DNV DNVGL-RP-C104 PDF

Introduction

This recommended practice (RP) presents recommendations for the strength analyses of main structures of self-elevating units.

The design principles, overall requirements, and guidelines for the structural design of self-elevating units are given in the DNV GL offshore standards:

— DNVGL-OS-C101 Design of offshore steel structures, general - LRFD method /1/.

— DNVGL-OS-C104 Structural design of self-elevating units - LRFD method /2/.

— DNVGL-OS-C201 Design of offshore units - WSD method /3/.

The above standards refer to two safety formats:

— LRFD = load and resistance factor design method. See [1.5].

— WSD = working stress design method. See [1.6].

The selected safety format must be followed for all components of the considered self-elevating unit, for example one can not use one safety format for the legs and another for the hull structure.

The units are normally designed to serve at least one of the following functions:

— production

— drilling

— accommodation

— special services (e.g. support vessel, windmill installation vessel, etc.).