Study Of Flexural Properties Of New Cold-form Thin-walled Steel And Concrete Composite Slabs

With light and high-strength mechanical properties and unique forming method,cold-formed thin-walled steel can be applied to composite structures by means of splicing or truss,which can reduce the weight of the structure and improve its bearing capacity and ductility.This paper proposes a new type of cold-formed thin-walled steel-concrete composite slab structure,which consists of cold-formed thin-walled steel and reinforcements to form a stress skeleton,filled with polystyrene foam board(EPS)inside,and then cast concrete to form a whole.This paper focuses on the experimental research and finite element analysis of the flexural capacity of this new composite slab structure,reveals its stress mechanism,and finally puts forward the calculation formulas of its bearing capacity and deflection.The specific research contents are as follows:(1)Two sets of composite slab specimens were made with different numbers of cold-formed thin-walled steel and polystyrene foam(EPS),and static tests were carried out.Through the analysis of the test phenomenon and test data,the bearing capacity and failure mode of composite slabs were studied.(2)The ABAQUS analysis software was used to establish and simulate the composite slab models.The simulated results were compared with the test results to verify the correctness of the finite element analysis.(3)Change the model parameters: concrete strength grade,the ratio of longitudinal reinforcement,the thickness of C-sections and composite slab,and study the influence of these four parameters on the bearing capacity of composite slab.(4)The calculation formulas of bending capacity and stiffness of composite plates are derived,and the deformation checking calculation is carried out.Through the above research,the following conclusions can be drawn: In the new cold-formed thin-walled steel-concrete composite slab structure,the existence of steel skeleton and polystyrene foam board(EPS)reduces the self weight of the structure and improves the bearing capacity of the composite slab.In the process of bearing,the composite slab has experienced three stages: elasticity,elasto-plasticity and plasticity.It has good stress and stable deformation without sudden failure,which proves that the composite slab has good ductility.The results of finite element simulation fit well with the test results.The ratio of longitudinal reinforcement and the thickness of composite slab have the greatest influence on the flexural capacity of composite slab,and the flexural capacity of composite slab will increase with the increase of the ratio of longitudinal reinforcement and the thickness of composite slab.The influence of C-sections thickness is the second,the bending capacity of composite plate will increase slightly with the increase of C-sections thickness.The influence of concrete strength grade is the least,and the flexural capacity of composite slab will not change with it.Finally,the results of bending capacity and flexural deformation calculated by the formula of them are in good agreement with the test results,which proves the correctness of the formula and can be used in the design of composite plates.