Innovation design of a ballastless cable-stayed bridge with main span of 300m in high-speed railway

Right now, for bridges paved with ballastless track on high-speed railway with operating speed of 350km per hour in the world, the maximum span is 185m, and larger span bridges are all paved with ballasted track. The speed of the train passing through the large span bridge has to be limited to be not more than 250km per hour, which becomes a neck for high-speed trains running on the whole line. Laying ballastless track on large span bridges has become a technical problem to expand application range of ballastless track. This paper is based on a cable-stayed bridge with main span of 300m. For this bridge, prestressed concrete box girders are used for edge span and box steel-concrete composite beam is used for mid-span. Cable-stayed bridge is a flexible structure, and the stiffness must be the problem to be solved first for high-speed railway. The hybrid girder and the composite beam for the middle span can increase the deadweight stiffness. Relative to the steel bridge deck, concrete deck has larger stiffness and smaller local deformation, which makes it more conducive to high-speed traffic. The technology of laying ballastless track in the concrete slabis mature. This bridge is the first cable-stayed bridge paved with ballastless track on high-speed railway with design speed of 350km per hour in our country. This paper focuses on the conception, structure design and innovation points of the bridge. And the adaptability of high-speed railway ballastless track to the bridge is also analyzed.