Investigating the Effect of Masonry Infill Walls on the 2D RC Structural Systems with Asymmetry along the Elevation

Abstract

Reinforced concrete (RC) frames with unreinforced masonry infill panels are common structural building systems all over the world. Although many analytical investigations and experimental observations emphasize the contribution of masonry infills to the overall stiffness and strength of the structures, their effects are not considered by the engineers in the design and the analysis calculations. Due to the variations in the actual behavior of the infill walls and using different parameters to define the infill walls in modeling and capacity calculations, they have unpredictable effects on the global response of the structural systems. The purpose of this study is the simulation of a collapse mechanism scenario that may be developed during the earthquake through applying incremental equivalent static load. Infill panels were represented using equivalent compression diagonal struts and their effects on the behavior of RC structural systems having asymmetrical placement of unreinforced masonry infill walls along the elevation has been scrutinized. The equivalent static load was applied to the structural system in +/-X directions to focus on the effects of using only one diagonal strut. It has been observed that the influence of the infill panels on the structural system has beneficial effects in decreasing the story drift, which may be attributed to the contributory effect of the infill panels on the lateral stiffness of the structural system. Furthermore, the axial forces and bending moment diagrams have been plotted for each increment in the equivalent static load, which can give insight to understand the significance of masonry infill walls.