Choice Of Optimum Strengthening Scheme For Continues Steel Truss Bridge By Using Fuzzy Analytic Hierarchy Method And The Analysis Of The Bridge

From the establishment of china to the year around1970, China has independently builtlots of steel bridges, there are over10,000porous which run more than50years, they arebears increasingly heavy transport tasks in China’s major railways and transportation lines,However, with the development of transport undertakings, greatly increasing traffic volume,coupled with the impact of common diseases, there is an existing steel bridge does not meet aconsiderable part of the requirements on the use,so reinforcement or reinforcing of dilapidatedSteel bridge is practical significance.In recent years, with the diversity of methods of structural reinforcement andreinforcement material, methods of structural reinforcement are no longer have to follow afixed manner, based on the economic, technological, structural response and other issues, theapplication of fuzzy comprehensive evaluation method and analytical hierarchy process(AHP)in structural reinforcement has been more and more in-depth.In this paper, combine with the Lanzhou petrochemical factory pipeline bridge, based onthe principle of Fuzzy hierarchical optimization, conducted optimal selection of reinforcementprogram and analysis/calculation, the main work is as follows:(1) Describes the development of steel truss bridges、research status of reinforcement ofsteel structure at home and abroad, analysis the necessity of reinforcing steel truss bridge inour country. this paper have introduce the application of AHP in scheme comparison forbridge reinforcement solution, and proposed the bridge detection-summary ofdiseases-AHP-fuzzy judgment-emulation technique bridge reinforce method.(2)Describes the main diseases in bolt welded steel truss bridge are: corrosion, fatiguecracking and deformation. Summarizing the methods of repair and reinforcement steel trussbridge, that refers to strengthening weak components, change the system, reduce the load(3)Introduces the principle of optimal selection of reinforcement.Base on Fuzzycomprehensive evaluation method and AHP basic theory, according to optimization purposesSelection bridge reinforcement program to determine the evaluation program of the first layerindex (technically feasible, effective and reliable, economical, convenient construction), thesecond basic indicators target(4)Considering the force mechanism and the features of diseases of Lanzhoupetrochemical factory pipeline bridge,as well as choosing the mechanics criterion andeconomic indicator for the reinforcement scheme, author have proposed triple-leveled fuzzyoptimized model,the bottom evaluation index and3sets of reinforcement (reinforcement ofcomponents, increase of main truss,suspension solution).After the optimized selection of thethree methods of reinforcement,it shows that increasing the main truss is the best choice. (5)According to the force analysis of both unreinforced bridge and reinforced bridge byFEM, the optimization selection for the reinforce solutions is feasible and practice in the caseof Lanzhou petrochemical factory pipeline bridge.