Overview & Interfaces: International Standards Organization Design Guidelines for Platforms to Resist Earthquakes

Abstract

Abstract This paper summarizes the work product and activities of anInternational Standards Organization (1S0) panel (committee) formed to create a set design standards for steel offshore platforms to be located in earthquake prone areas. This work product is a draft set of earthquake design standards which have been submitted for review and eventual incorporation, along with the products of other panels, into a comprehensive set of fixed steel offshore platform design provisions for worldwide use. The 1S0 committee heirarchy, the basic charge to the panel, the mix of necessary talents, liaisons, references, the code development process and the challenges to produce this draft are described. The basic earthquake design process is outlined. Future improvements to this draft are identified, as are the challenges that lie ahead. Background An industry initiative to forge a common set of sustainable engineering specifications for oil and gas industry use on a worldwide basis was started in 1993. The drivers behind this are potential cost savings through uniformity, consistency and better communication. These factors can reduce costs through less expensive fabrication and improved safety. The intent is to create global standards that reflect the use of 'Product Service Level' (PSL) philosophy, making maximum use of existing standards and minimum use of manpower. As in the other petroleum-related technical arenas, the global offshore platform design community had to decide how to best organize to meet this challenge, and what base document should be used, since there exist several professional society and national versions of platform design codes. This paper outlines the evolution of one part of this effort, relating to the design of offshore platforms against earthquake effects. ISO Heirarchy & Panel 5 Charge The various standing, advisory, oversight and ad-hoc 1S0 committees and technical panels formed to develop theseinternational design standards are by default numerous. The author's understanding of the offshore platforms ISO heirarchy is Standing Committee 7 on Offshore Structures (SC7) is responsible for the work products of three Work Groups (WG3 - Fixed Steel Structures, WG4 - Fixed Concrete Structures and WG5 - Floating Systems). These Work Groups direct the work of specialized technical resource panels, which work for one or more of these three Work Groups. This organization is depicted in Figure 1. Panel 5 on 'Seismic Loadings and Response' presently works for WG3/Steel and WG4/Concrete, and is charged with developing a comprehensive set of seismic design criteria for sizing fit-for-purpose platforms to be located in earthquake prone areas, while utilizing existing standards as much as possible, and incorporating PSL philosophy. Such areas include the Cook Inlet, Alaska, and offshore Southern California, Mexico, Venezuela, Peru, Australia, New Zealand, Indonesia, Japan, China, eastern Russia, india and in the Caspian Sea.