Structural Performance of Earthquake-damaged Beams in Fire

摘要

Post-Earthquake Fire (PEF) on frame structures usually leads to complicated and unpredictable thermal performance of damaged concrete members. In order to determine the structural performance of seismic-damaged Reinforced Concrete (RC) beams under PEF conditions, the RC frame structures are subjected to the shake table test. The test, used in conjunction with other existing seismic hazard data, demonstrates that the main geometric damage forms of RC beams after the earthquake are cracks and concrete spalling. Subsequently, calculating models of PEF RC beams are established in ABAQUS, and then the distribution of thermal field, high-temperature bearing capacity and reduction coefficient of seismic-damaged beams are proposed respectively. From experimental and numerical investigations, It can conclude that (a) the simplified numerical models are proven to accurately determine the fire performance of the damaged RC beams; (b) the thermal performance degradation caused by spalling is more severe than the degradation caused by cracking on PEF RC beams, which demonstrates that spalling takes a more important role than cracking; and (c) the prediction equation of the flexural bearing capacity reduction factor of PEF RC beams is feasible.