ABSTRACT

For the design of suction anchors for offshore foundations API standards are applicable. In order to investigate the exact behaviour and interaction of suction anchors in the sea bottom a combined numerical / experimental research was performed at Delft University of Technology. In centrifuge tests as well as by means of three-dimensional finite element calculations the influence of various parameters, among which the height / diameter ratio (H/D), the mooring attachment height (h/H) and the attachment angle (a), was investigated for suction anchors in dry sand. The research shows a good agreement between the numerical and experimental results. It is concluded that the actual horizontal bearing capacity of the suction anchors is well beyond the maximum anchor force that is allowed according to the API standards. The research also provides clear insight in the failure mechanism that occurs in the sea bottom due to excessive anchor forces. It is concluded that the best position of the cable attachment point is at 2/5 of the anchor height.

This paper mainly concentrates on the numerical modelling aspects and the (graphical) results. Graphs of the maximum anchor force are presented in non-dimensionalised form, so that they can be easily applied to suction anchors with other dimensions.