Settlement of Building on Pile Foundation in Sand

Displacement type compacted concrete piles (pressure-injected Franki type) were driven into the upper portion of a medium dense sand stratum for the foundation of a 19-story reinforced concrete building. Results of pile load tests and actual building settlements were recorded over a 2 yr. period. The settlement ranged from 1.6 in (4.0 cm) to 3.3 in. (8.4 cm), the average group settlement being approx. 2.5 in. (6.4 cm). These field measurements are compared with settlement predictions computed using: (1) classical elasticity theory which greatly overestimates the actual settlement of a single pile; (2) recent extensions of elasticity theory which provide reasonable results for both single pile and pile group settlement behavior; and (3) empirical curves which require pile load test data to give average group settlement and compare favorably with the field measured values.