Page 223 - Marine Structural Design
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Part I1
Ultimate Strength
Chapter 10 Ultimate Strength of Plates and Stiffened Plates
10.1 Introduction
10.1.1 General
Stiffened plates are frequently used as load-bearing components in marine structures. Typical
example uses are the hull girder of a ship, the pontoons of a semi-submersible, and the deck of
offshore platforms. The main type of framing system in hull girders consists of relatively
closely spaced longitudinal stiffeners with more widely spaced heavier girders in the
transverse direction. This is illustrated in Figure 10.1 for a bottodside structure. The
hydrostatic load, that is the difference between external and internal pressure, is transfer from
plates to stiffeners, which again, through beam action, transfer the loads to the transverse
girders.
Figure 10.1 Stiffened Panels in a Ship Bottom Structure
As illustrated in Figure 10.1, the bottom plates will, in addition to the hydrostatic pressure, be
subjected to bi-axial in-plane loads caused by the longitudinal bending of the hull girder and
by the hydrostatic pressure applied on the sides.
