预应力空心板梁火灾仿真分析与评估  

Simulation Analysis and Evaluation of Prestressed Hollow Slab Girders Subjected to Fire Disaster

作　　者：刘其伟[1] 王成明 罗文林[3] 

机构地区：[1]东南大学交通学院,南京市210096 [2]上海林同炎李国豪土建工程咨询有限公司南京分公司,南京市210016 [3]东南大学建筑设计研究院交通分院,南京市210096

出　　处：《公路》2014年第1期35-43,共9页Highway

摘　　要：以江苏省内某高速公路预应力空心板桥的突发性火灾为研究对象,阐述了火灾高温对混凝土、钢筋以及钢绞线力学指标的影响,总结了火灾现场温度的判定方法,提出了桥梁火灾仿真分析与评估的实施步骤。通过火灾燃烧物性质分析,选择了EUROCODE烃类火灾升温曲线,论述了火灾下混凝土爆裂机理,在此基础上建立了空心板混凝土与内腔封闭孔洞内空气的流固耦合传热模型并进行火灾温度场有限元仿真分析。根据有限元计算结果,比较了火灾作用下底板混凝土爆裂对空心板温度场的影响,最后结合火灾后材料性能的变化对板梁火损状况进行综合评估,研究成果可供火灾桥梁的分析与评估参考。Taking a sudden fire which happened under a prestressed hollow slab bridge of one expressway in Jiangsu Province as the research object, this paper expoundes the impacts of high temperature of fire on the mechanics performance of concrete, steel and strand, summarizes the temperature estimating method for the fire site, and then proposes implementation steps of simulation analysis and evaluation for bridge＇s fire disaster. Through the property analysis of the fire comburent, the authors select hydrocarbon temperature-time curve （EUROCODE）, and discuss the mechanism of concrete explosive spalling under fire disaster. On this basis, a fluid-solid coupling heat transferring model of hollow slab concrete and air in an enclosure is built to simulate the fire temperature field. According to the results of finite element calculation, the authors compare the influence of bottom concrete explosive spalling on hollow slab temperature field subjected to fire. Finally, this paper comprehensively evaluates the fire damaged situation of the hollow slab by analyzing the changes of the material properties after fire disaster. The research results of this paper could provide references for the analysis and evaluation of bridge＇s fire disaster.

关 键 词：桥梁工程 预应力空心板梁 火灾温度场 苯乙烯 爆裂 仿真分析与评估 

分 类 号：U445.75[建筑科学—桥梁与隧道工程]