Abstract
Reinforced concrete slabs with edges restrained against lateral displacement are capable of carrying ultimate loads which are considerably higher than the loads predicted by using conventional yield-line theory. An analytical relation for the load-deflection behavior is derived in the paper by using a plastic-flow theory. The compatibility condition introduced in the paper for the deformation of the centerline of the slab incorporates boundary displacements as well as the in-plane deformations of the slab. Combining the compatibility condition, the flow rule associated with the load-moment yield criterion, and the axial equilibrium condition, a nonlinear differential equation is obtained for the membrane force in the slab. The load on the slab is then calculated for a given deflection by balancing the external and internal energy dissipation. The predicted load-deflection curves are compared with those obtained from two test series and a good agreement is obtained up to the peak load. The load-deflection curve beyond the peak load is found to be predicted better by the incorporation of an analysis which approximates strain softening of the concrete.
