Experimental study on progressive collapse of self-centering precast concrete frame with infill walls

Abstract

The self-centering precast concrete (PC) frame has been proved to perform excellently under seismic load in many studies. However, its progressive collapse-resisting mechanism, especially in the presence of infill walls need to be investigated further. Three 1/2 scaled self-centering PC frame specimens, including one self-centering PC frame and two self-centering infilled PC frames were tested under quasi-static pushdown loading regime. The test results showed that the damage of self-centering bare frame was mainly concentrated at the beam ends under vertical load. The compressive arch action (CAA) and the tensile force in the prestressed strands undertook the vertical load together at the beginning of the test. The infill walls with lower strength could still obviously enhance the initial stiffness and progressive collapse resistance of self-centering frame, but did not change the failure location of the frame. The initial stiffness of self-centering infilled frame was 2.47 times of self-centering bare frame, and the peak load in the CAA stage was 1.33 times. The additional load path produced by the infill walls mitigated the concrete damage at the beam ends, thereby improving the ductility performance and repairability of the beams. As the beam span of self-centering infilled frame decreased by 1/4, the initial stiffness and peak load in the CAA stage increased by 1.65 times and 1.66 times respectively. Nevertheless, the concrete damage at the beam ends became severer and the ductility of the frame was reduced.