Summary
Upper bound solutions to the collapse of continuous slabs may be calculated by applying the yield-line theory, but corresponding lower bound solutions are not available. R. H. Wood has discussed this lack of knowledge of lower bound or safe solutions. In the present paper, a lower bound solution to the collapse of a uniformly loaded isotropically reinforced rectangular slab, with two opposite sides continuous and the other sides simply supported, is developed. This solution is compared with the upper bound values, over a wide range of values for the ratio of the sides of the slab, and the agreement is shown to be within 8%. The solution is used to determine the distribution of moments in the slab and the loads transmitted to the perimeter beams.
