Analysis Of Fatigue Property And Stability Of Prefabricated Steel-Concrete Composite Continuous Girder Bridges

Composite beam is applied in bridge engineering more widely.But the increase of bridge spans,traffic volume and vehicle axle load,bridge design reference period,and serious overload phenomenon greatly increase the possibility of fatigue damage of composite bridge during the operating period.And once the fatigue damage of bridges is occurred,the consequences are extremely serious.The steel-concrete composite continuous beam bridge will have a negative moment zone.The lower flange of the steel beam is pressurized,it may have a lateral instability before reaching the full section plasticity.Therefore,it is necessary to research the stability of steel-concrete composite beams.The main work and results achieved are as follows:(1)The analysis object is steel-concrete composite continuous beam bridge.By means of the finite element software for calculation the finite element model of composite continuous beam bridge is established for the internal force characteristics and change law in each construction stage and operation stages.(2)Finite element models of different layout of shear studs are established to explore the effect of shear studs layout type on the performance of the composite bridge,mainly aimed at the structural static analysis and the evaluation of the fatigue performance.The shear studs layout type has few effects on the performance of the composite bridge.So when the load bearing limit state and the slippage is satisfied,both types can be taken as reference to the construction plan.(3)A variety of models and calculating methods are used to calculate the lateral torsion buckling bending moment of the negative moment zone of composite bridge for a contradistinctive analysis.If the lateral torsion buckling critical moment is planned to be calculated by the simplified model method,the inverted u-shaped frame model is recommended.