Effect of in-plane damage on the out-of-plane mechanical performance of infill walls with recycled concrete blocks

Out-of-plane (OOP) damage is one of the main failure modes for infill walls in frames during earthquakes, which can result in significant economic losses, injuries, and fatalities, and is difficult to repair. This paper investigates the effect of in-plane(IP) damage on the out-of-plane performance of infill walls using recycled concrete blocks with the finite element software ABAQUS and t was used to model and analyse the infill walls with recycled concrete block frames, and the modelling method is verified by the test results. The out-of-plane performance of 20 infill walls with recycled concrete block specimens of different aspect ratios and block sizes was investigated under various inter-story drift damage conditions. The results indicate that in-plane damage has little effect on the out-of-plane bearing capacity when the inter-story drift is 0.15%, and the initial out-of-plane stiffness of the infill walls increases by 5.4%. However, when the in-plane inter-story drift reaches 0.5%, the out-of-plane bearing capacity decrease by more than 50%, and the initial stiffness and ductility also decrease significantly. The study found that the thickness-to-diagonal length ratio of the infill walls has a prominent effect on the out-of-plane strength reduction, and an empirical formula for the in-plane damage and the out-of-plane strength reduction coefficient was proposed and fitted to the data obtained from the finite element analysis with a root mean square error of 0.18.