ULTIMATE STRENGTH OF CLAMPED R.C SQUARE SLABS WITH CENTRAL SQUARE OPENING UNDER COMBIEND BENDING AND MEMBRANE ACTION

Abstract

Based on the flow theory of rigid-plastic bodies, a method is developed for assessing the ultimate strength as well as determining the post yield behavior of uniformly loaded R.C square slabs with central square opening which have all edges restrained against rotation and lateral movement . The method takes into account the significant effects of membrane forces which are usually induced in the plane of the slab along sagging and hogging yield lines as the slab deflects. Considering equilibrium and compatibility of the deformed slab element, load-deflections relations are derived starting from the initial compressive membrane action up to tensile membrane and full-depth cracking at large deflection.