Design of full block and all-welded steel truss girder of main bridge of pingtan straits rail-cum-road bridge

The Yuanhong Ship Channel Main Bridge of Pingtan Straits Rail-cum-Road Bridge is a steel truss girder cable-stayed bridge with span arrangement (132+196+532+196+132) m. The main girder of the cable-stayed bridge is the plate and truss composite steel truss girder structure provided with a secondary truss and is arranged into double decks. The upper deck of the bridge carries 6-lane expressway while the lower deck carries 2-track railway. In between the pylon No.3 and main girder, the longitudinal fixed bearings are arranged and in between the pylon No.4 and main girder, the longitudinal dampers are arranged. The main truss of the bridge is the N-shape truss that is 13.5 m high, 15 m wide and the typical panel length of the truss is 14 m. The center-to-center line distance of the upper chord top plates of the secondary truss is 35.7 m. In the areas of the highway and railway floor systems with stay cables, the integral orthotropic steel deck structures that are supported by the densely arranged cross beams are applied. In the area of the highway floor system without stay cables, the concrete deck structure that is supported by the densely arranged cross beams is applied and in the counterweight areas of the railway floor system, the closed steel box girders are arranged, in which the plain concrete is placed to serve as the concentrated counterweight. On the vertical members of the main truss at the piers, the plate type portal frames are arranged and the anchorage at the girder ends are the anchor tensile plate structures. The steel truss girder of the bridge is manufactured by all-welding and is lifted in large blocks in each two panels, the maximum lifting weight of the panels is 1 250 t and the panels are erected by the two-side cantilever method. ©, 2015, Wuhan Bridge Research Institute. All right reserved.