Construction Control For Large-Span Prestressed Conerete Continous Girder Bridges

With the improvement of the concrete pouring technology, prestressed technology development and development of bridge construction technology in China, more and more long-span bridge acrossing the great river, the river, the gulf and the canyon is being built, so prestressed concrete continuous girder bridge is going to be the first choice. As is known to all, the stress of the continuous girder bridge and its construction methods have a close relationship, especially the long-span prestressed concrete continuous girder bridge, the degree of indeterminacy and the nonlinear is high, so the structure of the mechanical characteristics is more complicated. There are many methods for the construction of prestressed concrete continuous girder bridge, including support cast-in-place by hole construction pusher, top pushes, cantilever construction and so on, the cantilever construction method is used most widely. Bridge structure of internal force, alignment are closely related to the construction method and construction process. Bridge construction control is mean to track monitoring the deflection and stress in all phases of the construction, in order to achieve the optimal state of bridge. Due to the heterogeneity of concrete, the change of material properties, geometrical parameters and the influence of complex factors such as temperature change, there is always exists internal force and linear error between the structure construction and design value.So it is very necessary to take reasonable control measures during the construction of the prestressed concrete continuous girder bridge, to ensure the quality and safety of bridge structure and the state of the bridge alignment and stress distribution in accordance with the design requirements before it finally closed.This article first states the development of prestressed concrete continuous girder bridge and the construction control technology, then discusses the basic theory of construction control for long-span prestressed concrete continuous girder bridge, finally summarises the basic principle of the contents and methods of construction control. Then takes Shenyang New Fort HunHe Bridge for instances, establishing finite element simulation of actual bridge. Finally, analysis the large-span prestressed concrete continuous girder bridge alignment and stress.The main conclusions of this research work are as follows:①In different stages of the main girder construction, the key points of the errors between theory of elevation and the measured values are effectively controlled;②Through the finite element modeling analysis, conditions of section girder is in a state of compression, pressure shall meets the requirements of design specifications, this shows the safety of the structure and provides the powerful guarantee for the construction monitoring;③Multiple factors influence the long-span prestressed concrete continuous beam during its construction, so it is important to carry on the corresponding parametric control;④The elevation and stress of the structure are correspondly with the design requirements after the construction stage, system transformation and deck overlays, finally the whole bridge camber setting is reasonable.In this paper, the research as to the further understanding of the continuous girder bridge structural performance, reasonable construction control implementation, to ensure the safety of bridge construction and the final bridge closure provides the technical support. The research work of this paper, which can be taken as reference to similar bridge construction control in the future.