Theoretical And Experimental Study On Closed-section Composite Slabs

Steel deck-concrete composite slab, as a very reasonable structure where steel and concrete material strength are completely utilized, has quick construction, good ductility and higher anti-earthquake capacity. In this paper, for a new closed-section steel deck-concrete composite slab, a test program has been carried out for bending capacity, shear capacity, fire-resistance capacity. The main research work includes as follows:1. By experimental study of sixteen composite slabs, bending capacities and collapse mechanisms are conducted. Contribution of shearing steel bar to ultimate load-bearing capacity is discussed and a design formula for predicting bending capacity is derived.2. A shear test of six composite slabs is completed and their shear capacities and collapse mechanisms are found. A simplified design expression for calculating shear capacity of this new closed-section composite slab is drawn, associated with the contribution of steel deck to shear capacity based on shear flow theory.3. Test results from fire-resistant test of one composite slab show that anti-fire requirement of 1.5 hours is satisfied. At the same time, load bearing capacity under fire condition is estimated for the sake of design,4. By studying natural frequency of composite slab and comparing current different stiffness-predicting formulae, a stiffness calculating formula of composite slab is derived. It is found that it is very reasonable when the natural frequency of composite slab is taken above 9 Hz in the design.5. A formula for calculating steel deck deflection under construction is obtained by using shell element, and this avoids a complex operation of effective width for thin-walled section.Simultaneously,the ultimate load-carrying capacities of composite slabs are analyzed by using Ansys, a finite element analysis software, and the obtained results is well agreement with test results.