AS ISO 19901.2:2022 PDF
AS ISO 19901.2:2022 identically adopts ISO 19901 2:2017, which provides requirements for defining the seismic design procedures and criteria for offshore structures.
The objective of this document is to provide requirements for defining the seismic design procedures and criteria for offshore structures; guidance on the requirements is included in Annex A. The requirements focus on fixed steel offshore structures and fixed concrete offshore structures. The effects of seismic events on floating structures and partially buoyant structures are briefly discussed.
The site-specific assessment of jack-ups in elevated condition is only covered in this document to the extent that the requirements are applicable.
Only earthquake-induced ground motions are addressed in detail. Other geologically induced hazards such as liquefaction, slope instability, faults, tsunamis, mud volcanoes and shock waves are mentioned and briefly discussed.
The requirements are intended to reduce risks to persons, the environment, and assets to the lowest levels that are reasonably practicable. This intent is achieved by the following:
(a) Seismic design procedures which are dependent on the exposure level of the offshore structure and the expected intensity of seismic events.
(b) A two-level seismic design check in which the structure is designed to the ultimate limit state (ULS) for strength and stiffness, and then checked to abnormal environmental events or the abnormal limit state (ALS) to ensure that it meets reserve strength and energy dissipation requirements.
