The aim of the thesis is to study the long-term behavior of suction caissons (bucket foundations) in drained sand. The project consists of two parts, a literature review and a numerical study part.

In the former first the most commonly used foundation types (gravity-based, monopile, jacket and suction caisson foundations) are presented in detail with a focus on bearing behavior, construction and transport and installation and operating. Consequently the most commonly used design codes and guidelines are demonstrated, pointing out the differences between and shortcomings of the deterministic, semi-probabilistic and probabilistic models. Additionally, based on field, lab and numerical model tests by experts in suction caissons, the behavior of such foundations are studied under different loading conditions.

In the numerical analysis part first the different soil constitutive models are presented, then the model is validated based on a convergence analysis and an already calibrated model by \citep{Achmus}. Later a numerical study is conducted to study the effects of different constitutive models, caisson geometries, loading types (uniaxial or combined loading), vertical loading on the response of the foundation.