Membrane action in orthotropically R.C. rectangular slabs supported on three edges only with variable axial restraints

Abstract EN

In this paper, large deformation analysis is carried out on uniformly loaded orthotropic ally reinforced concrete rectangular slabs that have one free edge and different restraints on the other edges.

For the purpose of such analysis, the slabs are assumed to behave in a rigid-perfectly plastic manner and to yield under the combined effect of bending and membrane action.

Two cases are analyzed ; the case of a slab having two adjacent edges fixed-one edge simply supported and one edge free, and the case of a slab having two adjacent edges simply supported-one edge fixed and one edge free.

Results of the analysis indicate considerable enhancements in the load carrying capacity of such slabs above those predicted by Johansson's simple yield line theory (1).

The amount of the load enhancement in a particular slab is found to depend on many parameters such as the steel ratio rx+, orthotropic ratio g, compressive strength of concrete fc, yield stress of steel fy, and the slab aspect ratio Ly / Lx, such that a higher enhancement in load is achieved for a slab having a higher value of fc but lower values of Ly / Lx, rx+, g and fy.