Membrane action in plain concrete slabs under concentrated loading

In certain circumstances, the elimination of steel bar reinforcement from concrete slab construction is made possible by the presence of compressive membrane action. Design practice cannot conveniently take advantage of this, because rigorous strength calculations are not straightforward. A direct method of calculating, by hand, a suitable load capacity has been developed which provides a load improvement factor to be applied to the pure flexure ultimate load. Such a method is unsatisfactory for plain (i.e. unreinforced) concrete slabs. This paper shows how the method can be employed for calculations on plain concrete bridge deck slabs and compares the results with laboratory experiments.