A Finite Element approach for determining the full load-displacement relationship of axially-loaded shallow screw anchors, incorporating installation effects

TY - JOUR

T1 - A Finite Element approach for determining the full load-displacement relationship of axially-loaded shallow screw anchors, incorporating installation effects

AU - Cerfontaine, Benjamin

AU - Knappett, Jonathan

AU - Brown, Michael

AU - Davidson, Craig

AU - Al-Baghdadi, Therar

AU - Sharif, Yaseen

AU - Brennan, Andrew

AU - Augarde, Charles

AU - Coombs, William M.

AU - Wang, Lei

AU - Blake, Anthony

AU - Richards, David J.

AU - Ball, Jonathan David

N1 - Funding Information: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant (agreement No. 753156). The authors would like to acknowledge the support of the Engineering and Physical Science Research Council (EPSRC) (grant No. EP/N006054/1: Supergen Wind Hub Grand Challenges Project: Screw piles for wind energy foundations). The fifth author would like to acknowledge the financial support of the Iraqi Ministry of Higher Education of Scientific Research (MOHESR). Elements of this work were undertaken using facilities developed as part of the ERDF-funded Scottish Marine and Renewables Test Centre (SMART) at the University of Dundee. Publisher Copyright: © Canadian Science Publishing. All rights reserved.

PY - 2021/4

Y1 - 2021/4

N2 - Screw anchors have been recognised as an innovative solution to support offshore jacket structures and floating systems, due to their low noise installation and potential enhanced uplift capacity. Results published in the literature have shown that for both fixed and floating applications, the tension capacity is critical for design but may be poorly predicted by current empirical design approaches. These methods also do not capture the load-displacement behaviour, which is critical for quantifying performance under working loads. In this paper, a Finite Element methodology has been developed to predict the full tensile load-displacement response of shallow screw anchors installed in sand for practical use, incorporating the effects of a pitch-matched installation. The methodology is based on a two-step process. An initial simulation, based on wished-in-place conditions, enables the identification of the failure mechanism as well as the shear strain distribution at failure. A second simulation refines the anchor capacity using soil-soil interface finite elements along the failure surface previously identified and also models installation through successive loading/unloading of the screw anchor at different embedment depths. The methodology is validated against previously published centrifuge test results. A simplified numerical approach has been derived to approximate the results in a single step.

AB - Screw anchors have been recognised as an innovative solution to support offshore jacket structures and floating systems, due to their low noise installation and potential enhanced uplift capacity. Results published in the literature have shown that for both fixed and floating applications, the tension capacity is critical for design but may be poorly predicted by current empirical design approaches. These methods also do not capture the load-displacement behaviour, which is critical for quantifying performance under working loads. In this paper, a Finite Element methodology has been developed to predict the full tensile load-displacement response of shallow screw anchors installed in sand for practical use, incorporating the effects of a pitch-matched installation. The methodology is based on a two-step process. An initial simulation, based on wished-in-place conditions, enables the identification of the failure mechanism as well as the shear strain distribution at failure. A second simulation refines the anchor capacity using soil-soil interface finite elements along the failure surface previously identified and also models installation through successive loading/unloading of the screw anchor at different embedment depths. The methodology is validated against previously published centrifuge test results. A simplified numerical approach has been derived to approximate the results in a single step.

KW - Design

KW - Finite element modelling

KW - Helical pile

KW - Sand

KW - Screw anchor

UR - https://www.scopus.com/pages/publications/85089861207

U2 - 10.1139/cgj-2019-0548

DO - 10.1139/cgj-2019-0548

M3 - Article

SN - 0008-3674

VL - 58

SP - 565

EP - 582

JO - Canadian Geotechnical Journal

JF - Canadian Geotechnical Journal

IS - 4

ER -