Scope of application

This recommended practice applies to the geotechnical design and installation of plate anchors in clay for taut, semitaut and catenary mooring systems. The design code is applicable to anchors for both production platforms and drilling platforms. The recommended method for calculating the resistance of a plate anchor is applicable to both dragin and pushin type plate anchors. To make the description of the design code as concise and transparent as possible, anchor specific text has been moved to the appendices. Some of the appendices originally written for dragin plate anchors are, to some extent, also applicable to pushin type plate anchors.

The design code outlined is a recipe for how plate anchors in clay can be designed to satisfy the requirements by DNV GL.

The partial safety factors presented for use in connection with this design code have been calibrated based on reliability analysis /3/. The scope of the calibration covers plate anchors in normally consolidated and layered clay, subjected to extreme line tensions representative of semisubmersibles and ship operating in a range of water depths and environmental conditions. A general description of the calibration procedure adopted is given in /6/.

Tentative recommendations are given for determination of the target installation depth of plate anchors that are designed to resist vertical loads.