Increasing demand on clean energy leads to the expanded construction of offshore wind turbines (OWT) worldwide. Different types of foundations of OWTs includes gravity, jackets, monopiles etc. When functioning, OWTs face severe conditions with complex loadings (e.g. varying loading amplitudes and loading frequencies). In this study, the influence of the loading amplitude and loading frequency on the lateral displacement of monopiles in marine clay was investigated by conducting 1-g physical model tests at a scale of 1:30. The p-y curves at different depths were derived as well from the recorded moment distribution along the monopile. According to the results, the lateral displacement increases with the loading amplitude and frequency and the monopiles experience response of shakedown under cyclic loading. The lateral displacement after N cycles is related to the initial displacement via an extended logarithmic function. Besides, the p-y curves available in literature underestimate the soil resistance but hyperbolic functions provide comparatively closer predictions.
