公路斜拉桥焊接残余应力的减小与消除的技术策略

Technical Strategy for Reducing and Eliminating Welding Resdual Stress of Highway Cable-stayed Bridge

以重庆某大桥工程为背景,采用有限元分析软件ANSYS,研究钢箱梁正交异性板单元纵向U型肋板的焊接工艺对大跨度钢箱梁斜拉桥的焊接残余应力的影响。实践证明:需要保证温度场在焊接过程中的合理分布,首条焊缝与焊接温度场分布具有类似性,如果升温,此时将得到焊缝在焊接过程中稳定温度场的最高温度范围1 994～2 008℃,波动范围为0. 71%。焊接等效残余应力主要在焊缝区集中,最大等效应力为439 MPa;在焊接终止点和起始点附近,个别区域仅出现压应力,拉应力未出现。在实际生产中,总共要进行完整板单元的八条焊缝的焊接,所以,此时将会出现更大程度的上翘现象,所以需要结合有效的矫正措施应用在实际生产过程中,确保处理过程的正常推进。

This paper,taking a bridge project in Chongqing as the background,uses the finite element analysis software ANSYS to study the influence of the welding process of the longitudinal U type rib of the orthotropic plate element of the steel box girder on the welding residual stress of the long span steel box girder cable-stayed bridge.Practice has proved that it is necessary to ensure the reasonable distribution of temperature field in the welding process,the first weld and the distribution of welding temperature field is similar.If the temperature rises,then the maximum temperature range of the stable temperature field in the welding process will be obtained from 1 994~2 008℃,fluctuation range is 0.71%.The welding equivalent residual stress is mainly concentrated in the weld zone,the maximum equivalent stress is 439 MPa.In the vicinity of the welding termination point and the starting point,only compressive stress appears in some areas,but tensile stress does not appear.In actual production,a total of eight welds of the complete plate unit are welded,so there will be a greater degree of warping phenomenon,so it is necessary to combine effective corrective measures in the actual production process to ensure the normal progress of the treatment process.