Abstract:Taking a compound beam cable-stayed bridge with the main span of 716 meters as an example, the key technologies such as structural system, position of steel-concrete combined section, design of side-span weight, and design of cable pylon foundation are studied. Aiming at two structural systems of full floating and half floating, the stress of the main beam, stiffness of the main beam and construction scheme are analyzed and studied. The full floating system used for the bridge can not only avoid the problems such as the influence of the large cantilever crossbeam on the appearance and unreasonable stress, but also facilitate the hoisting of the steel box girder. Therefore, the full floating system is finally adopted. The selection of the steel and concrete combined section at the side span and middle span is demonstrated from the bridge completion state, operation state, support and reaction forces, and construction scheme. Considering that the combined section at the mid-span side will lead to the unsatisfactory distribution of the constant load bending moment of the main girder, and at the same time, and cause the side span too heavy and the construction risk of high bracket high. Finally, the position 35 m from the side span side to the bridge pylon is selected. Aiming at the design of side-span weight, two schemes of iron sand concrete weight and thick plate concrete design are compared. The design structural stress considering the thick plate concrete meets the requirements, and there is no need for the weight fixing measures to simplify the construction process.
