Mechanical Properties And Stability Analysis Of Ordinary Fabricated Steel Trestle

With the increasing scale of bridge engineering,the load-bearing capacity of prefabricated steel trestle is also required to ensure the safety and stability when passing the vehicle.Due to the rerouting of the expressway,the vehicles need to pass through the ordinary fabricated steel trestle.This steel trestle is taken as the research object,this paper makes a systematic analysis on the mechanical performance and stability of the steel trestle,and establishes the model of the fabricated steel trestle by using the finite element analysis software,analyzes the structural stress,deflection under different finite element software differences,the results of parametric analysis on the model,The stability analysis of the key factors of steel trestle instability is carried out based on engineering examples.The research results can provide some reference for software selection and structural parameter setting of steel trestle in the future design of steel trestle.The main research contents and results are as follows:(1)According to the construction drawings,the finite element models of ordinary fabricated steel trestle of high-grade highway are established by using Midas and ABAQUS finite element software respectively.The mechanical performance of the bridge under self weight and vehicle wheel load is analyzed,and the component stress and overall deflection are checked.The results show that the data obtained by using different finite element software are not different,and the stress of each component of the bridge is within the allowable range.(2)According to the finite element model,the effects of span change,distribution beam spacing change and steel plate thickness change on the mechanical performance and deflection of steel trestle under the action of self weight,second stage load and lane load are discussed,and the change rules under the influence of different factors are obtained.(3)The stability of the fabricated steel trestle under on-line elastic conditions and different working conditions is studied,the stability coefficient under the most unfavorable working conditions is obtained,and the geometric nonlinearity is considered.Under the second type of stability problem,the geometric nonlinearity is also studied for the completion of the steel trestle,and the safety coefficient of it’s stability allowable bearing capacity is obtained.The results show that it is necessary to consider the geometric nonlinearity in the stability analysis of the steel trestle,It is also more in line with the real situation of the bridge.The stability coefficient is 6.4,which is 15%less than the linear elastic stability coefficient of 7.65.Therefore,it is necessary to consider geometric nonlinearity in the stability analysis of steel trestle.(4)The parametric stability analysis is carried out for the completed state under the most unfavorable working conditions.The effects of bridge span,steel pipe pile height,steel pipe wall thickness and inter pile connection form on the linear elastic stability of steel trestle are analyzed,and the corresponding stability coefficient and buckling mode are obtained.The stability failure of steel trestle poses a serious threat to the safety of structure,so the stability of Bailey steel trestle should be fully considered.The stability coefficients are greater than the requirements of the specification,and the stability of Bailey steel trestle should be fully considered.