Thus the curves in Fig. 7.8 are at the boundaries between different soil density states. For N60
values
other than those for which the curves are drawn in Fig. 7.8, the allowable soil pressure can be
obtained by linear interpolation between curves. According to Terzaghi and Peck (1967), if all of the
footings are proportioned in accordance with the allowable soil pressure corresponding to Fig. 7.8,
then the total settlement r
maxof the foundation should not exceed 1.0 in. (2.5 cm) and the maximum
differential settlement Δshould not exceed
3
/
4
in. (2 cm). Figure 7.8 was developed for the ground-water table located at a depth equal to or greater than a depth of 2Bbelow the bottom of the footing.