在役斜拉桥车致火灾作用下拉索抗火性能研究  

Fire Resistance Performance of Cables for In-service Cable-stayed Bridges in Vehicle-induced Fire Accidents

作　　者：冯锦鹏 李经纶 高康 杨兴 吴刚[1,2,3] FENG Jin-peng;LI Jing-lun;GAO Kang;YANG Xing;WU Gang(Key Laboratory of Concrete and Prestressed Concrete Structures of the Ministry of Education,Southeast University,Nanjing 211189,Jiangsu,China;National and Local Joint Engineering Research Center for Intelligent Construction and Maintenance,Southeast University,Nanjing 211189,Jiangsu,China;School of Civil Engineering,Southeast University,Nanjing 211189,Jiangsu,China;Shaanxi Transportation Holding Group Tongyu Transportation Research Co.Ltd.,Xi'an 710000,Shaanxi,China)

机构地区：[1]东南大学混凝土及预应力混凝土结构教育部重点实验室,江苏南京211189 [2]东南大学智慧建造与运维国家地方联合工程研究中心,江苏南京211189 [3]东南大学土木工程学院,江苏南京211189 [4]陕西交控通宇交通研究有限公司,陕西西安710000

出　　处：《中国公路学报》2024年第9期34-45,共12页China Journal of Highway and Transport

基　　金：国家自然科学基金青年科学基金项目(52208151);江苏省自然科学基金青年科学基金项目(BK20210254);江苏省研究生科研与实践创新计划项目(KYCX23_0271)。

摘　　要：拉索在桥梁服役期间易遭受腐蚀、车致火灾等因素的影响。当前在役斜拉桥复杂环境作用下结构安全评估方法研究尚不完善。因此,以某服役时间超过25年的斜拉桥拉索为研究对象,开展在役钢丝高温下的拉伸试验,得到在役钢丝高温下力学性能退化规律和计算模型。基于在役钢丝高温下力学性能退化规律,利用Fire Dynamics Simulator软件建立300 MW油罐车失火工况下的火源模型。通过ANSYS分别建立在役斜拉桥拉索传热分析模型和在役斜拉桥结构模型,并开展结构热力耦合分析。结果表明:最不利条件下,300 MW油罐车火灾总计造成桥梁1/4跨附近3组(共6根)斜拉索失效断裂,各组拉索断裂时间分别为551、592、1064 s;自重作用下主梁挠度最大下降0.08 m,挠跨比1/1250,主梁挠度变化速率最大值为9.6 mm·min^(-1),均处于规范(JTG/T D65-01—2007)的限值内;300 MW油罐车火灾不会造成该在役斜拉桥结构整体垮塌,但会对斜拉桥拉索造成不可逆的严重损伤。研究成果可为在役桥梁复杂环境作用下结构安全分析与评估提供参考。The cable is susceptible to corrosion,vehicular-induced fire,and other detrimental effects during bridge services.The current studies on the structural safety assessment methods of in-service cable-stayed bridges under complex environmental conditions are not complete.Therefore,this study focuses on the cables of a cable-stayed bridge with a service life exceeding 25 years and conducts tensile tests at elevated temperatures to obtain corresponding degradation patterns and computational models.After defining the degradation rule of in-service cable at high temperatures,a fire source model caused by a 300 MW tank car was created using the Fire Dynamics Simulator.The heat transfer analysis model and the structural model of the in-service cable-stayed bridge were established using ANSYS,and structural thermodynamic coupling analysis was conducted.The results indicate that under the most unfavorable conditions,the fire from the 300 MW oil tanker leads to the failure and rupture of three groups(six)of cables near 1/4 of the span of the bridge,and the failure times of the groups are 551 s,592 s,and 1064 s,respectively.Owing to the effects of the bridge dead weight,the maximum deflection of the main girder decreases by 0.08 m,the deflection span ratio is 1/1250,and the maximum deflection rate is 9.6 mm·min-1.All the outcomes are within the limits of the JTG/T D65-01—2007 standard.The 300 MW tanker truck fire cannot cause a complete collapse of the entire bridge structure but results in severe and irreversible damage to the cable.The study's findings provide a reference for structural safety analysis and evaluation of in-service bridges in complex environments.

关 键 词：桥梁工程 在役拉索 火灾试验 抗火性能 腐蚀火灾作用 

分 类 号：U447[建筑科学—桥梁与隧道工程]