Research On Optimal Design Of Steel Truss Pedestrian Bridge Based On Genetic Algorithm

The steel truss structure has become widely used in complex projects due to its many advantages,such as high strength,high load-bearing capacity,and ease of construction.However,traditional optimization design methods have limitations in meeting various problems arising in the field of structural optimization.Intelligent optimization algorithms offer an efficient and feasible solution for structural optimization design,as they improve the accuracy of solutions,increase the utilization of materials,improve structural performance,and reduce costs.Therefore,the application of the intelligent algorithm in the optimization of truss structure is very crucial.This paper introduces an improved genetic algorithm,the Non-Dominated Sorting Genetic Algorithm with Elite Strategy,based on the theoretical basis of genetic algorithm.Moreover,it has a unique advantage in dealing with multi-objective optimization problems by using real number coding based on the parameters of the optimization problem,with high solution efficiency,strong global search capability.Fast non-dominated sorting and elite strategy are used to maintain the diversity of the population and improve the performance of the algorithm while reducing the complexity of the algorithm.In the paper,a functional example of non-dominated sorting genetic algorithm with elite strategy is presented to verify the optimization performance compared with the basic genetic algorithm.Based on the application program interface(API)of the finite element software SAP2000 and MATLAB platform,a parallel calculation cycle path is built,and the effectiveness and feasibility of this optimization design method in solving truss related problems is further verified through the application and analysis of two cases: 11-bar plane truss and 72-bar space truss.Taking a large span complex structure‐steel truss pedestrian bridge as an example,the SAP2000 finite element parametric model of steel truss footbridge is established,and the total weight and maximum vertical displacement of the structure are taken as the objective function for optimization to determine the optimization mathematical model.A parallel calculation program is designed and written.The optimization results showed that the overall weight of the structure is reduced by 0.43% compared with that before optimization,saving 116.95 tons of steel;the maximum vertical displacement is increased,but still meets the limit value.Finally,the stress comparison,deformation comparison and dynamic characteristics analysis of the pedestrian bridge structure before and after optimization are carried out.The rationality of the optimization is confirmed,and new optimization ideas and design solutions are provided for other similar complex structural optimization problems.