| The arch bridges with the network arrangement of hangers have some obviously advantages,such as light self-weight,graceful shape,and the superior technical and economic indices,which have widely applied in the construction of railroad bridges.Currently,with the rapid development of bridge construction technology in China,this type arch bridges began to be gradually used in highway bridges.This paper mainly focus on the study on the static and ultimate load carrying capacity of the network arch bridges based on a research project of a highway network arch bridge in Anhui Province.The research content is as follows:(1)Developing the finite element model of a full bridge structure to analyze the force performance of the network arch bridges under the designed constant load,live load and its basic load combination;establishing a calculation model of the bridge under three types of hanger arrangements: vertical,Nelson and network,and comparing the force performance of these three cases,and analyzing the advantages of the network arch bridge.(2)Based on the characteristics of the network arch bridges,to study the structural parameters of the network arch bridge,by selecting different structural design parameters and establishing the corresponding calculation model,the force performance of the network arch bridges under the changes of structural parameters is studied,and the change law of the mechanical behavior of the network arch bridge under the structural parameters such as the inclination angle of suspender,rise-span ratio and arch beam stiffness ratio is obtained,and the range of the corresponding design parameters is recommended.(3)Constructing the finite element model of the bridge structure in ANSYS to analyze the elastic stability of the bridge,and obtaining the buckling coefficients under the eigenvalue analysis.Then,the double nonlinearities analysis is conducted,and further analyzing the ultimate bearing capacity of the bridge under the simultaneous effect on the dead and live loads.(4)Considering the material and geometric nonlinearity,the effects of key design parameters such as arch rib stiffness,rise-span ratio and cross brace type on the ultimate load carrying capacity of the bridge structure is further analyzed.According to the theory of susceptibility analysis,the susceptible suspenders of the network arch bridges are identified for fracture simulation,and their effects on the ultimate bearing capacity of the bridge after fracture are analyzed.The findings of this study can provide theoretical references for the design of highway network arch bridges. |
