Abstract:
Design of foundations for most light structures in South Africa, and in particular for low-cost
housing, relies heavily on particle size analysis and the determination of Atterberg Limits. The
tests for these properties are currently performed in commercial materials testing laboratories
using the procedures of the CSIR’s Technical Methods for Highways Part 1 (TMH1) (CSIR 1986).
SANS 3001 (SANS 2011) is being phased in to replace TMH1. Both are primarily concerned with
road construction. Investigations at the Central University of Technology indicate serious
shortcomings in both of these norms in the context of foundation design for light structures.
Highly plastic material is not usually used as road construction material, and these methods
may be adequate to simply identify material so plastic that they should not be used in road
construction. Structural foundations, particularly for low-cost housing, do not usually have this
option; it is essential to estimate the actual heave potential. This investigation suggests that
some of the changes proposed in SANS 3001 may be beneficial for heave assessment, but the
most likely application of SANS 3001 could be unsatisfactory in many cases.
