油轮爆火环境悬索桥安全性能预测与预警方法研究  

Research on Safety Performance Prediction and Warning Methods of Suspension Bridges Exposed to Oil Tanker Explosion Environments

作　　者：张岗[1] 陆泽磊 袁卓亚 傅彦青[3] 王世超 汤陈皓 ZHANG Gang;LU Ze-lei;YUAN Zhuo-ya;FU Yan-qing;WANG Shi-chao;TANG Chen-hao(School of Highway,Chang'an University,Xi'an 710064,Shaanxi,China;CCCC First Highway Consultants Co.Ltd.,Xi'an 710075,Shaanxi,China;Central Research Institute of Building and Construction Co.Ltd.,MCC Group,Beijing 100088,China)

机构地区：[1]长安大学公路学院,陕西西安710064 [2]中交第一公路勘察设计研究院有限公司,陕西西安710075 [3]中冶建筑研究总院有限公司,北京100088

出　　处：《中国公路学报》2024年第9期17-33,共17页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(52378476,52078043);陕西省自然科学基础研究计划项目(2022JC-23);陕西省创新能力支撑计划项目(2023-CX-TD-38);中央高校基本科研业务费专项资金项目(300102214903,300102214401)。

摘　　要：油轮爆燃火灾威力巨大,严重威胁跨海桥梁的安全性能。为研究悬索桥在油轮爆燃致复杂极端火灾环境中的结构响应,明确悬索桥遭遇复杂极端火荷载时的安全性能,选取某大跨径悬索桥作为研究对象,给出了油轮爆火(爆燃火灾)时悬索桥结构安全性能(耐火性能)预测过程。首先采用火灾动力学-有限元(CFD-FEM)耦合方法,重构了油轮爆燃火灾环境,建立了悬索桥局部受火梁段和全桥结构在油轮爆火环境的三维多尺度数值预测模型,深入揭示了油轮爆火时局部受火梁段的传热模式和全桥结构性能演变规律。继而,研究了油轮爆火时悬索桥钢箱梁(加劲梁)的高温响应和失效模式,分析了不同起火位置、起火面至钢箱梁底板距离和风速对悬索桥火灾响应行为的影响,提出了油轮爆火环境悬索桥耐火极限预警方法。研究结果表明:油轮爆火环境悬索桥局部受火梁段随受火时间其变形不断增大,受火梁段表现出整体下挠后中间区域上拱的失效模式,导致中间区域吊索索力呈现出先增大后减小的发展趋势;起火位置对悬索桥整体结构性能影响较大,随着起火位置接近悬索桥跨中区域,该区域梁段较近塔区域梁段受火下挠量增加62%;起火面至钢箱梁底板距离由50 m减到20 m时,局部梁段的下挠峰值和总上拱值(下挠峰值与上拱峰值之差)增幅超过19%,结构失效时间提前10 min;风速会改变油轮爆燃火焰形态,明显影响悬索桥加劲梁两侧边箱梁的受热面分布形态和高温响应特征,风速8 m·s^(-1)时迎风侧边箱梁受火强度明显减弱,相对2 m·s^(-1)时底板总上拱幅度减小17%;钢箱梁底板反弯变形时的临界温度介于510℃~550℃之间,钢箱梁底板屈曲失稳时的极限温度介于685℃~715℃之间,临界温度和极限温度可作为钢箱梁结构安全性能的两阶段预警温度,从而实现钢箱梁失效前的2次实时预警。研究结论可�Oil-tanker explosion fire has enormous power and poses a severe threat to the safety performance of crossing sea bridge.In order to study the structural response of suspension bridges exposed to complex extreme fire environments caused by oil-tanker explosions,and to clarify the safety of suspension bridges under complex extreme fire loads,a large-span suspension bridge was selected as the research object.The prediction process of suspension bridges safety performance(fire resistance)during oil-tanker explosion fires was provided.Firstly,the computational fluid dynamics-finite element method(CFD-FEM)coupling method was used to reconstruct the oil-tanker explosion fire environment.A three-dimensional multi-scale numerical prediction model for local girder segment and the entire bridge structure were established.The heat transfer mode of bridge segment and performance evolution of the entire bridge structure during oil-tanker explosion were revealed in depth.Subsequently,the high-temperature response and failure mode of steel box girder(stiffening girder)under oil-tanker explosion were studied,and the effects of different fire positions,distance from the fire surface to bottom plate of steel box girder,and wind speed on the fire response behavior of suspension bridge were analyzed.A fire resistance limit warning method for suspension bridges exposed to oil-tanker explosion environment was proposed.The research results indicate that the deformation of local suspension bridge segment under oil-tanker explosion continues to increase.And the fire affected bridge segment shows a failure mode of overall downward deflection followed by upward bowing in middle area,resulting in a development trend of first increasing and then decreasing for suspension cable force in the middle area.The fire position has a significant impact on the overall structural performance of the suspension bridge.As fire position approaches the mid span area,the deflection of girder segment in the middle area increases by 62%compared to the girder se

关 键 词：桥梁工程 油轮爆燃火灾 CFD-FEM耦合方法 安全性能预测 悬索桥 预警温度 

分 类 号：U448.25[建筑科学—桥梁与隧道工程]