Analysis And Research On Structural Force And Main Tower Inclination Angle Of Single-tower Unequal Span Cable-stayed Bridge

Cable-stayed bridges are more and more built in the traffic field of our country.Because of their beautiful shape and infectious characteristics,they are often used in the construction of landmarks.However,for single-tower unequal-span cable-stayed bridges with more complex structure,the selection and establishment of the calculation model directly affect the safety and reliability of the design,construction and operation stages,and there is little domestic research on this.Therefore,it is necessary to discuss and study the finite element modeling method,force law and model design parameters.In this paper,a single-tower cable-stayed bridge with unequal span in Hubei Province is taken as the engineering background.With the help of the finite element software Midas Civil 2019,a full bridge model is established to analyze the static force,dynamic force and seismic resistance of the bridge in its completion stage,and to summarize the force law.Secondly,by changing the angle of the main tower of the cable-stayed bridge,the finite element model of the whole bridge with the angle of the main tower of 70°,75°,80°,85° and 90° was established respectively by taking 5°as the grade difference.Through the comparative analysis of the internal force and displacement of the important positions of the structure,the influence law of the main pylon Angle parameter variation on the cable-stayed bridge structure is summarized,and the optimal main pylon Angle is obtained.The main conclusions are as follows:(1)According to the design drawings and related data,the finite element modeling method is summarized,the structural components and boundary conditions of the cable-stayed bridge are simulated,and the whole bridge model of the single tower unequal span cable-stayed bridge is established.(2)Through the analysis of static,dynamic and seismic characteristics,the data of internal force and displacement at key positions of cable-stayed bridge are obtained.The results show that:the internal force and deformation of the cable-stayed bridge in static analysis meet the requirements of the code,and the mechanical performance of the whole bridge is well;In the dynamic analysis,the eigenvalue analysis method is used to calculate the natural vibration characteristics of the cable-stayed bridge,and the first five-order mode characteristics of the bridge are described in the completion stage;In the seismic analysis,the bending moment and axial force at the bottom of the main girder tower are larger under the transverse earthquake action,while the transverse bridge deformation of the main tower is larger under the longitudinal earthquake action.It is recommended to install an energy-consuming device to reduce the deformation of the main tower and install a thrust box to transmit the axial force.(3)The finite element software is used to analyze the influence of the variation of main tower Angle parameters on the structural strength,stiffness and cable-stayed force at the key position of single-tower unequal span cable-stayed bridge,and the influence curves of the internal force,displacement and cable force of the structure are obtained.The reasonable range of inclination angle of the main tower of the cable-stayed bridge is determined.The closer the main tower is to 80°,the better its mechanical performance.In summary,this thesis analyzes the modeling method,mechanical properties and inclination parameters of the main tower of a single-tower unequal-span cable-stayed bridge,and its conclusions can provide references for similar projects.