Comparison of P-Y methods with large-scale tests of impact- and vibratory-driven piles

The design of support structures for offshore wind farms is a challenge for the industry. For the design of laterally loaded piles, the p-y method is generally used. This method was initially developed for long slender impact-driven piles used in the oil and gas industry and is not validated for geometries of typical monopiles supporting offshore wind turbines. Additionally, it disregards the influences of other installation techniques on the lateral load-bearing behaviour. Between 2015 and2018, the TANDEM research project was carried out to optimise the design of monopiles for offshore wind turbines. In this project, advanced numerical modelling and physical modelling across three different scales were undertaken. In this contribution, the experimental campaign is briefly described, and some test results are presented. The applicability of selected p-y approaches is then analysed on the base of the presented results. It is shown that the standard p-y method can only poorly approximate the test results. Moreover, it is given evidence that the installation technique affects the lateral bearing behaviour of piled foundations.