梁端受框架约束的平端板连接组合节点抗火性能试验研究  

Experimental study on flush bolted end-plate composite connections in fire considering axial force effect

作　　者：李国强[1] 李侥婷[2] 楼国彪[2] 

机构地区：[1]同济大学土木工程防灾国家重点实验室,上海200092 [2]同济大学土木工程学院,上海200092

出　　处：《建筑结构学报》2011年第4期125-133,共9页Journal of Building Structures

基　　金：国家自然科学基金项目(50738005;50728805);科技部国家重点实验室基础研究项目(SLDRCE08-A-06)

摘　　要：对梁端轴向约束作用下平端板螺栓连接组合节点的抗火性能进行了试验研究。试验共设计制作四个试件,一个为梁端无轴向约束的组合节点抗火试验试件、两个为梁端受框架约束的组合节点抗火试验试件,另一个梁端无轴向约束的组合节点试件作为对比试件,进行常温下受力性能试验,以研究梁端轴向约束对组合节点耐火性能的影响。试验结果表明,常温下组合节点因柱腹板受压屈曲而破坏。火灾作用下组合节点温度场分布不均匀,组合节点均出现梁下翼缘屈曲,但二者在梁下翼缘屈曲后的受力行为不同。梁端无轴向约束组合节点在梁下翼缘屈曲后承载力迅速降低;而梁端有框架约束的组合节点在梁下翼缘屈曲后由于钢梁出现悬链线效应(在梁大挠度情况下,梁内轴力由压力转为拉力来承受竖向荷载),节点由压弯受力转为拉弯受力,表现出较好的承载能力和变形能力。试验反映了组合节点在结构中与梁的相互影响和共同作用,为理解火灾下组合节点在梁轴力影响下的结构反应、承载机理和破坏模式提供了依据。The objective of this study is to experimentally investigate the behavior of the flush end-plate bolted composite connection with axial restraints in fire.The full-scale test series included one test at ambient temperature,one transient state test on flush end-plate bolted composite connection without axial restraints,and two transient state tests on composite connections with axial restraints.The test at ambient temperature shows that the buckling of column web results in the failure of the specimen.From the elevated temperature tests,it is found that there is a wide range of variation in the temperature distribution across the composite connections,the failures of specimens are due to the buckling of the lower flange of steel beams.This is different from what happens to the same connection at ambient temperature.The axial restraints have considerable influence on the behavior of the composite connections after the buckling of steel beam lower flange.The capacity of unrestrained composite connection decreases rapidly,whereas restrained composite connection can keep its capacity due to the catenary action of restrained steel beam under large deflection.

关 键 词：组合节点 高强螺栓 平端板连接 约束梁 抗火试验 

分 类 号：TU398.9[建筑科学—结构工程] TU317.1