Study On The Related Technical Problems Of Construction Control Of Extradosed Cable-stayed Bridge

Extradosed cable-stayed bridge is a kind of combined structure of continuous girder(rigid frame) bridge and cable-stayed bridge in the development of bridge, and it absorb the advantages of the two. This paper takes Zhongshan city chicken crow channel bridge as the engineering background, studied some technical problems related to the construction control of bridge construction process. The main study contents are as follows:(1) By establishing the finite element model, this paper analyzes the impact of tare weight deviation, the initial tension deviation, relative humidity, temperature, the variation of elastic modulus, elastic modulus, temporary load cable, bridge deck pavement, prestressed tension deviation on linear, the cable force, the stress of the main girder, the cable stress of the structure of the maximum cantilever stage and finished stage, and determine the extent of the influence of various parameters, identify which is sensitive to parameters, which are non sensitive parameters. It also study on parameter identification of sensitive parameters, and provides the reference and suggestions for the construction control.(2) Bridge camber is mainly used for offsetting bridge deflection produced by the creep of concrete and the moving load. The rationality of bridge camber distribution affect the ride comfort of the bridge alignment. Through the analysis and comparison the bridge camber results of parabolic curve distribution method, the experience curve distribution method, the cosine curve fitting distribution method and orthogonal polynomial fitting distribution method, comparison the advantages and disadvantages of each method, ensure the rationality of the bridge camber settings.(3) The parallel steel wire bunch tension will produce force uniformity problem. By using the backstepping method to calculate each cable tension comparing with the numerical algorithm for the calculation of parallel strand stayed cable tension, this method force the uniformity meet the requirements after the completion of cable tension.(4)The adjustment of cable force of cable-stayed bridge is a common problem. This paper analyzes the calculation principle of iterative method, influence matrix method and the elongation control method for cable force adjustment. And it calculate the cable force adjustment of the extradosed cable-stayed bridge of engineering background by using these three methods.This paper study the advantages and disadvantages of the iterative method, influence matrix method, control method in the elongation of cable adjustment process. Elongation control method in the process of adjusting cable force in the most practical.(5) The heat of hydration of large volume concrete is a common problems in the construction of large span bridge. This paper analyzes the calculation principle of heat generated and conducted in the process of concrete hydration heat. Through the establish the finite element model of large volume concrete construction, and simulate of various environmental conditions, this paper simulates the construction of large volume concrete. This paper provides effective guidance for the actual construction.