| The multi-tower cable-stayed bridge is more and more popular in the construction of long-span cable-stayed bridges because of its excellent spanning ability,beautiful appearance and good economy.For the multi-tower cable-stayed bridge,how to choose the appropriate beam structure and tower structure is a practical engineering problem that bridge designers often have to face.In order to find the more suitable tower structure and beam structure for the multi-tower cable-stayed bridge,this thesis takes a multi-tower cable-stayed bridge as the engineering background,starting from the mechanical analysis of the completion state and construction state,the mechanical properties of multi-tower cable-stayed bridges with different forms of tower and beam are compared and analyzed.The main research contents and results are as follows:(1)Carry out the comprehensive research on theory and method of calculating the completion and construction state of multi tower cable-stayed bridges,and discuss the characteristics and application range of each method.On this basis,according to the structural characteristics of multi-tower cable-stayed bridge,put forward a comprehensive algorithm based on the internal force balance method and a step-by-step algorithm based on the forward iteration method.They are used to solve the completion state and the construction state respectively,and the calculation processes of the above two optimization algorithms are given.(2)According to the engineering background,the bridge model is established by using the bridge structure analysis software,and the reasonable cable force of the bridge is calculated by using the comprehensive algorithm,the stress state of the main components of the bridge is analyzed under the reasonable completion state.With the goal of reasonable completion state of the bridge,the reasonable construction cable forces are calculated by using the step-by-step algorithm,the mechanical analysis of the main components in the two tensioning processes is carried out.Finally,the feasibility of the two optimization algorithms is verified by comparing the forward completion state with the reasonable completion state.(3)According to the mechanical characteristics of tower structure and beam structure in the multi tower cable-stayed bridge,the beam structure and the tower structure are optimized,and the multi-tower cable-stayed bridge models based on different forms of tower and beam are established.Starting from the mechanical properties analysis of the completion state and construction state,the cable-stayed bridges with different forms of tower and beam are compared and analyzed,and the influence of different forms of tower and beam on the bridge is studied.It is used to find a more suitable beam structure and tower structure for the multi-tower cable-stayed bridge.(4)Summarizing the mechanical analysis results of multi tower cable-stayed bridges under different forms of tower and beam,and draw some practical conclusions: compared to the concrete beam,it is found that the self-weight of the steel beam is lighter,and the overall force is smaller,while the internal force and deformation of the solid concrete tower are the smallest,and the mechanical properties are the best,so for the multi-tower cable-stayed bridge,using the steel beam and the solid concrete tower is a better structural combination,which can provide some reference for the design of similar multi-tower cable-stayed bridges. |
