Study On Mechanical Properties Of Prestressed Steel-Concrete-Steel Sandwich Slab

Steel-concrete-steel sandwich (SCSS) slab is a relatively new and innovation form of construction consisting of a layer of concrete, sandwiched between two layers of relatively thin steel plate, connected to the core concrete by shear connector. Such structural elements have widely applications in a variety of protective structures, rush repair engineerings, and shear walls and basements in tall buildings.Recently, many civil engineering scholars have studied the working performance of SCSS slab. From the research results, we found that the bending resistance and shear resistance of this structure is very high. But due to the small stiffness of SCSS slab, there will be a big deformation when failure. Meamwhile the cracks will form at the early age of external load and then effect structural using. In order to improve the mechanical properties of structures, we introduce prestress technology and form prestressed steel-concrete-steel sandwich (PSCSS) slab. It is an entirely new project. The dependent report is not seen yet.In this paper, the mechanical properties of PSCSS slab are studied by the methods of theory analysis and numerical evaluation. Meanwhile the theoretical calculating system is also established systematically, which is suitable for the mechanical properties of PSCSS slab. The concrete works of this thesis are as follows:The stress calculating formulae of each section in the different loading stages of PSCSS simple supported slab with unbonded prestressing tendon in straight, polygonal and curve line are given and the formula of PSCSS simple supported slab with adhensive prestressing tendon in straight line is given. It forms calculating formulae of resisting crack bearing capacity, elasticity flexural bearing capacity and plastic collapse flexural bearing capacity of unboned PSCSS simple supported slab and adhensive PSCSS simple supported slab; The slippage calculating formulae are established under the influence of prestress with setting up the formulae of deformation and axial force subjecting to slippage effect and prestress. Through theoretical arithmetic and analysis, the slippage and the axial force are obtained in different position along with PSCSS slabs with different stiffness of connector, different external load, different concrete strength grade and different steel ratio; Slippage and axial force under the influence of increment of prestress is received. The result illuminates that it make no great difference to slippage and axial force. The weighted analysis of PSCSS continuous slab prestressed with unbonded prestressing tendon in polygonal line is carried out. The nonlinear analysis program of PSCSS slab prestressed with unbonded prestressing tendon is developed. The curve of the bending moment-curvature and load-deformation are received.