Study On The Design Of 300m Concrete Arch Bridge With Cantilevering Method

Using the cantilever cast method to construct concrete arch bridge is favorite by bridge constructers because it is not limited by terrain and the arch ring integrity and the shape is well-done, which is used by many foreign bridge constructers to build the long span concrete arch bridge Currently, only 4bridges are utilized the cantilever cast method construction technology in China, the longest span of whom is only 182m(Sichuan Xinmidi bridge).With the rapid development of statically indeterminate structure analysis theory, with the advancement of computer simulation technology, and with the application of high strength material in arch bridge construction, China will further increase the cantilever bridge's span,and competitors will be favorable in arch bridge of long span. Therefore, to carry out the research of long span concrete arch bridge with cantilever casting technology has practical significance and application to promote the development of bridge construction in China.This paper is supported by the National Natural Science Foundation of Theory and Method of Configuration and Safety of Concrete Arch Bridges with Cantilever Casting Construction on Multi-obiective.Based on the design and construction technology of concrete arch bridge at home and abroad, in view of the current domestic cable-stayed cantilever pouring concrete arch bridge constantly emerging, the 300 m span cable-stayed cantilever pouring concrete arch bridge is tried to design research in this paper. The specific research work is:1.Aiming at the present situation of the long span concrete arch bridge design and construction, this paper adopts the cantilever bridge program to build the 300 m span cable-stayed cantilever pouring concrete arch bridge, and the key parameters of arch bridge is carried out to be tested the design of research. Considering the characteristics of cantilever casting concrete arch bridge, based on a large number of domestic and foreign construction of long span concrete arch bridges on the statistics of the reasonable span ratio of 1/6 vector, this design adopts catenary as the reasonable arch axis, through the exhaustive method calculation of arch axis coefficient, m=1.998.The main arch section applies the commonly used single box double room section.2. This paper expounds the related theory of cantilever casting bridge for determining the reasonable finished state of the bridge, on the basis of which the Midas-civil is used to deal with the formation of arch(bridge) and the iterative analysis considering construction process for this design scheme. Taking the arch bridge section stress as the control target, using the thought of the moment the feasible region and the bridge design has been checked. The results show that the structural safety of the bridge design and the stress related section under the main arch bridge are both within the range of allowable.3. The cantilever bridge construction technology has been studied, and combined with the actual situation of the design, the construction steps which are suitable for the engineering practice have been proposed. On this basis, using the stress balance method to conduct the formal analysis of construction process of arch bridge in Midas-civil, and the analysis results show that: the 300 m cantilever bridge construction process is reasonable, and the arch section upper and lower stress are both within the range of allowable and the structural stress is safe under different conditions in the process of construction.