| In the context of the rapid development of today ’s society,traffic travel is an important part of people ’s lives.The construction and improvement of highways and railways has become a basic requirement.Therefore,many bridge projects are constantly being built on a large scale.Due to too many infrastructure projects,crossing each other,it is impossible to design according to conventional symmetrical bridges.In order to solve the problems of bridge crossing capacity and lower navigation clearance,many large-span bridges and asymmetric bridges have appeared in the design.Long-span asymmetric single-tower partial cable-stayed bridge is a bridge type often used in bridge design.However,the asymmetry of the asymmetric single-tower partial cable-stayed bridge increases the difficulty of design and construction,and the asymmetric deformation and internal force distribution may cause the main beam to have a linear mutation,thereby reducing the safety factor of the structure.Therefore,it is of great significance to study the asymmetric single-tower partial cable-stayed bridge.Based on the engineering background of the asymmetric single-tower partial cable-stayed bridge across Changtai Expressway and Sujia Canal(35 + 168 + 136 + 35)m,this paper studies the structural parameter design of the large-span asymmetric high-speed railway single-tower partial cable-stayed bridge,the cable force optimization based on the reasonable bridge state and the precise positioning construction control of the cable duct.The main work is:(1)The finite element analysis software Midas Civil is used to simulate the construction and operation stages of the(35 + 168 + 136 + 35)m asymmetric single tower partial cable-stayed bridge.The internal force and deformation of the main girder of the asymmetric single tower partial cable-stayed bridge in each construction stage are studied.It provides a theoretical basis for the design of structural parameters,the optimization of cable force and the positioning of cable duct,and provides a theoretical basis for construction control.(2)The structural parameter design of the cable-stayed bridge is studied.The transverse and vertical first-order natural frequencies of the bridge under the parameters such as the section size of the bridge tower,the section area of the stay cable,the section size of the main beam and the position of the auxiliary pier are analyzed.At the same time,the change of vertical deflection of main girder under ZK live load is also studied.The variation law and influence range of the research results in this paper provide a reference for the selection of design parameters of the same type of bridge.(3)Based on the reasonable bridge state,the optimal cable force is determined by the minimum bending energy method,and the cable force is adjusted.The internal force distribution of the main girder and the main tower before and after optimization is compared and analyzed.The cable force monitoring data of(35 + 168 + 136 + 35)m asymmetric single tower partial cable-stayed bridge are processed and compared with the theoretical results,which provides a theoretical basis for cable force control in construction.(4)The three-dimensional positioning method of cable duct of cable-stayed bridge is studied.According to the analysis results of finite element software Midas Civil and FEA,the method of determining the three-dimensional coordinates and inclination angle of cable duct end is given,and the three-dimensional coordinates and inclination angle of cable duct of this bridge are calculated by this method.The measured data and theoretical data of the positioning monitoring of the cable duct are compared and analyzed to ensure that the center position of the cable duct is aligned with the stay cable after the bridge is completed.So as to avoid the mutual wear of the cable duct and the cable,and improve the safety and reliability of the structure. |
