Influencing Factors Analysis On Fatigue Life Of Steel-Concrete Composite Continuous Beam

The steel-concrete composite continuous beam can give full play to the advantages of the two materials and it is convenient to construct and has good economy.It is widely used in bridge engineering.Bridges need to bear the repeated effects of vehicle loads during service,so it is necessary to study the fatigue life and influencing factors of steel-concrete composite continuous beams under fatigue loads.This paper carried out theoretical and numerical analysis and experimental research on the fatigue life of steel-concrete composite continuous beams under fatigue load.The specific work and conclusions of this article are:(1)According to the fatigue damage accumulation theory,based on the Miner criterion,the material residual strength theory and the fatigue process analysis method,a fatigue process analysis method suitable for steel-concrete composite continuous beams is proposed.Combined with the existing material fatigue damage model and failure criterion,the calculation method of fatigue life of steel-concrete composite continuous beam is given.(2)The fatigue test results of four steel-concrete composite continuous beams verify the accuracy of the fatigue life calculation of steel-concrete composite continuous beams using the full-process analysis method of fatigue,which can be used to calculate the fatigue life of steel-concrete composite beams.(3)The finite element software ABAQUS and the fatigue analysis software FE-SAFE were used to establish the numerical model of the steel-concrete composite continuous beam,calculate its fatigue life and compare it with the test results to verify the reliability of the finite element analysis.Based on this,the effects of concrete strength grade,concrete slab thickness,reinforcement ratio,steel beam height and stud spacing on the fatigue life of steel-concrete composite continuous beams were studied.The research shows that the fatigue life of steel-concrete composite continuous beams increases with the increase of concrete strength,concrete slab thickness,reinforcement ratio and steel beam height,and decreases with the increase of stud spacing.The thickness of the concrete slab and the height of the steel beam have a great influence on the fatigue life of the composite beam.In the fatigue design of the composite beam,you can focus on the impact of these two aspects.