Analysis of Structural Characteristics of Shangshen Bridge

The Shangshen Bridge is a half-through continuous steel truss bridge with span arrangement(62+100+62) m.The finite element software is used to analyze the static behavior and stability of the bridge.The results of the analysis show that the effect of live load on the global deformation of the bridge is great,the amplitude of increased vertical displacement at the midspan of central span is maximum,the effect of geometric nonlinearity on the vertical displacement of the bridge is little and can be ignored and the deflection-to-span ratio is less than the limitation values as required in the codes.To ensure the better safety and rationality of the structure,at the time the structure is designed,the rigidity of panel points and the stress in the middle of members are calculated by the hinged model,the stress in the ends of the members is calculated by the rigid model and the axial stress of the hinged model plus the bending stress of the rigid model are taken as the design control stress.The stability safety factor of the whole bridge is greater than 4 that can satisfy the service requirement.The transverse rigidity is weaker than the vertical rigidity and all instability modes of the bridge are of the out-of-plane torsional overturn or out-of-plane lateral overturn of main truss.