Chapter-19 - Allowable bearing pressure for building foundations

Abstract

Foundation on weak and highly undulating rock surfaces poses serious problems. Rocks can be more heterogeneous than soil. The problem of differential settlement is serious in heterogeneous subsurface rocks. The design of a foundation depends upon the subsurface strata and its bearing capacity. Many factors influence the safe bearing pressure, which is frequently controlled by settlement criterion. Nevertheless, it is often useful to estimate the safe bearing pressure for preliminary design on the basis of the classification approach, although such values should be checked or treated with caution for final design. This chapter also discusses the net safe bearing pressure and the allowable bearing pressure. The net safe bearing pressure means the ultimate safe bearing pressure, whereas the allowable bearing pressure means the bearing pressure being considered for the designs, that is, allowable bearing pressure after taking into account the factor of safety.