Seismic performance of the extended end-plate high-strength steel beam-to-column connections after fire

This study investigates the seismic performance of the extended end-plate high-strength steel beam-to-column (EEP-HSSBC) connections after fire. The accuracy and effectiveness of the computational model are validated using existing experimental results. Considering actual engineering parameters, a parametric analysis is conducted to evaluate the seismic performance of the EEP-HSSBC connections after fire. The parameters include the ratio of column width to thickness (alpha), column height-to-thickness ratio (R), beam width-to-thickness ratio (gamma), beam height-to-thickness ratio (8), and beam stiffener length-to-thickness ratio (ti). 25 computational models are established to examine the seismic performance, stiffness degradation, ductility, and energy dissipation capacity of these beam to column connections under post-fire cyclic loading. Results indicate that increases in parameters gamma and 8 enhance both the stiffness and bearing capacity of the beam to column connections. Temperature significantly affects the stiffness, stress distribution, energy dissipation capacity, and bearing capacity of the beam to column connections. The findings can provide a theoretical basis for evaluating the performance of such connections under post-fire seismic action and offer reference and technical support for their design.