title: Seismic analysis of offshore wind turbines on bottom-fixed support structures.
abstract: This study investigates the seismic response of a horizontal axis wind turbine on two bottom-fixed support structures for transitional water depths (30-60 m), a tripod and a jacket, both resting on pile foundations. Fully coupled, nonlinear time-domain simulations on full system models are carried out under combined wind-wave-earthquake loadings, for different load cases, considering fixed and flexible foundation models. It is shown that earthquake loading may cause a significant increase of stress resultant demands, even for moderate peak ground accelerations, and that fully coupled nonlinear time-domain simulations on full system models are essential to capture relevant information on the moment demand in the rotor blades, which cannot be predicted by analyses on simplified models allowed by existing standards. A comparison with some typical design load cases substantiates the need for an accurate seismic assessment in sites at risk from earthquakes.
authors.affiliation: Department of Civil, Energy, Environmental and Materials Engineering (DICEAM), University of Reggio Calabria, Via Graziella, Località Feo di Vito, Reggio Calabria 89124, Italy.
authors.forename: Natale
authors.initials: N
authors.lastname: Alati
authors.affiliation: Department of Civil, Energy, Environmental and Materials Engineering (DICEAM), University of Reggio Calabria, Via Graziella, Località Feo di Vito, Reggio Calabria 89124, Italy giuseppe.failla@unirc.it.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Failla
authors.affiliation: Department of Civil, Energy, Environmental and Materials Engineering (DICEAM), University of Reggio Calabria, Via Graziella, Località Feo di Vito, Reggio Calabria 89124, Italy.
authors.forename: Felice
authors.initials: F
authors.lastname: Arena
keywords: flexible foundation; jacket; offshore wind turbine; seismic analysis; tripod