Study On Comparison & Selection Of Erection Scheme Of Steel Trusses Of Zhengzhou Yellow-river Rail-and-Road Bridge

According to the Medium-and-long Term Planning for Chinese Rail Network Development adopted by the State Council on January 7, 2004, by the year 2020, the total railway operational mileage in our country will reach 120,000km. Passenger and freight transport will separated from each other for all the busy artery railway lines. Both the double line percentage and electrification percentage wil reach 50%. The overall transport capacity will meet the need of national economy and social development. Key technical equipment will reach or approach the advanced international level. A total of over 12,000km of passenger dedicated line will be constructed with a target speed of 200km/h or above, forming a network of"four longitudinal and four altitudinal"main railroads, among which is one-of-the-four longitudinal Beijing-Guangzhou line with a speed up to 350km per hour. Formulation, selection and optimization of a general construction plan is the key to the realization of building such line in a good and rapid way.This article focuses on comparison and selection of various erection methods of Zhengzhou Yellow-River Combine Rail-and-Road Bridge steel truss through scientific study, with an effort to screen out the most optimal construction plan so as to complete this project in a rapid, safe, quality, effective and economic way.As passenger dedicated line is a systematic project, therefore, it's imperative to adopt the theory and method for systematic project as a guidance, of which the establishment of assessment system is foundamental. In this article, various theories and methods are analyzed and compared in light of the features of the project. Finally, analytic hierarchy process (AHP) is applied for assessing the three proposed construction plans in the following procedure: establishment and constitution of index system→setting up hierarchy structure model→experts'scoring on judgement matrixes→matrix calculation through hierarchy single sequencing and overall sequencing. This article introduces the AHP model used for assessment and selection of the construction plans at four levels. Based on the characteristics of the construction of the major steel truss bridge over the Yellow River, five indices (i.e, investement, construction duration, technological condition, construction condition, environmental protection) are adopted as criteria for assessing the adoptability of the construction proposals. Then the five criteria are developed further into criterion hierarchy and thus forming the hierarchy structure model.Included in this article are a brief summary on the final result of comparison and selection of steel truss erection plans via AHP and an introduction to the progress of the construction plan.The research method and conclusion presented in this article provide a ground for scientific adoption on erection method of steel truss of the bridge. It's propagable from the perspective of methodology and may serve as a source of reference for similar major bridge steel truss erection on other passenger dedicated lines under certain circumstances.