The design of the grouted connections in jacket structures has until recently been based on a control of capacity with respect to axial force in the pile while the effect of the bending moment has been neglected, ref. ISO 19902 (2007). In later design of grouted connections it is observed that the moments in the piles can contribute to more than two times larger stress in the pile than that due to axial load only. A significant moment can hardly be transferred from the pile to the sleeve without sliding of the steel against the grout. This sliding is considered to increase with increasing diameter of the pile. Therefore it is difficult to develop design criteria based on small scale testing. The contact pressure between grout and steel will lead to compressive and tensile stresses in the grout. This requires design criteria for compressive stress and tensile stress in the grout.
ISO 19902 do not require fatigue assessment of grouted connections subjected to wave loading. This was based on a review and assessment of jackets present in the Lloyds database at the time the design formulation was developed. It was assessed that fatigue assessment was not required as long as design was performed with respect to the Ultimate Limit State. However, it is now judged that fatigue is important for jackets with significant dynamic load that exceeds the axial and bending moment from permanent loads.
A review of design standards for grouted connections in jacket structures has shown that there is a need for more relevant test data and revisions of these standards such as ISO 19902 in order to assure reliable design with respect to all potential failure modes.