Design of a Railway Steel and Concrete Hybrid Box Girder Cable-Stayed Bridge with Main Span of 468m

The Yongjiang River Bridge on the North Ring Link of the Ningbo Railway Terminal is a steel and concrete hybrid box girder cable-stayed bridge of semi-floating structural system.The span arrangement of the bridge is(53+50+50+66+468+66+50+50+53)m.The cut-off joint of the steel and concrete sections on one side is located in the central span of the main girder,24.5mapart from the pylon.With the exception that the 419mlong section of the central span is of the steel box girder,the rest sections of the bridge are all of the concrete box girders.The pylons of the bridge,each being 177.91min height,are the diamond-shape concrete structures.In the upper column of a pylon,the built-in steel anchor box is arranged.The stay cables are made up of the7mm galvanized parallel steel wires and are arranged in fan-shape in spatial double cable planes.The foundations of the bridge are the ones supported on the very long and large diameter group piles.The concrete box girders are cast in situ on scaffoldings span by span while the steel box girder is lifted and installed in blocks.In the light of the characteristic that the railway load of the bridge is great and the required rigidity is high,the reasonable completed bridge state is determined in the design and at the same time,the structural static analysis, the study of the seismic resistance,wind resistance,the analysis of vehicle-bridge and wind-vehicle-bridge coupling vibration are carried out and the structural safety and comfort are verified as well.