Study On The Mechanical Characteristics And Fatigue Performance Of Profiled Steel Sheeting-concrete Composite Bridge Decks Under Vehicle Loading

Profiled steel sheeting-concrete concrete composite slab has attracted much attention from scholars because of its multiple strengths like conveniences of construction and beautiful structure.Besides,it has been extensively applied to the field of steel-concrete composite bridges.Studying its mechanical properties and fatigue properties is a necessary prerequisite to promote this new type of composite structure.At present,numerous studies about this type of composite slab are focused on the longitudinal shear bearing capacity.Howerer,there are a few articles that involved the mechanism of the bond slip and the calculation of stiffness.The fatigue checking method of profiled steel sheeting-concrete concrete composite slab as a deck slab structure under repeated loading of vehicle loads has not been standardized.In order to make up the shortage of these studies,this paper deduces the stiffness calculation of the composite slab.Then it discusses the fatigue checking method of the profiled steel sheeting-concrete concrete composite bridge slab.Finally,it analyzes the fatigue properties of the bridge,and puts forward the measures to improve the fatigue properties of the composite slab.In consideration of the effect of bond slip of composite interface on mechanical properties of composite slab,this paper takes theoretical derivation on the deformation and internal force components of the composite slab and uses the MATLAB program to solve.The calculated results of mid span deflection and end slip are in good agreement with the test results.It is found that increasing the shear stiffness of the composite interface or setting end studs can effectively improve the stiffness of the composite slab.But the improvement of composite slabs with good bonding effect could be dropped greatly.In order to study the fatigue properties of the the profiled steel sheeting-concrete concrete composite bridge slab,it establishes full-bridge finite element models of the Sultan kashmu Alfa Bridge and analyses the fatigue properties of the bridge slab under the load of the vehicles.Then it reviewes fatigue design criterion of steel concrete composite bridge at home and abroad and studies on the fatigue design method of composite slab with the fatigue test of profiled steel sheeting-concrete concrete composite slab.Based on this,the fatigue checking calculation is carried out on the real bridge.The calculation results show that the fatigue properties of the bridge slabs of the Sultan kashmu Alfa subbridge can not meet the design requirements.The shear resistance of thecomposite interface in the life period of the bridge will obviously degenerate,which would produce fatigue damage.In view of this,analyzed the fatigue properties of the bridge slabs.The parameters include the thickness of the steel slabs,the section geometry of the compression slabs,the strength of concrete and the thickness of the concrete slabs.Finally,put forward the measures to improve the fatigue properties.The calculation and analysis show that the thickness of the steel slabs and the geometry of the section have great influence on the amplitude of the shear stress at the end of the slabs.The concrete strength grade has little effect on the fatigue property of the composite slabs.