Evaluating scour at marine gravity foundations

This paper analyses scour at offshore foundations, with special reference to gravity base foundations which are used in a range of applications including oil and gas production, wind farm foundations and subsea infrastructure protection, such as concrete covers to pipelines. Two published empirical methods available for evaluating scour are reviewed and compared with laboratory and field data. The methods that are presented are reasonable for first-order assessment although they do not represent the inclusion of skirts. In a vigorous scour environment the foundation is liable to be undermined and scour protection will be required. A flow chart for a scour management plan is proposed to integrate scour considerations into the life cycle management of the gravity base foundations and some improvements that can be made to the predictive capabilities are outlined.