Showing papers on "Shear wall published in 1978"

Seismic response of structures free to rock on their foundations

Abstract: SUMMARY The possibility of foundation rocking of shear wall structures designed to NZS 4203 is discussed. Theory developed by Housner for the free rocking of a rigid block is compared with experimental results from a simple structural model with a number of different foundation conditions. A simple design method for assessing maximum rocking displacements, using equivalent elastic characteristics and a response-spect ra approach is proposed, and compared with results from simulated seismic excitation of the model using an electro-hydraulic shake-table. A typical design example is included.

Racking Strength of Light-Frame Nailed Walls

Abstract: Horizontal forces, such as wind, are resisted by the walls parallel to the wind direction. These forces, which lie in the plane of the wall, are known as the shear or racking loads, and are transmitted to the sheathing through the fastener system. Qualification of sheathing materials has generally been limited to performance testing of 8-ft by 8-ft (2.4-m by 2.4-m) stud wall assemblies. An analytical procedure has been developed that accurately predicts racking strength based upon the lateral resistance of the individual fasteners. The structural model is applicable to any sheathing size or geometry, so it is possible to determine the racking strength of light frame walls from simple lateral nail tests or small scale racking tests. The procedure offers a direct means for designers and code officials to predict racking strengths of panels incorporating various sheathing materials and fasteners.

Orthotropic Membrane for Tall Building Analysis

Abstract: A method for analyzing tall framed buildings based on the concept of equivalent elastic membrane is presented. The elastic properties of the membrane are evaluated taking into account the effects of finite size joints and axial deformations in the columns. Floors are assumed to be rigid in plane. The equivalent membrane is then analyzed using two-dimensional plane stress, specially orthotropic finite elements. The displacements thus obtained represent directly those of the actual structure, and the member forces are determined by integrating the corresponding stress components in the membrane. Two multistory multibay frames were analyzed, and the results show that a high degree of accuracy can be obtained with significantly smaller number of unknowns than by the exact and other simplified methods. The present technique can be readily applied to the static and dynamic analysis of tubed structures, clad multistory frames, and shear wall and frames structures.

Borehole Shear Test for Stiff Soil

Abstract: The Iowa Borehole Shear Test (BST) is a rapid, direct shear test performed on the walls of borehole in soil. The test measures in-situ soil shear strength by failing the soil along the circumference of the hole. Sharply ridged, diametrically opposed shear plates are expanded by gas pressure to apply a normal stress against sides of the hole. A shearing stress is then applied by pulling the plates axially along the hole while maintaining a constant normal stress until failure occurs. By repeating the test with different values of normal stress, a series of shearing stress values are obtained from which a Mohr-Coulomb failure envelope is drawn. Allowing time for drainage between successive points permits interpretation of results on a consolidated-drained basis.

Approximate frequency analysis of shear wall frame structures

Abstract: The finite strip method is used to determine the natural frequencies of shear wall frame buildings. The structure can be modelled in two different ways. In the first approach both the shear walls and the frames are idealized simply as an assemblage of finite strips of varying thicknesses with given or computed properties, while in the second approach the shear walls are still idealized as a series of finite strips, but the frames are regarded as a number of long columns which are interconnected with each other or with finite strips through the horizontal beams. Numerical results obtained from both models indicate good agreement with finite element solutions. The proposed models can be applied to a wide range of shear wall frame assemblies and are therefore more versatile than most existing models.

Approximate Stiffness Analysis of High-Rise Buildings

Abstract: Developments in computer software have made many programs available for more exact high-rise space frame design. However, in practical structural engineering design such programs may be too expensive and time consuming especially for the preliminary design. This paper presents a simple, yet reasonably accurate method to solve problems of lateral load distribution among the different frames of a high-rise building by simple programming using small computers. The cantilever method for approximated lateral load analysis is incorporated to derive the flexibility and the stiffness matrices of each frame. By the method presented, the lateral loads are distributed among the frames according to the approximate stiffness matrix of each frame and the final sway of the building can be found. This method can also be used for buildings with a combined system of frames and shear walls.

Closure of "Effective Width of Coupling Slabs in Shear Wall Buildings"

Abstract: The stiffness of a coupling slab between two shear walls is computed by means of the finite element method. A number of common wall configurations are considered. The results are expressed in terms of the effective widths of the slab and are presented in design chart form. Comparisons to available experimental results are made. It is concluded that the theoretical calculations are sufficiently accurate for design purposes, provided a correction for local deformation of the walls is made when the wall opening is small.

Natural vibrations of shear wall buildings on flexible supports

Abstract: A shear wall building is considered as an assembly of plane and curvilinear shear walls tied together by floor slabs to act as a composite unit. Based on this conception and the continuous medium approach, the governing dynamic equations and boundary conditions are derived from energy principles, using Vlasov's theory of thin-walled beams. All primary and secondary inertia forces, as well as the influence of elastic foundation flexibility, have been taken into consideration. A numerical solution of the dynamic equations is achieved by employing the Ritz-Galerkin technique, yielding both natural frequencies and mode shapes. The technique is applicable to buildings containing coupled and non-coupled, open section shear walls oriented in plan in any arbitrary manner. The use of the method is illustrated by the example of a complex building with unsymmetric plan, and the analytical natural frequencies of two shear wall building models are compared with those obtained experimentally by other investigators.

Behaviour of coupled non-linear shear walls

Abstract: This paper describes an investigation of coupled non-linear shear walls subjected to lateral load increasing monotonically up to overall collapse. Overall collapse includes base hinges in walls as ...

Analysis of buildings with interconnected shear walls

Abstract: A method for analysis of interconnected shear walls is described that accounts for the torsional stiffness caused by non-uniform warping. Floor to floor, plane wall members are idealized as part of...

Special considerations in design of an asymmetrical shear wall building

Abstract: Two special considerations in the design of the Harbour Square Apartment Complex in Toronto are presented. Firstly, due to the irregular shape and overall size of the building, volumetric change of the floor slab can become a potential problem. Actual shrinkage tests were carried out on the materials used to estimate the ultimate shrinkage strain. A scheme of permanent and temporary construction joints was designed to solve the floor slab's shrinkage problem.Secondly, due to the asymmetrical nature of the floor plan, the distribution of wind loads on different shear walls was calculated based on a special three-dimensional computer program, taking torsion of the building into account. This program treats the shear walls as thin-walled beams coupled by the diaphragm action of the floors. The program is efficient both in terms of input data and CPU time and is believed to be a viable design tool for highrise shear wall buildings.