焊接缺陷对超大跨拱桥钢管拱肋力学性能的影响

超大跨拱桥钢管拱肋本身对温度比较敏感,且误差累积效应明显,因此拱肋在焊接施工过程中的焊接缺陷对结构性能产生的不利影响将十分突出,甚至威胁结构安全性。为研究焊接缺陷对超大跨拱桥钢管拱肋整体力学性能影响,采用ANSYS有限元软件分析了拱肋钢管焊接残余变形大小与分布,并引入结构整体分析当中,得到了焊接残余变形对整体结构的影响规律,并从拱肋焊接制造方面提出了减小焊接变形的具体措施。结果表明：钢管-钢管对接焊接沿轴向焊接残余变形最大,为1.26mm；焊接缺陷使拱肋最大节点变形与最大杆件内力分别增大34.6%和22.9%；提出的施工措施对类似500m级拱桥工程减小焊接变形具有一定的指导性作用。

Effects of Welding Defects on Mechanical Properties of Super Length Steel Tube Arch Rib

Super length steel tube arch rib is sensitive to temperature, and the error accumulation is obvious, therefore, the adverse effects of the welding defects of the arch rib during the welding construction on the structural performance will be very prominent, and even threaten the structural safety. In order to study the effects of welding defects on global mechanical properties of super length steel tube arch rib, the ANSYS finite element software was used to investigate the welding residual deformation and distribution of the arch rib steel pipe, and it was introduced into the structure overall analysis. The influence of welding residual deformation on the overall structure was obtained, and specific measures to reduce welding deformation were proposed from the aspect of arch rib welding. The results show that the residual deformation along the axial direction of the steel pipe which is 1.26×10-3 m is the largest; The welding defects increase the maximum joint deformation and the maximum member internal force of the arch rib by 34.6% and 22.9% respectively; The proposed construction measures have a certain guiding effect on reducing the welding deformation of the similar 500 m arch bridge project.