The Fatigue Performance Analysis Of Welded Detail Of Fully Welded Truss Plate Based On Hot Spot Stress Method

Steel truss bridge has the advantages of beautiful appearance and high bearing capacity, the building technology is mature. Fully welded truss structure will reduce the difficulty of manufacture and installation, and speed up the construction progress. At present, some new bridges including the Pingtan Strait Rail-cum-Road Bridge,Tongling Changjiang River Bridge and Hutong Changjiang River Bridge have adopted this structure. The fully welded truss structure has many weld details and integral joints. The fatigue of welding details will directly affect the service life of the bridge. At present, the special studies on the fatigue problems of the weld details of fully welded beam are few. Therefore, in this paper, the hot spot stress method is used to study the fatigue life of this special weld detail.The main research contents and steps are as follows:1.Fatigue experiments for the welded detail of fully welded truss, and obtained the fatigue life of the weld detail.2.By establishing finite element models, calculated and analyzed the stress distribution of the weld detail of the fully welded truss. Calculated the hot spot stress at the weld toe, compared and analyzed the influence of different grid sizes and two kinds of extrapolation methods on the hot spot stress calculation.3.S-N curve is used to assess the fatigue life of the weld detail, by comparing the experimental results with the estimated results, obtained some conclusions of practical value.4.By establishing several finite element models, carry out the analysis of influencing parameters, compared and analyzed the change trend of maximum stress value and stress concentration factor of welded joint of welded plate when the weld size, access hole radius and loading conditions are different. It provides some references for the design of this special weld detail and the evaluation of fatigue life in the future.