Experimental and Numerical Investigation on the Effect of Infill Walls on Dynamic Behavior in Rc Structures: Shake Table Tests

Abstract

Infill walls have many positive and negative effects on reinforced concrete (RC) buildings under the effect of earthquakes, but these are often not taken into consideration sufficiently. The contribution of walls to stability and stiffness in particular is considerable. In the negative sense, due to various reasons, incorrect/incomplete use of infill walls can cause extremely fatal irregularities such as short columns and soft stories. In this study, the effect of infill walls on the dynamic behavior of reinforced concrete buildings was examined. The study was conducted on a dynamic basis in order to approach the behavior under the effect of earthquakes in a more realistic way. For this purpose, a 1/3 scale 2-storey single-span reinforced concrete frame was produced for the experiments. Forced vibration tests were carried out on the shake table in the reference state (bare frame) and in the infill-walled state. The sample was subjected to an artificial ground motion with a peak ground acceleration (PGA) value of 0.54 g in both states. Experimental modal analysis, load-displacement analysis, and numerical analysis on ETABS structural analysis software were done. As a result, it was observed that the infill walls significantly enhanced the stiffness, leading to a considerable reduction in displacement values. Calculations showed that the natural frequencies increased by approximately 5-10%, while the global damping ratio decreased by about 20%.