Loadbearing structures and detailed design - Concrete Structures for Wind Turbines - page 141

Table 4.8 Partial safety factors g M for ultimate resistances of concrete structural components

according to [11] Table 5.4.1

Material Ultimate limit state Serviceability

limit state

Failure or stability Fatigue

1.50 a) (1.20) b)

Concrete ( g C ) 1.50 1.00

1.40 a) (1.20) b)

Fibre-reinforced concrete ( g C ) 1.40 1.00

1.15 a) Reinforcing and prestressing

steel (

1.15 1.00

g S )

a) When designing for accidental situations, for example earthquakes,

g CA ¼ 1.30 may be

used for concrete and fibre-reinforced concrete, g SA ¼ 1.00 for reinforcing and pre-

stressing steel.
b) The value in brackets

g Cm ¼ 1.20 may be used in deformation calculations if the
geometric and physical non-linearities are taken into account.
The value

g Cm ¼ 1.20 may be used for concrete in calculations based on second-order
theory, see [11] 5.4.1.4.2 (1). This corresponds to f cR ¼a f ck / g Cm ¼a f ck /1.20 ¼ 0.85

a f ck according to [33] 8.5.1 (4).

5. Performing the deformation calculation according to second-order theory generally
requires the help of a computer program.
6. Checking the capacities of the cross-section:
If the deformation calculation was carried out according to [33] 8.6.1 (6) using the
theoretical mean values for the material strengths according to [33] 8.6.1 (4), then the
ultimate load-carrying capacities at the critical cross-sections must be verified using
the uniform partial safety factor

g R or g RA for the design value of the ultimate resistance

(see above):

E d R ð f cR ; f yR ; f p0 : 1R Þ=g R or E dA R ð f cR ; f yR ; f p0 : 1R Þ=g RA

Performing the deformation analysis according to [33] 8.6.1 (7) as an alternative
approach means using the following design values for the material strengths and
associated partial safety factors

g M when calculating the ultimate load-carrying
capacities at the critical cross-sections:

Concretes up to C 50/60:
f cd ¼a f ck /

g CA
Concrete grade C 55/67 and higher:
f cd ¼ a f ck =ðg C g

g C or f cdA ¼a f ck /

0 C Þ or f cdA ¼ a f ck =ðg CA g 0 C Þ

Reinforcing steel:
f yd ¼ f yk /

g S or f ydA ¼ f yk / g SA