Dynamic Behavior And Seismic Response Analysis Of Spatial Y-shaped Half-through Steel Box Arch Bridge

People’s aesthetic change of bridge appearance is more and more novel,a large number of special-shaped arch bridges with unique shape are designed,and the bridge structure is frequently used as the traffic lifeline during the service period.If it is damaged in the earthquake,it will seriously threaten the safety of human life and property.In the bridge design scheme of a water conservancy project,under the premise of ensuring the structural safety,service performance and economy,a half through space Y-shaped steel box arch bridge is conceived,which is a special-shaped bridge.For the heterosexual arch bridge with novel structure,there are few references and projects available,so it is necessary to study the structural performance of the bridge.In this paper,the finite element software MIDAS / civil is used to analyze its dynamic characteristics and seismic response under different design parameters.Main works in this paper are summarized as follows:(1)Based on the finite element model of half through space Y-shaped steel box arch bridge,the natural frequency,vibration mode and period are calculated,and the influence of different rise span ratio and cross brace number,as well as changing the boundary conditions of main girder and arch foot on structural dynamic characteristics is studied.(2)Based on the response spectrum method,the seismic response of half through space Yshaped steel box arch bridge is analyzed,and the seismic response law of typical section of the structure is obtained.At the same time,in order to obtain the change law of structural seismic effect,four aspects of structural parameter analysis are carried out by changing the number of transverse braces,the ratio of rise to span,the boundary conditions of main girder and the release of arch foot constraint.(3)By using the time history analysis method,the seismic response of the structure under the uniform excitation and considering the traveling wave effect is analyzed respectively.The results under the uniform excitation are compared with the results under various wave velocity changes,and the traveling wave effect law of the middle through space Y-shaped steel box arch bridge is obtained.To sum up,this paper studies the design parameters and seismic response of the middle through space Y-shaped steel box arch bridge,and obtains some conclusions on the structural dynamic characteristics and seismic response,which is helpful to promote the application and development of the middle through space Y-shaped steel box arch bridge.