A study of preliminary structural design of pontoon type VLFS

Abstract

In general the loads due to ocean wave are considered as the main design parameters governing the global structural safety of VLFS (Very Large Floating Structure). In order to predict the design wave loads accurately, hydro-elastic analysis must be conducted considering the initial global flexural rigidity of the VLFS. However, the static and design wave loads are necessary for explicit derivation of the structural scantling of major members (deck, bottom, side panels and longitudinal/transverse BHD etc.). Therefore in order to determine a proper structural arrangement and scantlings of the VLFS at initial design stage, both calculations of structural scantling and hydro-elastic analysis for wave condition must be conducted iteratively and the convergence of their results must be checked. In this paper, based on the case design of a 500×300 m size's floating marina resort, the details of structural design technique using hydro-elastic analysis are explained and discussed. At first, the environmental conditions and the system requirements of the design of marina resort are described. The scantling formulas for the major members of pontoon type VLFS are proposed from the local and global design points of view. Considering the design wave loads as well as static design loads, the structural safety is checked iteratively. Copyright ？ 2004 by The International Society of Offshore and Polar Engineers.