Offshore Structure Platform Design - Offshore Structures: Design, Construction and Maintenance - page 124

TABLE 3.1 Partial Load Factors for In-Place Situation

Partial Load Factors a

Design Situation γ f,G1 γ f,G2 γ f,Q1 γ f,Q2 γ f,Eo γ f,Ee

Permanent and variable actions only 1.3 1.3 1.5 1.5 0.0 0.0

Operating situation with corresponding
wind, wave and/or current conditions b

1.3 1.3 1.5 1.5 0.9 γ f,E 0.0

Extreme conditions when the action
effects due to permanent and variable
actions are additive c

1.1 1.1 1.1 0.0 0.0 γ f,E

Extreme conditions when the action
effects due to permanent and variable
actions are opposed d

0.9 0.9 0.8 0.0 0.0 γ f,E

a A value of 0 for a partial action factor means that the action is not applicable to the design situation.
b For this check G 2 ,Q 1 and Q 2 are the maximum values for each mode of operation.
c For this check G 1 ,G 2 and Q 1 include those parts of each mode of operation that can reasonably be
present during extreme conditions.
d For this check G 2 and Q 1 exclude any parts associated with the mode of operation considered that
cannot be guaranteed to be present during extreme conditions.

3.6 CYLINDER MEMBER STRENGTH
Traditionally, the member in the jacket and in some cases for the topside is a
cylinder member, so this section focuses on design of the tubular member
according to ISO 19902, which is principally concerned with load resistance
factor design (LRFD), as in the AISC. In addition, the strength of the cylinder
member is also presented according to API RP2A, which focuses on the work-
ing stress design.

3.6.1 Cylinder Member Strength Calculation According
to ISO 19902
According to ISO 19902, tubular members subjected independently to axial ten-
sion, axial compression, bending, shear or hydrostatic pressure should be
designed to satisfy certain strength and stability requirements.

Axial Tension
Tubular members subjected to axial tensile forces should be designed to satisfy
the condition:

F t
γ R,t
where f t is the axial tensile stress due to forces from factored actions; F t is the
representative axial tensile strength, F t = F y ,andF y is the representative yield

f t ≤