Analysis of Two-Way Acting Composite

An ultimate strength analysis procedure was formulated for five full-scale, two-way slabs tested to failure. The concrete slabs were reinforced with composite corrugated cold-formed steel decking. Three slabs contained supplementary reinforcing in the form of welded wire fabric. Nominal out-toout plan dimensions of the slabs were 16 ft by 12 ft (4.88 m by 3.66 m). All slabs were subjected to four symmetrically placed, concentrated loads. Utlimate failure occurred by a shear-bond action initiated by slippage between the steel deck and the concrete. The analysis procedure was founded on the principles of yield-line theory and of shear-bond regression analysis. A collapse mechanism established by yield-line procedures was utilized to determine the effective load-carrying-segment width of the slabs. A shear-bond regression analysis was used on the effective width to predict the total shear force distributed to the reactive edge perpendicular to the deck corrugations. The shear existing along the sides of the effective load-carrying segment was subsequently added to the shear-bond component to give the predicted ultimate load for each slab. The calculated load agreed very closely (within 9%) with the experimental ultimate for all five slabs.