Double-deck Suspension Bridge Steel Truss Fatigue Performance Analysis And Experimental Study On The Integral Joint

In order to meet the requirements of the rapid development of traffic, the construction of long-span double-layer steel bridge occupies an important place in the future. To use the integral joint connection technology on the long-span double-layer steel bridge will also be an inevitable trend. Integral node is between the thicker steel plate welding, and the welding seam and more intertwined. So for long-span double-layer integral joint of steel bridge fatigue test research is particularly important. Taking the Dalian XingHaiWan Sea-crossing Bridge as the research background in this thesis. Simulation fatigue of the integral joint of the bridge is analyzed in large commercial finite element software Ansys-Workbench. And developed the fatigue test plan according to the results of the limit element analysis.By comparing the experimental data and the theoretical data, to determine the reliability of the finite element analysis software and the anti-fatigue performance of steel bridge.First of all, leading to fatigue concepts introduced by fatigue failures in this thesis. By comparing the linear accumulated damage theory and nonlinear accumulated damage theory, to explain the applicable scope of the two theories respectively. And expounds the advantages and disadvantages of both.Secondly,the fatigue fracture of several stages were analyzed from the perspective of fracture mechanics. The fatigue source area, the steady expansion of area and transient breaking area characteristics is given respectively. The difference and commonness is discussed between fatigue fracture and the common static load fracture from the macro and micro. Provides reference for readers to understand the fatigue fracture mechanism.One more, the BS5400codes in Britain and the United States AASHTO codes is introduced respectively in thesis. Through learning from successful experience of the domestic similar bridge and basing on the dalian city traffic conditions, to select "standard fatigue car " in BS5400as the test load. Using relevant formula to calculate the equivalent stress. And find out the most unfavourable position of the whole bridge by the finite element analysis for internal force influence line. Provide the basis for integral joint simulation analysis.Finaly, in the process of load the model for2million times. In500000times,1million times,1.5million times,2million times when collecting the measured value of the static load cases. Compared to the maximum stress value measured are close to the theoretical maximum stress value. Based on comprehensive analysis of each stage of the data. The materials may maintain a good linear elastic after2million times cyclic loading, and most of the number of numerical values close to the theoretical analysis. The relative error in the allowed range. Illustrates that the Ansys-Workbench software analysis of integral node of steel bridge fatigue is feasible.