Research On A Bridge Steel Box Girder Stability Analysis And Structure Optimization By The Finite Element Simulation

Since the 21 st century,the industrial technology has been developed rapidly in China.In the field of bridge engineering,the structure of the steel box girders has been widely used due to the excellent performance.In this dissertation,the stability of steel box girder and bridge ultimate bearing capacity of an engineering example were analyzed systematically according to relevant theoretical analysis and finite element calculation.The structure parameters and bridge fitting formula for computing the data were summarized,and the structural stability and some effects of coefficients on ultimate bearing capacity were discussed.Finally,Fitting optimization design was carried out.The main works are as followings.First,the application,development and structure of steel box girder were introduced.Then research achievements in domestic and foreign study about stability analysis and yield stability of steel box girder were summarized,in addition,technical route was described.Second,based on the modeling of finite element analysis theory and mechanics,steel box girder bridge was expounded,and the plate and shell element model was established by finite element analysis software Midas Civil and FEA.In addition,the structure theory and analysis methods on static strength problems were summarized during the operation stage of steel box girder.The dynamic and static analysis of the structure were carried out to verify the rationality of the structure and the accuracy of the model.Static analysis was mainly calculated the structural force especially under static load,dynamic load and temperature load,and deformation and stress distribution were calculated under load combined.The subspace iteration method was used to analyze bridge vibration modal,and reflection spectrum method was used to calculate seismic response of the bridge.Furthermore,based on the self-vibration mode,analysis the difference effects of whether to consider pile-soil interaction or not on steel box girder bridge.Finally,the stability of the structure with the plate element models was analyzed.The whole linear stability coefficient,yield coefficient and stability safety coefficient in the operational phase can be got by changing structure height and thickness of the plate.Through the result,it can be found that the second kind of stability safety coefficient of the steel box girder is far less than the linear stability safety factor when non-linear effect is considered.After fitting parameters and calculating data,the bridge design was optimized to provide a reference for the stability analysis and design of steel box girder bridge.