Optimization Method for a Lap-Assembled Parabolic Concrete Channel Structure

Abstract

Based on the structural force analysis of a lap-assembled parabolic concrete channel, it is thought that the longitudinal tensile stress is the main factor that influences channel damage. The locations where the channel is most likely to be damaged were determined, and an optimization model was established with the tensile-stress value of the structure most prone to damage area as the objective function. The calculation method of the optimization model parameters is proposed, and the calculation formula of the lap assembled parabolic concrete channel structure is derived. The multi-objective optimization model is transformed into a single-objective model by using the weighted sum method, and the resulting model was solved with the Fmincon function in MATLAB R2010a. The example analysis shows that the channel with the optimum structure section obtained by optimization is better than the channel of the practical economic section in hydraulic performance and structural force performance, and the breadth–depth ratio is reduced by 48.51%, which greatly reduces the occupied land area. In a comparison with the optimum hydraulic cross section, the hydraulic performance of the optimum structure section was slightly worse, but the breadth–depth ratio decreased by 22.98%. Regarding the structural force performance, the transverse maximum tensile stress of the channel with the optimum structure section increased by 6.02%, the longitudinal tensile stress decreased by 5.63%, while the longitudinal tensile stress was the primary influencing factor of channel damage. Therefore, the optimum structure section is better than the optimum hydraulic cross section, which indicates that the optimization method is feasible and can provide significant guidance for the structural optimization of an assembled channel and similar structures.