In order to study the effect of welding process on residual stress of intersecting joint of arch rib of concrete-filled steel tube arch bridge,an indirectly sequential coupled thermal-mechanical finite element analysis method was established to numerically simulate the temperature field and residual stress field of intersecting joint of arch rib,and the accuracy of the finite element analysis method was verified by comparing with the experimental results in literatures.Furthermore,the intersecting joint of arch rib at arch foot of Shuangbao bridge on Xiangyu expressway was numerically simulated to analyze the temperature field and residual stress field.On the basis,the effect of different welding process parameters such as welding heat input,welding speed,preheating treatment and post-weld heat treatment on welding residual stress changing at different positions of the intersecting joint of arch rib were compared and analyzed.The result shows that the distribution of welding residual stress is basically the same in different welding heat input and welding speed.Welding residual stress is positively correlated with welding heat input,and is negatively correlated with welding speed.With the decrease of welding heat input and the increase of welding speed,residual stress in tension and compression reduces in general.When the intersecting joint of arch rib is subjected to the preheating treatment at the temperatures of 150-200 ℃,the decrease of total residual peak stress is above 4％.But the preheating treatment has little effect to the distribution of welding residual stress.Increasing the preheating temperature reduces the residual peak stress efficiently.When the intersecting joint of arch rib was subjected to the post-weld heat treatment at the temperatures of 550-650 ℃ for a holding period of 4 h,the decrease of total welding residual stress is above 40％.Increasing the post-weld heat treatment temperature reduces residual stress efficiently.The intersecting joint of arch rib of the concrete-filled steel tube arch bridge can reduce welding residual stress by decreasing welding heat input,increasing welding speed,preheating treatment and post-weld heat treatment.
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