The Optimum Design And Stability Study On U-Shaped Girder Of Reactive Powder Concrete For Footbridge

With the progress of society, passenger footbridges find wide application in the city. Footbridge of reactive powder concrete(RPC) which is a new kind of composite material can allow for lighter and safer structures with shorter construction periods. Because u-shaped girder has the features of reducing building height greatly and making full use of RPC when the section of RPC footbridges is chosen, u-shaped girders of RPC for footbridges are studied tentatively in this paper. According to the applicable design codes for footbridges, the study is focused on the following aspects based on the present research achievements of RPC in this paper:1, For the simple supported u-shaped girders of footbridges, the optimal analysis model is established according to structural optimal theory based on the FEA software ANSYS by taking the lowest volume of girder as the object function and the stress and deflection of girder as the constraint conditions. At the same time, the height of the sternum and the flange as well as the width of the sternum and the flange are used as design variables in optimal design.2, To simply supported u-shaped girders of RPC footbridges including the spans of 15m, 20m, 25m and 30m, the optimal calculation studies are carried out by three-dimensional finite element analysis software ANSYS. At the same time, the calculations of the bearing capacity limit condition and the normal application limit condition of the deflection are finished for the optimal design of the structure. Some valuable results are acquired and provide the important reference for the practical engineering design. The study results indicate the plain RPC structure with a small mount of structure reinforcement only can satisfy the stress requirements and application functions completely, which can reduce the weight of girders and decrease both the construction difficulty and construction workload.3, Based on the optimal results of the girders, the stability analyses of the girders including the integral stability of elastic theory and the linear stability by using FEA software ANSYS are completed in order to check the stabilities of the optimal designs of the girders. The calculation results show that the simple supported u-shaped girders of RPC for footbridges can't be buckling under normal working loads.