Seismic fragility analysis of unbonded post-tensioned fabricated RC frame structures

Abstract:

To investigate the seismic performance of unbonded fabricated frame, a numerical model of the beam-column connection was built in OpenSEES. The comparison between test results and numerical analysis proved the effectiveness of the numerical model. Eighteen different ground motions were employed in the seismic fragility analysis according to the site conditions. The maximum story drift and tensile force in prestress strands were chosen as the damage indexes. Through IDA analysis for two 6-story frame structures, i.e. the common RC frame and unbonded fabricated frame, the IDA curves and fragility curves were obtained. According to the analysis, the unbonded fabricated frame can sustain ground motion record with smaller intensity index than the common RC frame with the same configurations, i.e. the cross-section of column, reinforcement ratio etc. Under small earthquake, the two frame structures present similar performance, while under strong earthquake, the collapse resistance performance of common RC frame is better than that of the unbounded fabricated frame.