Fore-aft and the side-to-side response of monopile supported offshore wind turbine in liquefiable soil
Sangeet Kumar Patra, Sumanta Haldar
Abstract
This study investigates the effect of combined operational and seismic loads on the dynamic fore-aft, and the side-side response of monopile supported OWT in liquefiable soil under operational and parked conditions. A two dimensional (2 D) coupled soil-pile-structure interaction model is formulated in OpenSees, where the monopile and tower are modeled as Euler-Bernoulli beam elements, the soil is modeled as a quadrilateral plane strain element with solid-fluid fully coupled material. The soil column and monopile are connected by p-y springs. The effect of various strong-motion parameters, such as peak frequency, peak base acceleration (PBA), sustained maximum acceleration (SMA), and arias intensity (IA) on the dynamic response of the OWT structure is studied. Also, the effect of peak frequency on the dynamic response of the OWT structure is studied by varying the hub height and RNA mass so as to keep the fundamental frequency of the OWT structure closer to the peak frequency of the ground motion records. Finally, the implication in the performance-based seismic design is suggested.