Experimental Study And Creep Analysis On Steel-concrete-steel Sandwich Composite Panels

Steel-concrete-steel sandwich composite structure is a structure type, which is pouring concrete into double steel plates, in order to increase the interaction between the steel plates and the core concrete slab, usually, shear connectors are welded to the upper and lower steel plates to ensure the interaction between the steel plates and the core concrete slab. As one new structure type of steel and concrete composite structure, the advantages of steel-concrete-steel sandwich composite panels are that the upper and lower steel plates can serve not only as bearing steels and as permanent templates, but also as resistance membrane of the structure to be impermeable and to bear impact load and explosion load. The good bonding effect between the steel plates and the core concrete slab is the foundation to ensure the coordination work of the steel plates and the concrete slab, which will directly have effects on the failure mode, rigidity, bearing capacity, cracks and deformation of the composite panels. Currently, the domestic and international study on steel-concrete-steel sandwich composite panels is still at a preliminary stage, so it is short of systemic and complete experiment study and calculation theory. Thus, to carry out the study on work performance of steel-concrete-steel sandwich composite panels has the vital significance.Based on a comprehensive analysis on the achievements of the steel-concrete-steel sandwich composite panels by domestic and foreign researchers, the contents of this paper are determined:Through the experiment of steel-concrete-steel sandwich composite panels, the working mechanism and failure mode of composite panels are studied, the strain variation of steel and concrete and the load- deformation relationship are analyzed, and also the effects of steel ratio and concrete thickness on the bearing capacity of steel-concrete-steel sandwich composite panels are discussed. The results of experiment show that the bearing capacity of composite panels increases with the increments of steel ratio or concrete thickness.The stress analysis model in each elastic stage of steel-concrete-steel sandwich composite panels, the calculation formulas of elastic flexural bearing capacity, ultimate flexural bearing capacity and shear-bearing capacity are established theoretically.The creep effects analysis models of steel-concrete-steel sandwich composite panels are established by use of age-adjusted-effective-modulus method and time-dependent creep superposition method. Furthermore the computer program RHSCSC is created. The numerical examples have also been done. The results of calculation show that under the influence of the creep effects, stress, deformation, interface slip and other basic variables of composite panels increase over time, which tends to be steady after the rapid change during the initial stage. The bigger the width of composite panels and the thickness of steel plates, the smaller the increments of mid-span deformation over time. The bigger the stiffness of connections, the smaller the increments of end-span interface slip over time.