Research On Strengthening Technology Of Composite System Of Railway Low Height Beam

The existing reinforced concrete bridges account for a large proportion of railway bridges,and the bridge forms are mainly slab and ribbed slab bridges.Due to their relatively long service life,the deterioration of the beam body is generally serious,and some of the bridges are affected by the disease,resulting in serious security risks of the bridge,which can not be opened to traffic normally.At the same time,in recent years,with the rapid increase of train load and speed,as well as the continuous renewal of heavy load concept,the axle load and load of the train have been greatly improved,resulting in the increase of bridge operation live load.Therefore,there is a big doubt whether the existing railway bridge can be applied to the safe passage of trains in the current situationt.Therefore,it is very important to evaluate the safety of existing railway bridges.At the same time,it is necessary to reinforce and reconstruct the severely damaged bridges.This paper mainly focuses on a low height slab girder bridge on Lanzhou Xinjiang Railway,and discusses the applicability of the bridge to train load through bearing capacity checking and finite element simulation.(1)Based on the field investigation data of this kind of bridge,several common disease types are summarized.Analyze the causes of different diseases and put forward corresponding repair measures or solutions.(2)According to the original design data and relevant design specifications of this kind of bridge,carry out the stress checking calculation,and the live load is taken as Zhong live load,ZKH load and ZH load respectively.Through the stress state and deformation of the beam,Judge the applicability of different load trains passing the bridge;through the establishment of the beam finite element model to simulate the stress of the beam,discuss on the influence of transverse force on beam deformation.(3)In view of the problem of Insufficient stiffness of the bridge,this paper puts forward the strengthening method of the combination system of the post-added steel beam and the original structure,and introduces the relevant technology and construction method in detail.(4)Based on the field test data,Analysis of the reasons for the insufficient rigidity of beams,and establishing the finite element model of the damaged beam by simulating the corrosion and sliding of the reinforcement;Simulation of beam reinforcement based on the model of damaged beam,and comparison of model calculation results and field test data to verify the beam reinforcement effect.(5)The beam model is loaded by ZH load(z=1.2).Based on the calculation results of the model,dicuss the applicability of the reinforced bridge for the passage of 30t axle load heavy-duty train.