Simple Pad Footing.

If P is small, or qs is large, A will also be small. In tha case, the footing may consist of simple concrete block projecting out from the column face on all sides. The shape of the footing is generally kept the same as that for the column (i.e. trapezoidal square or circular), as illustrated in Fig. 3.4, so that equal projection (=a) is obtained for the base concrete.

FIG. 3.4 SIMPLE ISOLATED FOOTINGS OF LIGHTLY LOADED COLUMNS.

The value of offset a may vary from 10 to 20cm. As a thumb rule, the base dimensions of the concrete base should not be less than twice the appropriate lateral dimension of the column in that direction. The thickness of concrete block should atleast be equal to a in the case of cement concrete and 3/2 a in the case of lime concrete base.