Optimum Shear Walls Distribution in Framed Structures for Buildings Subjected to Earthquake Excitations

Abstract

Reinforced concrete shear walls, which are vertically oriented plate-like elements, are efficient members in controlling the response behavior of buildings against seismic actions. In this research work, the performance of reinforced concrete buildings with shear walls having different shear wall-to-frame stiffness ratios is investigated. The considered buildings were designed in compliance with the requirements of the Algerian seismic code RPA99v2003 and were supposed to be located in regions of high seismicity. Seven 3D finite element models with different shear wall-to-frame stiffness ratios were developed and assessed using the nonlinear static analysis. Engineering Demand Parameters (EDPs) such as lateral displacement, inter-story drift ratio, shear force, and bending moment along the building height were presented. The results clarified that the induced responses can be classified into two major groups: force-based and displacement-based EDPs. Moreover, as the shear wall-to-frame ratio increases, the observed force-based EDPs increase whereas the displacement-based EDPs decrease. From a force point of view, distributing shear walls so that the packet of stiffness is lumped at the center of the building, model G with a stiffness ratio of 6.0906, amplifies the induced forces. This distribution requires more reinforcements and can lead to a conservative design. From a displacement point of view, distributing shear walls so that the packet of stiffness is lumped at the periphery of the building, model C with a stiffness ratio of 1.7879, minimizes the induced shear force and bending moment and produces the lowest values. This represents the optimum case with maximum performance and minimum strength.