Optimization And Analysis Of Reactive Powder Concrete Low-height Bridge

Reactive Powder Concrete (RPC) is a new generation complex material, which possesses excellent properties such as ultra-high strength, high toughness and high durability etc. Currently, the study of RPC is mainly concentrated in material proportioning optimization and primary mechanics performance, while seldom research work is conducted on RPC bridge design theory and method. The application of RPC in bridge engineering will decrease the direct maintenance, improve the general performance and reduce the bridge total cost and so on. This paper carries out the optimization design research on RPC simply-supported box-girder bridges in low-height to provide the reference for the practical application of RPC.This paper combines finite element analysis and optimization method to theoretically analyze RPC simply-supported low-height box-girder bridges. The optimal parameters of cross-section and optimal prestressed RPC cross-sectional areas can be determined by optimization analysis. The girder total construction cost is taken as objective function, while the sectional dimensions of the box-girder and prestressed reinforcement area as design variables, under constraints of the strength and deflection, finite element parameter optimal analytical method single run method is applied to optimally analyze the main working conditions of the box-girder's normal performance. The results indicate that the sectional height is the key deciding factor when the total construction cost of prestressed RPC simply supported box-girder is optimal, and prestressed reinforcement area is the key deciding factor of girder deflection when the sectional height is certain.This paper carries out optimal calculation and analysis on 20m-span, 24m-span, 32m-span, 40m-span double-line single-hole simply supported box-girders in the ratio range of height and span (H/S) from 1/12, 1/13, 1/14, 1/15 to 1/16, and at last optimal sectional parameter and optimal prestressed reinforcement area of all spans are gained. During the analytical calculation, since the end cross-section of the RPC box-girder with constant section has well met the structural strength requirement, the common reinforced bar and the section only have to satisfy the structural requirements.