The SUPERB Project: Reliability-based Design Guideline for Submarine Pipelines
Authors: Sotberg Torbjøm , Bruschi Roberto , Mark Kim 
Published: October 2008

This paper gives an overview of the research programme SUPERB, the main objective being the development of a submarine pipeline reliability based Design Guideline with a comprehensive setup of design recommendations and criteria for pipeline design. The motivation of this program is related to the fact that project guidelines currently in force do not account for modem fabrication technology and the findings of recent research programs and by advanced engineering tools. The mainvstructure of the Limit State Based Design (LSBD) Guideline is described followed by an outline of the safety philosophy which is introduced to fit within this framework. Focus is on the development of a reliability-based design guideline as a rational tool to manage future offshore projects with an optimal balance between project safety and economy. Selection of appropriate limit state functions and use of reliability tools to calibrate partial safety factors is also discussed.

Introduction

Reliability based design an alternative to the traditionaldeterministic stress based design has received increase attention during the recent year for the application to offshore pipelines. Reliability engineering and structural safety assessment is considered to be ;in efficient tool in order to develop rational, e.g. safe and cost effective designs.

The Design Guideline under preparation in the SUPERB Program is thus concerned with reliability based -limit state design of submarine pipelines. contains recommended design equations with association partial safety factors established using reliability based calibration methodology guided by engineering judgement and experience from recent R&D projects. The design formats methodology of the Guideline also provide a framework for extension of the basic design methodology into new areas where the experience is limited. Targeting the analysis towards adequate safety levels, a morebalanced and cost optimal code of practice can h, achieved. The premises for the work are based on the most recent technical development and research within the fields of pipeline technology and applied structural reliability theory. The developed design formats me, however, not in a narrow sense to be interpreted as complete or exhaustive as the technical knowledge within the industry is expected to be further improved also in the future. However, the limit state design formats provide a rational and well suited setup in order to account for new technology, e.g. by updating the partial factors or the characteristic load-and resistance properties.

In addition to the SUPERB Guideline' which is due late 1996. some other standards are also under preparation with the aim to allow reliability analysis and Load and Resistance Factor Design (LRFD) methods.

A new pipeline code for both offshore, and onshore application is currently under development by International Standardization Organization (1S0 DLS 136232). This new international code allow for the use structural reliability techniques by means of limit state based design procedures as those prepared within SUPERB.