Showing papers on "Shear wall published in 1982"

Formulas for Wood Shear Walls

Abstract: Formulas are presented for the analysis of typical wood-frame shear walls with sheathing attached by nails or other types of discrete fasteners. Formulas are derived for the sheathing fastener forces, for the linear shear stiffness of a wall, and for the nonlinear shear load-strain behavior of a wall. These formulas are shown to be in agreement with the results of load tests and of finite element, linear, and nonlinear analyses. Details of the load tests and finite element analyses are given. The formulas are relatively simple and should be applicable to the design of wood frame shear walls with plywood or other types of sheathing.

Cyclic loading tests of slender concrete masonry shear walls

Abstract: The design, construction and testing of three slender concrete masonry shear walls is reported. The three walls, modelling 190 mm thick blockwork walls of four to five stories height to a scale of 1:0.737 were subjected to cyclic reversals of in-plane displacements at gradually increasing ductility factors, simulating the effects of seismic loading. Variables between walls included axial load level, and whether or not confining plates were placed in the mortar beds in the compression zones of the potential plastic hinge region. All walls were constructed by conventional methods, and included lapped starter bars within the plastic hinge. Results indicated that the unconfined walls suffered strength degradation at levels of ductility lower than those required by current ductile design practice. This was particularly the case for the wall with heavy axial> loading, and confirmed theoretical predictions of available ductility based on a limiting ultimate compression strain of 0.25%. Response of the confined wall exhibited greatly improved behaviour compared with an otherwise identical unconfined wall. In all walls behaviour was significantly, and adversely, affected by the lapping of flexural steel at the wall base.

Dynamic characteristics of coupled wall‐frame systems

Abstract: The paper presents the first three natural frequencies and the corresponding mode shapes for fixed-base multistorey buildings which can be idealized as an equivalent planar coupled shear wall connected in series to an equivalent frame. The coupled wall is modelled as a continuum of uniform properties and the frame as a uniform shear beam, the connection between the two elements being taken as continuous. Solutions are obtained by treating the structure as a lumped parameter system with twenty equidistant discrete masses having only translational inertia. The relevant flexibility matrix is, however, generated from the exact solution of the governing differential equation for the continuum subjected to point loading. The results are presented for various combinations of the three non-dimensional parameters which are sufficient to describe all the geometric and material properties of the system. The mode shapes are presented in terms of the first three normal modes of a uniform slender cantilever. The non-dimensional base shears required for the response spectrum analysis of buildings of the type under consideration are also given for the three modes and for the various combinations of the three non-dimensional parameters mentioned above. The use of the results is illustrated by an example.

Dynamic Characteristics of Frame-Wall Systems

Abstract: The first three natural frequencies and the corresponding mode shapes for fixed-base frame-wall systems are presented. The system is modelled as a continuum of uniform properties incorporating the shear deformation in the wall. The resulting fourth-order homogeneous differential equation in terms of lateral displacement is solved exactly using an appropriate numerical technique. The results are presented for various combinations of the two nondimensional parameters which together incorporate all the geometric and material properties of the frame-wall system. The mode shapes are presented in terms of the first three normal modes of a uniform slender cantilever. The nondimensional base shears appropriate for the response spectrum analysis of the system under seismic loading are also given.

An Economic Analysis of Earthquake Design Levels.

Abstract: : This report presents data on the cost of increasing the seismic design strength of buildings for three strengthening concepts; moment frame, braced frame, and shear wall. Damage is related to drift and acceleration of key elements of the structure. A damage matrix was constructed relating damage to design level and applied loading. An economic analysis was performed evaluating cost of strengthening, the present worth of expected damage, and the probability of site acceleration levels. (Author)

Structural integrity of precast panel shear walls

Abstract: Precast panel shear walls are investigated for conditions simulating progressive collapse. The latter are simulated by assuming ineffective panels at various levels within the structure. The analysis is performed by an efficient finite element substructuring procedure for both static and seismic loadings, and by a simple rigid-cantilever approximation for static loading only. The principal interest concerns the magnitude and distribution of design forces in vertical and transverse ties which, in the finite element analysis, are modelled by discrete connectors along horizontal and vertical joints. For static loading the results evaluate the accuracy of the simple cantilever design procedure, whereas for seismic loading the magnitude and distribution of connector forces resulting from local panel failure are examined. In particular, it is shown that failure of an exterior panel leads to unexpectedly large concentrations of shear force in the vertical joint, something that is not adequately predicted by the ...

Ductility of confined concrete masonry shear walls

Abstract: Calculations for the ductility capacity of unconfined concrete masonry shear walls developed in a previous paper are extended to cover the case of confined masonry shear walls. Design charts are presented which show that the available ductility will always be greater than three times the value for a corresponding unconfined wall. Recommendations to govern the required extent of confinement are made.

Closure of "Response of RC Shear Wall under Ground Motions"

Abstract: The formulation is presented of an analytical model using the finite element technique to compute the nonlinear dynamic behavior of reinforced concrete planar structures under earthquakes. The model is based on a lumped-mass approach, and utilizes the Newmark β\\N-method to perform the step-by-step integration of the equations of motion. This model is applied to trace the response of a three story shear-wall subject to the El Centro earthquake of May 1940. The results computed are compared with an experimental investigation.

Shear Capacity of Reinforced Concrete Masonry Beams

Abstract: Extensive research is under way in many parts of the world to move masonry design from an allowable stress approach to a more consistent ultimate strength approach based on limit states criteria. At Carleton University over the past three years work towards limit states design has concentrated on concrete masonry flexural members such as lintel beams or slender shear walls. This paper deals with the ultimate strength and behavior of flexural members subjected to high shear forces. The experimental investigation, comprising over 70 concrete masonry beams, studied the effect of a number of key parameters on shear capacity. These parameters were the ratio of shear span to effective depth, joint spacing, type and slump of fill, effective depth, coursing of beams, and percentage of reinforcement. The results show that ultimate beam shear capacity of reinforced concrete masonry falls between the shear strengths of reinforced concrete and reinforced brick masonry. The results also show that the ratio of shear span to effective depth has the most pronounced effect on shear capacity and that, in general, composite behavior exists up to ultimate failure. No serviceability problem exists for deflections at working load levels.