悬索桥索梁销接节点抗火性能研究  

Experimental Study on Fire Resistant Performance of Hanger Cable-Girder Pin Connections in Suspension Bridge

作　　者：李雪红[1] 华晓烨 杨国明 李亮 吴豪放 LI Xuehong;HUA Xiaoye;YANG Guoming;LI Liang;WU Haofang(College of Civil Engineering,Nanjing Tech University,Nanjing 211816,China;Nanjing Public Engineering Construction Center,Nanjing 210019,China)

机构地区：[1]南京工业大学土木工程学院,江苏南京211816 [2]南京市公共工程建设中心,江苏南京210019

出　　处：《桥梁建设》2025年第2期100-107,共8页Bridge Construction

基　　金：江苏省交通运输科技项目(2021QD06)。

摘　　要：为了解悬索桥索梁销接节点在火灾下的响应特性和破坏形态,对该类节点开展了持载火灾试验和有限元研究。以南京新生圩长江大桥为背景,设计、制作索梁销接节点模型,采用拉压试验机张拉吊索至成桥索力后,采用电阻炉模拟火灾升温,分析持载过程中节点应力、应变、温度、破坏形态等,并采用有限元法研究其应力及温度分布规律。结果表明:持载火灾试验中,节点模型在103 min时发生塑性变形,临界温度为864℃;134 min时叉耳发生颈缩拉断破坏,表面温度为1015℃。有限元模拟中,节点破坏时,叉耳的最大应力位于销孔两侧,吊耳受应力重分布影响,最大应力由销孔两侧逐渐转移到腹板底部,销轴两端应力较小、中间应力较大。对比有限元与试验结果,碳氢(HC)升温曲线和ISO834标准升温曲线作用下节点响应及抗火性能的变化规律基本一致,HC升温曲线作用下的节点破坏时间约30 min。This study investigates the response characteristics and failure modes of hanger cable-girder pin connections in the suspension bridge by the fire test and numerical simulation.Based on the Xinshengwei Changjiang River Bridge in Nanjing,a specimen containing the hanger cable-girder pin connection was prepared.The hanger cable was tensioned to the required level in the completed bridge by the tensile and compression testing machine,afterwards,heated by a resistance furnace(creating temperature-rising environment in a fire event),to observe the variation of stress,strain,temperature and failure mode of the pin connection under sustained loading.Numerical simulation was conducted to study the stress and temperature distribution.It is shown that the specimen experienced plastic deformation at the 103 min of the sustained loading,with a critical temperature of 864℃.At 134 min,the fork necked and ruptured under tensile force,with the surface temperature reaching 1015℃.In the numerical simulation,when the pin connection failed,the maximum stress in the fork appeared on the two sides of the pinhole,while the maximum stress in the lifting lug gradually moved from the two sides of the pinhole to the web bottom,due to stress redistribution.The stresses at the two ends of the pin rod were smaller than that in the center.The tested responses and fire resistance of the pin connection agree with the numerical simulation under both the hydrocarbon heating and the ISO834 time-dependent heating,and the pin connection fails under hydrocarbon heating of about 30 min.

关 键 词：悬索桥 索梁销接节点 抗火性能 破坏形态 耐火极限 持载火灾试验 有限元法 

分 类 号：U448.25[建筑科学—桥梁与隧道工程] U441.5[交通运输工程—道路与铁道工程]