栓接钢箱梁高强度螺栓病害分析

Analysis on High-strength Bolt Disease of Bolting Steel-box Girder

某主跨618 m的栓接钢箱梁出现螺栓439套断裂、16073套严重锈蚀的现象。采用病害情况调查、金相分析、化学成分分析、有限元分析等方法从材质初始缺陷、加工工艺、应力腐蚀、受力性能、疲劳断裂等方面分析断裂原因。结果表明,桥面积水从铺装破损处的连接接头渗入箱梁,引起的应力腐蚀是该桥高强度螺栓断裂的主要原因。基于该分析,对严重锈蚀和断裂的螺栓进行了更换,对渗水点进行封堵,高强度螺栓锈蚀断裂情况明显减少。

There are 439 sets of broken bolts and 16073 sets of seriously corroded bolts on a bolted steel box girder with a main span of 618 m.The fracture reasons are analyzed from the aspects of initial material defects,processing technology,stress corrosion,mechanical properties and fatigue fracture by using the methods of disease investigation,metallographic analysis,chemical component analysis and finite element analysis.The results show that the bridge deck water seeps into the box girder from the connection joint at the pavement damage.The caused stress corrosion is the main reason to cause the fracture of the high-strength bolt of the bridge.Based on the analysis,the bolts with serious corrosion and fracture have to be replaced,and the seepage point is blocked,and the corrosion and fracture of high-strength bolt will be obviously reduced.