Reassessment and Requalification of Infrastructure: Application to Offshore Structures

Abstract

A general four-tier reassessment and requalification engineering system is developed. The first-tier approach is the simplest. It is based on a qualitative scoring process. The fourth-tier approach is the most complex. It is based on a detailed study of the nonlinear dynamic performance characteristics of the structure when it is subjected to extreme conditions. The primary objective of this system is to qualify structures at the simplest possible level. Requalification or fitness-for-purpose guidelines have been developed based on economic, historic, and standard-of-practice evaluation procedures. Probabilistic and decision analysis methods underlie both the reassessment and requalification approaches. This reassessment and requalification system has potential applications to a wide variety of infrastructures. Application to offshore platforms is illustrated.