钢桁桥横梁裂纹病害原因分析与处治对策  

Analysis of Crossbeam Crack of Steel Truss Bridge and Countermeasures

作　　者：刘华[1,2] 裴庆红 阳春龙 王之俊 

机构地区：[1]中铁大桥勘测设计院集团有限公司,湖北武汉430050 [2]中铁大桥(南京)桥隧诊治有限公司,南京210061 [3]九江长江大桥(公路桥)管理局,江西九江332000

出　　处：《中国铁道科学》2012年第B08期92-98,共7页China Railway Science

基　　金：铁道部科技研究开发计划项目（20110019A）

摘　　要：某钢桁桥在运营十余年之后，支承行车道板的横梁相继出现裂纹。通过对该桥梁裂纹病害分布和发展情况以及钢横梁在外荷载作用下受力的研究，分析钢桁桥裂纹病害的原因并提出整治措施。钢横梁的裂纹分布和发展具有很强的规律性，伸缩缝处横梁的裂纹相对其他部位出现的早而且严重；产生裂纹的原因与构造细节和车辆活载作用有关，属于疲劳裂纹；对局部构造进行加固改造可有效减小应力峰值，延迟疲劳裂纹的出现。应力集中和疲劳是导致钢桁梁出现裂纹的主要内因，桥梁的长期超负荷运营则是裂纹病害发生和发展的外因，提出的增设加劲板方案可以有效改善桥梁的局部受力情况，并在一定程度上可延缓裂纹的出现和发展。After open to traffic for more than ten years, some cracks occurred on the crossbeams of a cer- tain steel truss bridge. Through investigating the crack distribution and development as well as the me- chanical performance of crossbeam under external load, the causes for crack disease and countermeasures were presented. It was found that the crack distribution and development had obvious characteristic of reg- ularity. The crossbeams adjacent to expansion joints are easier to crack than other crossbeams and the cracks are severe. The structural details and live load action have direct influence on the crack, and this crack can be classified as fatigue crack. Retrofit of partial structural details will largely reduce the stress range, and delay the occurrence of fatigue crack. Stress concentration and fatigue are the major internal causes for crack, while the long-term overload operation of bridge is the critical external cause for the oc- currence of crack and its development. The proposal for the retrofit of crossbeam by adding transverse stiffened plates can effectively improve the mechanical performance of bridge and postpone the occurrence and development of crack to a certain extent.

关 键 词：钢桁桥 横梁 疲劳 裂纹 加固 

分 类 号：U448.36[建筑科学—桥梁与隧道工程] U448.211[交通运输工程—道路与铁道工程]