Structural Response Characteristics Analysis Of Large-span Continuous Rigid Truss And Flexible Arch Bridge Under Wind And Train Load

The operating environment of high-speed railways is complex in China,and the proportion of bridges account for a large proportion,including many long span bridges;the lines are widely distributed and pass through different types of wind areas;Strong winds pose great challenges to the safety and stability of high-speed trains on the bridge.It takes the Tianshenggang dedicated channel bridge of the Shanghai-SuzhouNantong Yangtze River Bridge as the engineering background,takes wind load and train load as the main excitation,calculates the nonlinear dynamic response of the bridge under the action of wind and train load,and the dynamic response of the bridge and the safety of train running under different wind speeds are analyzed.Tianshenggang Channel Bridge is a three-span continuous rigid truss flexible steel arch bridge with a main span of 336 m and a total span of 616 m,which is the largest span of its kind.It is a highway and railway steel-truss arch bridge.The main girder consists of three trusses,and the lateral rigidity is relatively large.This paper relies on the main research work and results of this bridge as follows:(1)It introduces the main characteristics of natural wind,and analyzs the wind field data of the HMS on the Tianshenggang channel bridge to get the characteristics of average wind and fluctuating wind in bridge site.and the bridge site area The measured wind field characteristics of the bridge site are compared with the existing wind spectrum.Finally,according to the wind speed power spectrum that conforms to the characteristics of the wind field in the bridge site,the time-historical fluctuating wind speed data acting on the bridge is simulated by the harmonic synthesis method.(2)According to the bridge construction drawings and the actual situation,the bridge finite element model and track model are established with ANSYS software;and on this basis,the bridge is modal analysis to get its natural vibration characteristics;based on the CRH3 high-speed train,according to the bridge meshing situation,established Train ANSYS model.(3)Based on Davenport’s quasi-steady theory,the static wind and buffeting load loading models were established.A simple vehicle-bridge coupling analysis system model is established by combining the train model,the bridge model and the wind load through the displacement contact method of the Displacement-contact method in ANSYS.(4)It analyzs the dynamic response of the bridge caused by different wind speeds and train speeds,relying on the vehicle-bridge coupling system.According to the analysis of the train running safety under different wind speed and train speed,the wind speed and speed condition to ensure the safe running are obtained.(5)According to the characteristics of rigid truss girder and flexible arch combination bridge,response against arch bridge and comparative analysis of the main beam,rib partial deletion contrast conditions,to find such a law in response to a combination of wind and bridge under train load.