Analysis Of Causes Of Deterioration Railway Slab Girder Bridge In Service And Calculation Of Bearing Capacity Of Bonded Steel Reinforcement

With the increase in the operational years of railway concrete bridges,the bridge will have different degrees of disease,such as cracks in the beam,corrosion of steel bars,peeling and falling of concrete,whitening due to water damage,and other diseases.A lot of expenses have been expended,and at the same time,these diseases will cause the bearing capacity of the bridge to decline,affecting the safe operation of bridges.Therefore,it is particularly important to analyze the causes of these diseases.After a disease occurs in the beam,it will affect the bearing capacity.Affecting the safe operation of bridges,it is necessary to check the bearing capacity of diseased bridges to evaluate the safety bearing performance of the bridges;due to the small stiffness of the plate beams,the bearing capacity will be insufficient after the occurrence of diseases,and the beam body needs to be carried out.The restoration and improvement of the bearing capacity and the strengthening of the beam are performed in this paper by means of a method of reinforcing the steel plate.The reinforced concrete beam is composed of two kinds of steel and concrete materials.This article starts from the two kinds of steel and concrete materials,analyzes the cause of the disease caused by the beam body,the precipitating factors and the damage to the beam body,and carries the bearing capacity of the disease beam body.The calculations and adhesion of the bridges with insufficient bearing capacity are reinforced.The main content of this article is as follows:(1)Present the domestic and foreign status of research on the durability of concrete,the contents of bridge durability research,and some existing problems,some common diseases of bridges,and common maintenance reinforcement methods.(2)Analyze the types of major diseases causing concrete deterioration,the causes of these diseases,the predisposing factors of these diseases,and the hazards to the beams.(3)Using the loading standards of the “85 Railway Bridges and Culverts Design Code” to check the bearing capacity of existing railway girder bridges in accordance with design standards,assess the bearing performance of the girders according to stress and beam deflection;The load standards of bridges and culverts in the Design Code of bridges and culverts are used to check the bearing capacity of existing bridges,and whether the bearing capacity of the bridge can meet the design requirements of the new standard and how the safety reserves of the bearing capacity of the beam under the new specification can be checked.Using Midas Civil finite element software to simulate the three kinds of loads respectively,comparing the simulated value with the theoretically calculated value,the simulated value is basically consistent with the theoretical value,which shows that the model is basically accurate,and then the finite element model is used to analyze the beam body in the vertical direction.The stress and stiffness conditions of the beam body when the loads and lateral loads are coupled together.(4)Considering the corrosion of reinforcing steel bars,the bond performance between steel bars and concrete decreases,the yield strength of steel bars decreases,and the effective area of steel bars decreases.Then,based on the principle of reinforced concrete,beams are established on steel beams that have been corroded by reinforcing bars in tension zones.The calculation model of the ultimate bearing capacity of the body,and verified the established calculation model of the ultimate bearing capacity of the corroded beam body using test data;based on the load experiment,the results were compared with the experimental calculation results and the theoretical calculation values according to the allowable stress method to evaluate the beam body.The bearing capacity;using ANSYS finite element software for the experimental plate beam modeling analysis,the finite element analysis results and experimental values,theoretical values for comparison.(5)Paste steel plate reinforcement technology is a reinforcement method for the restoration and improvement of the bearing capacity of the bridge.Because of its simple construction and obvious reinforcement effect,this method is often used in the reinforcement of bridges.This paper analyzed the technology of the adhesion steel plate reinforcement technology.Processes,and construction details that need attention when sticking steel;this chapter aims at the problem of insufficient rigidity and bearing capacity of the existing concrete slab girders in railways.Force formula and deflection formula;using Midas Civil finite element software for simulation analysis,the numerical simulation results are in good agreement with the theoretical values,indicating the basic accuracy of the model establishment,and analyzing the maximum compressive stress and the outermost layer of the concrete before and after reinforcement.Steel stress,cracking moment,vertical deflection,and mid-span bending moment indicate the effect of steel reinforcement.