a massive structure, and of the segmentation of a prism uplift into sections. Alimit equilibrium method is used for the analysis.

One of the common lateral load resisting systems in multi-story timber buildings in Central Europe are reinforced concrete shear walls. The RC shear walls are not optimal for timber buildings for several reasons such as: (i) the difference in tolerance between concrete and timber construction procedures, (ii) elevated construction time caused by necessary curing of concrete, (iii) moisture of concrete affecting the integrity and mechanical properties of timber, (iv) relatively high shear stiffness resulting in increased forces in seismic design, and (v) eccentricity with regard to applied seismic forces depending on the location of the shear walls. A light-frame timber shear wall (LFTSW) with OSB sheathing stapled to glued-laminated timber framing and strong anchorages has been investigated in this research program to be used as the single lateral load resisting system being located in the perimeter of the building. Results of experiments and numerical calculations showed 20% and 37% increases in shear stiffness and shear resistance, respectively, of the investigated LFTSWs in comparison with established LFTSW configurations. In addition to the conventional racking tests, vertical loads and bending moment were applied to the edge studs in order to study their effect on the in-plane behavior of the investigated LFTSWs. A marginal decrease in shear stiffness and shear resistance was observed due to the vertical load and bending moment applied. The decrease was more significant when applying the vertical loads due to the deformation, to which the staples were exposed, before applying the lateral load. Independent from level and combination of internal forces a ductile behavior was observed experimentally on the investigated LFTSWs, where the failure was governed by ductile displacements in the stapled connection between sheathing and framing.

The RGHLS is a type of diagrid structure that has been developed in recent years. It consist of two columns. The major columns are designed as inclined members in major direction from bottom to top of RGHLS. They sustain the major percentage of vertical loads. The secondary columns have to be segmented in a helical direction in order to form the hyperboloid latticed shells. Secondary columns sustain much less vertical load than major columns. They are more commonly used in purpose-driven structures, such as water towers (to support a large mass), cooling towers, and aesthetic features. The objective of this study is to compare the result of the Model analysis by changing the shape of major and secondary column and also the performance of the structure when the position of the central axis of the structure is varied with respect to its height. The software used for this study is ANSYS. Height on the either side of the horizontal axis is varied and optimum height that exhibit best result is determined.

The multi-story buildings are susceptible to progressive collapse in the event of the removal of one or more columns due to the exposure to blast loads. The lack of structural continuity in precast concrete buildings makes these buildings more vulnerable to progressive collapse as compared to the regular cast-in-situ concrete buildings. This study presents experiments involving two types of detailing of precast beam-column joints using half-scale test specimens when the middle column is suddenly removed. The test specimens represent the most prevalent precast beam-column joints. One conventional cast-in-situ test specimen, having continuous top and bottom beam rebars, was used for comparison. The progressive collapse scenario was simulated by removing the central column support and applying a sudden vertical load on this column at a rate of 100 mm/s until failure. Test results helped in developing better understanding about the progressive collapse potential in the existing precast buildings. This study highlights the need for the rehabilitation of beam-column connections in existing precast buildings and necessitates the need for innovative beam-column connections for improving the progressive collapse resistance.

This paper studies the interaction between an infill masonry wall and its surrounding frame. The investigation is motivated by the lack of experimental data on the interaction regarding the contacted and detached areas between the wall and the frame and the interaction tractions at the contact regions. It is important to note that the interaction between the masonry wall and the surrounding frame plays a critical role in the frame response as it governs the shear and bending moment resultants along the frame elements. It is more critical in the case of strong infill walls surrounded by a relatively weak frame and it may lead to premature failure of the frame at an early stage of loading and affect the overall resistance of the wall-frame system. Such observations were obtained in numerous tests on masonry infilled frames subjected to lateral loading to simulate earthquake loading and in a limited number of tests on masonry infilled frames subjected to a vertical load simulating the case of loss of a supporting column. This paper investigates the interaction behaviour in terms of the infill-frame contact regions and interfacial tractions in such event of loss of a supporting column. In this scenario, the interactive action becomes critical to the structure’s safety against the possible development of progressive collapse. This scenario has gained considerably less attention compared with the behaviour of this system to lateral loading. The main goal of this study is to shed light on the frame-infill wall interaction with focus on the contact zones and the contact pressures between an infill wall and a confining frame. The paper presents a new experimental methodology that follows the interaction between the frame and the infill wall along their common interfaces in order to detect the contact regions and the interaction stresses along these areas as well as their evolution and change during a loading process. The effect of monotonic and cyclic loading patterns on cracking of the infill wall and its impact on the contact regions with the frame and the interfacial tractions are also investigated. The experimental results of this study can support the development of new models that consider the infill-frame interaction and its impact on the structural response.

This paper investigates geometrical effects on the load transfer mechanism of off-ground capped pile groups subjected to vertical load by four three-dimensional numerical simulations, including a circular single pile, an X-shaped cross-sectional concrete (XCC) single pile, a 4 × 4 circular pile group, and a 4 × 4 XCC pile group. The ultimate bearing capacities of the XCC and circular piles within pile groups are approximately 0.86 and 0.74 times that of the XCC and circular single piles, respectively. The group efficiency of the XCC pile group is mainly improved by its side resistance. Comparing the XCC pile group to the circular pile group, the increment in side resistance is almost larger than the increment in pile perimeter, indicating that the pile geometry alters the load transfer mechanism via stress concentration and lateral stress arching. A nonuniform load distribution on piles within a capped pile group causes a bending moment along the pile shafts. The bending moment of XCC piles is smaller than that of circular piles because the raft stiffness of an XCC pile group is increased by its larger circumscribing pile diameter.