Cantilever Construction Control Of Reconstruction Projects Of Dalian Fast Railway 3# Line Engineering

Before the middle of 19th century, all kinds of bridges were constructed with bracket. Itmeans seting up bracket on the bridge span. On the bracket it could assemble steel girder andlay concrete main girder. The main girder has no stress during construction. This is a veryeasy and reliable method. With the development of technology, the span of bridge becomeslarger and larger. So it is difficult and impossible to build bridges using old method, especiallyto the bridges that span the big river and deep gully. In the 1970's German engineers took thelead in using cradle cantilever in laying concrete, and building prestressed continuous beambridge. They provided foundation for construction without bracket, such as cantileverconcrete beam bridge, T-type rigid frame bridge, cable-stayed bridge and so on. In the middleof 1960's, China transfered cantilever construction into prestressed concrete bridge from steelbridge. And prestressed concrete beam bridge becomes the main type bridge in China.The concept, method and character of prestressed concrete cantilever constructioncontrol are introduced in this paper. According to former model experiment and the torsionalanalysis basing on space model, it can be concluded that the curved bridge can be simplifiedstraight bridge in a certain range of span and radius of plane curve, which can simplifycalculation and greatly improve work efficiency.This paper is based on the extending line of Dalian fast railway 3# line engineering.Through building plane frame model, the safety and stability during the construction processof cantilever-casting are analyzed. This paper also checks the strength, stress, crackwidthsand deformation of bridge during service stage. The safety of cradle is also checked inthis paper. Through building plane frame model, it simulates the process of cantileverconstruction and supervises cantilever construction.At last this paper provides control data of main girder elevation and stress in the courseof construction. The data indicate that construction control based on this calculation model issafe and accurate. It can be an guidance and reference to the similar project.