Study on seismic performance of welding beam reinforced with symmetrical flange plate to H-shaped column after fire

The objective of this paper is to investigate the seismic performance of welding beam strengthened with symmetrical flange plates to H-type column (WBSFPHC) after fire. The accuracy effectiveness of the calculation model was verified using the existing experimental results. Considering the application of practical engineering parameters, the column width-thickness ratio (α), ratio of beam width to column width (β), height-thickness ratio of beam web (γ), width-thickness ratio of stiffener (ε), length thickness ratio of flange plate (η) and temperature (T) were used to perform a parametric study against the post-fire seismic performance of the WBSFPHC connections. Then, 25 calculation models were established to explore hysteretic behavior, stiffness degradation, ductility and energy dissipation capacity of the WBSFPHC connection under post-fire cyclic load. The results showed that the stiffness and bearing capacity of the WBSFPHC connection were improved with the increase of the parameters β and γ, temperature had great effect on the stiffness, stress distribution, energy dissipation capacity and bearing capacity of the WBSFPHC connection. The findings can provide reference and technical support to the seismic performance design, maintenance and reinforcement of such joints after fire.