SEISMIC IMPROVEMENT OF INFILL WALLS CONSIDERING IN-PLANE AND OUT-OF-PLANE DEMANDS

Kahramanmaras earthquake sequence (Mw = 7.8 and Mw = 7.6) that hit several highly populated cities in eastern Turkiye resulted in extensive structural and non-structural damage to the building stock dominated by mid-rise reinforced concrete (RC) frames infilled with light masonry infill walls (IWs). Among various observed damages induced by infills, out-of-plane (OOP) failure triggered by previous in-plane (IP) damage was perceived as the most dangerous, considering the direct threat to life safety due to falling hazards and the sudden loss of infill contribution, which pave the way for soft/weak story mechanism. In order to improve the seismic performance of IWs under combined loading, a testing setup capable of simultaneous implementation of constant OOP inertial forces and increasing IP cyclic displacements was constructed in the METU structural mechanics lab. Two surface coating techniques, namely bilateral mesh reinforcement and fiber mesh overlay, applied to solid walls constructed with hollow clay bricks (HCB) and aerated concrete blocks (ACB) were tested. The performance of both systems was assessed under IP, OOP and combined actions. Although no connection to the bounding frames was made, proposed retrofit techniques achieve superior seismic performance compared to traditional infill systems.