Research on the long-span combined bridge type of continuous rigid frame and flexible arch

The Yangtze River Bridge in Yichang is a railway bridge with a total length of 2 446 m, which is unique in the style and greatest span in the world. The main bridge with the spans arranged as (130+2×275+130) m is a combined structure composed of prestressed concrete continuous rigid frame and concrete-filled steel tubular flexible arch. The paper summarizes the systemic analysis and research results on continuous rigid frame-arch bridge, which is the study of the performance of the structure against forces, ultimate carrying capacity, nonlinear analysis, seismic resistance, coupled vibration of vehicle and bridge. As a new combined bridge, it has the following features:Girder and arch resisting forces together;Moment and size of girder decrease dramatically due to the arch under compression and the girder under tension;The bridge type brings the girder and arch on resisting forces into full play, because the forces are balanced between the horizontal thrusts of the arch and axial tension of girder;Great in vertical stiffness and slender in appearance; The adoption of the new bridge type will promote the development of technology for long span railway bridge.