Coupled Shear Walls Research Articles

12層T型並列壁の地震時におけるせん断力負担割合の変化機構に関する実験的研究 : ハイブリッド構造に関する日米共同構造実験研究(HWS)

12層T型並列壁の地震時におけるせん断力負担割合の変化機構に関する実験的研究 : ハイブリッド構造に関する日米共同構造実験研究(HWS)

Analysis of shear wall structures on elastic foundations

A method for analyzing shear wall structures on elastic foundations is presented. The shear walls are modeled using a nine-noded isoparametric quadrilateral plane stress element and the soil is modeled using a three-noded quadratic element that includes the vertical subgrade reaction and soil shear stiffness. It is observed that analyzing shear wall structures as fixed cantilevers, i.e. ignoring soil-structure interaction, significantly underestimates the wall drift. It is shown that including soil shear stiffness in the analysis reduces the maximum drift and increases the normal stresses in the wall, especially for poor soil. It is also shown that ignoring the soil deformation underestimates the bending moment in the lintel beams of coupled shear walls, and the transverse bending moment in core structures.

Nonlinear behaviour of a coupled shear wall and shear core system under random ground excitation

Nonlinear behaviour of a coupled shear wall and shear core system under random ground excitation

Nonlinear behaviour of a coupled shear wall and shear core system under random ground excitation

Nonlinear behaviour of a coupled shear wall and shear core system under random ground excitation is presented. Random vibrational theory is used for the response analysis of hysteretic structural systems under stochastic earthquake excitation. An equivalent linearization technique, based on Wen's model, is used to convert the nonlinear differential equations to the equivalent linear differential equations, under bi-axial hysteretic restoring forces. The damping is assumed to be linear and a Clough–Penzien double filter is used to calculate the input ground excitation forces on the structure. A comparison has been made between coupled shear wall and shear core systems, to get a best model for a 15 storey building. © 1997 John Wiley & Sons, Ltd.

NON-PLANAR COUPLED SHEAR WALLS IN MULTISTOREY BUILDINGS.

Keywords J & W STOCKHOLM BUILDINGS, TALL, MULTI STOREY, WALLS, SHEAR, NON PLANAR, COUPLED, METHODS, ANALYSIS, STRUCTURES, THREE DIMENSIONAL, HOMOGENEOUS, THEORY, CONTINUUM, PLANAR, BEHAVIOUR, FLEXURAL, TORSIONAL, NUMERICAL, CALCULATIONS, SYSTEMS, ELEMENTS, COMPUTERS, PROGRAMS, FINITE ELEMENTS, STABILITY, LOADS, LATERAL, LAMINAR, CONTINUOUS, PIERS, COUPLING, EFFECT, BEAMS, NON SYMMETRICAL... Show All

STIFFNESS, STABILITY AND FUNDAMENTAL PERIOD OF COUPLED SHEAR WALLS OF VARIABLE THICKNES.

In this paper simple expressions are presented to assess the deflection curve, elastic critical load and fundamental period of coupled shear walls of variable thickness. A numerical example is given for illustration. In addition, it is shown that a coupled wall of certain static and dynamic properties can be designed by reducing appropriately the thickness of a uniform system with the same properties such that, in many cases, lengthy calculations need not be carried out for practical design.

Structural analysis of multi-stiffened coupled shear walls on flexible foundations

The purpose of this paper is to extend previous research on the static analysis of mono-stiffened or boundary stiffened coupled shear walls to the analysis of multi-stiffened coupled wall structures. Up to four stiffening beams are considered; these may be located at the top and bottom of a structure and at two arbitrary intermediate levels along the height of the walls. The simple yet accurate continuum approach is employed for analysing the multi-stiffened coupled shear walls.

On The Methodics Providing Software Quality InCivil Engineering Applications

The paper presents some experiences in a software development for civil engineering applications. It is oriented towards software quality maintenance. It relates to the computerbased analysis of three-dimensional coupled shear wall structures in multistorey buildings. The implemented method provides the calculation of internal forces, stresses and displacements due to lateral and vertical loads and to the vertical settlement, as well as it enables a dynamic analysis by means of response spectrum method. An integrated system for analysis of coupled torsional-flexural vibrations due to seismic actions and for static analysis is presented.

Upgrading the degree of coupling of coupled shear walls

This paper presents a simple method for upgrading the degree of coupling of coupled shear walls in need of retrofit. The method considers two basic systems: (i) walls linked solely by slabs in which coupling is ineffective, and (ii) walls coupled by beams and (or) slabs in which coupling is insufficient. The method is based on enhancing the stiffness and strength of the coupling system by introducing a limited number of deep coupling beams. The method is cost-effective, since it optimizes the number and location of added coupling beams, which demand special detailing and are very costly. In addition, the method minimizes the reduction of the clearance for the passage of services along corridors, particularly in buildings with low interstorey height. Three cases are treated in this paper corresponding to the retrofit of one, two, and three upgrading coupling beams. Design tools are presented in this paper as easy to use diagrams. Finally, numerical examples demonstrate the applicability of the proposed upgrading method. The paper is thought to be a useful tool for practicing engineers.

12層立体並列壁の地震時における全体挙動に関する実験的研究 : ハイブリッド構造に関する日米共同構造実験研究(HWS)

12層立体並列壁の地震時における全体挙動に関する実験的研究 : ハイブリッド構造に関する日米共同構造実験研究(HWS)

Classification Methodology for Coupled Shear Walls

This paper presents guidelines for classification of ductile coupled shear walls (CSWs). It includes two parts: the evaluation of the degree of coupling (DC) between the walls and the coupling beams, and the classification of CSWs. In present practice, DC is defined as the percentage of the base overturning moment carried by the axial tension and compression forces resulting from shears in the coupling beams. The evaluation of DC requires a structural analysis of CSW, which presents serious shortcomings during the preliminary proportioning process. A simple method is proposed in this paper for the evaluation of DC without need for structural analyses. A classification method based on the dynamic properties of CSWs is also proposed. This allows the classification of CSWs into one of the following three categories: a series of linked isolated walls, CSWs, and walls with openings (pierced walls). Finally, numerical examples demonstrate the applicability of the proposed methods. This paper is thought to be ve...

Response of Large Panel Precast Wall Systems: Analysis and Design

A general design procedure proposed by Clough is applied to a precast coupled shear wall structure located in UBC Seismic Zones 2, 3 and 4. Both slender and deep coupling beams are considered. Inelastic static analyses using the finite element method are carried out to compare the results with Clough's method. This study showed that large panel structures with deep coupling beams behave in a satisfactory manner in all seismic zones. In comparison, coupled walls with slender beams showed a less satisfactory response. The application of Clough's method is illustrated with the aid of a fully worked design example.

Drift-based methodology for seismic proportioning of coupled shear walls

This paper presents a design tool for size proportioning of reinforced concrete coupled shear walls built in seismic regions. It is based on the maximum allowable drift that can be selected by the designer. Free vibration and modal analyses are performed on a variety of coupled shear walls of different heights and geometries. From these analyses, fundamental periods are first related to geometric properties of coupled shear walls and then to maximum interstorey drifts. These maximum drifts are obtained from both spectrum analysis and pseudo-static approach. Closed-form formulas for estimating the required fundamental periods of coupled wall systems as a function of maximum allowable drift are derived. The design of the wall system can be based on geometric dimensions to yield the stiffness to achieve the required period. These formulas not only are thought to be useful for preliminary size proportioning, but also can constitute an advantageous starting point for more sophisticated analyses. To demonstrate the applicability of these formulas and to clarify design issues, a design example is treated and results are compared with static and dynamic analyses. Key words: coupled shear wall, reinforced concrete, ductility, force modification factor, interstorey drift, fundamental period, seismic.

Seismic Response of Flexibly Supported Coupled Shear Walls

Results from seismic analyses performed on 20-story ductile coupled-shear-wall models designed for Montreal, Canada, are presented. A two-dimensional model was used to idealize the structure including the supporting ground. Allowances were made for nonlinearities not only in the walls and the coupling beams, but also in the soil and foundation elements. The soil foundation was modeled by equivalent massless springs (hangers), located at the base of the structures, allowing for inelastic bearing of the soil and loss of contact (uplift) of base from supporting soil. The stiffnesses of massless foundation springs were obtained using the soil properties that were derived on the basis of strain-dependent shear moduli of real borings. The study showed that the model is capable of tracing the response of coupled shear wall, taking into account the soil-structure interaction effects. Results showed that allowing for foundation flexibility lengthened the fundamental period by a maximum of 33; it amplified deflections by a maximum of 81. However the stresses in the walls and the coupling beams attenuated particularly in lower stories. Finally, no substantial variations were observed in the rotational ductility demands of the coupling beams.

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.

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.

DYNAMIC ANALYSIS OF COUPLED SHEAR WALL-FRAME SYSTEMS

In this paper, the dynamic behaviour of coupled shear wall-frame systems is analyzed. A continuum approach for coupled shear walls with any number of opening rows is used, accounting for shear strain effects in both solid walls and lintel beams. A finite element formulation based on hierarchical shape functions is developed for the coupled walls, and an assembling procedure is presented for obtaining the global mass and stiffness matrices of the wall-frame assembly. The free vibrations of coupled shear walls are studied first to test the convergence of the proposed method, and the results obtained agree very well with theoretical and experimental results reported in the literature. Finally, the model analysis and the response spectrum technique are used to study the coupled shear wall-frame interaction for two high-rise reinforced concrete buildings subject to earthquake excitation.

Elastic Analysis of Spatial Shear Wall Systems With Flexible Bases

SUMMARY The static linear elastic analysis of spatial shear wall systems with flexible base foundations subjected to lateral loading is considered in this investigation. The discrete force method is adopted, in which the base flexibility is modelled by vertical and rotational springs. The soil and structure were coupled by imposing compatibility conditions along the discrete force method interfaces. The proposed method enforces compatibility of deformation on the relative vertical displacement between adjacent release positions, which are established at assumed contraflexural points of the connecting beams which link the slab together and also at storey level intervals along the intersection lines of adjoining non-coplanar walls. The solution of the compatibility conditions provides the redundant shear forces at the assumed contraflexural positions and the stress resultant solution is completed by statical considerations. The displacement solution corresponding to the stress resultants is then evaluated using the linear elasticity assumption. The objective of the current work is to provide a theoretical treatment of foundation-structure interaction, suitable for implementation in the discrete force method. In addition, the work presents results obtained with the discrete force modelling of soil interaction, and discusses its applicability to some representative problems. The majority of methods of analysis commonly used by engineers for the design of shear wall structures make the assumption that the structure is built into a rigid foundation. Such a procedure simplifies the mathematical analysis of the problem, and may often be sufficiently accurate for all practical purposes. However, depending on the form of structure and the particular soil conditions encountered, it may be considered desirable to estimate the effects of differential settlement produced by foundation movement. The first study of the effect of flexible bases was reported by Coull',2 who treated rotational and vertical base flexibility separately, employing the continuum approach, and then superimposed the results to assess the general case of coupled rotational and vertical base boundary conditions. In a subsequent study, Tso and Chan3 examined simultaneous vertical and rotational movement at the bases of the coupled walls. Pekau4 considered the importance of base flexibility on the nonlinear behaviour of coupled shear walls subjected to pseudo-static lateral loading using the classic continuum method. So far, only a few papers have dealt with the analysis of three dimensional soil-structure interaction problems. Swaddiwudhipong et aL5 were the first to investigate three dimensional

Dynamic soil-structure interaction of coupled shear walls by boundary element method : D. Capuani, R. Klein, H. Antes & A. Tralli, Earthquake Engineering & Structural Dynamics, 24(6), 1995, pp 861–879

Dynamic soil-structure interaction of coupled shear walls by boundary element method : D. Capuani, R. Klein, H. Antes & A. Tralli, Earthquake Engineering & Structural Dynamics, 24(6), 1995, pp 861–879

A continuous-discrete approach to the free vibration analysis of stiffened pierced walls on flexible foundations

A hybrid approach, based on the analysis of an equivalent continuous medium and a discrete lumped mass system, is presented in this paper for conducting dynamic analysis of stiffened coupled shear walls supported on foundations which are flexible rotationally, and in both the vertical and horizontal directions. The effect of shear deformation on the free vibration behaviour of coupled shear walls reinforced by stiffening beams located at the top and the base level, and at an arbitrary level along the structural height is considered. The stiffened coupled shear wall system is represented by either a continuous system or a discrete system at various stages of the analysis. The advantage of using these two ways of representing the shear wall system is that the stiffness and mass matrices required for structural dynamic analysis are easily obtained. Numerical studies on a typical example structure, carried out by this continuous-discrete approach, to investigate the effects of shear deformation and the incorporation of stiffening beams on the free vibration characteristics of stiffened coupled shear wall structures, are also presented.