Research On The Design Of Rotating Weight And The Key Technology Of Steel Shell Closure For High-speed Railway Bridge

With the rapid construction and development of traffic lines,new bridges often need to span the existing traffic lines.However,the construction of the existing lines will have a certain impact on the lower lines,so how to reduce the impact on the existing traffic lines is particularly important.In order to reduce the impact of the construction stage on the existing traffic lines,the method of bridge turning is generally used for construction.In this paper,Huanggu super large bridge of Jingxiong intercity railway is taken as the research object.The bridge needs to span the existing Beijing Jiulong Railway,with high traffic density and difficult safety protection.The bottom of the beam is close to the railway contact network.The traditional construction method of hanger seriously affects the existing traffic line below.Therefore,the bridge adopts a new closure technology steel shell closure.This technology not only greatly reduces the impact on the existing lines,especially in traffic safety almost zero impact,but also makes the middle span closure construction process simple and fast.Steel shell closure is a new closure technology used in recent years,which has been successfully applied in many bridges.Through the investigation,it is found that the technology is only used in the actual project,and there is no detailed theoretical analysis and Research on steel shell closure technology.Therefore,this paper focuses on the theoretical calculation and analysis of the stress and deformation of the steel shell.(1)This paper studies the general situation of the development of the bridge Swivel Construction at home and abroad,and summarizes and prospects the latest research results and development prospects of the bridge swivel technology.According to the complexity and particularity of construction environment,this paper adopts a new bridge closure technology steel shell closure.(2)In this paper,the monitoring and key technology of bridge swivel construction are studied,and the weighing test is carried out by using the method of spherical hinge rotation.Considering that the cantilever structure is installed with steel shell in advance,in order to improve the shear resistance of the section after the steel shell is connected,the steel shell adopts the inclined section form.In order to avoid interference and collision at the mid span connection,it is necessary to design and calculate the counterweight scheme in the process of turning,and obtain the required counterweight data and position.(3)In order to make the turning process go smoothly,the traction force,turning time,friction coefficient and braking distance shall be calculated before the formal turning;meanwhile,the bridge shall be strictly controlled during the turning process,including the synchronization,stability,safety and fine adjustment after the turning is in place during the trial turning and the formal turning process,so as to make the beam accurately rotate to the design axis Connect and lock the beam body to ensurethe smooth closure of the middle span of the bridge.(4)In this paper,the finite element software Midas Civil is used to build the whole bridge model,analyze the stress situation of closure section,and extract its internal force;Midas FEA is used to build the closure section steel shell solid model,analyze the influence of concrete pouring process,system transformation,concrete shrinkage and creep process on the steel shell stress and deformation,to ensure the safety of steel shell construction and later use.