Structural Optimization Analysis Of Pedestrian Tied Arch Bridge

Tied arch bridge,as a bridge type with reasonable structure,beautiful shape and strong adaptability,has broad application value.Most of the studies on tied arch bridges in domestic and foreign literatures focus on highway bridges and railway bridges,while few scholars are concerned about the application of tied arch bridges in pedestrian bridges.From the design point of view,the span,shape and economy of tied arch bridge are suitable for pedestrian bridges with less load.Therefore,this paper takes a pedestrian tied arch bridge with a span of 100 m as the background,and explores the parameters optimization,size optimization and topology optimization of pedestrian tied arch bridge.The main research contents are as follows:The design process of the through pedestrian tied arch bridge is introduced,and the effects of various loads on the structure under the finished bridge state are introduced,then the structure is analyzed for elastic stability.The parameters of the tied arch bridge with vertical hangers are analyzed from the aspect of rise-span ratio and stiffness ratio,and then the SiPESC.OPT,an integrated optimization calculation system independently developed by Dalian University of Technology,is used to optimize the size of the tied arch bridge in order to reduce the cost.This paper briefly introduces the mechanical characteristics of the tied arch bridge with network hangers,the structural forms of arch and several common network hanger arrangements,and analyses their remarkable advantages comparing to tied arch bridges with vertical hangers: the arrangement of network hangers greatly improves the stiffness of tied arch bridges under live loads,greatly reduces the bending moment of main girders and arch ribs,and significantly improves the mechanical performance of the structure.The parameters of the network tied arch bridge are optimized.The influence of the number of hangers,the inclination angle of hangers,rise-span ratio and arch-beam stiffness ratio on the structural behavior is analyzed,and a reasonable range of parameters for pedestrian tied arch bridge is proposed.A new type of hanger arrangement for tied arch bridge,sparse inclined hanger system,is proposed,and a dimensionless optimization method based on genetic algorithm and finite element method is developed.This method can be used to optimize the layout of sparse inclined hanger system,so as to obtain a number of tied arch bridges with optimized mechanical properties and aesthetic configurations.It can improve the mechanical properties of structures and enrich the diversity of design from the aesthetic point of view.