A centrifuge investigation of the relationship between the vertical response of footings on sand and CPT end resistance

This paper presents results from a systematic investigation of footing response in four different types of sands placed and tested under controlled conditions in a geotechnical centrifuge. A parallel series of cone penetration tests (CPTs) was performed to examine correlations between CPT end resistance (q_c) and footing bearing pressure (q). The experimental results show that there is a unique relationship between the normalised bearing stress (q/q_c) and the settlement normalised by footing diameter (s/B), irrespective of footing diameter, stress level, sand grading, mineralogy and angularity. These results are shown to compare well with findings from published databases of field-scale footing tests when allowance is made for the significant effects of creep. The study enables simple and robust recommendations to be established for the ultimate capacity (defined at s/B = 0·1) and allowable bearing pressure of a footing on sand.