Modelling of monopile response to cyclic lateral loading in sand

Abstract

This paper outlines experimental and theoretical research exploring the response of rigid piles to cyclic lateral loading, relevant to large diameter monopiles for offshore wind applications. The experimental work comprised of 1-g laboratory scale model tests in sand, where up to 100,000 cycles were applied. The tests were designed specifically for identification of key mechanisms behind the pile response with the results demonstrating that the resulting moment-rotation curves are dominated by ratcheting, whilst also conforming approximately to the extended Masing rules. These results provide impetus for the development of a new constitutive model, HARM, which can accurately capture the pile response to cyclic lateral loading. A brief overview of the model is presented, along with a calibration method and illustrative results. This modelling approach could, in future, be developed further to supplement current design methods for SLS and FLS.