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1.
Avigdor Rutenberg 《Bulletin of Earthquake Engineering》2013,11(5):1727-1751
Effect of higher vibration modes on the seismic shear demand of reinforced concrete cantilever walls has been studied since the 1970’s. The shear amplification becomes more important with increasing fundamental period (tall buildings) and increasing ductility demand (R or q factors). Yet, studying the relevant recommendations of structural engineering researchers and provisions of various seismic codes reveals that there is no consensus regarding the extent of shear amplification and of the inter-wall distribution of shear demand in structural systems comprising walls of different lengths. The paper presents the available formulas for predicting shear amplification in ductile walls and dual systems (wall-frames). One effect that impacts the shear amplification is shear cracking mainly in the plastic hinge zone of the wall near the base leading to appreciably lower shear amplification than previously predicted. Post yield shear redistribution among interconnected unequal walls is also addressed. Finally, an extensive bibliography is provided. 相似文献
2.
The reinforced concrete (RC) shear wall serves as one of the most important components sustaining lateral seismic forces. Although they allow advanced seismic performance to be achieved, RC shear walls are rather difficult to repair once the physical plastic hinge at the bottom part has been formed. To overcome this, a damage‐controllable plastic hinge with a large energy dissipation capacity is developed herein, in which the sectional forces are decoupled and sustained separately by different components. The components sustaining the axial and the shear forces all remain elastic even under a rarely occurred earthquake, while the bending components yield and dissipate seismic energy during a design‐level earthquake. This design makes the behavior of the system more predictable and thus more easily customizable to different performance demands. Moreover, the energy dissipation components can be conveniently replaced to fully restore the occupancy function of a building. To examine the seismic behavior of the newly developed component, 3 one third‐scale specimens were tested quasi‐statically, including 1 RC wall complying with the current design codes of China and 2 installed with the damage‐controllable plastic hinges. Each wall was designed to have the same strength. The experimental results demonstrated that the plastic‐hinge‐supported walls had a better energy dissipation capacity and damage controllability than the RC specimen. Both achieved drift ratios greater than 3% under a steadily increasing lateral force. 相似文献
3.
Unstiffened steel plate shear walls (SPSWs) are used as lateral load‐resisting systems in building structures. The energy dissipation mechanism of SPSWs consists of the tension yielding of web plates and the formation of plastic hinges at the ends of horizontal boundary elements. However, vertical boundary elements (VBEs) of high‐rise SPSWs may experience high axial forces under lateral loading. This study explores the effectiveness of staggering of web plates on the reduction of VBE forces and drift response of SPSWs during an earthquake event. An analytical study has been conducted to determine the base shear reduction factor so as to match the overstrength of staggered systems with conventional SPSWs. A design methodology has been proposed for staggered SPSWs. Six‐, 9‐, and 20‐storey staggered and conventional SPSWs with varying aspect ratios are considered in this study to compare their seismic response. These study frames are modelled and analysed in OpenSEES platform. Nonlinear static and dynamic analyses are performed to compare the drift response, hinge mechanisms, and steel tonnage. Staggered SPSWs showed uniform drift distribution and reduction in interstorey drift and axial force demand on the VBEs. 相似文献
4.
Higher mode effects in frame pin‐supported wall structure by using a distributed parameter model 
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下载免费PDF全文 Frame pin‐supported wall structure is a kind of rocking structure, which releases constraints at the bottom of the wall. The wall is affiliated to the frame and can rotate around the hinge. Previous studies have investigated seismic performance (such as deformation pattern and plastic hinge distribution) of frame pin‐supported wall structure. Strength demand of this system was investigated through static pushover analysis. However, dynamic characteristics, especially higher mode effects, remain to be quantified. As demonstrated in several researches, higher mode effects have non‐negligible effects on seismic response. For this purpose, a distributed model for analyzing higher mode effects in frame pin‐supported wall structure was proposed, where the pin‐supported wall and the frame were simplified as a bending beam and a shear beam, respectively. The model was solved by differential equations derived from equilibrium and compatibility. Displacement and inner force distribution of frame pin‐supported wall structure in higher modes were quantified according to the model. Influence of critical parameters, such as wall stiffness and structure period, was assessed on higher mode effects. It was demonstrated that response in higher modes cannot be neglected in the design of frame pin‐supported wall structure. Capacity design based on the fundamental mode is not conservative, especially in the wall. Furthermore, pin‐supported walls tend to force the frame to vibrate in the rocking mode and suppress higher mode effects in the frame. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
5.
Ryan D. Hoult Helen M. Goldsworthy Elisa Lumantarna 《Bulletin of Earthquake Engineering》2018,16(10):4825-4860
Poor performance of lightly reinforced and unconfined concrete structural walls have been observed in recent earthquake events. This research investigates the displacement capacity of such walls by comparing the results of a series of state-of-the-art finite element analyses for a range of different structural walls to that estimated using plastic hinge analyses. The common expressions used in estimating the yield curvature, yield displacement and plastic displacement are scrutinised for these types of walls. Some recommendations are given to improve the prediction of the displacement capacity of lightly reinforced and unconfined rectangular and C-shaped walls for flexural actions using a plastic hinge analysis. Importantly, a parameter has been recommended to be used in a “modified” approach for estimating the nominal yield displacement of lightly reinforced concrete walls. Different expressions are also recommended depending on the amount of longitudinal reinforcement used in the wall in comparison to that required to initiate secondary cracking. This is important for providing better estimations of the displacement capacity of RC structural wall buildings in low-to-moderate seismic regions such that vulnerability studies can be conducted. 相似文献
6.
Zhi Zhang Robert B. Fleischman Jose I. Restrepo Gabriele Guerrini Arpit Nema Dichuan Zhang Ulina Shakya Georgios Tsampras Richard Sause 《地震工程与结构动力学》2018,47(10):1987-2011
A new floor connecting system developed for low‐damage seismic‐resistant building structures is described herein. The system, termed Inertial Force‐Limiting Floor Anchorage System (IFAS), is intended to limit the lateral forces in buildings during an earthquake. This objective is accomplished by providing limited‐strength deformable connections between the floor system and the primary elements of the lateral force‐resisting system. The connections transform the seismic demands from inertial forces into relative displacements between the floors and lateral force‐resisting system. This paper presents the IFAS performance in a shake‐table testing program that provides a direct comparison with an equivalent conventional rigidly anchored‐floor structure. The test structure is a half‐scale, 4‐story reinforced concrete flat‐plate shear wall structure. Precast hybrid rocking walls and special precast columns were used for test repeatability in a 22‐input strong ground‐motion sequence. The structure was purposely designed with an eccentric wall layout to examine the performance of the system in coupled translational‐torsional response. The test results indicated a seismic demand reduction in the lateral force‐resisting system of the IFAS structure relative to the conventional structure, including reduced shear wall base rotation, shear wall and column inter‐story drift, and, in some cases, floor accelerations. These results indicate the potential for the IFAS to minimize damage to the primary structural and non‐structural components during earthquakes. 相似文献
7.
The seismic performance of a self-centering precast reinforced concrete (RC) frame with shear walls was investigated in this paper. The lateral force resistance was provided by self-centering precast RC shear walls (SPCW), which utilize a combination of unbonded prestressed post-tensioned (PT) tendons and mild steel reinforcing bars for flexural resistance across base joints. The structures concentrated deformations at the bottom joints and the unbonded PT tendons provided the self-centering restoring force. A 1/3-scale model of a five-story self-centering RC frame with shear walls was designed and tested on a shake-table under a series of bi-directional earthquake excitations with increasing intensity. The acceleration response, roof displacement, inter-story drifts, residual drifts, shear force ratios, hysteresis curves, and local behaviour of the test specimen were analysed and evaluated. The results demonstrated that seismic performance of the test specimen was satisfactory in the plane of the shear wall; however, the structure sustained inter-story drift levels up to 2.45%. Negligible residual drifts were recorded after all applied earthquake excitations. Based on the shake-table test results, it is feasible to apply and popularize a self-centering precast RC frame with shear walls as a structural system in seismic regions. 相似文献
8.
This paper explores the notion of detailing reinforced concrete structural walls to develop base and mid‐height plastic hinges to better control the seismic response of tall cantilever wall buildings to strong shaking. This concept, termed here dual‐plastic hinge (DPH) concept, is used to reduce the effects of higher modes of response in high‐rise buildings. Higher modes can significantly increase the flexural demands in tall cantilever wall buildings. Lumped‐mass Euler–Bernoulli cantilevers are used to model the case‐study buildings examined in this paper. Buildings with 10, 20 and 40 stories are designed according to three different approaches: ACI‐318, Eurocode 8 and the proposed DPH concept. The buildings are designed and subjected to three‐specific historical strong near‐fault ground motions. The investigation clearly shows the dual‐hinge design concept is effective at reducing the effects of the second mode of response. An advantage of the concept is that, when combined with capacity design, it can result in relaxation of special reinforcing detailing in large portions of the walls. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
9.
Dionysis Biskinis Michael N. Fardis Apostolos Psaros-Andriopoulos 《Bulletin of Earthquake Engineering》2016,14(3):769-803
In seismic retrofitting of concrete buildings, frame bays are converted into reinforced concrete (RC) walls by infilling the space between the frame members with RC of a thickness of not more than their width. The cyclic behavior of the resulting wall depends on the connection between the RC infill and the surrounding RC members. The paper uses the results from 56 cyclic tests on such composite walls to express their properties in terms of the geometry, the reinforcement and the connection. Properties addressed are: (a) the yield moment at the story base; (b) the secant-to-yield-point stiffness over the shear span of the wall in a story; (c) the deflection at flexural failure in cyclic loading; (d) the cyclic shear resistance, including a sliding shear failure mode. Separate models are given for squat walls failing in shear and for those where the top of the column shears-off. The proposals are modifications of models developed in the past for monolithic RC walls from several hundred cyclic tests; blind application of these latter models as though the walls were monolithic gives, in general, unsafe predictions. By contrast, the diagonal compression strut approach in ASCE41-06 is safe-sided, but gives unacceptably large prediction scatter. 相似文献
10.
In the conventional seismic design of high‐rise reinforced concrete core‐wall buildings, the design demands such as design shear and bending moment in the core wall are typically determined by the response spectrum analysis procedure, and a plastic hinge is allowed to form at the wall base to limit the seismic demands. In this study, it is demonstrated by using a 40‐story core‐wall building that this conventional approach could lead to an unsafe design where the true demands—the maximum inelastic seismic demands induced by the maximum considered earthquake—could be several times greater than the design demands and be unproportionately dominated by higher vibration modes. To identify the cause of this problem, the true demands are decomposed into individual modal contributions by using the uncoupled modal response history analysis procedure. The results show that the true demands contributed by the first mode are reasonably close to the first‐mode design demands, while those contributed by other higher modes are much higher than the corresponding modal design demands. The flexural yielding in the plastic hinge at the wall base can effectively suppress the seismic demands of the first mode. For other higher modes, however, a similar yielding mechanism is either not fully mobilized or not mobilized at all, resulting in unexpectedly large contributions from higher modes. This finding suggests several possible approaches to improve the seismic design and to suppress the seismic demands of high‐rise core‐wall buildings. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
11.
The static and seismic sliding limit equilibrium condition of retaining walls is investigated, and analytical solutions for the angle of the active slip surface, the critical acceleration coefficient and the coefficient of active earth pressure are provided for different surcharge conditions. In particular, walls retaining a horizontal backfill without surcharge, walls supporting an extended uniform surcharge applied at different distances from the wall and walls supporting a limited uniform surcharge or linear uniform surcharge parallel to the wall are considered in the analysis.The solutions have been derived in the framework of the limit equilibrium approach, considering the effect of the wall through its weight, and accounting for the shear resistance at the base of the wall and the inertia force arising in the wall under seismic conditions.For the wall without surcharge the effect of the vertical component of the seismic acceleration as well as the effects of the inclination of the wall internal face and of the soil–wall friction were also investigated.The angle of the slip plane, the critical seismic acceleration coefficient and the coefficient of active earth pressure are given as functions of dimensionless parameters and the boundary conditions for the applicability of each solution are specified. The influence of soil weight, surcharge conditions and inertia forces on the active earth pressure coefficient is analysed. 相似文献
12.
Gopal Adhikari Lorenza Petrini Gian Michele Calvi 《Bulletin of Earthquake Engineering》2010,8(4):897-919
The paper investigates the applicability of current direct displacement based seismic design (DDBD) procedure, developed by
Priestley and his coworkers, for straight long span bridges under transverse seismic excitation synchronous to all supports.
This category of bridges often possess some additional features such as massive tall piers, highly irregular distribution
of mass and stiffness due to unequal superstructure spans and pier heights, large deformation capacity etc. that are absent
in short-to-moderate span bridges for which DDBD has extensively been verified. It is shown that DDBD in its current form
is unable to capture both displacement and base shear demand when compared with nonlinear dynamic analysis results. Accordingly,
a simple mechanics based extension of the current procedure that takes into account the effect of pier mass while computing
base shear demand as well as a modal combination rule for estimating displacement demand is proposed and validated using a
series of parametric studies. The new procedure also allows engineer to allocate strength at the potential plastic hinge location
in more general terms. 相似文献
13.
In order to develop new standards related to structures in seismic regions, a series of research programmes has been conducted
on slightly reinforced structural walls commonly used in France. Based on these researches, a method of design of such walls
submitted to a seismic action has been set up. This method used in the PS92 code differs from that used for ductile walls,
where a plastic hinge can develop at the base of the wall. The analysis is similar to the push over analysis presently given
in Eurocode 8. These various researches have confirmed the validity of the design concept developed for the PS92 code, on
one hand, and highlighted a number of phenomena linked to the non linear behaviour of reinforced concrete walls, on the other
hand. The present article aims at presenting a synthesis of the results obtained during these research programmes. 相似文献
14.
Analytical and empirical models for predicting the drift capacity of modern unreinforced masonry walls 下载免费PDF全文
下载免费PDF全文 Displacement‐based seismic assessment of buildings containing unreinforced masonry (URM) walls requires as input, among others, estimates of the in‐plane drift capacity at the considered limit states. Current codes assess the drift capacity of URM walls by means of empirical models with most codes relating the drift capacity to the failure mode and wall slenderness. Comparisons with experimental results show that such relationships result in large scatter and usually do not provide satisfactory predictions. The objective of this paper is to determine trends in drift capacities of modern URM walls from 61 experimental tests and to investigate whether analytical models could lead to more reliable estimates of the displacement capacity than the currently used empirical models. A recently developed analytical model for the prediction of the ultimate drift capacity for both shear and flexure controlled URM walls is introduced and simplified into an equation that is suitable for code implementation. The approach follows the idea of plastic hinge models for reinforced concrete or steel structures. It explicitly considers the influence of crushing due to flexural or shear failure in URM walls and takes into account the effect of kinematic and static boundary conditions on the drift capacity. Finally, the performance of the analytical model is benchmarked against the test data and other empirical formulations. It shows that it yields significantly better estimates than empirical models in current codes. The paper concludes with an investigation of the sensitivity of the ultimate drift capacity to the wall geometry, static, and kinematic boundary conditions. 相似文献
15.
Research on seismic performance of shear walls with concrete filled steel tube columns and concealed steel trusses 总被引：1，自引：1，他引：0
In order to further improve the seismic performance of RC shear walls, a new composite shear wall with concrete filled steel
tube (CFT) columns and concealed steel trusses is proposed. This new shear wall is a double composite shear wall; the first
composite being the use of three different force systems, CFT, steel truss and shear wall, and the second the use of two different
materials, steel and concrete. Three 1/5 scaled experimental specimens: a traditional RC shear wall, a shear wall with CFT
columns, and a shear wall with CFT columns and concealed steel trusses, were tested under cyclic loading and the seismic performance
indices of the shear walls were comparatively analyzed. Based on the data from these experiments, a thorough elastic-plastic
finite element analysis and parametric analysis of the new shear walls were carried out using ABAQUS software. The finite
element results of deformation, stress distribution, and the evolution of cracks in each phase were compared with the experimental
results and showed good agreement. A mechanical model was also established for calculating the load-carrying capacity of the
new composite shear walls. The results show that this new type of shear wall has improved seismic performance over the other
two types of shear walls tested. 相似文献
16.
完成了8个1/2比例的型钢混凝土(SRC)柱在低周反复荷载作用下的试验研究.对试件塑性铰区域的弯曲变形和剪切变形进行了量测,通过量测数据计算不同变形成分对SRC柱层间位移的贡献并分析了其随加载过程的变化规律.试验研究表明,SRC柱塑性铰区的弯曲变形是引起层间位移的主要变形分量,塑性铰区的剪切变形对层间位移的贡献相对较小... 相似文献
17.
为提高混凝土剪力墙受弯性能计算的准确度,开展强震下混凝土剪力墙受弯性能试验研究。选取1个混凝土剪力墙对比试件和3个测试试件作为研究对象,对试件施加垂直荷载和水平荷载,模拟强烈地震作用力。试验前期准备工作完成后,建立分离式有限元模型,通过计算混凝土在受压和受拉状态下的损伤弹塑性刚度,完成对有限元模型中混凝土塑性损伤分析,在此基础上,计算混凝土剪力墙受弯承载力。利用有限元模型对3个测试试件进行模拟试验,结果表明,强烈地震后3个试件的荷载-位移曲线均与实际位移值接近,且混凝土剪力墙受弯承载力试验结果与实际值的误差在2%以内,表明试验研究方法具有一定的可行性,数值模拟结果较为准确。 相似文献
18.
本文设计了1片普通混凝土剪力墙试件和5片混杂纤维混凝土剪力墙试件,进行低周往复加载试验,研究混杂纤维混凝土分布位置和高度对剪力墙抗震性能的影响。根据拟静力试验数据,分析了墙体试件的滞回曲线、骨架曲线及关键点、位移延性、刚度退化性能、耗能能力以及关键位置钢筋应力应变分布情况。结果表明:（1）剪力墙试件中采用混杂纤维混凝土的区域以均匀的水平裂缝为主,有效控制了剪力墙的斜裂缝的产生,最终表现出弯曲破坏模式。（2）相比混杂纤维混凝土分布在约束边缘区域,混杂纤维混凝土分布在底部的试件滞回曲线更加饱满,耗能能力更好。（3）混杂纤维混凝土分布高度越高,滞回曲线越饱满。当分布高度大于0.3h （h为全长）时,混杂纤维混凝土分布高度的提升对承载能力和变形能力的影响较小。（4）混杂纤维混凝土的掺入提高了剪力墙的抗剪性能,在一定程度上可替代水平分布筋。 相似文献
19.
直接基于位移可靠度的抗震设计方法中目标位移代表值的确定 总被引：8，自引：0，他引：8
针对20多个现役结构，以基于力的抗震设计方法所求基底剪力与直接基于位移的抗震设计方法所求基底剪力相等为原则，回归给出了直接基于位移的抗震设计中基底剪力的调整系数。在此基础上，通过进一步分析，提出了直接基于位移可靠度的抗震设计中层间目标位移代表值的确定方法。最后，总结给出了直接基于位移可靠度的抗震设计步骤。 相似文献
20.
Mid‐rise to high‐rise buildings in seismic areas are often braced by slender reinforced concrete (RC) walls, which are interconnected by RC floor diaphragms. In design, it is typically assumed that the lateral forces are distributed in proportion to the wall's elastic stiffness. Pushover analyses of systems comprising walls of different lengths have, however, shown that large compatibility forces can develop between them, which should be considered in design, but the analyses have also shown that the magnitude of the computed forces is very sensitive to the modelling assumptions. Using the results of a complex shell element model as benchmark, different simple hand‐calculation methods and inelastic beam element models are assessed and improved to yield reliable estimates of the base shear distribution among the individual walls comprising the interconnected wall system. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献