This International Standard specifies general principles for the design and assessment of structures subjected to known or foreseeable types of actions. These general principles are applicable worldwide to all types of offshore structures including bottom-founded structures as well as floating structures and to all types of materials used including steel, concrete and aluminium. This International Standard specifies design principles that are applicable to the successive stages in construction (namely fabrication, transportation and installation), to the use of the structure during its intended life and to its decommissioning. Generally, the principles are also applicable to the assessment or modification of existing structures. Aspects related to quality control are also addressed. This International Standard is applicable to the design of complete structures including substructures, topsides structures, vessel hulls, foundations and mooring systems.