低温焊接工况下管线拱桥耳板开裂机理研究

陈金义，廖伟华，范佐银

摘要:

针对某下承式钢结构系杆管线拱桥吊耳侧板环向焊缝裂纹的病害开展理论研究。在详细调查了现场吊耳侧板裂纹情况的基础上,对吊耳节点进行了空间有限元分析。分析结果表明引起吊耳裂缝的主要原因是：在低温环境下对吊耳节点进行现场施焊,由于吊耳侧板与盖板之间存在着较强的约束关系,阻碍了焊缝的冷缩效应,钢结构焊接残余应力和其他作用叠加下,在吊耳盖板中造成较大的应力,导致本次病害发生的主要原因。若将构造较复杂的节点采用工厂加工,采取反变形法、散热法等有利的措施可以避免低温工况下管线桥焊接裂纹。

Abstract:

A theoretical study was carried out on the cracks in the circumferential welding seam of the lug side plate of a through-type steel structure tied-bar pipeline arch bridge. Based on the detailed investigation of the cracks on the side plates of the lifting lugs on site, a spatial finite element analysis was carried out on the lug joints. The analysis results show that the main cause of the lifting lug cracks is: the on-site welding of the lug joints in a low temperature environment, due to the strong restraint relationship between the lug side plate and the cover plate, which hinders the cold shrinkage of the welding seam The effect, the welding residual stress of the steel structure and other effects superimposed, caused a relatively large stress in the lug cover plate, which led to the main reason for the occurrence of this disease. If the nodes with more complex structures are processed in the factory, and advantageous measures such as anti-deformation method and heat dissipation method can be adopted to avoid welding cracks of the pipeline bridge under low-temperature conditions.