TY - JOUR

T1 - Optimum geometry of monopiles with respect to the geotechnical design

AU - Schmoor, Kirill Alexander

AU - Achmus, Martin

PY - 2015/2/1

Y1 - 2015/2/1

N2 - In the near future, several offshore wind farms are planned to be erected in the German North Sea. Monopile foundations are often a favorable solution to transfer environmental loads into the subsoil. In most cases, the Serviceability Limit State (SLS) proof is design-driving, i.e., compliance with admissible deflections or rotations of the monopile is key. A crucial point herein is the required limitation of cyclically accumulated irreversible rotations of the pile head due to operational constraints of the wind turbine. Since several design solutions fulfill the technical demands, the most important issue in monopile design is the determination of a suitable monopile geometry, i.e., the diameter D and the embedded length L, which also fulfills economic demands. An optimization analysis was conducted with respect to the geotechnical design requirements and the economic criteria for two optimization targets, namely the minimum pile mass and a combination of the pile mass and the embedded pile length. An optimum slenderness ratio L/D is presented as a function of the required accumulated rotation, system dimensions, and number of cyclic loads. With the presented results, a monopile design can be obtained that fulfills both geotechnical and economic demands.

AB - In the near future, several offshore wind farms are planned to be erected in the German North Sea. Monopile foundations are often a favorable solution to transfer environmental loads into the subsoil. In most cases, the Serviceability Limit State (SLS) proof is design-driving, i.e., compliance with admissible deflections or rotations of the monopile is key. A crucial point herein is the required limitation of cyclically accumulated irreversible rotations of the pile head due to operational constraints of the wind turbine. Since several design solutions fulfill the technical demands, the most important issue in monopile design is the determination of a suitable monopile geometry, i.e., the diameter D and the embedded length L, which also fulfills economic demands. An optimization analysis was conducted with respect to the geotechnical design requirements and the economic criteria for two optimization targets, namely the minimum pile mass and a combination of the pile mass and the embedded pile length. An optimum slenderness ratio L/D is presented as a function of the required accumulated rotation, system dimensions, and number of cyclic loads. With the presented results, a monopile design can be obtained that fulfills both geotechnical and economic demands.

KW - Laterally loaded pile

KW - Optimized design

KW - Pareto optimization

KW - Serviceability limit state

KW - Stiffness degradation method

UR - http://www.scopus.com/inward/record.url?scp=85015659941&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:85015659941

VL - 2

SP - 54

EP - 60

JO - Journal of Ocean and Wind Energy

JF - Journal of Ocean and Wind Energy

SN - 2310-3604

IS - 1

ER -