铰接约束圆孔蜂窝组合梁抗火性能试验研究与数值模拟

Experimental study and numerical simulation on fire resistance of round⁃hole honeycomb composite beam with hinged restraint

为研究铰接约束圆孔蜂窝组合梁的抗火性能,对圆孔蜂窝组合梁进行恒载升温试验和数值模拟分析,研究圆孔蜂窝组合梁在火灾全过程的温度分布、位移变化、破坏形态和耐火极限。结果表明:圆孔蜂窝组合梁孔间腹板和孔边腹板的温度变化基本一致;停止升温后,圆孔蜂窝组合梁经历收缩反拱、挠曲回落和变形恢复三个阶段;圆孔蜂窝组合梁板端形成明显的斜裂缝,且板端斜裂缝在升温阶段和降温阶段发展方向相反,板面纵向裂缝在降温阶段进一步形成、延伸和扩展;蜂窝钢梁端部腹板和下翼缘形成明显的局部屈曲,且下翼缘局部屈曲主要位于梁端第一开孔处;铰接约束圆孔蜂窝组合梁耐火极限时间为78min;数值模拟结果和试验结果吻合良好。

To study the fire resistance of round-hole honeycomb composite beam with hinged restraint,transient state tests and numerical simulation analyses were conducted on round-hole honeycomb composite beam to investigate the cross-sectional temperature field,displacement changes,damage patterns and fire resistance limit of round-hole honeycomb composite beam during the entire fire process.The results show that the temperature changes in the webs between the holes and the webs at the edge of the holes of round-hole honeycomb composite beam are nearly the same.After the heating is stopped,the deformation of the round-hole honeycomb composite beam passed through three stages,i.e.,shrinkage back-arching,deflection fallback,and deformation recovery.Obvious diagonal cracks are formed at the slab ends of the round-hole honeycomb composite beams,the diagonal cracks at the slab ends develop in opposite directions during the warming and cooling phases,and the longitudinal cracks at the slab surface form,extend,and expand further during the cooling phase.The end webs and lower flange of the honeycomb steel beam form significant local buckling,and the local buckling of the lower flange is mainly located at the first opening of the beam end.The refractory limit time for the round-hole honeycomb composite beam with hinged restraint is 78min.The numerical simulation results are in good agreement with the experimental results.