轴压与偏压状态下高强钢轴向约束柱受火后剩余承载力试验研究  

Experimental study on post-fire residual capacity of axially restrained high strength steel columns under axial and eccentric compression

作　　者：宋林昕 李国强[1,2] Song Linxin;Li Cuogiang(College of Civil Engineering,Tongji University,Shanghai 200092,China;State Key Laboratory of Disaster Reductionin Civil Engineering,Tongji University,Shanghai 200092,China;Fuzhou University,Fuzhou 350108,China)

机构地区：[1]同济大学土木工程学院,上海200092 [2]同济大学土木工程防灾减灾全国重点实验室,上海200092 [3]福州大学,福建福州350108

出　　处：《土木工程学报》2025年第3期23-37,共15页China Civil Engineering Journal

基　　金：国家自然科学基金(51878506)。

摘　　要：文章设计10根截面尺寸与长度均相同的高强钢柱,根据钢柱受力状态分为轴心受压与偏心受压2组。在每组5根试件的试验中,1根钢柱不受火,在室温下加载直至失效,以得到其未受火的极限承载力;另外4根钢柱受到轴向约束,在恒载作用下先升温至设计温度后再在空气中自然冷却至室温,最后在室温下加载直至失效,以得到其受火后的极限承载力(剩余承载力)。通过试验得到高强钢轴向约束柱的火灾响应与受火后响应,并对试验进行数值模拟。结果表明:高强钢轴向约束柱在高温下发生整体屈曲后,其侧向挠曲迅速发展,受火后仍有很大的残余弯曲变形,大幅降低其受火后剩余承载力;在同一条件下,高强钢轴向约束柱受火后剩余承载力的折减程度随着偏心距的增大而减小;有限元模型可较好地模拟高强钢轴向约束柱的恒载升降温全过程响应与高温后响应。Ten high strength steel columns with the same cross-section and length were designed and divided into two groups according to axial and eccentric compression.In each group of five specimens,one column did not go through the heating and cooling cycle and was loaded until failure at ambient temperature to obtain its load carrying capacity without being heated.The other four columns were axially restrained,heated to target temperatures and cooled down to ambient temperature in air under sustained applied loads,and then load tested to failure at ambient temperature to obtain their post-fire load carrying capacity(residual capacity).The behaviors of axially restrained high strength steel columns under fire and after fire were obtained,and corresponding numerical simulations were conducted.It was found that after the axially restrained high strength steel columns underwent overall buckling at elevated temperatures,the lateral deflection developed rapidly,and retained significant lateral deflection after fire,resulting in significant reduction of the post-fire residual capacity.Under the same condition,the post-fire residual capacity reduction degree of axially restrained high strength steel columns decreased with the eccentricity.The behavior of axially restrained high strength steel columns during the whole heating and cooling process and after fire can be simulated reasonably well using the numerical model proposed in this study.

关 键 词：高强钢柱 轴向约束 偏心受压 受火后剩余承载力 试验研究 

分 类 号：TU391[建筑科学—结构工程] TU317.1