Structural Performance Analysis Of Three-tower Self-anchored Suspension Bridge

With the development of the times,bridge aesthetics is paid more attention.Self-anchored suspension bridge has a strong advantage in bridge type selection because of its smooth lines,beautiful appearance,good economy and adaptability to topographic and geological conditions,and gradually gaining the favor of bridge engineers.As for self-anchored suspension bridge,the main cable anchors at both ends of stiffened beam,so it has great difference from that of ground-anchored suspension bridge,but the self-anchored suspension bridge in our country has developed relatively late,especially the theoretical research and engineering construction of multi-tower self-anchored suspension bridge is relatively few and not deep enough.In this paper,a three towers self-anchored suspension bridge under construction is taken as the engineering background.The full bridge analysis model is established by Midas-civil finite element software,and the structural performance of three towers self-anchored suspension bridge is analyzed.The main contents are as follows:This paper summarizes the structural characteristics,advantages and disadvantages of self-anchored suspension bridges,expounds the development history of self-anchored suspension bridges at home and abroad,and lists examples of self-anchored suspension bridges built or under construction at home and abroad,the calculation theory and analysis method of suspension bridge are introduced in detail.Combined with an engineering,by analyzing the parameters such as main cable shape,the length of the main cable without stress,the length of the sling without stress,and the cable force of the bridge,it is determined that the finite element model of the suspension bridge is reasonable in the state of the bridge,and the error between the calculation and the design value is small,which is in line with the structural safety requirements.The finite element model of Abaqus is established,and the stress characteristics of bridge tower under construction and completion condition are analyzed,and the reinforcement plan for bridge tower is given.For the cable tensioning scheme,the cable force,the bridge tower force,the main beam force,the main cable shape and the main cable force during the construction process are analyzed in detail,it indicates that the structure is safe during the tensioning process,which meets the safety requirements of specification and structure.As for bridge-finished condition,through the analysis of the main cable,sling and stiffening beam,under dead and live load,the bridge has more ideal force performance,and meet the safety requirements.As for the three towers self anchored suspension bridge,the longitudinal flexural rigidity of the middle tower is analyzed,the influence law of the middle tower stiffness on the bridge structure is obtained,and the reasonable range of the stiffness of the tower is given.Through the comparative analysis of different longitudinal and vertical restraints of stiffening girder,the influence of different supporting modes on the mechanical performance of stiffening girder,bridge tower and main cable is studied.The research shows that the vertical support of the stiffened beam is set at the middle tower and the longitudinal bridge to set the longitudinal limit device,such as elastic cable and damper,is more favorable to the overall mechanical performance of the structure,and the reasonable stiffness range of the elastic cable device is given to the bridge.