Experimental investigation on the in-plane and out-of-plane interaction of isolated infills in RC frames

This paper presents the findings of a series of bidirectional quasi-static tests conducted on isolated infilled frames to investigate the in-plane and out-of-plane interaction of the infills with different boundary constraints. The effects of prior in-plane damage on the out-of-plane behavior of isolated infill walls were assessed. It was found that the presence of existing cracks that developed during the in-plane loading stage had an effect on the out-of-plane cracking patterns, decreased the integrity of the isolated infills, and weakened the infill-frame boundary restraints. The behavior of isolated infill walls under combined in-plane and out-of-plane loading was also affected by the effectiveness of boundary constraints. The experimental results demonstrated that reliable boundary constraints were necessary for forming arching mechanisms and preventing rigid body motion.