Experimental and Numerical Investigation on Progressive Collapse Resistance of Post-Tensioned Precast Concrete Beam-Column Subassemblages

Abstract

In this paper, four 1/2 scaled precast concrete (PC) beam-column subassemblages with high-performance connection were tested under push-down loading procedure to study the load-resisting mechanism of PC frames subjected to different column removal scenarios. The parameters investigated include the location of column removal and effective prestress in tendons. The test results indicated that the failure modes of unbonded post-tensioned precast concrete (PTPC) frames were different from that of RC frames: No cracks formed in the beams and wide opening formed near the beam to column interfaces. For specimens without overhanging beams, the failure of side column was eccentric compression failure. Moreover, the load-resisting mechanisms in PC frames were significantly different from that of RC frames: The compressive arch action (CAA) that developed in concrete during column removal was mainly due to actively applied precompressive stress in the concrete; CAA will not vanish when severe crush in concrete occurred. Thus, it may provide negative contribution for load resistance when the displacement exceeds one-beam depth; the tensile force that developed in the tendons could provide catenary action from the beginning of the test. Moreover, to deeper understand the behavior of tested specimens, numerical analyses were carried out. The effects of concrete strength, axial compression ratio at side columns, and loading approaches on the behavior of the subassemblages were also investigated based on validated numerical analyses.