Numerical study on the influence of in-plane damage on the out-of-plane seismic performance of masonry infill walls with opening in reinforced concrete frames

The reinforced concrete (RC) frames with masonry infill walls are always subject to in-plane (IP) and out-of-plane (OOP) interaction under earthquakes, and IP damage will affect OOP seismic performance. In order to study IP and OOP interaction of the masonry infill walls with opening in RC frames, we establish a finite element model of RC frame with solid and opening infill walls based on existing tests. We simulated the influence of opening rate and opening aspect ratio on IP and OOP interaction of RC frames with masonry infill walls. The results show that IP damage significantly reduces the OOP stiffness of the RC frames with masonry infill walls; The IP storey drift between 0.5%-2%, the OOP stiffness is reduced by 58.3%-73.7%; Under the same IP damage, the OOP bearing capacity and stiffness of RC frames with masonry infill wall in a larger opening rate has greater degradation level and faster degradation rate; For a given opening rate, the opening with an aspect ratio that closer of infill wall has the least influence on the IP and OOP interaction. Finally, based on the simulation results, a two-parameter exponential equation is found to describe the relationship between the OOP bearing capacity reduction, IP storey drift and the wall opening rate.