施工过程箱梁腹板斜裂缝成因分析  

Analysis of Formation Causes of Diagonal Cracks in Box Girder Web in Construction Process

作　　者：王卫锋[1] 叶敬彬[1] 林致胜[1] 刘兵[1] 

机构地区：[1]华南理工大学土木与交通学院,广东广州510640

出　　处：《桥梁建设》2010年第1期32-35,共4页Bridge Construction

摘　　要：某预应力连续刚构桥,主梁为单箱双室箱梁,采用挂篮悬臂浇筑施工,施工过程中,箱梁腹板的下部出现斜裂缝。从设计、材料、环境温度、施工方法几方面对裂缝成因进行分析。进一步采用ANSYS有限元软件对该桥箱梁腹板进行局部受力分析,得知不张拉竖向预应力筋而继续悬臂挂篮施工,是造成腹板下部出现斜裂缝的主要原因。建议:尽快张拉前面节段竖向预应力筋,以后须先张拉前一节段的竖向预应力筋,才能移篮进行下一节段的施工。对现有裂缝,观察确定其不再发展,即进行封闭处理。Abstract： The main girder of＇a prestressed concrete continuous rigid-frame bridge is of the twin-cell single box girder that was cantileveredly cast with form traveler. In the construction process of the box girder, the diagonal cracks occurred in the lower part of the web of the girder. The formation causes of the cracks are analyzed from aspects of the design, material, environ- mental temperatures and construction methods and the finite element software ANSYS is further used to conduct the local stress analysis of the box girder web of the bridge. It is found that the main cause leading to the Cracks can be attributed to the continuous cantilever construction with form traveler without tensioning the vertical prestressing tendons and it is therefore proposed that the vertical prestressing tendons of the previous segment should be tensioned as early as possible and the form traveler can be shifted to the next segment only after the tendons are tensioned. For the existing cracks in the web, the cracks can be covered after it is certain that the cracks will not propagate any further through observation.

关 键 词：连续刚构桥 箱形梁 悬臂浇筑 腹板 裂缝 成因 受力分析 

分 类 号：U448.213[建筑科学—桥梁与隧道工程] U445.7[交通运输工程—道路与铁道工程]