Design versus load testing: a case study on 124 load tests-Paper

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The study examines how pile designs based primarily on ultimate compressive capacity compare with settlements measured under service loads. It reports five static load tests and 127 dynamic load tests at a petrochemical plant in Antwerp, where 20,000 piles were installed in broadly consistent ground conditions.<br /><br />Static tests on sacrificial piles verified ultimate capacity, while calibrated dynamic tests assessed working-pile performance at service working load (SWL). Across the 127 tested piles, settlement at SWL ranged from 1 to 10 mm, averaging 4 mm. The analysis focused on 57 piles designed for similar compressive load factors: their settlements ranged from 2 to 10 mm, with a standard deviation of about 2 mm.<br /><br />The authors investigated whether pile type, location, installation practices, or dynamic testing conditions explained the variation. They found no clear influence from pile type, site location, or loading-rate effects. However, installation equipment mattered: one of the two auger types produced settlements about 1.3 times lower than the other. Differences between piling rigs were also observed, though the study identifies auger type as the installation factor most clearly linked to performance.<br /><br />All tested piles met the project’s 10 mm settlement criterion, and some performed better than required. The findings suggest that installation choices may offer opportunities to refine pile design and reduce foundation impacts, while some settlement variability may reflect inherent uncertainty in geotechnical engineering.

Keywords

pile design

settlement

dynamic load tests

static load tests

service working load

ultimate compressive capacity

petrochemical plant

installation equipment

auger type

geotechnical engineering