Key Construction Techniques for Pingtan Straits Rail-cum-Road Bridge

The Contract FPZQ-3 of the Pingtan Straits Rail-cum-Road Bridge project consists of three navigational channel bridges (all two-pylon steel truss-concrete hybrid girder cable-stayed bridges), a 34-span simply-supported steel truss-concrete composite girder bridge and a 119-span concrete box girder bridge, with a total length of about 11.15 km. The construction of the bridge faces challenges imposed by heavy winds, high waves, deep seawater, raging torrents and large tidal ranges and complex geological conditions. The winds and waves are monitored and forecasted to direct the construction. For the foundation construction, the platform is erected before the launching of the cofferdam, and long trestles, pile hole drilling platforms and large-diameter bored piles are used. The pile caps of the pylon piers are constructed with the aid of the dumbbell-shaped anti-collision box cofferdams. The pylons are erected by the use of fully-closed hydraulic climbing formworks. Different wind-resistant measures are taken, such as choosing the fully-closed wind-resistant hydraulic climbing formworks, attaching walls to stabilize the tower crane that has a lifting capacity of 11 000 kN•m, and using spatial trusses as the lateral bracings. The steel truss girders in the navigational spans are assembled from integral fully-welded truss sections that are lifted and installed by girder erection cranes or the floating crane with a capacity of 3 600 t. The concrete box girders are cast by the use of offshore bridge building machine and scaffoldings. The simply-supported steel truss girders in a span are manufactured as an integral unit, and delivered to the construction site to be lifted and installed by the 3 600 t-capacity floating crane. © 2019, Journal Press, China Railway Bridge Science Research Institute, Ltd. All right reserved.