Collapse Load of Reinforced Concrete Footings

Investigations on the collapse load of reinforced concrete footings subject to central or eccentric loads are presented. Limit analysis solutions are developed for several limiting distributions of contact pressure and the influence of contact pressure distribution on the collapse load is brought out. Results of experimental investigations on square footings resting on sand, clay, or rigid base are presented together with some typical distributions of contact pressure measured at the failure of the footings. On the basis of theoretical collapse load from limit analysis and soil failure load from bearing capacity theory, an interpolation technique is suggested to predict the collapse loads for eccentrically loaded footings on soil. Collapse load curve of eccentrically loaded footing on rigid base is shown to follow the theoretical collapse load curve and the punching failure curve.