Cyclic loading of monopiles at a saturated dense sand site in Germany

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Model testing of medium scale monopile foundations in the field provides the best evidence of full-scale pile behaviour, and hence the basis for the development and validation of new design methods. The PICASO project focuses on the development of new design methods that address cyclic loading of the monopile foundations and explores the accumulated rotation that develops after a number of cycles, as well as the post-cyclic monotonic capacity of the pile. The field test results are interpreted within a hardening plasticity theory that is set within the framework of hyperplasticity, called the hyperplastic accelerated ratcheting model, HARM. The fieldwork includes medium scale pile testing at a stiff clay site in Cowden, UK, completed during 2021, and a dense sand at Cuxhaven in Germany, completed during 2024. This paper describes the details of the field testing at the Cuxhaven dense sand site, and provides: (i) an overview of the site characterisation and the detailed site preparation undertaken for the field testing, (ii) information about the pile designs (1.22 m and 2.50 m diameter) and range of instrumentation adopted, (iii) a description of the loading paths applied to the piles, and the logic behind various of the tests undertaken, (iv) some preliminary cyclic loading data that demonstrates some of the key outcomes from the testing campaign.

5th International Symposium on Frontiers in Offshore Geotechnics (ISFOG2025)

9 - Monopile design to cyclic loads: quasi-static, dynamic and seismic loads