Chapter 6 - Offshore Structural Analysis

Abstract

This chapter discusses the primary considerations that the design engineer should bear in mind during the initial design and subsequent structural analysis. The designer is faced with a large number of rules, codes, standards, and specifications describing the general policy for structural systems and the detailed design of structural components, which includes government requirements, certification/classification authorities, and other technical documents. The notation “Structures” refers to all types of marine units ranging from floating ship-shaped vessels to bottom founded platforms. Emphasis has been placed on ship-shaped structures. Consideration is also given to column-supported structures, e.g., semi-submersibles, tension leg platforms, spars, and mooring buoys, etc., and also to steel bottom founded offshore structures, such as fixed steel jackets. The main output of the planning process is a “Design Basis,” describing the criteria and a “Design Brief,” describing the procedure to be followed and software to be used. This chapter discusses the finite element method, which is a powerful computational tool that has been widely used in the design of complex marine structures over the decades. This chapter gives a general overview for the design of marine structures using a finite element modeling technique. It also addresses structural modeling defined by industry codes for fixed platforms and floating production installations. Throughout this chapter, emphasis is placed on the design process where the finite element analysis will be employed.