Design fatigue strength of concrete f_cd,fat

The design fatigue strength of concrete, f_cd,fat, is calculated from:

where:

f_ck

is the characteristic compressive strength of concrete, see Table 3.1

f_cd

is the design compressive strength of concrete, see § 3.1.6 (1)P

β_cc(t)

is a coefficient which depends on the age of the concrete t:

βcc(t) = exp { s [1 - (28/t)1/2] }

(3.2)

with

t

the age of the concrete in [days]

s

a coefficient which depends on the type of cement:
= 0,20 for CEM 42,5 R, CEM 52,5 N and CEM 52,5 R (Class R)
= 0,25 for CEM 32,5 R and CEM 42,5 N (Class N)
= 0,38 for CEM 32,5 N (Class S).

t₀

is the time of the start of the cyclic loading on concrete

k₁

is a Nationally Determined Parameter, see § 6.8.7 (1).