Large-scale model tests of a single pile and two-pile groups for an offshore platform in sand

Abstract

Estimating pile group efficiency for open-ended steel piles in small group arrangements is a challenging task for designers. This paper reports on the large-scale experimental campaign performed for the BorWin gamma offshore converter platform, which involved single piles and two-pile group systems on a scale of 1:10. The experimental works included installation, dynamic end-of-driving tests, dynamic restrike tests, and static load tests of a single pile and a pair of two-pile groups in densely compacted, artificially prepared homogeneous sand. The CPT profiles and the blow counts confirmed that the foundation systems are comparable to each other. The experimental results of the single pile system were compared with conventional design methods. Such comparison indicated that CPT-based methods and load-transfer methods are applicable at the considered model scale. The bearing capacity prediction obtained via the CAPWAP method is conservative with respect to the static capacity. A consistent setup effect can be detected by analyzing the complete dynamic loading session. The pile group efficiency for the given foundation system was found to be less than 1.0 at both very small and very large soil strains, while it equaled 1.0 at failure.

Pile group behavior under unsymmetrical cyclic thermal loading in dry silty sand: 1g Physical modeling

“…They reported a reduction in elastic response of the soil during longer thermal cycles. Foglia et al [27] conducted large-scale model tests of a single pile and two-pile groups for an offshore platform in sand. The study found that the pile spacing and pile group configuration significantly affect the bearing capacity and settlement of the energy pile group.…”

The Transverse Bearing Characteristics of the Pile Foundation in a Calcareous Sand Area

“…As the backfill of the foundation, the calcareous sand can not only shorten the construction period but also save landfill resources, which is of great significance for the development of the modern marine economy [ 16 ]. Reviewing literature revealed that the studies on the bearing characteristics of pile foundation mainly focuses on clay [ 17 , 18 , 19 ], ordinary sand [ 20 , 21 , 22 ], loess [ 23 ], saline soil [ 24 ]. and other areas [ 25 ].…”