Punching Shear Performance Of Steel-Ultra-High Performance Concrete-steel Sandwich Slabs

Steel-concrete-steel sandwich structure consists of two steel plates on both sides,an inner concrete core and connectors.Compared with traditional reinforced concrete structure,it exhibits excellent mechanical properties and remarkable advantages of modular construction.It has been more and more widely used in the containment of nuclear power plant,subsea immersed tunnel and offshore platform.Ultra-high performance concrete has become a new carrier to achieve long-span performance of cement-based materials due to its characteristics of high strength,high ductility and high durability.Take ultra-high performance concrete as the inner core of steelconcrete-steel sandwich structure and form steel-ultra-high performance concretesteel sandwich structure,which is a new type of high performance structure system.S-UHPC-S sandwich structure can exert their advantages and ensure the mechanical properties and durability,on the basis of efficient modular constructionIn this paper,the punching failure of steel-ultra-high performance concrete-steel sandwich protective structure during service time is systematically studied.The punching shear performance and failure mode of steel-ultra-high performance concrete-steel sandwich slab under concentrated load are analysed.On this basis,the finite element analytical model for punching shear performance of steel-ultra-high performance concrete-steel sandwich slab is established,and the influence of structural design parameters on punching shear performance is systematically investigated through the finite element parametric analysis.Finally,a theoretical formula for punching shear capacity of steel-ultra-high performance concrete-steel sandwich slab is proposed.The main works and research results are as follows:(1)The mix proportion of ultra-high performance concrete is determined,by which can prepare ultra-high performance concrete with high strength,high ductility,high durability and good fluidity under non-steam curing condition.(2)Punching shear tests of three steel-ultra-high performance concrete-steel sandwich slabs with different headed studs spacing are carried out.The results show that the spacing of headed studs has significant influence on punching failure mode and failure mechanism of steel-ultra-high performance concrete-steel sandwich slabs.Three failure modes of structure are defined,namely slip failure,partial slip failure and non-slip failure.The failure mechanism of each failure mode is explained.(3)Based on ABAQUS finite element software,a numerical simulation analysis model of punching shear performance of steel-ultra-high performance concrete-steel sandwich slab is established.The model takes account of both material nonlinearity behavior and slip effect between steel and concrete,which can truly reflect the punching failure characteristics of the specimens under concentrated load.The applicability of the numerical simulation method is verified with comparing with the experimental results.(4)The numerical simulation of punching shear performance of steel-ultra-high performance concrete-steel sandwich slabs with different structural design parameters is systematically analyzed.The effects of headed stud spacing,steel plate thickness,concrete cross section height and type of concrete are investigated.On this basis,combined with the results from experiments and finite element analysis,the theoretical calculation method of punching shear bearing capacity of steel-ultra-high performance concrete-steel sandwich slabs is proposed,and the effectiveness of the method is verified.