Page 229 - Marine Structural Design

Chapter10 Ultimate Strength of Plates and Stiffened Plates 205

(10.13)

Another well-known solution is the so-called Johnson-Ostenfeld formula that is adopted by
several North American Design Codes:

(1 0.14)

10.2 Combined Loads
In limit state design, buckling criteria and ultimate strength criteria are also termed
Serviceability Limit State (SLS) and Ultimate Limit State OJLS).
10.2.1 Buckling - Serviceability Limit State
In the case of a combined loading, as shown in Figure 10.6, the above procedure may be
applied if an equivalent stress and an equivalent elastic buckling stress are defined. This is
conveniently expressed by the following interaction formula:

(10.15)

where CT,,CT,,, and zE are the elastic buckling stresses when the corresponding stress
component acts alone and CT,, is the equivalent elastic buckling stress corresponding to the
equivalent stress CT, = + a: - CT~CT,, + 32’ .

Figure 10.6 Combined Loading.