既有桁架屋盖建筑火致倒塌试验与数值模拟  

Experimental and numerical study on fire-induced collapse of an existing truss roof building

作　　者：李晋宇 李国强[1,2] 朱劭骏 张超 陈彬 吉蔚 戚洪辉 王尧 陈楠 杨晓琳[5] 江黎明 聂勇峰 罗齐 LI Jinyu;LI Guoqiang;ZHU Shaojun;ZHANG Chao;CHEN Bin;JI Wei;QI Honghui;WANG Yao;CHEN Nan;YANG Xiaolin;JIANG Liming;NIE Yongfeng(College of Civil Engineering,Tongji University,Shanghai 200092,China;State Key Laboratory for Disaster Reduction in Civil Engineering,Tongji University,Shanghai 200092,China;School of Civil Engineering,Wuhan University,Wuhan 430072,China;Shanghai Urban-construction Information Technology Co.,Ltd,Shanghai 200092,China;China Academy of Safety Science and Technology,Beijing 100012,China;Department of Building Environment and Energy Engineering,The Hong Kong Polytechnic University,Hongkong 999077,China;Fire and Rescue Department of Hubei Province,Wuhan 430061)

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国家重点实验室,上海200092 [3]武汉大学土木建筑工程学院,湖北武汉430072 [4]上海城建信息科技有限公司,上海200092 [5]中国安全生产科学研究院,北京100012 [6]香港理工大学建筑环境及能源工程学系,中国香港999077 [7]湖北省消防救援总队,湖北武汉430061 [8]宜昌市消防救援支队,湖北宜昌443003

出　　处：《建筑结构学报》2025年第3期153-163,共11页Journal of Building Structures

基　　金：上海市浦江人才计划(22PJ1414000)。

摘　　要：为研究火灾下桁架屋盖建筑等大空间建筑的升温规律及结构响应,对一真实既有钢-混凝土混合桁架屋盖建筑开展火灾倒塌试验。试验采用木垛为火源,通过综合应用热电偶、地磅、微波雷达和耐高温倾角仪等手段采集数据,测量火源的热释放速率、建筑内部空气温度、结构构件温度、关键节点的位移及转角等数据,并得到结构在真实火灾下的升温特点及位移和转角变化规律。采用场模拟和有限元法分别对试验的建筑空气温度场与结构热-力耦合响应进行模拟,通过与实测结果的对比验证数值模拟的有效性。研究表明:试验中建筑内部空气温度场呈现出明显的非均匀分布特点,测点温度分布范围为500~900℃;火源燃烧规律可划分为闪燃、缓升、稳定与衰退等4个阶段;空气温度场变化趋势与热释放速率变化趋势基本一致;混合桁架屋盖的倒塌由上弦混凝土杆弯曲失效引发,与纯钢桁架由杆件屈曲失效所致的倒塌明显不同。场模拟可以较为准确地复现桁架内部的空气温度场分布,模拟精度随着距火源距离的增加而提高,远离火源的测点模拟结果与试验结果基本一致;有限元模拟可以准确得到桁架以弯曲失效为主的倒塌模式及变形规律。To investigate the temperature rise patterns and structural responses of large-space buildings like truss roof structures under fire,a fire collapse test was conducted on an actual steel-concrete mixed truss roof building.The test utilized stacks of wood as the fire source.The thermocouples,weighbridges,microwave radars,and high-temperature resistant inclinometers were used to measure the heat release rate of the fire source,internal air temperature of the building,temperature of structural components,and the displacements and rotations of key joints.The study identified the characteristics of the temperature rise and the laws of change in displacements and rotations of the structures under real fire conditions.Field simulation and finite element methods were employed to simulate the building's air temperature field and the thermal-structural coupled response,respectively.The accuracy of the numerical simulations was validated against the test results.The study reveals that the gas temperature field of the building shows a distinctly uneven distribution.The temperature range at the measurement points is from 500℃ to 900℃.The combustion pattern of the fire source could be divided into four stages:flashover,slow rise,steady state,and decay.The variation trend of the air temperature field is generally consistent with the variation of the heat release rate.The collapse of the mixed truss roof is initiated by bending failure of the top concrete chord,which is distinctly different from the collapse mechanisms due to buckling failure in pure steel trusses.The field simulation can accurately reproduce the air temperature distribution within the truss,and the simulation accuracy increases as the distance from the fire source increasing.The measurement points far from the five source are generally consistent with the simulation results.Finite element simulation can accurately determine the collapse mode,primarily due to bending failure,and the deformation patterns of the truss.

关 键 词：桁架 火灾 倒塌试验 场模拟 热力耦合 倒塌模式 

分 类 号：TU323.4[建筑科学—结构工程]