Construction Control Of The Extending Line Of Dalian Fast Railway 3# Line Engineering

Before the middle of 19th century, all kinds of bridges are constructed with bracket. This means it sets up bracket on the bridge span. On the bracket it could assemble steel girder and lay concrete main girder. The main girder has no stress during construction. This is the most easy and reliable method. With the development of technology, the span of bridge becomes larger and larger. So it is difficult and impossible to build bridges using old method, especially to bridges that span the big river and deep gully. In the 1970's German engineers took the lead in using cradle cantilever in laying concrete, and building prestressed continuous beam bridge. They provided foundation for construction without bracket, such as cantilever concrete beam bridge, T-type rigid frame bridge, cable-stayed bridge and so on. In the middle of 1960's, China t ransfered c antilever c onstruction i nto p restressed c oncrete b ridge from s teel b ridge. And prestressed concrete beam bridge becomes the main type bridge in China.This paper introduces concept, method and character of prestressed concrete cantilever construction control. It also presents the difference between curved bridge and straight bridge in the deflection, bending moment, torsional moment, angle of section rotation, camber, stretching tendon in the curved bridge cantilever construction.This paper bases on the extending line of Dalian fast railway 3# line engineering. Through building space shell element model, plane model, it analyzes torsion of main girder that is caused by vertical load and stretching tendon in the curved bridge cantilever construction. This paper also proves the computing data by means of curved bridge model experiment and draws to some conclusions about curved bridge cantilever construction. Through building plane frame model, it simulates the process of cantilever construction and supervises cantilever construction.At last this paper provides control data of main girder elevation and stress in the course of construction. The data indicate that construction control based on this calculation model is safe and accurate. It can be an guidance and reference to the similar project.( It can instruct and use for reference in the approximative engineering)...