Research On Optimization Of Suspension Cable Force And Suspension Error For Long Span Y-shaped Steel Box Ribbed Arch Bridge

For large-span arch bridges,the suspension is an important force transmitting component that connects the arch ribs and the main beam.The force of the suspension directly affects the stress situation of the bridge structure and the overall shape of the bridge,affecting the safety of the bridge.At present,there is relatively little research on the suspension of special-shaped arch bridges,so it is of great significance to conduct research on the suspension of such arch bridges.This article takes a large span Y-shaped steel box rib arch bridge as the engineering background,and conducts analysis on the suspension of the bridge.Firstly,based on the characteristics of the supporting projects,the calculation methods for bridge cable forces were compared and an improved particle swarm optimization algorithm was introduced.By combining the improved particle swarm algorithm and energy minimization method,the optimization of the suspension cable force during the bridge completion stage were carried out.The forward iteration method was used to calculate the suspension tension force during the bridge construction stage.The influence of suspension design parameters on the bridge was analyzed and the response surface method was used to establish the influence matrix of suspension design parameters.Finally,the impact of suspension tension error on the bridge was analyzed,and a prediction model for suspension tension error was established using BP neural network.Research shows:(1)The combination of improved particle swarm optimization algorithm and energy minimization method can effectively optimize the suspension cable force of the Y-shaped steel box ribbed arch bridge during the completion stage.After optimization,the suspension cable force of the bridge is reduced from both sides to the middle,and the relative difference in cable force between adjacent suspension does not exceed 15.4%.The internal force and displacement of the bridge meet the requirements of the specifications.(2)The influence matrix of suspension design parameters established through the response surface method has high accuracy,with correlation coefficients are above 0.9,which can effectively reflect the relationship between suspension design parameters and suspension cable force.Among the design parameters of suspension,the cross sectional area of the suspension has the greatest impact on the cable force of the suspension during the bridge completion stage,followed by the material,and the influence of the inclination angle is the smallest.(3)Compared to other suspension,the short suspension on both sides are more sensitive to the influence of suspension tension error.Taking the displacement change of the main beam not exceeding 1cm of the original design value as a constraint condition,while ensuring that the change in cable force of the suspension does not exceed 6% of the design value,it can be obtained that the tension error of the suspension cannot exceed 8% of the design tension value.(4)The prediction model for suspension tension error established through BP neural network has high accuracy,and the correlation coefficients of the models are all close to 1.It can effectively predict the tension force of suspension based on the suspension cable force,and infer the suspension tension errors.The calculated suspension tension error can be combined to adjust the bridge suspension cable force.