Page 7 of European technical approval ETA–11/0390, issued on 27.08.2012
English translation prepared by CSTB
4.3.2
Determination of anchorage depth.
4.3.2.1 General points
The design anchorage length l
bd
must be determined according to EN 1992-1-1, section 8.4.3.
The anchorage depths and overlap lengths must not be less than the minimum values given in annex
8. The maximum permissible anchorage depth is given in annex
8.
4.3.2.2
Calculation of the basic anchorage length l
b,rqd
The
basic
anchorage
length l
b,rqd
, for
anchoring
the force
A
s
.f
yd
in
the
rebar
assuming
constant
bond
stress equal to f
bd
follows from:
l
b,rqd
= (
/4).(
sd
/f
bd
)
where :
= diameter of the rebar
sd
= calculated stress in the rebar under the design action
f
bd
= design value of the bond strength according to table 5 in annex 8
f
bd
= 2.25
1
2
f
ctd
(according to EN 1992-1-1)
with
f
ctd
=
ct
f
ctk,0.05
/
c
ct
= 1 and
c
= 1.5
1
coefficient relative
to the quality of the bond condition and
position of the rebar
during concreting
1
= 1,0 (“good” bond conditions)
1
= 0,7 (all other conditions)
2
= 1,0 (for
25mm)
4.3.2.3
Calculation of the minimum anchorage length l
b,min
Anchoring rebar
In the case of anchoring rebar, the minimum anchorage length l
b,min
must be determined as follow:
l
b,min
=
crack
x
Max (0,3 l
b,rqd
; 10
; 100mm)
under tension
l
b,min
=
crack
x
Max (0,6 l
b,rqd
; 10
; 100mm) under compression
Overlap joint
In the case of overlap joint, the minimum anchorage length l
0,min
must be determined as follow:
l
0,min
=
crack
x
Max (0,3.
6
.l
b,rqd
; 15
; 200mm)
where
6
= (
1
/25)
0.5
≤ 1.5
1
is
the percentage
of reinforcement
lapped
within
0.65 l
0
from
the
centre
of the length considered.
Concrete class
crack
C20/25
1.0
C25/35
1.2
C30/37 to C50/60
1.4
