The Structure Design And Mechanical Property Analysis Of Pylon For Long-span Cable-stayed Bridge

In recent years, a large number of cable-stayed bridges have emerged in our country. Due to the increase of the span, the design of pylon is being paid more and more attention in long-span cable-stayed bridge. Pylon is the main load-bearing component of the cable-stayed bridge, connecting girder through cables and forming a whole of "girder-cable-pylon" to ensure the integrity. The force behavior of pylon is relatively complicated considering wind load, temperature load, seismic force, huge cable force and concrete shrinkage and creep. It is necessary to do some analysis research on short-term and long-term performance of pylon and the whole bridge structure under these effects combination. According to above analysis, a design scheme of large-span cable-stayed bridge is taken as project case, performed detailed calculation and analysis for pylon. The main work is as below:A. Based on a great number of references, this paper introduces the structure form and the mechanical characteristics of pylon. The analysis theory of cable-stayed bridge and the method of finite element simulation are also reviewed.B. In this paper, the finite element model is made according to the construction sequence of the bridge and the cable tension is determined through forward-iteration calculating to correspond the requirement of structural design by finite element process for bridge.Calculation and analysis of super-structure are worked out, including girder stiffness, counterforce of the support, internal force and stress of girder, internal force of pylon and intensity of stay-cables.C. Through establishing the construction stage and the constructed model of the pylon, calculation and analysis of pylon are made under the corresponding function combination, it consists of the structural response under the wind load in constructing and constructed stage, the temperature, the stability analysis, the seismic behavior of pylon, shrinkage and creep effects of concrete(time-dependence, surroundings relative humidity and loading-age).D. The effect of stiffness, height and form of pylon on mechanical properties of super-structure for the bridge is investigated. Different parameters lead to different levels of internal force for each structure. In this paper, the change trends of internal force distribution and deformation of the "girder-cable-pylon" are analyzed through adjusting those parameters.