Study On Fatigue Characteristics Of Tensile Anchor Plate Of Steel-concrete Composite Girder Cable-stayed Brige Based On Residual Stress

As an important part of cable stayed bridge,the tensile anchor plate has a complex stress transfer mechanism.The fatigue problem of tensile anchor plate under the alternating load has been a research hotspot.However,the welding residual stress will make the fatigue problem of tensile anchor plate become more complicated.At present,the research on the tensile anchor plate’s fatigue performance was relatively single.There were few studies to research the influence of welding residual stress on the fatigue characteristics.Therefore,this article relied on the Lanzhou Xigu Yellow River Bridge to study the impact of welding residual stress on the fatigue characteristics of tensile anchor plate combined with experimental research and numerical simulation methods.Firstly,the welding residual stress and fatigue characteristic of tensile anchor plate were studied by experimental research and numerical simulation.And the influencing mechanisms of welding residual stress on the fatigue characteristics were summarized.The results showed that the welding residual stress and fatigue strength of the tensile anchor plate specimen by the finite element analysis were basically consistent with the experimental measurement,which verified the accuracy of the numerical simulation method.In addition,the welding residual stress of tensile anchor plate would cause the change of the fatigue load amplitude and equivalent stress amplitude.Therefore,the cumulative fatigue damage and fatigue life of the model under fatigue loading also be changed.Secondly,on the basis of finite element simulation,the fatigue strength and fatigue life of tensile anchor plate under different welding residual stress states were studied.The simulation results showed that the fatigue strength and fatigue life would decrease,with the increase of welding residual stress.And the relationship between the welding residual stress and the material fatigue strength was basically linear.At the same time,based on the finite element analysis data,the fatigue strength prediction model of tensile anchor plate specimen with welding residual stress was established.Finally,based on the Monte-Carlo simulation method,the time-stress curves of the Lanzhou Xigu Bridge’s tensile anchor plate were calculated.And the stress spectrums were analyzed by the rain-flow counting method and the Goodman model.On the basis of this,the fatigue life of tensile anchor plate was studied.The results showed that the stress amplitude of the tensile anchor plate was basically maintained within a certain range,and the maximum stress was less than the material yield strength under normal operating conditions.And only considering the vehicle cycling load and welding residual stress,the fatigue life of the tensile anchor plate meted the requirements of the bridge design life.However,the welding residual stress had a greater impact on the fatigue life of the tensile anchor plate,which needed to be emphasized in the actual project.