Effect of ESB container geometry on seismic behaviour of offshore wind turbine jacket Available to Purchase

This study investigates the influence of centrifuge container geometry on the seismic response of offshore wind turbine (OWT) jacket models with pin-pile foundations embedded in saturated sand. Two equivalent shear beam (ESB) containers, identical in design but differing in size, were employed to evaluate whether container dimensions affect coupled soil–structure interaction under dynamic loading. The older ESB container (ESB-M) was constructed using lightweight duralumin alloy rings with rubber interlayers, whereas the newer ESB container (ESB-L) utilised duralumin C-sections with rubber interlayers to achieve increased rigidity. Identical soil stratigraphy, comprising a loose sand layer overlying dense sand, and the same jacket model were adopted in both containers to ensure direct comparability. Seismic input motions were applised under two loading conditions: purely axial loading and combined axial–lateral loading. Comparative analysis of acceleration response, foundation rotation, excess pore pressure development, and amplification characteristics carried out for this study indicates that the overall seismic response trends are consistent between the two containers. Minor differences are observed in local response amplitudes, particularly under combined axial–lateral loading, reflecting variations in boundary confinement and wave propagation associated with container size. However, these differences do not alter the governing response mechanisms or behaviour, as the response remains primarily controlled by soil–structure interaction, with container geometry contributing only secondary and transient effects. Overall, the findings indicate that variations in container size do not materially affect serviceability-level response trends derived from the centrifuge tests.