Study on Fatigue Extension and Fatigue Life of ERE Pavement Steel Bridge Panel
To investigate the influence of ERE pavement on the fatigue details of welding between U-ribs and top plate of orthotropic steel bridge panel,the equivalent structural stress theory was used to study the fatigue behavior of actual orthotropic steel bridge panel structure details of suspension bridge.The fatigue crack propagation behavior was further analyzed by using the theory of linear elastic fracture mechanics.Firstly,ABAQUS software was used to establish finite element models of orthotropic steel bridge panel segments for both original and ERE pavements.Based on the equivalent structural stress method,the fatigue detail fatigue performance and equivalent structural stress at different load positions were analyzed.Subsequently,FRANC.3D and ABAQUS software were used to establish the three-dimensional equivalent model of top plate U-rib structure with the same equivalent structural stress amplitude.The cracks were implanted to compare and analyze the crack propagation performance of local structural model.The result indicates that the cracking mode of mid span section of the bridge is dominated with C.3 cracking mode.The fatigue life is the shortest calculated through equivalent structural stress,which is 4.271 million times.For the crack propagation modes of C.1 and C.2 after reinforcement by using ERE pavement,the stress intensity factors decrease to varying degrees at the same crack propagation depth with an average life increase of 138.22%.When the crack depth is over 2 mm,the stress intensity factor with crack mode in the original pavement structure increases rapidly.However,after ERE pavement reinforcement,the amplitude of stress intensity factor is lower than that of original pavement structure,and the value is relatively stable with an average life increase of 99.26%.The crack propagation life after ERE pavement reinforcement is improved by 75.13%to 163.51%with an average increase of 125.23%.By comparing the fatigue crack propagation life,it can be concluded that ERE pavement can effectively reduce the amplitude of equivalent stress intensity factor at crack location.The fatigue life of components is increased by suppressing the crack growth rate.
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