| Along with the advancement of SAAM and welding techniques, the orthotropic steel bridge deck is widely used in the field of bridge construction. But because of its complex structures, the welding residual stress, structural faults and the repeated wheelloads. the fatigue failure of orthotropic steel bridge decks attracts more and more attentions by bridge researchers. An investigation of ASCE has shown that 80 to 90 percent of the steel structural damage is closely related with fatigue. So it's very necessary to research the fatigue failure of orthotropic steel bridge decks. According to the orthotropic steel bridge decks of double-truss four-line plate-truss composite continuous steel trusses, this dissertation analyzed the fatigue properties of some typical constructed specifications.This paper induced the basic theories of conceptions of fatigue, mechanisms of the fatigue failure, factors influencing the fatigue strength, etc. And it summarized research methods of the fatigue failure of steel bridges, mechanisms of the fatigue failure and the mechanics characteristics of orthotropic steel bridge decks, typical constructed specifications and fatigue assessment methods of orthotropic steel bridge decks, etc.In this paper, some typical constructed specifications of orthotropic steel bridge decks were selected for the pattern design, then the project of loading was corroborated on the basis of structure forms and mechanical characteristics. AN SYS is used for the linear stress analysis of finite element models. Stress distributions of all typical constructed specifications were detailed researched. On that basis, MSC.Fatigue is used for the analysis of fatigue life. Based on the preceding analysis, we got the regression curves about fatigue lives and stress amplitudes. S-N curves and allowable stressranges of fatigue were deduced. The research results can be used as references of fatigue designs of orthotropic steel bridge decks. |
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