A Risk-Informed Approach to Performance Assurance - Structural Integrity of Offshore Wind Turbines - page 71

tation of insurance companies and is an explicit requirement of many
flag states.
Historically, rules and regulations in the maritime industry have been
experience-based and prescriptive, as has been the case for those developed
by API. The reliance on prescriptive regulations meant that regulatory
development in the maritime industry, as in the oil and gas industry, was
primarily reactive, usually relying on a catastrophic event to trigger the
next round of changes. This began changing in the 1970s with the intro-
duction of probability-based methodologies for evaluating the survivabil-
ity of ships. IMO has now adopted guidelines for formal risk assessment
that are used in assessing new and updating existing regulations (IMO
2002). IMO has recently adopted goal-based standards applicable to ship
structures. This approach is discussed later in this chapter in the section
“Risk Mitigation Through Performance-Based Engineering.”
Buildings, Bridges, and Civil Infrastructure
The first probability-based standards and specifications in the United
States were introduced in the early to mid-1980s [American National
Standards Institute Standard A58, now American Society of Civil Engi-
neers Standard 7, and the AISC load and resistance factor design (LRFD)
specification for steel buildings]. They have been followed by other spec-
ifications as the rationale of the approach has taken hold in the structural
engineering community. In these standards and specification documents,
the load and resistance criteria were predicated on a set of reliability tar-
gets for member and component limit states, expressed as a reliability index
that was determined from an extensive assessment of reliabilities associ-
ated with members designed by traditional methods. Over the years, most
building construction materials that have moved toward probability-
based limit states design have adopted similar benchmarks, indicating a
degree of professional consensus in the structural engineering standard-
writing community in the United States. More recent specifications in
the bridge and transportation area, typified by the American Associa-
tion of State Highway and Transportation Officials LRFD Bridge Design
Specifications (AASHTO 2007), have adopted essentially the same prob-
abilistic methodology as that used in building structures. These first-
generation probability-based limit states design standards continue to be