Study on Structure and Stiffness Indexes Long span Road-Rail Suspension Bridge

It is rapidly developing the construction of long-span suspension bridges in China. It is an important issue for the structural design of suspension bridges. It is a problem that needs further study for high-speed and heavy-haul railway suspension bridges. There is the characteristics of heavy train live loads, high speed and high demand for running security and passenger comfort, the technical standards and so on. The paper is analysis the stiffness evaluation indexes of railway suspension bridges adopted by the codes of various countries in the world, and compares them with the regulations in China’s general bridge codes. The key technologies of the thousand-meter-scale road-rail suspension bridges for high speed for passenger trains, 120 km/h for freight trains) and heavy load are studied. Based on the research on the road-rail suspension bridge with main span of 1 196 m, the influences of different supporting systems, arrangement of auxiliary piers, ratio of height to span, ratio of width to span and ratio of vertical to span on the vertical and lateral stiffness of the bridge are analysis, and the stiffness evaluation indexes and suggested values for thousand-meter-scale road-rail suspension bridges are proposed. The proposed long-span suspension bridge scheme is technically feasible, economically reasonable, and has good horizontal and vertical stiffness, smoothness and running comfort.