Key Techniques for Design of Main Bridge of Tongling Changjiang River Rail-cum-Road Bridge

The main bridge of Tongling Changjiang River Rail-cum-Road Bridge is a steel truss girder cable-stayed bridge with a main span 630mand is currently the longest span railcum-road bridge being constructed.In this paper,the key techniques for the design of the bridge are summarized.For the pylon foundations of the bridge in the deepwater area,the open caisson foundations that are cost-saving and have good ship collision performance are used.The main truss members in the range of each two panels of the steel truss girder are welded into a 30mlong stable truss unit and the work load of field assembling of the members is therefore reduced.In the areas close to the pylons and of the counterweight sections that are subjected to tremendous forces,the orthotropic steel box decks are designed for the part of the railway deck.The design in such a way can reduce the dimensions of the chord members and can provide space for arrangement of the counterweight.On the railway cable-stayed bridge,the steel strand stay cables are used.The test study of the fatigue performance of the cables has been made and moreover,a new type of the damping device that can satisfy the service requirements of the bridge under different load cases has been developed as well.