IS0 Standard for Fixed Concrete Structures

Abstract

Abstract The present paper presents the work being done in order to develop an international standard, ISO-Standard for the design of fixed offshore concrete platforms. The work is a part of the joint effort of IS0 and API in developing a total set of engineering standards for the offshore industry. The first part of this standard IS0 13819-1, PART I General Requirements, is already published. Parts to follow will cover applications such as fixed steel platforms, fixed concrete platforms, floating platforms etc.. The standard for fixed concrete structures will be issued as PART 3 of the suite of standards, IS0 13819-3. PART 3 will cover the entire engineering process, and consequently contain the requirements and criteria for all engineering aspects such as environmental actions, structural analyses, geotechnical design, mechanical systems, marine operations, inspection and condition monitoring as well as concrete design, materials and execution. History It is 50-years since the start of the offshore industry, by the installation of two steel drilling platforms in the Gulf of Mexico. The concrete offshore history is seen as started with the installation by Phillips Petroleum of the Ekofisk Tank in the Norwegian sector in 1973. The water depth at Ekofisk was 70m. Since then more than 30 major offshore Concrete platforms have been built. The majority of them are located in the North Sea, UK and in particular the Norwegian sector. Major platforms are also located outside Australia, Netherlands, Canada. Also barges and minor concrete structures have been built a number of places. There is a great variety in structures built, from the larger structures like Troll installed in 220m waterdepth, the Hibernia which is designed for ice-berg impact, to the minor concrete structures in the Gulf area of US. The development in materials and construction technology, as well as in design capabilities, has been very significant over this period. While the first structures would typically have a cylinder strength of 30-40MPa is presently concrete in strength classes up to C75- C90 being used in large quantities. A total of some 3 million cubic metres of high strength concrete has been produced to build these platforms. At present the activity within the offshore concrete industry is low, the potential should however still be there considering the advantages in using concrete. Scope The scope of the IS0 standard for fixed concrete structures is to develop a basis document that outlines the requirements for the entire engineering process involved in building a concrete platform. In this context there are a number of other engineering disciplines than the concrete discipline, that becomes important. The standard is intended to cover all these disciplines, related to design as well as execution. The intention by the development of this suite of international standards has been for the industry to eliminate the need for a large number of proprietary and general specifications. Different for all companies and containing unnecessary peculiarities, making it difficult both for company personnel, engineering and contractor personnel at all times to keep updated.