(a) not greater than one half the clear distance (b) between the footings. However, when footing are founded on rock, b should not excedd a.
FIG. 3.36 ADJACENT FOOTINGS AT DIFFERENT LEVELS.
In clayey soils, the line (AB) drawn between the lower adjacent edge of the super upper footing and upper adjacent edge of the lower footing should not have a steeper slope than n1 (horiontal) : 1 (vertical), where n1 is equal to 2.
In granular soils, the line (AB1) drawn between the lower adjacent edges of adjacent footings should not have steeper slope than n2 (horizontal) : 1 (vertical), where n2 is equal to 2.