Research on the Dynamic Performances of the Steel Truss Girder Main Bridge of Jinan Yellow River Extra Large Bridge for High-Speed Railway

Jinan Yellow River extra major bridge is a four-track railway bridge for both Beijing-Shanghai high-speed railway and Taiyuan-Qingdao passenger dedicated line.Through type continuous steel truss of(112+3×168+112)m was used for its main bridge.By combining the methods of field test and finite element analysis,the dynamic behaviors of the main bridge,train operation safety and stability were researched.The results show that both the lateral and vertical rigidity of bridge meet the requirements of related specifications and design files.The tested lateral and vertical first natural frequency of the beam is 1.57and 1.72Hz respectively,which is far away from the lateral and vertical forced frequency of EMU under test speed and resonance does not appear.The maximum vertical dynamic increment of beam subjected to EMU is 3%of design load,and the maximum vertical acceleration of beam(after 20Hz low-pass digital filter is done)is less than 0.5m.s-2.Both the lateral and vertical amplitudes of beam are very small,which can meet the operation requirements of 300km.h-1 EMU.The safety index of EMU passing through the main bridge with ballast track is less than the allowable value.Both the lateral and vertical stability indexes of carbody are less than 2.5.There is little difference between the tested results of vehicle dynamic response of EMU passing through different track structure sections of the main bridge and approach bridge.