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 five-span continuous steel truss girder cable-stayed bridge with span arrangement(90+240+630+240+90)m.The upper deck of the bridge carries 6-lane expressways while the lower deck carries 4-track railways.Longitudinally,the main girder is designed as the one of floating system and in between the main girder and the pylon lower cross beams,the damping devices are arranged.The main girder is comprised of 3N-shape main trusses and the main trusses are all of the all-welded truss units.For both the roadway and railway decks of the bridge,the monolithic orthotropic steel decks with densely arranged cross beams are employed.In the area close to a pylon and of the counterweight section that is subjected to tremendous force,the box structure is employed for part of the lower deck.At each vertical member,the triangle truss lateral bracing is arranged.The pylons of the bridge are the inverted Y-shape C50 concrete structures and the height of a pylon above the pile cap is 212m.The stay cables are arranged in three cable planes and at each side of a pylon,3×19 steel strand cables are arranged.With the exception that the foundation for the pylon pier No.3in the deepwater area is of the open caisson foundation,the foundations for the rest of the piers are all of the pile foundations.The caisson is a round-end caisson,of which the upper 18mpart is the concrete structure while the lower 50mpart is the steel structure.