Seismic behaviour of full-scale hollow bricks-infilled RC frames under cyclic loads

Abstract

This paper studies the seismic performances of three full-scale reinforced concrete (RC) frames infilled by masonry hollow bricks (MHBs) under cyclic loads focusing on the effects of infills and openings. The studied performances include strength, stiffness, ductility and energy dissipation capacity of the frames. Results show that infilled masonry wall has a significant influence on the stiffness and deformation resistance of RC frames at early stage, especially for the one without openings. This was attributed to the strong diagonal strut action of masonry infills which was confirmed without obvious cracking at this stage. After main diagonal cracks were developed, however, the lateral force of infilled frames sharply decreases with lateral displacement. Besides, results show that openings provide a buffer effect to suit the deformation of infilled wall which then reduces its damage at early stage such as collapse. According to reported test results, the failure mode of the frames was discussed in detail and existing stiffness and strength models were examined. A lateral resistance strength model was proposed for the RC frames infilled by MHBs and presented good prediction accuracy. In addition, to study effect of opening to the MHB infilled frames, strength and stiffness reduction models were developed which both evaluate test results well.