Shallow foundations are designed by geotechnical engineers on a daily basis. Settlements are predicted based on elastic propertiesof soil. Soil is, however, non-linear even at small strains. A method was developed for testing circular shallow foundations on sand in the beam centrifuge at Cambridge University. The problem of bedding errors due to an uneven sand surface had to be overcome. Digital images were captured during the loading of soil bodies to observe deformation mechanisms. Instrumentation was used to confirm various quantities. Mechanisms and strain plots have been presented along with a comparison between settlements observed and a trial prediction based on the concepts of Mobilizable Strength Design (MSD).