Static And Dynamic Analyses And Shear Lag Effect Of CFST Truss Composite Bridge

Firstly,the development and research status of concrete filled steel tube(CFST)truss composite bridge at home and abroad are introduced.Taking a highway CFST truss composite girder bridge(3×30+5×40)m as the engineering background,the finite element software MIDAS/Civil was choosed to establish the bridge model and simulate bridge deck by three methods considering the shear lag effect of the bridge deck.Based on the whole bridge model,the internal force and deformation rule of the main beam under dead load and combined action are analyzed,and the bearing capacity and fatigue strength of the main beam are checked.At the same time,the vibration frequency and vibration type of structure are analyzed,by using the response spectrum method and time history analysis method,the response of structure under earthquake is caculated,in accordance with the rules in the E1 earthquake and the E2 earthquake on the pier strength computation.Then the whole 3D finite element model is established by MIDAS FEA,the stress distribution of bridge deck dead load and combined action and longitudinal normal stress distributions along the longitudinal direction and the thickness direction are analyzed,then d the shear lag coefficient variation along longitudinal direction is studied.Finally,the stress law of CFST joint under constant load and live load is studied.