Abstract:The pseudo-static experiment was finished to investigate progressive collapse performance of a reinforced concrete spatial frame structure,which was designed without seismic demand.The middle-side column of the bottom floor was replaced by mechanical jacks to simulate its failure.Based on the experimental results,resistance-displacement curve,plastic hinge development history and load transferring mechanism of the model frame were analyzed.It is concluded that beam mechanism,compound mechanism and catenary mechanism all work to resist progressive collapse as for the longitudinal frame,while only beam mechanism plays a part as for the transverse frame.