Page 521 - Marine Structural Design

Part IV

Structural Reliability

Chapter 28 Probability and Risk Based Inspection Planning

28.1 Introduction

In-service inspections of marine structures are carried out in order to assure structural integrity.
To optimize the in-service inspections, it is necessary to deal with the uncertainties in design,
fabrication and damage detection as well as the adequacy of examining only limited amount of
critical elements. Many efforts have been devoted to reliability updating through inspection
and repair, see Moan (1993, 1997), Xu and Bea (1987). Moan and Song (1998), Song and
Moan (1998) have studied inspection updating based on system consideration. Uses of
probability-based inspection in other engineering fields are given by e.g. Yazdan and Albrecht
(1 990).
Risk assessment can be used as a valuable tool to assigning priorities among inspection and
maintenance activities. A throughout discussion of risk assessment is given in Part V of this
book. This Chapter shall present the following:
Concepts of Risk Based Inspection
Reliability Updating Theory for Probability Based Inspection
Risk-Based Inspection Examples
. Risk-Based Optimum Inspection

28.2 Concepts for Risk Based Inspection Planning

In general, the dimensions of risk can be considered in the following three main categories:
Personnel risk
Fatality risk
Impairment risk
Environmental risk

Assetrisk
Material (structural) damage risk
Production delay risk
Risk is defined as
R=f(Pf,C) (28.1)