| Recent years, with the rapid economic development and transportation urgent demand, steel truss bridges have been built more and more, given that they be used in various bridge types. The fatigue performance of steel bridges with repeated alternating load has become one of the hot spots of bridge engineering. As one of the main forms of large span steel bridge, the steel truss bridges’fatigue performance is still open to study. Therefore, based on reviewing the fatigue accidents of steel truss bridges, the fatigue performance of the welded detail of the ventral rod of steel truss bridge is calculated by means of hot spot stress method.The main research contents and steps are as follows:1. Assessment theory of steel bridge fatigue life in great detail and the geometry design of the fatigue experiment’s specimen are described. According to fatigue experiment results, the fatigue life of welded details with access hole and welded details with the semicircle arc plate in access hole are obtained, and the fatigue performance of them is compared.2. Through 3-D finite element model of ANSYS, stress on welded details with access hole and welded details with the semicircle arc plate in access hole are analyzed, and then the finite element model are conducted to calculate hot spot stress of welding site. According to the hot spot stress method, the fatigue life of welded details is calculated, and these results are compared with the experiment result.3. During the calculation of hot spot stress of welding site with access hole, the parameters affecting the hot spot stress are analyzed, and mainly grid division of the finite element model near welding site and extrapolation formula are compared and analyzed through 3-D finite element analysis, and some useful conclusions are obtained.4. The influence parameters of the stress concentration factor are studied, and the conclusions will provide some reference value to the design and fatigue life evaluation of welded details with access hole in the future. |
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