FINITE ELEMENT ANALYSIS OF BI ANGLE SHAPED SQUARE FOOTING UNDER TWO WAY ECCENTRIC LOADING

Abstract

Footing subjected to eccentric loading along two mutually perpendicular axes is quite a common field problem. Due to this bearing capacity is reduced considerably as the effective size is drastically reduced. A footing may be subjected to two-way eccentricity due to many reasons. In the case of footing subjected to one-way eccentricity the common practice is to match the centre of gravity of column loads to centre of gravity of footing area. Strap footings are also commonly used when the footing is subjected to two-way eccentric load. These footings not only resist the eccentric loading without (negligible) tilt but increase the bearing capacity also. Using the idea of angle-shaped footings, which was a result from the study of partial confinement, another new idea, has been developed. These footings have shape in the form of two vertically downward projections towards the eccentric side of two adjacent edges. In the present paper bi-angle shaped footings have been analyzed by the Finite Element Technique using ANSYS Software. Square footings under a point load at some eccentricity along diagonal with two vertically downward footing projections of equal length along two adjacent sides towards the eccentricity have been analyzed. It has been observed that footings subjected to two-way eccentricity could be designed for no tilt by using bi-angle shaped footings. The depths of two footing projection of equal length will depend upon the eccentricity along the diagonal.