火灾后斜拉桥斜拉索损伤检测与结构安全性能评定方法研究  

Stay Cable Damage Detection and Structural Safety Evaluation for Cable-Stayed Bridge After Fire Exposure

作　　者：许肇峰 陈映贞 李毅 张建[1] XU Zhaofeng;CHEN Yingzhen;LI Yi;ZHANG Jian(Southeast University,Nanjing 211189,China;Guangdong Jiaoke Testing Co.,Ltd.,Guangzhou 510550,China;Guangdong Hualu Transportation Technology Co.,Ltd.,Guangzhou 510550,China;Bay Area Bridge Maintenance Technology Center at Guangdong Provincial Highway Construction Co.,Ltd.,Guangzhou 511447,China)

机构地区：[1]东南大学土木工程学院,江苏南京211189 [2]广东交科检测有限公司,广东广州510550 [3]广东华路交通科技有限公司,广东广州510550 [4]广东省公路建设有限公司湾区特大桥养护技术中心,广东广州511447

出　　处：《桥梁建设》2024年第2期48-56,共9页Bridge Construction

基　　金：国家重点研发计划项目(2019YFC1511100)。

摘　　要：为准确分析火灾后斜拉桥斜拉索损伤状况,评定桥梁结构安全性能,根据桥梁火灾应急检测工程需求,提出一套火灾后斜拉桥斜拉索损伤检测与结构安全性能评定方法。该方法包括火灾现场勘察、斜拉索烧损状况检查、斜拉索损伤检测分析和结构安全性能评定4个阶段。根据斜拉索火灾损伤特点,开展高温后斜拉索高强钢丝和高密度聚乙烯(HDPE)护套试件拉伸试验,研究其高温后表观特征和力学性能指标随历经温度的变化规律,建立斜拉索历经温度及损伤定量检测分析计算公式,并将该方法应用于某独塔预应力混凝土斜拉桥火灾后斜拉索损伤检测与结构安全性能评定。结果表明:高温后斜拉索高强钢丝和HDPE护套的表观特征、力学性能均随温度升高呈现出明显的规律性变化;随着温度升高,高温后斜拉索高强钢丝的抗拉强度、屈服强度先降低后升高,弹性模量衰减缓慢,HDPE护套断裂标称应变逐渐降低;火灾后斜拉索和主梁承载能力满足使用要求,结构整体安全;所提出的火灾后斜拉桥斜拉索损伤检测与结构安全性能评定方法科学、实用、有效,可为火灾后斜拉桥损伤检测评定、营运管理和维修处治提供技术借鉴。This paper presents a method to detect damages of stay cables and evaluate structural safety of the cable-stayed bridge after fire exposure,considering the requirements of bridge fire emergency inspection projects.The fire emergency inspection incorporates four stages,including fire site survey,stay cable burned damages inspection,stay cable damages analysis and structural safety evaluation.Considering the characteristics of fire damages of stay cables,tensile tests were conducted to examine the changes of visual appearance and mechanical property indicators of high-strength steel wires and HDPE sheaths of stay cables after a fire event.Equations to quantitatively calculate the exposure temperatures and damages of stay cables were established.The presented method has been applied to an existing prestressed concrete cable-stayed bridge with a single pylon.It is concluded that the visual appearance and mechanical property of the high-strength steel wires and HDPE sheaths of stay cables show sign of regular changes with the temperature rising.As the temperature rises,the tensile and yield strengths of the high-strength steel wires first decrease,and increase afterwards,the elastic modulus attenuate slowly,and the nominal strain at break of HDPE gradually decrease.After the fire event,the load bearing capacity of the stay cables and main girder meet the requirements,and the overall structure is safe,proving the presented method to detect the stay cable damages and structural safety evaluation is applicable and efficient,which can provide technical support for cable-stayed bridge damage detection,evaluation,maintenance,management and retrofit after a fire event.

关 键 词：斜拉桥 斜拉索 火灾损伤 损伤检测 结构安全性能评定 拉伸试验 

分 类 号：U448.27[建筑科学—桥梁与隧道工程] U446.3[交通运输工程—道路与铁道工程]