三塔自锚式悬索桥主缆抗火性能评估方法  

Evaluation Method for Fire Resistance of Main Cable of Three-Tower Self-anchored Suspension Bridge

作　　者：马如进[1] 邹明明 MA Rujin;ZOU Mingming(School of Civil Engineering,Tongji University,Shanghai 200092,China;Anhui Transport Consulting&Design Institute Co.,Ltd.,Hefei 230088,Anhui,China)

机构地区：[1]同济大学土木工程学院,上海200092 [2]安徽省交通规划设计研究总院股份有限公司,安徽合肥230088

出　　处：《重庆交通大学学报（自然科学版）》2022年第12期77-84,共8页Journal of Chongqing Jiaotong University(Natural Science)

基　　金：交通运输部公路工程行业标准制修订项目(JTG-202015)。

摘　　要：提出了一种简易的桥梁结构抗火性能评估方法。首先,通过开展构件传热分析,获取了车致火灾下构件温度场时程曲线;建立了全桥热-结构耦合作用模型,对全桥结构高温下静力响应及安全性进行了分析与评估。然后,以某钢-混简支梁试件为对象,数值模拟分析了火灾下构件温度场及静力响应,并将分析结果与试验结果进行对比以验证所建模型的准确性。最后,以某悬索桥为工程背景,开展了油罐车、货车、客车及小汽车等4种车型发生火灾工况下构件传热分析及结构响应分析;根据自定义缆索损伤评估标准,采用所提出的评估方法对主缆局部损伤状况进行了评估。研究表明:油罐车发生火灾对结构的危害最严重,主缆最高温度可达830℃,虽然跨中挠度仅增加160 mm,但主缆产生了严重的不可逆损伤;所提出的评估方法可用于大跨径缆索承重桥梁结构抗火性能及安全性分析。A simplified evaluation method for fire resistance of bridge structures was proposed. Firstly, the time history curve of component temperature field under vehicle-induced fire was obtained by conducting component heat-transfer analysis. The thermal-structural coupling model of the whole bridge was established, and the static response analysis and safety of the whole bridge under high temperature were evaluated. Then, taking a steel-concrete simply supported beam specimen as the object, the temperature field and static response of members under fire were analyzed by numerical simulation, and the analysis results were compared with the test results to verify the accuracy of the proposed model. Finally, based on the engineering background of a suspension bridge, the heat-transfer analysis and structural response analysis of components under fire conditions of four types of vehicles, such as oil tankers, trucks, buses and cars, were carried out. According to the self-defined cable damage assessment criteria, the local damage of the main cable was evaluated by the proposed evaluation method. The research shows that the most serious damage to the structure is caused by the fire of the oil tanker. The maximum temperature of the main cable can reach 830 ℃. Although the mid-span deflection increases by only 160 mm, the main cable suffers serious irreversible damage. The proposed method can be used to analyze the fire resistance and safety of long-span cable supported bridges.

关 键 词：桥梁工程 自锚式悬索桥 车致火灾 传热分析 热-结构耦合模型 损伤评估 

分 类 号：U447[建筑科学—桥梁与隧道工程]