Uplift load–movement response of bell pier foundations in Gobi gravel

The purpose of the study described in this paper was to investigate the load–movement behaviour of uplift-loaded bell pier foundations in Gobi gravel. In total, 40 full-scale field tests were carried out in Gobi gravel at seven sites in China. Both the site conditions and the load tests were documented comprehensively. Under tensile loading, the behaviour of the foundations followed a typical two-phase pattern. Normalising the measured load–displacement curves reduced the scatter in the curves. Furthermore, it was found that the normalised uplift load–movement behaviour of the foundations could be characterised by a hyperbolic model. Explicit hyperbolic curve-fitting constants were suggested for the foundations at the 50% and 95% confidence levels. The hyperbolic curve of the normalised load–displacement relationship for the foundations revealed a substantially stiffer response than that of spread footing foundations in backfilled soil.