Optimization Design And Local Force Analysis Of Double Cantilever Reinforcement Construction Scheme Of Steel Truss Bridge

In the process of using the bridge,the bearing capacity of the bridge structure decreases gradually due to the aging of the structure brought by the service time and the continuous traffic load.Therefore,the maintenance and reinforcement of the existing bridge is the focus of the future development of traffic.Steel truss bridge is widely used in large span bridges because of its advantages of light weight,clear structure stress and convenient construction.There are many ways to strengthen steel truss bridges.Adopting appropriate methods can not only greatly improve the bearing capacity of the structure,but also bring better economic benefits.In this paper,a double-cantilever flat rotary open steel truss bridge over a canal is taken as the background.Based on the finite element software,the girder of the steel truss bridge is numerically simulated and analyzed.The main work is as follows:(1)The main bridge reinforcement methods are sorted out and analyzed,the reasons for bridge reinforcement,the advantages and applicable conditions of various reinforcement methods are studied,and the stress characteristics and calculation instructions of the main reinforcement methods are analyzed.(2)The jacking optimization of steel truss bridge before reinforcement is studied.In order to make the stress state of the structure to achieve the best before reinforcement need to be on both ends of the main tower side span and middle span cantilever roof to reinforce to the corresponding position,respectively adopt three kinds of optimization scheme,through the finite element software analysis of jack-up bridge in the process of stress and linear change,and combining with the field configuration of hydraulic equipment,determine the final optimized scheme.(3)According to the overall finite element calculation model,the most unfavorable load position of the main girder of the bridge is selected,and the local model is established by the FINITE element software ABAQUS.Based on the data of the overall model,the corresponding load is applied locally to analyze the local stress state at the end of the cantilever and jacking.The reinforcement method of increasing the section is adopted to increase the section area of the main longitudinal beam,and the stress before and after the reinforcement is compared with the local analysis by ABAQUS finite element software.ABAQUS software was used to model the body of the upper string anchor box of the bridge,and the stress change of the anchor box was analyzed under grouping prestressed tension.(4)Analyze the state of open steel truss bridge after closure.The domestic and European train load codes are adopted respectively,and the most unfavorable mid-span load is applied in the overall model,and the deformation of bridge structure under different codes is compared.The stress difference of bridge girder under domestic and European temperature load codes is studied.