Construction Control Of The Yangtze River Railway Bridge In Yi Chang

With the rapid development of transportation, a large number of bridges with long span and high complexity have being built by our bridge builders. The type of long span beam-arch composite bridges has been used widely because of its high compatibility to the ground,reasonable stress of the structure,low cost,facilitating constructing and beautiful appearance. For the sake of keeping the safety of constructing, achieving the goal of designing and enhancing the quality of constructing , construction control should be executed in the process of constructing.Yi Chang Yangtze River Railway Bridge is a composite structure composed of prestressed concrete continuous rigid frame and concrete-filled steel tubular flexible arch. It is regarded as an instance, the spatial finite element software MIDAS /CIVIL is selected to make a simulating analysis of overall process of the constructing which considers a lot of factors such as shrinkage and creep of concrete,prestressing loss and terminal condition's alteration in the course of system conversion. Judging by the generalization of stress and deflection changing rule in every stage of construction, the work of stress control is prepared for this bridge. Furthermore, modern control theory such as parameter identifying method is adopted in the stress control of Yi Chang Yangtze River Railway Bridge's constructing, Stress control is applied successfully by a perfect system of construction monitoring.Temperature difference of sunlight is an important question affecting the bridge's constructing, the determination of temperature field is the key factor to solve this problem. According to the 24 hours continual observation to the stage of cantilever construction and the closure of the continuous rigid bridge, the effect of temperature difference is thoroughly analyzed on the basis of the temperature gradient, and the calculating results match well to measured ones, which demonstrate the temperature gradient model presented our country railway norm and New Zealand norm is feasible. Finally we give a simple introduction to the reduction temperature stress measures. The Yangtze River Railway Bridge in Yi Chang is still under construction and a lot of issues need to be studied such as stress control of arch rib,the initial tension of suspender,creep and shrinkage of concrete etc.