Rotating Balance Test Simulation Of Multi-Point Support And Key Structure Of Cable-Stayed Bridge With Double Cable Plane

With the continuous development of China’s transportation infrastructure and the continuous improvement of the density of the road network,when the bridge construction require across the existing railway and highway lines,the swivel construction method is mostly used to avoid the impact of bridge construction on the traffic of the existing lines.The longspan swivel cable-stayed bridge has the characteristics of large swivel weight,wide road of bridge and high structural center of gravity.The use of single point support swivel system not only brings some difficulties to the manufacture,transportation,and construction of ball joint,but also the anti-overturning stability is prominent in the swivel process.Therefore,this paper focuses on the Xiangyang North Station Swivel Cable-Stayed Bridge,takes its multi-point support swivel system as the research object,and explores the feasibility,stress characteristics and reasonable structure of the multi-point support swivel system through scale model test and finite element numerical analysis.The main contents include the following aspects:(1)The segment model of cable-stayed bridge based on the rotating part of T3 tower of Xiangyang North Station Bridge is designed.Firstly,in order to verify the rationality of the swivel structure,combined with the existing actual conditions of the model test,the general idea of model design is put forward.Then,the scale ratio of the cable-stayed bridge model is determined to be 1:10,and the static similarity relationship of the model bridge is deduced based on the principle of equal stress.Finally,based on the stiffness similarity principle and similarity theory,the structural design of the model bridge is carried out,and the treatment methods of key and detailed structures in the manufacturing process are put forward.(2)The balance tests of rotating cable-stayed bridge under three groups of outrigger structure conditions,two groups of outrigger number conditions and four groups of rotation speed conditions were carried out.By changing the outrigger structure,the number of outriggers and the rotation speed,the key structural stress,the inclination angle of the main beam and the rotation traction force of the model bridge in the rotation process under different working conditions are obtained,and the effects of the outrigger structure,the number of outriggers and the rotation speed on the stability of the rotating cable-stayed bridge are revealed.The results show that the rubber pad structure rotates most smoothly;Increasing the number of outriggers has a positive effect on reducing the fluctuation range of rotational traction force,the stress of key components and the inclination angle of main beam;The increase of rotation speed has a significant impact on the stability and internal force of the rotating bridge.(3)The finite element local analysis models of single point and multi-point supported swivel cable-stayed bridges are established.Based on the finite element model of the multipoint support swivel system of the model bridge,the finite element analysis model of the single point support swivel system is established by adjusting the height of the outrigger and deleting the additional load imposed on the outrigger.Compared with the calculation results of the multipoint support finite element model,the influence of the multi-point support on the stress of the upper and lower bearing platform,the pile foundation structure and the anti-overturning stability of the swivel structure is studied.In addition,by changing the position and bearing capacity of the bearing leg of the multi-point support swivel system model,the reasonable structure of the multi-point support swivel system is defined.