Static And Dynamic Calculation Of Long-Span Composite Cable-Stayed Bridge And Detailed Stress Analysis Of Cable-Girder Anchorage Zone

In order to study the static and dynamic characteristics of long-span composite cable-stayed bridge and the mechanical properties of cable-girder anchorage zone,the paper takes the Kezhushan bridge as the engineering background.The finite element software MIDAS/CIVIL is used to establish a spatial finite element model of the full bridge.Then the deformation and mechanical properties of the bridge during construction and operation stages are calculated and analyzed.Considering the effect of pile-soil,the multi-ritz-vector method is used to calculate the free vibration characteristics of the bridge.Furthermore,the seismic response of the bridge is calculated and analyzed by response spectrum and linear time history method respectively.The local finite element model is established by the finite element software ANSYS to calculate and analyze the stress distribution of the anchorage zone.Meanwhile,the parameter analysis of the anchor plate and anchor board is carried out to study the influence of the thickness change on the overall stress of cable-girder anchorage zone.The results of the study show that the deformation and stress of the composite cable-stayed bridge during construction and operation stages meet the requirements,which proves that the construction method of the bridge is safe and feasible.The first order vibration mode of the bridge is the longitudinal drift of the whole bridge,which embodies the characteristics of its semi-floating system and is beneficial to the seismic resistance of the structure.The torsional phenomenon of the main beam appears earlier,which shows that the torsion stiffness of the main girder of the composite cable-stayed bridge is small.And under the action of earthquake,the internal force of bridge tower is very large.Under the action of dead load and dead load plus live load,the overall stress level of cable-girder anchorage zone is relatively low,and the stress concentration at the joints of different plates shows different degrees.However,the range of stress concentration is very small,so the quality of welds should be strictly ensured in construction.Besides,the appropriate thickness of anchorage plate and anchorage board can make the overall stress of cable-girder anchorage zone at a good level.