Foundations can often be subjected to eccentric loading due to moment(s) applied to it. The figure illustrates an eccentrically loaded footing. The pressure at the bottom of the foundation, therefore, can be evaluated asqmax = P/A + Me/I = P/A(1+6e/B)
qmin = P/A - Me/I = P/A(1-6e/B)
where e = M/P = eccentricity; P = applied load; M = applied moment; I = moment of inertia; A = Area of the footing (B x L)
One of the implications of the above equations is the fact that qmin = 0 when e = B/6
Thus, for e > B/6, qmin < 0 which shows that there would be a development of tension in such a case. Now, we all know soil cannot take tension, therefore, the foundation would separate from the underlying soil in such a case.
We'll start with a problem tomorrow.
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