钢桁梁桥典型节点高强螺栓受力影响因素分析

Analysis of influencing factors of high-strength bolt force on typical joint of steel truss bridge

随着高强螺栓的出现以及制造工艺的进步,螺栓连接在钢桁梁桥中逐渐占据主体地位,然而钢桁梁桥螺栓脱落的情况较为严重。本文对预紧力、螺栓腐蚀和螺栓缺失等因素对螺栓受力特性的影响进行系统分析。结果表明:在外荷载作用下,节点板最外侧的第一排螺栓的拉应力最大,在养护过程中需重点关注;随螺栓预紧力的减小,螺栓应力呈减小趋势,在养护过程中,需关注预紧力的变化,防止其造成螺栓松动;随螺栓腐蚀面积的增大,螺栓的应力有较大幅度的增加,会增大其断裂概率,需加强巡视并及时更换被腐蚀螺栓;一侧节点板螺栓缺失,会对另外一侧节点板相应位置的螺栓应力产生较大影响,需关注这些螺栓的异常。

With the appearance of high-strength bolt and the progress of manufacturing technology,bolt connection gradually occupies the main position in the steel truss bridge.However,the bolt falling off of steel truss bridge is more serious at present.In this paper,the influences of preloading,bolt corrosion and bolt absence on bolt stress characteristics were analyzed systematically.Results showed that under the action of external load,the tensile stress of the first row bolt on the outmost side of the nodal plate was the largest,which should be paid more attention in the curing process.With the decrease in bolt pretension,bolt stress tended to decrease.During the maintenance process,the change of pretension should be paid attention to prevent bolt loosening.With the increase in the corrosion area of the bolt,the stress of the bolt increased greatly,which would increase the probability of fracture,it was necessary to strengthen the inspection and replace the corroded bolt in time.The absence of bolts on one side of the nodal plate would have a great impact on the bolt stress at the corresponding position of the other side of the nodal plate,so it was necessary to pay attention to the anomalies of these bolts.