高温骤冷后不同截面高强钢管超高性能混凝土约束效应分析OA

Firefighting water spray significantly affects the material and mechanical properties of high-strength steel tube ultra-high performance concrete(UHPC)structures.To investigate the evolution of axial compression behavior in high-strength steel tube UHPC columns after high-temperature exposure and water quenching,an experimental and finite element analysis was conducted on 12 square and circular UHPC-filled steel tube columns subjected to different temperatures.Axial compression tests were performed to analyze failure modes,load-displacement curves,ductility,and axial compressive capacity.Furthermore,the confinement effects of the two cross-sectional types were compared under conditions of equal steel ratio and equal cross-sectional area.Results indicate that after high-temperature exposure and water quenching,the peak load-bearing capacity initially increases and then decreases,with 400℃serving as the critical threshold.Under identical conditions,circular specimens demonstrate superior load-bearing capacity,ductility,and post-failure performance compared to square specimens,attributable to their uniform circumferential confinement.These findings provide valuable references for structural design and post-fire performance assessment.