某正交异性板钢桥弧形切口疲劳开裂的现场监测分析  

Field monitoring analyses of diaphragm cutout fatigue cracking at an orthotropic steel bridge

作　　者：祝志文[1] 黄炎[1] 陈魏[1] 向泽[1] 

机构地区：[1]湖南大学土木工程学院,湖南长沙410082

出　　处：《铁道科学与工程学报》2018年第1期118-128,共11页Journal of Railway Science and Engineering

基　　金：国家重点基础研究发展计划("973"计划)资助项目(2015CB057701;2015CB057702);湖南省交通科技资助项目(201522)

摘　　要：正交异性桥面板弧形切口开裂问题在早期建成的钢桥上时有发生。通过现场监测随机车流下弧形切口的应力时程,获得弧形切口的应力谱,基于等效损伤原则获得构造细节的等效应力幅和加载次数,并基于AASHTO规范开展弧形切口疲劳评价。研究结果表明:横隔板弧形切口仅能分别轴组,在超载车辆作用下,横隔板弧形切口将产生很大的应力响应,应力峰值可能会超过钢材的设计应力。弧形切口面内应力主导,横隔板厚度增大可以有效降低总体应力水平。结果显示弧形切口疲劳寿命远小于设计寿命,横隔板偏薄、货车通行比例高、通行量大和超载严重是导致该桥过早出现疲劳开裂的主要原因。The cutout cracking was occasionally happened at early constructed orthotropic steel bridge, the relevant report of its fatigue field measurement under random traffic had not seen at home and abroad. The recorded stress time histories of the cutout under random traffic were analysed to obtain stress spectrum, effective stress range and loading cycles were determined according to the damage equivalent principle, and finally to evaluate its fatigue performance based on AASHTO LRFD. The research finds that the effects the axles group could be observed at diaphragm cutout, the overloaded truck would produce significant stress response at cutout, and even exceed the design stress of steel. Diaphragm cutout was controlled by the in-plane stress, increasing the thickness of diaphragm could effectively reduce total stresses. The results show that the fatigue life was much shorter than the design life of cutout, the thin diaphragm plate, the high fraction of trucks with overweight gross weight and axle weight primary caused the bridge early fatigue cracking.

关 键 词：正交异性钢桥面板 疲劳 弧形切口 应力监测 超载 

分 类 号：U448.36[建筑科学—桥梁与隧道工程]