ULTIMATE STRENGTH OF ISOLATED R.C. FOOTINGS

Abstract

Isolated reinforced concrete footings are normally designed assuming a uniform soil pressure and critical moments to occure at the column face. The method though widely followed is not realistic since it does not take into consideration the actual contact pressure as well as structural behaviour of footing. The present work deals with a realistic approach to determine the ultimate load derived from the flexural strength of footing slab. It assumes parabolic distribution of soil pressure, consistent with the current knowledge of interaction between soil and footing slab. The Structural analysis adopted here is based on yield line theory which is well applicable to under reinforced concrete slab. The analysis also takes care of effect of top slope provided sometimes in the Rot-ing slab. General expression for ultimate load has been deriVed and thereafter detailed computations have been done for some specific cases. The results thus obtained are given in graphical form and can be directly used for prac-tical purposes with considerable accuracy.