Assessment of Existing Structures and Repairs - Offshore Structures: Design, Construction and Maintenance - page 481

TABLE 7.11 Reduction Factors for Stress-Strain Relationship of Carbon Steel

at Elevated Temperatures

Reduction Factors at Temperature θ Relative to the Value of

f y or E a at 20 C

Reduction Factor
(Relative to f y ) for
Effective Yield
Strength
k y,θ = f y,θ /f y

°

Reduction Factor
(Relative to E a ) for
the Slope of the
Linear Elastic
Range k E, θ = E a, θ /E a

Reduction Factor
(Relative to f y ) for
Proportional Limit
k p,θ = f p,θ /f y

Steel
Temperature,

θ

20 ° C 1.0 1.0 1.0

100 ° C 1.0 1.0 1.0

200 ° C 1.0 0.807 0.900

300 ° C 1.0 0.613 0.80

400 ° C 1.0 0.42 0.700

500 ° C 0.780 0.360 0.600

600 ° C 0.470 0.180 0.310

700 ° C 0.230 0.075 0.130

800 ° C 0.110 0.050 0.090

900 ° C 0.06 0.0375 0.0675

1000 ° C 0.040 0.025 0.045

1100 ° C 0.02 0.0125 0.0225

1200 ° C 0.00 0.0 0.0

Note that there is no need to consider lateral torsional buckling unless
λ LT :θ com >

0 : 4, and the correction factor of 1.2 simply allows for uncertainties.

In the load resistance domain, buckling capacity at maximum temperature
θ a.max is

●

1
γ M : fi

Ak y :θ: max f y χ fi
1

N b : fi : t : Rd =

: 2

In the load resistance domain, buckling capacity at maximum temperature
θ a.max is reduced yield strength = k y.q.max f y at θ a.max

Reduction factor χ fi for flexural buckling based on:

●

Buckling curve (c)

●