In 1952 a series of tests were carried out on a reinforced concrete building and unexpected results were obtained from two tests to destruction on interior slab panels.
In both tests the collapse load was more than twice the load predicted by the yield-line method. In a later paper Professor Ockleston, who carried out the tests, showed that this unexpected result can be explained by an arching action due to the development of compressive membrane stresses in the concrete. It was, however, not possible at that time to predict the extent to which arching action will affect the strength of a slab. This paper presents an analysis of arching action in beams and one-way slabs with lateral restraints and a method of estimating the ultimate strength of interior slab panels due to the combined effect of bending and membrane stresses. The ultimate strength is presented in graphical form as a function of the steel ratio and the ratio of span to effective depth. The results of a short series of tests show good agreement with values calculated according to the theory.
K. P. CHRISTIANSEN