Showing papers on "Shear wall published in 1975"

Reinforced Concrete Structures

Abstract: The Design Approach. Stress--Strain Relationships for Concrete and Steel. Basic Assumptions of Theory for Flexural Strength. Strength of Members with Flexure. Strength of Members with Flexure and Axial Load. Ultimate Deformation and Ductility of Members with Flexure. Strength and Deformation of Members with Torsion. Bond and Anchorage. Service Load Behavior. Strength and Ductility of Frames. Shear Walls of Multistory Buildings. The Art of Detailing.

Two-dimensional, antiplane, building-soil-building interaction for two or more buildings and for incident planet SH waves

Abstract: Two-dimensional SH-type vibration of several shear walls erected on an elastic, homogeneous, half-space has been studied. The choice of the cylindrical coordinate system, suitable for analysis of rigid foundations with semi-circular cross section, has lead to the exact infinite series solution, which is ideal for the analysis of the physical nature of this problem and its dependence on several key parameters. It has been shown that the presence of neighboring buildings may change the nature of the single soil-structure interaction problem appreciably and that scattering, diffraction, and interference of waves from and around several foundations with the incident SH waves can lead to significant shielding, as well as amplification of input motion for any of the buildings in a group. The effects of relative size of two, three and several foundations and their separation distances have been studied and presented in some detail.

Seismic shear loading at flexural capacity in cantilever wall structures

Abstract: An investigation is described into the effect of various combinations of the normal modes of vibration of cantilever shear wall structures on the maximum shears at flexural capacity. It is shown that the base shear can be much higher than would be derived by assuming a normal code lateral load distribution of sufficient magnitude to cause flexural yielding. The results of elastic normal mode response spectrum analyses of a 10-storey building considering several structural variables are presented in terms of envelope values of the ratio of maximum base shear at flexural capacity to that assuming a code lateral load distribution. The same effect is investigated with a series of step-by-step numerical integration dynamic analyses of cantilever wall structures responding inelastically to a range of earthquakes. On the basis of the results suggestions are made for the shear design of cantilever walls.

Design Aspects of Shear Walls for Seismic Areas

Abstract: This presentation, taking the form of a state of the art report, considers several aspects of the behavior of tall and squat shear walls In particular the problems of brittle and ductile failure modes, diagonal tension, construction joints, alternating plasticity, sliding shear, stiffness degratation, and strength loss under reversed cyclic loading are discussed The behavior of coupled shear walls is examined in some detail and the problems related to the components of this structure are reviewed The principles rather than techniques of design for earthquake resistance are stated Wherever possible the issues are studied against the background of experimental evidence The material presented indicates that carefully detailed shear walls, designed to possess an intelligent hierarchy in their failure mechanisms, can be made to possess the properties so desirable in earthquake resistant structures

A Critical Review of the Seismic Design Provisions for Ductile Shear Walls of the Canadian Code and Commentary

Abstract: The 1975 Canadian Building Code for the design of reinforced concrete shear wall buildings in high seismic risk areas includes provisions that are new and significant. This paper critically examines some of these provisions, especially as they apply to cantilever shear walls. Clarifications in the definitions of curvature, member, and system ductilities are attempted. The relationship between curvature and system ductility is examined. Code provisions on allowable shear stress in the wall in the plastic hinge region and the provisions for the classification of the walls are discussed. Attention of the designer is drawn to some aspects of the code and the commentary that may result in structures of doubtful safety.

Torsional Analysis of Perforated Core Structure

Abstract: A simple method for torsional analysis of perforated core wall structures considering shear deformation is presented. The governing differential equation is derived from compatibility using open section thin-wall torsion-bending theory. The method is compared with conventional analysis in which shearing strains are ignored to show that for a narrow band of openings or stiff connecting beams the conventional analysis overestimates the rotational stiffness of the core wall assembly. This is also borne out by the experimental evidence. Since the governing differential equation has the same form as that of the conventional solution, existing tables and graphs can be used to obtain the deformations and internal forces.

A generalized continuum method for dynamic analysis of asymmetric tall buildings

Abstract: The paper presents a continuum method for dynamic analysis of asymmetric tall buildings with uniform cross-section in which the horizontal stiffness is provided by shear walls and columns of arbitrary shape and layout, coupled by horizontal beams. The equations of motions are formulated in variational terms, including axial strain energy. Numerical solutions, obtained by using finite time differences and infinite polynomials, are presented for the response of a twenty-storey building with six shear walls to an impact load and earthquake accelerations. It is shown that omission of the axial deformations results in a substantially distorted pattern of behaviour, some of its effects being: 1Overestimation of the bending stiffness of the coupled shear walls, with corresponding changes in their stiffness ratios. 2Underestimation of the periods of the principal modes, with a corresponding change in the dynamic response. 3Distortion of the magnitude, form, time of onset and coupling of the maximum displacements. 4Pronounced change in the shear force and moment diagrams for the shear walls, the beams and the building as a whole.

Coupled Shear Wall Analysis by Lagrange Multipliers

Abstract: A special finite element technique is described which permits interconnection of line elements in flexure and first-order plane stress elements. Continuity of displacements and rotations at the junction of the two types of elements is satisfied by imposing certain constraint conditions through use of Lagrange multipliers. The method can be employed to analyze coupled shear walls as well as frame-shear wall systems. Accuracy is checked by analyzing a coupled shear wall system with three degrees of mesh refinement. Results are further compared with those from a conventional finite element scheme, which idealizes the coupling beams by plane stress elements. The proposed method is shown to be more accurate and more efficient than the conventional method.

Analysis of Interconnected Open Section Shear Wall Structures

Abstract: A study is made of three-dimensional behavior of open section shear walls subjected to lateral loads. Emphasis is placed on the warping behavior of the open section shear walls and interaction provided by bending and warping interconnecting floor slabs. Comparisons are made between the analytical results of the present method and those of a three-dimensional analysis in which warping is ignored. The order of magnitude of warping effects are such that to neglect them in the analysis of open section shear wall system might lead to serious errors in the calculated stresses and consequent design of structures.

Analysis of Shear Walls in Large-Panel Construction

Abstract: A study is made on the behavior of shear wall systems made from large precast panels. Three commonly used wall arrangements are studied. The loading consists of monotonically increasing lateral uniform load. Realistic vertical joint and connecting lintel characteristics are incorporated into the mathematical model. A step by step calculation technique is used to study the vertical joint and lintel behavior and its effect on the overall stiffness degradation of the system as load increases. The effect of flexible foundation on the overall behavior is also studied.

Shear and Overturning Moment for Earthquake-resistant Building Design

Abstract: The provisions of the present Canadian and U.S. seismic codes are examined with respect to their requirements on the distribution of seismic forces and overturning moments throughout the heights of...

Continuum Method for Overall Stability of Tall Asymmetric Buildings

Abstract: A solution for the buckling loads of asymmetric tall buildings with uniform cross section is presented, using a three-dimensional continuum model and including the effects due to normal strains in columns and shear walls. The layout of the stiffening elements in the plane of the structure is arbitrary, without restrictions as to shape of the shear wall cross section, direction of its principal axes, and orientation of the frames. The equilibrium equations for rotation, lateral and normal displacements are formulated in variational terms. Buckling loads are calculated by means of infinite polynomial series, using the existence criterion for a nonzero solution of the homogeneous system of differential equations. For practical application of the method, the use of a computer is essential. The numerical example worked out shows that for slightly deformable connecting beam systems, largely overestimated buckling loads may result by omission of axial strains.

Simplified Analysis of Staggered Wall-beam Frames

Abstract: Simplified analyses of wall-beam frames, based on previously determined equivalent member stiffnesses, are given. The analyses are based on two approaches: (i) using the methods of difference calculus and (ii) using the continuum method, commonly used in shear wall analysis, in which the beams connecting the columns are replaced by a continuous connecting medium. It is shown that the analyses using difference and differential calculus are equivalent if an approximation of the column bending is introduced. Comparison of the proposed approximate methods with exact skeletal analysis shows excellent agreement. One conclusion of practical importance is that many analyses applied to shear walls, and available in the literature, may be applied to wall-beam frames as well. It is suggested that in many cases it is possible in practice to neglect the column bending stiffness altogether and details of an analysis based on this assumption are also given.