液化天然气油罐车火灾下悬索桥主缆受火性能  

Suspension bridge main cable fire resistance in liquefied natural gas tanker truck fire

作　　者：宋恒宇 黄侨[1] 吴向阳 刘志 郭晓月 SONG Hengyu;HUANG Qiao;WU Xiangyang;LIU Zhi;GUO Xiaoyue(School of Transportation,Southeast University,Nanjing,Jiangsu 211189,China;Expressway Operation&Administration Center of Jiangsu Province,Nanjing,Jiangsu 210009,China;Zhejiang Communications Investment Group Co.,Ltd.,Zhoushan,Zhejiang 316053,China;School of Civil Engineering,Nanjing Tech University,Nanjing,Jiangsu 211816,China)

机构地区：[1]东南大学交通学院,江苏南京211189 [2]江苏省高速公路经营管理中心,江苏南京210009 [3]浙江舟山跨海大桥有限公司,浙江舟山316053 [4]南京工业大学土木工程学院,江苏南京211816

出　　处：《公路交通科技》2025年第3期136-146,共11页Journal of Highway and Transportation Research and Development

基　　金：江苏省基础研究计划(自然科学基金)项目(BK20181278)。

摘　　要：【目标】悬索桥作为重要的交通基础设施,其主缆的耐火性能直接关系到火灾下桥梁的安全性与稳定性,因此研究悬索桥液化天然气油罐车(LNG)火灾下不同环境因素对主缆受火性能的影响,对桥梁火灾防护和结构抗火设计具有重要意义。【方法】本研究针对国内某通行LNG油罐车的特大跨悬索桥,建立了LNG油罐车火灾数值模型,并对火灾场景下的火源高度、环境风速和持火时间等影响因素进行了参数分析。重点研究对比了不同条件下LNG油罐车火灾对悬索桥跨中主缆截面的影响,并提出了一种基于“加权平均”概念的主缆刚度折减计算方法,以评估主缆在火灾中的刚度变化。【结果】火源高度对火灾模拟结果有显著影响,在无风情况下桥面火灾是较为不利的场景,而在有风情况下车身起火的场景更为关键。环境风在最不利情况下可能导致火焰向主缆方向倾斜,进而导致主缆直接接触火焰,需根据火源与缆索系统的相对位置综合考虑风速及环境风的影响。火焰持续时间决定了火焰的发展状态、构件的温度变化及结构的响应,应根据具体研究对象和实际需求来确定。【结论】综上所述,火源与缆索系统的相对位置、环境风速和持火时间是影响悬索桥主缆受火性能的关键因素。在进行桥梁抗火设计时,应针对桥梁工程的实际结构确定最不利火灾场景,以指导桥梁火灾防护和结构抗火设计。[Objective]Suspension bridges are critical transportation infrastructure.The fire resistance of suspension bridge main cables directly impacts the bridge safety and stability.This study investigated the influence of various environmental factors on main cable fire resistance in liquefied natural gas(LNG)tanker truck fire.It has significance for bridge fire protection and structural fire resistance design.[Method]The numerical model of LNG tanker truck fire was established for a LNG tanker truck allowed long-span suspension bridge in China.The influencing factors,e.g.,fire source height,ambient wind speed and fire duration in fire scene,were analyzed with parameters by using the model.The influences of LNG tanker truck fire under different conditions on the suspension bridge mid-span main cable cross-section were primarily studied and compared.Based on the concept of weighted average,a calculation method for main cable stiffness reduction was proposed to evaluate the main cable stiffness variation in fire.[Method]The fire source height significantly affects the fire simulation outcomes.In windless conditions,the fire primarily occurs on bridge deck.Whereas,in windy conditions,the fire originating from vehicle is more critical.Under the most unfavorable wind conditions,the flames can tilt toward main cables,potentially causing the direct contact between flames and cables.The wind speed and ambient wind effects need to be considered comprehensively based on the relative position of fire source to cable system.The fire duration determines the flame development state,components temperature variation,and structure response,which should be determined based on the specific study subject and practical needs.[Conclusion]The relative position of fire source to cable system,ambient wind speed,and fire duration are the key factors influencing the suspension bridge main cable fire resistance.For fire resistance design,it is essential to analyze the worst-case fire scenarios specific to the bridge structure,thereby guiding the

关 键 词：桥梁工程 主缆受火性能 热力耦合方法 主缆温度 刚度折减 安全与事故 

分 类 号：U447[建筑科学—桥梁与隧道工程]