Influence of seabed profile on the seismic response of monopile-supported offshore wind turbines including dynamic soil-structure interaction

• Published in: Marine structures 2023-11, Vol.92, p.103500, Article 103500
• Main Authors: Rodríguez-Galván, Eduardo, Álamo, Guillermo M., Medina, Cristina, Maeso, Orlando
• Format: Article
• Language: English
• Subjects: Kinematic interaction; Monopile; Offshore wind turbines; Seabed profile; Seismic response; Soil-structure interaction
• ISSN: 0951-8339; 1873-4170
• DOI: 10.1016/j.marstruc.2023.103500

In this article, the seismic response of four different Offshore Wind Turbines (OWTs) from 5 to 15 MW, founded on monopiles embedded in homogeneous and non-homogeneous soil profiles with equivalent shear-wave velocities from 100 to 300 m/s is analysed. Two types of variable soil profiles with a semi-parabolic variation of the shear-wave velocity as depth increases are considered. The system seismic response under ten different accelerograms is computed through a finite element substructuring model in frequency domain. The foundation behaviour is obtained by a continuum model including kinematic and inertial interaction. Several models, in addition to that of rigid base condition, are considered to determine the influence of soil-structure interaction (SSI), as well as the contribution of each kinematic interaction (KI) factor. The seismic response of the OWTs is obtained in terms of maximum shear forces and bending moments at mudline level, as well as the acceleration amplification factor at hub level. It is found that the maximum response is produced when SSI is considered, including both the inertial and kinematic interaction. The differences arising due to the soil profile definition are shown to be mainly related to the rotational KI factor, which significantly affects the second vibration mode of the system. The largest responses are obtained for the homogeneous equivalent profile. •The seismic response of monopiled OWTs on different seabed profiles is studied.•The effects of SSI and of each KI factor on the seismic response are analysed.•Higher responses are obtained when a homogeneous profile and SSI are considered.•KI only has a significant effect if the rotational KI factor is taken into account.•The influence of the soil profile arises when the rotational KI factor is included.