ABSTRACT
For the increasing size of the offshore wind turbines and their erection in greater water depths, multi-legged substructures with suction bucket foundations are gaining popularity. The individual foundations of these multipod structures are mainly axially loaded, with tensile loads being expected to be decisive for the design. However, the tensile bearing behaviour is not yet fully understood, so that tensile loads are either totally avoided or limited to the drained capacity although the partially drained response involves an additional resistance, due to the development of negative differential pressure beneath the suction bucket’s lid. This paper presents results of physical model tests and numerical simulations focussing on tensile loads exceeding the drained resistance. The evaluation concentrates on the heave accumulation and development of negative differential pressure. The results indicate that tensile loads beyond the drained resistance might be acceptable, but only for few events and not for longer duration or repeated occurrence within a short period of time.
