Design of plate and screw anchors in dense sand: failure mechanism, capacity and deformation

Benjamin Cerfontaine (Lead / Corresponding author), Jonathan Knappett, Michael Brown, Aaron S. Bradsaw

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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Abstract

Plate and screw anchors provide a significant uplift capacity and have multiple applications in both onshore and offshore geotechnical engineering. Uplift design methods are mostly based on semi-empirical approaches assuming a failure mechanism, a normal and a shear stress distribution at failure and empirical factors back-calculated against experimental data. However, these design methods are shown to under- or overpredict most of the existing larger scale experimental tests. Numerical FE simulations are undertaken to provide new insight into the failure mechanism and stress distribution which should be considered in anchor design in dense sand. Results show that a conical shallow wedge whose inclination to the vertical direction is equal to the dilation angle is a good approximation of the failure mechanism in sand. This shallow mechanism has been observed in each case for relative embedment ratios (depth/diameter) ranging from 1 to 9. However, the stress distribution varies non-linearly with depth, due to the soil deformability and progressive failure. A sharp peak of normal and shear stress can be identified close to the anchor edge, before a gradual decrease with increasing distance along the shear plane. The peak stress magnitude increases almost linearly with embedment depth at larger relative embedment ratios. Although further research is necessary, these results lay the basis for the development of a new generation of design criteria for determining anchor capacity at the ultimate limiting state.
Original languageEnglish
Title of host publication7th International Symposium on Deformation Characteristics of Geomaterials (IS-Glasgow 2019)
EditorsA Tarantino , E Ibraim
PublisherEDP Sciences
Pages1-6
Number of pages6
Volume92
Edition2019
ISBN (Electronic)9782759890644
ISBN (Print)978-2-7598-9064-4
DOIs
Publication statusPublished - 25 Jun 2019
Event7th International Symposium on Deformation Characteristics of Geomaterials (IS-Glasgow 2019) - Strathclyde's Technology & Innovation Centre, Glasgow, United Kingdom
Duration: 26 Jun 201928 Jul 2019
https://www.is-glasgow2019.org.uk/

Publication series

NameE3S Web of Conferences
Volume92
ISSN (Print)2555-0403
ISSN (Electronic)2267-1242

Conference

Conference7th International Symposium on Deformation Characteristics of Geomaterials (IS-Glasgow 2019)
CountryUnited Kingdom
CityGlasgow
Period26/06/1928/07/19
Internet address

Fingerprint

failure mechanism
Anchors
anchor
Sand
Stress concentration
sand
design method
shear stress
Shear stress
uplift
offshore engineering
Geotechnical engineering
dilation
geotechnical engineering
Formability
Soils
Computer simulation
simulation
distribution
soil

Cite this

Cerfontaine, B., Knappett, J., Brown, M., & Bradsaw, A. S. (2019). Design of plate and screw anchors in dense sand: failure mechanism, capacity and deformation. In A. Tarantino , & E. Ibraim (Eds.), 7th International Symposium on Deformation Characteristics of Geomaterials (IS-Glasgow 2019) (2019 ed., Vol. 92, pp. 1-6). [16010] (E3S Web of Conferences; Vol. 92). EDP Sciences. https://doi.org/10.1051/e3sconf/20199216010
Cerfontaine, Benjamin ; Knappett, Jonathan ; Brown, Michael ; Bradsaw, Aaron S. / Design of plate and screw anchors in dense sand : failure mechanism, capacity and deformation. 7th International Symposium on Deformation Characteristics of Geomaterials (IS-Glasgow 2019). editor / A Tarantino ; E Ibraim . Vol. 92 2019. ed. EDP Sciences, 2019. pp. 1-6 (E3S Web of Conferences).
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title = "Design of plate and screw anchors in dense sand: failure mechanism, capacity and deformation",
abstract = "Plate and screw anchors provide a significant uplift capacity and have multiple applications in both onshore and offshore geotechnical engineering. Uplift design methods are mostly based on semi-empirical approaches assuming a failure mechanism, a normal and a shear stress distribution at failure and empirical factors back-calculated against experimental data. However, these design methods are shown to under- or overpredict most of the existing larger scale experimental tests. Numerical FE simulations are undertaken to provide new insight into the failure mechanism and stress distribution which should be considered in anchor design in dense sand. Results show that a conical shallow wedge whose inclination to the vertical direction is equal to the dilation angle is a good approximation of the failure mechanism in sand. This shallow mechanism has been observed in each case for relative embedment ratios (depth/diameter) ranging from 1 to 9. However, the stress distribution varies non-linearly with depth, due to the soil deformability and progressive failure. A sharp peak of normal and shear stress can be identified close to the anchor edge, before a gradual decrease with increasing distance along the shear plane. The peak stress magnitude increases almost linearly with embedment depth at larger relative embedment ratios. Although further research is necessary, these results lay the basis for the development of a new generation of design criteria for determining anchor capacity at the ultimate limiting state.",
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Cerfontaine, B, Knappett, J, Brown, M & Bradsaw, AS 2019, Design of plate and screw anchors in dense sand: failure mechanism, capacity and deformation. in A Tarantino & E Ibraim (eds), 7th International Symposium on Deformation Characteristics of Geomaterials (IS-Glasgow 2019). 2019 edn, vol. 92, 16010, E3S Web of Conferences, vol. 92, EDP Sciences, pp. 1-6, 7th International Symposium on Deformation Characteristics of Geomaterials (IS-Glasgow 2019) , Glasgow, United Kingdom, 26/06/19. https://doi.org/10.1051/e3sconf/20199216010

Design of plate and screw anchors in dense sand : failure mechanism, capacity and deformation. / Cerfontaine, Benjamin (Lead / Corresponding author); Knappett, Jonathan; Brown, Michael; Bradsaw, Aaron S.

7th International Symposium on Deformation Characteristics of Geomaterials (IS-Glasgow 2019). ed. / A Tarantino ; E Ibraim . Vol. 92 2019. ed. EDP Sciences, 2019. p. 1-6 16010 (E3S Web of Conferences; Vol. 92).

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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T1 - Design of plate and screw anchors in dense sand

T2 - failure mechanism, capacity and deformation

AU - Cerfontaine, Benjamin

AU - Knappett, Jonathan

AU - Brown, Michael

AU - Bradsaw, Aaron S.

N1 - 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.

PY - 2019/6/25

Y1 - 2019/6/25

N2 - Plate and screw anchors provide a significant uplift capacity and have multiple applications in both onshore and offshore geotechnical engineering. Uplift design methods are mostly based on semi-empirical approaches assuming a failure mechanism, a normal and a shear stress distribution at failure and empirical factors back-calculated against experimental data. However, these design methods are shown to under- or overpredict most of the existing larger scale experimental tests. Numerical FE simulations are undertaken to provide new insight into the failure mechanism and stress distribution which should be considered in anchor design in dense sand. Results show that a conical shallow wedge whose inclination to the vertical direction is equal to the dilation angle is a good approximation of the failure mechanism in sand. This shallow mechanism has been observed in each case for relative embedment ratios (depth/diameter) ranging from 1 to 9. However, the stress distribution varies non-linearly with depth, due to the soil deformability and progressive failure. A sharp peak of normal and shear stress can be identified close to the anchor edge, before a gradual decrease with increasing distance along the shear plane. The peak stress magnitude increases almost linearly with embedment depth at larger relative embedment ratios. Although further research is necessary, these results lay the basis for the development of a new generation of design criteria for determining anchor capacity at the ultimate limiting state.

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M3 - Conference contribution

SN - 978-2-7598-9064-4

VL - 92

T3 - E3S Web of Conferences

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BT - 7th International Symposium on Deformation Characteristics of Geomaterials (IS-Glasgow 2019)

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Cerfontaine B, Knappett J, Brown M, Bradsaw AS. Design of plate and screw anchors in dense sand: failure mechanism, capacity and deformation. In Tarantino A, Ibraim E, editors, 7th International Symposium on Deformation Characteristics of Geomaterials (IS-Glasgow 2019). 2019 ed. Vol. 92. EDP Sciences. 2019. p. 1-6. 16010. (E3S Web of Conferences). https://doi.org/10.1051/e3sconf/20199216010