Elasto-plastic analysis of coupled shear walls

The problem of yielding in the components of coupled shear walls under strong earthquake excitation reduces, for purposes of design, to estimation of ductility requirements. To provide a basic treatment of this problem, a simplified elasto-plastic analysis of coupled shear walls subjected to lateral loading is suggested. It is based on an approximate distribution of the coupling shear for post-elastic behaviour. A continuous lamina replaces the coupling beams, and hinges are permitted in the walls as well as in the beams. Four examples are included to demonstrate the application of the proposed analysis and to assess the validity of the approximations involved. Results confirm the proposed analysis to within good accuracy.     

带竖缝钢筋混凝土剪力墙板的简化静力分析模型

带竖缝钢筋混凝土剪力墙板在弹性状态下有较大刚度,而在弹塑性状态下又有较好的延性,是一种抗震性能较好的结构单元。但由于缺少有效的分析模型,带竖缝钢筋混凝土剪力墙板在国内的工程应用很少。根据带竖缝钢筋混凝土剪力墙板的V-u曲线,按照侧向刚度相同的原则将之等效为偏心交叉支撑简化模型,并给出了简化模型的截面特性和材料本构关系曲线。通过算例统计分析给出了偏心距的取值范围及简化分析模型的适用范围。与更接近于实际墙板特性的等效带竖缝板模型的算例对比分析表明,在框架结构静力分析中采用简化模型模拟带竖缝钢筋混凝土剪力墙板是可行的。     

Static analysis of laterally arbitrarily loaded non-planar non-symmetrical coupled shear walls

This paper describes the static analysis of non-planar non-symmetrical coupled shear walls, employing the continuous connection method in conjunction with Vlasov's theory of thin-walled beams. All previous authors concerning themselves with symmetrical systems, the present authors give particular attention to non-symmetrical systems in both the formulation and the numerical applications. The method of analysis presented was compared with SAP2000 structural analysis program (frame method). The results obtained showed good agreement, verifying the accuracy of the proposed method, which can efficiently be used in the predesign computations of tall buildings.     

Free vibrations of stiffened coupled shear walls

This paper presents the free vibration analysis of stiffened coupled shear walls based on a discrete–continuous approach. The stiffened system is reinforced by an additional stiffening beam at some level of the structure. This induces additional axial forces, and thus reduces the bending moments in the walls, as well as helping to reduce the lateral deflection. The effect of the stiffening beam on the free vibration characteristics of coupled shear walls is studied, and numerical investigations show that the natural frequencies of vibration can be significantly increased. The optimal position for the stiffening beam to increase as far as possible the first natural frequency of vibration is also presented. © 1998 John Wiley & Sons, Ltd.     

带暗支撑剪力墙损伤累积静力弹塑性分析

在多垂直杆剪力墙单元模型的基础上进行改进,把多垂直杆的轴向刚度和剪切刚度相结合,即每根垂直杆传递轴力的同时还传递剪力,考虑钢材和混凝土损伤累积效应对剪力墙的影响,在上述基础上提出考虑材料损伤累积效应的带暗支撑剪力墙模型,模型更接近带暗支撑剪力墙的受力性能。利用该模型编制的相应程序,对两片分别带有型钢暗支撑和钢筋暗支撑的剪力墙模型进行弹塑性静力加载数值模拟分析,计算结果和试验结果吻合较好,说明方法应用可行。     

An approximate method for static and dynamic analyses of multi‐bay coupled shear walls

In this study an approximate method based on the continuum approach and transfer matrix method for static and dynamic analyses of multi‐bay coupled shear walls is presented. The whole structure is idealized as a sandwich beam in this method. Initially the differential equation of this equivalent sandwich beam is written, then shape functions for each storey can be obtained by the solution of differential equations. By using boundary conditions and storey transfer matrices which are obtained by these shape functions, system modes and periods can be calculated. Reliability of the study is shown with a few examples. A computer program has been developed in MATLAB and numerical samples have been solved for demonstration of the reliability of this method. The results of the samples display the agreement between the present method and the other methods given in the literature. Copyright © 2007 John Wiley & Sons, Ltd.     

RC联肢剪力墙宏观数值计算模型研究

已有的钢筋混凝土联肢剪力墙宏观数值计算模型在墙体单元和连梁单元连接处采用水平变形协调,即连梁单元的梁端转动与墙体单元水平刚性梁的转动变形相协调。然而,水平变形协调并不能反映墙体和连梁的实际变形协调条件。为此,提出了一种钢筋混凝土联肢剪力墙宏观数值计算模型,该模型中墙体单元为具有分布式剪切弹簧且考虑平面外自由度的三维宏观墙体单元模型,连梁单元为具有3个子单元串联的一维杆单元模型,墙体单元与连梁单元的连接采用竖向变形协调,即连梁单元的梁端转动与墙体单元边垂直杆元的变形相协调。并通过算例对其模拟的准确性进行校验。结果表明：采用竖向变形协调方式建立的计算模型能更加准确地模拟联肢剪力墙的力学行为,提出的钢筋混凝土联肢剪力墙宏观数值计算模型可用于三维的非线性分析,其中墙体单元能更好地模拟剪切变形和面外变形,连梁单元能够更好地模拟与墙肢的变形协调。     

Dynamic analysis of non-planar coupled shear walls with stiffening beams using Continuous Connection Method

In this paper, the dynamic analysis of non-planar non-symmetrical coupled shear walls on a rigid foundation has been considered. The analysis deals with coupled shear walls having a finite number of stiffening beams, whose properties vary from region to region along the height. In the analysis, Continuous Connection Method (CCM) and Vlasov׳s theory of thin-walled beams are employed to find the stiffness matrix of the structure. The system mass matrix has been found in the form of lumped masses at the heights where the unit forces have been applied. Following the free vibration analysis, uncoupled stiffness, damping and mass matrices have been found employing the mode superposition method. A time-history analysis has been carried out using Newmark numerical integration method to find the system displacement vector for every time step. Finally, a computer program has been prepared in Fortran language and an asymmetrical example has been solved. The results have been verified via comparisons with those of the SAP2000 structural analysis program using frame method and a perfect match has been observed.     

Interaction based analysis of continuous transfer girder system supporting in-plane loaded coupled shear walls

This paper presents a method of analysis for a structural system of coupled shear walls supported on continuous transfer girder framing into columns. It is proposed that the analysis of the system be discretized into two parts. The coupled shear wall is analysed first based on the continuum technique assuming an ideal fixed support. Charts are presented to modify the continuum forces for the interactive effect of the non-rigid support. The internal forces of the walls at the level of the transfer girder are defined as the interface forces of the girder and the coupled shear walls. These forces are then used in the analysis procedure for the supporting structure. Finite element simulation is used to capture and interpret the interaction mechanism of the system. Effects of different wall and support system characteristics on the structural behaviour of the system are also discussed. Copyright © 1998 John Wiley & Sons, Ltd.     

Stiffening of laterally loaded coupled shear walls on elastic foundations

An investigation is made of the relative effectiveness of using either a top or bottom connecting beam to stiffen a pair of laterally loaded coupled shear walls supported on independent elastic foundations. By basing the analysis on the continuous medium approach, a closed solution to the problem is achieved. A numerical example for a typical structure illustrates the influence of the stiffening beams on the forces and deformations in the structure for two different soil conditions.     

On the accuracy of the continuum method for analysis of coupled shear walls of unequal width

The continuous medium technique has been widely used in the preliminary analysis and design of coupled shear walls in tall buildings by practising engineers for many years. One of the basic assumptions made when using this approximate method is that the coupling beams deform with points of contraflexure at mid-span. However, when there is a non-negligible difference between the stiffness's of the structural walls connected by the coupling beams, the points of contraflexure of the beams can move off-centre, and hence noticeable error in the analysis may occur. This paper presents a study on the accuracy of the continuous medium technique for the preliminary analysis of concrete coupled structural walls with unequal width. Comparison of the analytical results between the method and the wide-column analogy has been made. Recommendations for using the continuum method to analyse coupled shear walls are presented.     

A transfer matrix approach to free vibrations of coupled shear walls

A conceptually simple and computationally efficient numerical model, based on the transfer matrix technique, is proposed for the prediction of the elastic behaviour of coupled shear walls. The model developed allows for: variation of geometric and material properties with the height; shear as well as axial deformation of both walls and beams; a certain degree of rigidity at their joints; and subsidence as well as elastic movement of the foundations. The method is numerically implemented and applied to the evaluation of natural frequencies and modes of free vibrations of the structure. Good agreement of its predictions with experimental results confirms its accuracy and efficiency. Further comparisons with previously obtained numerical results lead to an assessment of the effect of shear deformation of the walls on the higher frequencies and demonstrate the capacity of the method to yield all types of vibrational modes within a predefined frequency range. The paper also assesses the effect of elastic foundation properties on the lower natural frequencies.     

受损剪力墙的非线性分析

砼剪力墙一种有效的抗偶力构件,成功地应用于各种抗震结构。但剪力侧向刚 大,地震时所承受的地震作用也较大,因此,在强地震作用下时常受损。本文作者采用钢筋砼非线笥有限元程序,对受损砼剪力墙进行了计算分析。计算模型考虑了钢筋和砼之间粘结－滑移,任意反复加载过程,砼开裂和裂缝闭合,裂缝宽度模拟。最后与试验结果进行了对比分析。     

钢筋混凝土短肢剪力墙结构非线性分析研究

针对两类混凝土短肢剪力墙结构形式,分别进行了4片相同的4层1∶3缩尺模型的短肢剪力墙结构非线性全过程试验研究。采用基于损伤能释放率的混凝土弹塑性损伤本构模型,针对两种类型的短肢剪力墙结构,进行了较为全面的非线性分析,给出了典型时刻整体结构的应力和损伤分布与演化过程。分析发现:随着结构逐渐进入非线性,刚度不断劣化,损伤程度不断增大,导致结构各个不同层次上的反应均出现了重分布现象。将分析结果与试验结果进行了对比,发现混凝土材料随机性导致结构反应具有显著变异性,模型的非线性分析结果仅能在均值意义上描述结构非线性行为。     

Seismic behaviour of coupling beams in a hybrid coupled shear walls

Steel coupling beams in a hybrid coupled shear wall provide a viable alternative for concrete coupling beams coupling individual reinforced concrete wall piers. Due to the lack of information, current design methods for calculating embedment lengths are silent about cases in which hybrid coupled walls have connection details of stud bolts and horizontal ties. In this work, an analytical study was carried out to develop a model for calculating the embedment lengths of embedded steel sections. Five models for calculating embedment lengths in a hybrid coupled wall are developed as variations of the Prestressed Concrete Institute guidelines for steel brackets attached to reinforced concrete columns. In addition, experimental studies on the hybrid coupled shear wall were carried out. The main test variables were the ratios of the coupling beam strength to the connection strength. The test results indicate that it is more advantageous to design the coupling beams as shear yielding members since the shear-critical coupling beam exhibits a more desirable mode of energy dissipation than the flexure-critical coupling beam.     

双肢型钢混凝土短肢剪力墙抗震性能试验及数值模拟

通过一榀双肢实腹式型钢混凝土短肢剪力墙模型试件的低周反复荷载试验,揭示该类双肢墙的破坏机制及抗震性能.试验结果表明:试件从型钢混凝土连梁屈服形成塑性铰,再到墙肢屈服发生破坏;试件延性系数、等效黏滞阻尼系数分别为3.58和0.191,表明该类双肢墙结构的破坏表现为强墙肢弱连梁型,具有较好的抗震性能.考虑到连梁破坏时只有少...     

Hysteretic analysis of thin steel plate shear walls

Thin steel plate shear walls (TSPSWs) are especially concerned due to the economic factor and excellent energy dissipation capacity. TSPSWs commonly define as steel plate with height-to-thickness ratio over 300. The post-buckling capacity, deformability and energy dissipation capacity of TSPSWs are now accepted by structural engineers. This brings about evident economic benefit. This paper presents a finite element analysis of TSPSWs under cyclic loading. The calculated results are compared with experimental results to validate its accuracy. Then based on the finite element model, the influence of height-to-thickness ratio and span-to-height ratio on the hysteretic behavior of TSPSWs is analyzed. Also, the influence of column moment rigidity on the development of tension field is studied. At last, a new simplified Combined Strip Model is introduced which is suitable for the hysteretic analysis of TSPSWs. Based on the Combined Strip Model, a formula for calculating shear strength is proposed, which considers the compression effects of TSPSWs.     

高层建筑中剪力墙的结构设计分析探讨

介绍了剪力墙的作用,对简单解法、准则法、同步失效准则法三种高层建筑剪力墙结构优化设计的方法进行了研究,并结合工程实例,阐述了结构优化设计的计算依据及方案选取方法,以合理布置框架剪力墙结构。     

Thin steel plate shear walls behavior and analysis

Steel plate shear walls have been used in buildings in North America and Japan. Until recently, the design practice has been to limit the strength of the wall to the buckling strength of the plate. The post-buckling strength of thin plates subjected to shear has been recognized for more than 60 years, since it was outlined by Wagner in the early 1930s. Tests of a quarter and one third scale specimens of thin steel plate shear walls under cyclic loading were performed; the tests are described and the results are summarized. An analytical model to determine the behavior of thin steel plate shear walls was developed and is given. The model is capable of depicting the behavior of walls with plates welded or bolted to the surrounding beams and columns of the building frame. Comparisons between the analytical and experimental results are made.     

An investigation on the behavior of stiffened coupled shear walls considering axial force effect

In most of tall buildings, the main contribution of lateral loads is carried by coupled shear walls. In some cases, the necessary stiffness to withstand the lateral load may not be afforded due to low depth of connecting beams. In order to increase the capacity of the coupled shear walls, beams with high stiffness are added to the system at particular levels. Hence, stiffened coupled shear walls (SCSW) will be produced. Such walls are under axial load resulting from their weight, and this axial load affects the behavior of walls because of their excessive height. In this paper, a new method considering the effect of axial force for geometrically nonlinear analysis of the SCSW has been presented. A computer program has been developed in matlab , and numerical examples have been solved to demonstrate the reliability of this method. The results of the examples show the agreement between the present method and the other methods given in the literature. The effects of the various positions and rigidities of the stiffening beam on the internal forces and the lateral deflection of the structure considering axial force effect have also been investigated. Copyright © 2012 John Wiley & Sons, Ltd.