Soil-Structure Interaction for Non-Slender, Large-Diameter Offshore Monopiles: Vol 1

Sørensen, Søren Peder Hyldal

doi:10.13052/rp-9788792982292

Cited by 25 publications

(22 citation statements)

References 13 publications

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“…The initial modulus of subgrade reaction with the suggestion of Wiemann and Lesny [9], Sørensen et al [10], and Sørensen et al [11] showed API [6] overestimated the initial modulus of subgrade reaction. However, the initial modulus of subgrade reaction that calculated with the suggestion of According to Wiemann and Lesny [9], Sørensen et al [10], Sørensen [11], and Kallehave et al [12], the initial stiffness of p-y curve E py for monopile foundation increased with depth. The initial modulus of subgrade reaction n h with the suggestion of Wiemann and Lesny [9], Sørensen et al [10], and Sørensen [11] showed API [6] overestimated the initial modulus of subgrade reaction.…”

Section: Introductionmentioning

confidence: 89%

“…Sørensen [11] proposed Equation (8) to modify the initial modulus of subgrade reaction n * h ; Equation (8) includes the adjusted elastic modulus of soil that changes with depth:…”

Section: Introductionmentioning

confidence: 99%

“…Figure 2 shows modified initial modulus of subgrade reaction suggested by various researchers. According to Wiemann and Lesny [9], Sørensen et al [10], Sørensen et al [11], and Kallehave et al [12], the initial stiffness of -curve for monopile foundation increased with depth. The initial modulus of subgrade reaction with the suggestion of Wiemann and Lesny [9], Sørensen et al [10], and Sørensen et al [11] showed API [6] overestimated the initial modulus of subgrade reaction.…”

Section: Introductionmentioning

confidence: 99%

“…According to Wiemann and Lesny [9], Sørensen et al [10], Sørensen et al [11], and Kallehave et al [12], the initial stiffness of -curve for monopile foundation increased with depth. The initial modulus of subgrade reaction with the suggestion of Wiemann and Lesny [9], Sørensen et al [10], and Sørensen et al [11] showed API [6] overestimated the initial modulus of subgrade reaction. However, the initial modulus of subgrade reaction that calculated with the suggestion of According to Wiemann and Lesny [9], Sørensen et al [10], Sørensen [11], and Kallehave et al [12], the initial stiffness of p-y curve E py for monopile foundation increased with depth.…”

Section: Introductionmentioning

confidence: 99%

“…However, the initial modulus of subgrade reaction that calculated with the suggestion of Kallehave et al [12] showed that API [6] underestimated the initial modulus of subgrade reaction. The reason is that Wiemann and Lesny [9], Sørensen et al [10], and Sørensen [11] used a pile deformation curve obtained according to a field test or numerical method to correct the initial stiffness of the p-y curve for a monopile foundation. Kallehave et al [12] modified the initial stiffness of the p-y curve for a monopile foundation that caused the predicted natural frequency of the support structure of an offshore turbine to fit the measured natural frequency of the offshore turbine supporting structure.…”

Section: Introductionmentioning

confidence: 99%

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An Investigation into the Effect of Scour on the Loading and Deformation Responses of Monopile Foundations

2017

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Severe foundation scour may occur around monopile foundations of offshore wind turbines due to currents and waves. The so-called p-y curves method is suggested in the existing design recommendations to determine the behavior of monopiles unprotected against scour and the reduction of effective soil stress is accounted for by the extreme scour depth. This conservative design approach does not consider the geometry of the scour hole and the effect of pile diameter on the soil resistance. An underestimated foundation stiffness would be obtained, thereby influencing the predicted overall response of the support structure of an offshore wind turbine. In this study, we calculated the load-deformation response and foundation stiffness of a monopile when scour occurred. The influence of pile diameter on the initial modulus of subgrade reaction, and the modification of the ultimate soil resistance of a monopile subject to scour are evaluated. The commercial software BLADED was used to simulate the dynamic response of the reference offshore wind turbine with monopile unprotected against scour at Chang-Bin offshore wind farm in Taiwan Strait. The results showed that when the p-y curve suggested by existing design regulation was used to calculate the load-deformation response, the foundation stiffness was underestimated where the scour depth was greater than the pile diameter, but the foundation stiffness was overestimated when the scour depth was less than the pile diameter.

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Section: Introductionmentioning

confidence: 89%

“…Sørensen [11] proposed Equation (8) to modify the initial modulus of subgrade reaction n * h ; Equation (8) includes the adjusted elastic modulus of soil that changes with depth:…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

An Investigation into the Effect of Scour on the Loading and Deformation Responses of Monopile Foundations

2017

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Entwurf und Bemessung von Gründungen für Offshore‐Windenergieanlagen

Savidis¹,

Richter²,

Kirsch³

et al. 2018

Grundbau‐Taschenbuch

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On the ultimate limit state design proof for laterally loaded piles

2014

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According to Eurocode 7, the geotechnical ultimate limit state (ULS) design proof can be provided by either a GEO‐2 or a GEO‐3 design equation. In offshore engineering applications a GEO‐3 proof is usually carried out in the design of laterally loaded piles. In Germany a GEO‐2 proof is required according to DIN 1054; this standard also describes a special procedure on how to do this. This paper compares the results of the different approaches. The p‐y method, usually used for calculating the pile load‐bearing behaviour, is validated with respect to German regulations (e.g. with DIN 4085 regarding ultimate bedding stresses). In general it was found that the p‐y method can be used in ULS design. It is further shown that the special ULS design procedure described in DIN 1054 can yield erroneous results (i.e. depending on system parameters and loading type, admissible loads may be either too small or too large). The GEO‐3 proof generally produces reasonable results, but here the actual level of safety depends on the soil parameters. This paper recommends a new and simple design procedure, which is a GEO‐2 proof but also gives correct admissible pile head loads in all cases considered and allows for the consideration of soils with strength degradation.Zum Tragfähigkeitsnachweis für horizontal belastete Pfähle. Gemäß Eurocode 7 kann der Tragfähigkeitsnachweis (ULS) sowohl im Grenzzustand GEO‐2 als auch im Grenzzustand GEO‐3 geführt werden. Im Bereich der Offshore Anwendungen ist international der Nachweis für horizontal belastete Pfähle im Grenzzustand GEO‐3 üblich. In Deutschland ist dagegen gemäß der DIN 1054 ein Nachweis im Grenzzustand GEO‐2 vorgeschrieben, dessen spezielle Vorgehensweise zur Durchführung ebenfalls in dieser Norm dargelegt ist. Im folgenden Artikel werden die Ergebnisse dieser beiden Nachweisverfahren miteinander verglichen. Die p‐y Methode, welche üblicherweise zur Ermittlung des Lastverschiebungsverhaltens eingesetzt wird, wird unter Berücksichtigung der deutschen Regularien validiert (d.h. der maximale Bettungswiderstand wird den Ergebnissen der DIN 4085 gegenübergestellt). Hierbei kann die p‐y Methode grundsätzlich als geeignet für den Tragfähigkeitsnachweis identifiziert werden. Weiterhin kann gezeigt werden, dass die in der DIN 1054 beschriebene spezielle Vorgehensweise des Nachweises zu fehlerhaften Ergebnissen führen kann (d.h. in Abhängigkeit der Systemparameter und der Belastungsart können die zulässigen Belastungen sowohl zu klein als auch zu groß sein). Der Nachweis GEO‐3 gibt grundsätzlich plausible Ergebnisse, allerdings hängt das tatsächliche Sicherheitsniveau von den Bodenparametern ab. Der Artikel empfiehlt einen neuen und einfachen Bemessungsansatz im Grenzzustand GEO‐2, der für sämtliche Randbedingungen korrekte zulässige Pfahlkopfbelastungen ergibt. Der Ansatz erlaubt zudem auch die Berücksichtigung von Böden mit Entfestigung.

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Soil-Structure Interaction for Non-Slender, Large-Diameter Offshore Monopiles: Vol 1

Abstract: Revised expression for the static initial part of p-y curves for piles in sand.

Cited by 25 publications

References 13 publications

An Investigation into the Effect of Scour on the Loading and Deformation Responses of Monopile Foundations

An Investigation into the Effect of Scour on the Loading and Deformation Responses of Monopile Foundations

Entwurf und Bemessung von Gründungen für Offshore‐Windenergieanlagen

On the ultimate limit state design proof for laterally loaded piles

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