Effect of cracking and wall openings on shear wall stiffness in medium-rise buildings subjected to seismic loads

The lateral stiffness of a building is one of the most important parameters in structural engineering which controls the period of vibration, torsional shears, lateral forces and drifts. Different stiffness values can ultimately affect the behavior of a structure under seismic loads and lateral forces that will be applied to it. In this study two of the most important parameters that can affect lateral stiffness of shear wall-frame buildings have been studied: Cracking in walls due to lateral loads and size of openings in shear walls. For a medium rise building (10 stories), a finite element analysis was performed to investigate the effects of wall cracking and openings on lateral stiffness and their impact on a structures' response to seismic loads. The finite element simulation of cracking in shear walls under lateral loads used a fine mesh and provided a precise yet computationally intensive approach to identify cracked elements based on a step-by-step iterative method. The analysis results for the effect of openings showed that openings with an area less than 10% of the total wall area at each level did not have a significant impact on the stiffness of the building. However, walls with larger openings experienced substantial loss of stiffness and larger displacements.