Abstract:Abstract:Research purposes: Minjiang is the inland waterway for grade II, single hole two-way navigable requirements are clearance of 170 m and height of 24 m. The main bridge span of Minjiang super large bridge of Fuzhou-Pingtan railway uses (110+198+110) m continuous rigid frame. Due to the large span of this bridge, it is a key project, and the bridge structure design must be selected in many directions. The beam depth, double thin-wall pier column spacing, double thin-wall pier thickness, arrangement of pile foundation, bridge structure were compared and selected combining with the navigation and geological situation, and the suitable bridge structure and outline size for the project were obtained. Research conclusions: Based on the calculation and analysis of different selection conditions, we can draw the following conclusions: (1) The stress, displacement and other indicators of the main structure meet the specification requirements, and the outline dimensions of the bridge design is appropriate.(2) For the ballasted track continuous rigid frame within 200 m of the main span, the main span increasing steel truss beam, has little influence on the creep deformation of the structure after construction, but the cost will increase a lot, so it should not be used. (3) The research results are applied to the design and construction of Fuzhou-Pingtan railway, which can provide reference for similar engineering.