EUROCODE 2 WORKED EXAMPLES - Federbeton

EC2 – Worked examples 4-4
EXAMPLE 4.3 [EC2 clause 4.4]
Calculate the concrete cover of a TT precast element, made of prestressed reinforced concrete,
placed outside an industrial building situated close to the coast.
The exposure class is XS1.
We use concrete with strength class C45/55.
At the lower side of the two ribbings of the TT element we have:
− longitudinal φ 12 reinforcement bars;
− φ 8 stirrups at 100 mm ;
− strands φ 0,5” .
The maximal aggregate size is: dg = 16 mm.
The design working life of the structure is 50 years.
An accurate quality control of concrete production is put in place.
Refer to figure 3.3.
We find out from table E.1N - EC2 that for exposure class XS1, the minimum concrete
strength class is C30/37; strength class C45/55 is therefore adequate.
The original structural class is S4.
In accordance with table 4.3N:
− the structural class is reduced by 1 as the concrete used (C45/55) is of strength class
higher than C40/50;
− the structural class is reduced by 1 as special quality control of the concrete production
is ensured
We then refer to structural class S2.
Calculating first the concrete cover for stirrups.
We have:
c = 8 mm .
min,b
We obtain from table 4.4N - EC2:
c = 25 mm .
min,dur
Moreover:
Δc dur, γ = 0 ;
Δc dur,st = 0 ;
Δc = 0 .
dur,add
From relation (3.2):
cmin = max (c min,b ; cmin,dur +Δcdur, γ −Δcdur,st −Δc
dur,add;
10 mm) =
= max (8; 25 + 0 – 0 – 0; 10 mm) = 25 mm .
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