Construction Control During The Hauling Construction Of Large Tonnage Curved Concrete Box Girder

The main bridge of railway separated interchange on Jing-xin Highway is a single tower and single cable plane cable-stayed bridge with five spans curved prestressed continues concrete beam. It is a tower and pier consolidation system, and the girder is supported by the tower and pier. This bridge connected Jing-Bao railway,13th urban railway and Jing-Zhang inter-city railway. There are many technical difficulties and challenge in the construction of this bridge which are either rare or unprecedented in the construction practices both domestic and abroad. Take this bridge as the engineering background, this paper analyzed the hualing process, details are as follows:(1) The hualing construction of large-tonnage curve concrete box girder. Pushing and hualing construction is one common method in bridge construction. But it is rarely used for large-tonnage curves for concrete box girder. The hualing girder section has a horizontal curvature radius of 3500m, cross slope of bridge deck change dramatically; besides, the elevation radius is 11000m. The conditions of Spanning over railways increase the difficulties of construction. To ensure that the beam would be moved along within the drag track, and prevent great lateral displacement, ensure structural safety during the hualing, accurate and reliable theoretical calculation and strict construction control measures are needed. This paper used finite element analyzed the drag construction of main beam.(2) The hualing construction control and structural stress monitoring. The real-time monitoring of the stress of girder and temporary pier during hualing process is commenced; the results are compared with the theoretical solution. The accuracy and the speed of corrective are improved and safety of structure is guaranteed; besides, the effect of correction is proven by this method. Given consideration to the large distance and great amount of monitoring points, some specific points need extra-long time of monitoring, girder and temporary pier need real-time monitoring; the FBG sensors are introduced in the stress monitoring during hualing process.(3) Several key issues in hualing construction are studied and investigated. After the comparative analysis of theoretical values and actual values, reasonable analysis and solutions are proposed in this paper. The conclusion and experience in this paper could provide reference and guidance for the design and construction of similar bridge.