Reliability based earthquake design guidelines for marine structures

This paper describes a reliability based formulation to determine earthquak e LRFD parameters for conventional, steel, pile supported, tubular member p latforms that is proposed as a basis for earthquake design criteria and gui delines for offshore platforms and that is intended to have worldwide appli cability. The formulation is illustrated with application to platforms loca ted in five areas: offshore California, Venezuela (Rio Caribe), the East Co ast of Canada, the Caspian Sea (Azeri), and the Norwegian sector of the Nor th Sea. The approach and proposed quantifications have been verified with s ite specific results from four locations. Good agreements have been develop ed between the site specific results and those based on these guidelines. T he approach provides an important element of information sensitivity that a llows the loading and resistance factors to be varied as a function of the desired reliability for a platform, the unique aspects of its seismic envir onment, and the primary uncertainties in the earthquake loadings and platfo rm element capacities.