Conceptual design of a topside structure

Abstract

Today’s platform design builds on years of experience. Previous platform designs for similar environmental and operational conditions usually form the basis. The design and analysis is done in accordance to established rules and guidelines, namely standards, to secure that an offshore structure is able to withstand the loads it is exposed to during its lifetime.

Based on literature study, Eurocode 3 and NORSOK standards, a conceptual design of topside has been performed. The topside is modelled, analyzed and optimized in SESAM GeniE.

The structure is optimized for the inplace condition, with the Ultimate Limit State (ULS-1a) as the governing condition.

Further, a local analysis is performed, by the use of shell elements. The shell model was connected with the beam model and the gained Von Mises stress was 632.98 MPa. The gained stress concentration factor, SCF, was 9.85.

Considering the results gained for the global beam model, and for the shell-beam model, the importance of simulating the joint stiffness is seen.