Numerical simulation and parametric analysis of the residual load‐bearing capacity of steel‐PVA hybrid fiber‐reinforced concrete stub columns after high‐temperature exposure

This study investigated the mechanical properties of steel‐PVA hybrid fiber‐reinforced concrete short columns after high‐temperature exposure through axial compression tests. The results demonstrated that at 800°C, the NCP1S14 specimens achieved a residual bearing capacity of 787.9 kN, showing a 15.9% improvement over NC specimens, confirming that hybrid fibers effectively enhance post‐fire bearing capacity and crack suppression. Using ABAQUS software, we validated the reliability of both the temperature field and mechanical models for these fiber‐reinforced columns after high‐temperature exposure. The analysis specifically compared five parameters affecting the residual capacity reduction coefficient, revealing that fire exposure duration, concrete strength grade, and fiber content had significant impacts, while cross‐sectional size and fiber volume fraction showed relatively minor influence. Through regression analysis, we derived a simplified calculation formula for the influence coefficient ( k ) of residual bearing capacity, with results showing strong agreement with numerical simulation data.