Civil Engineering Reference
In-Depth Information
to the edge of the support,
a
L,t
=
50mm:
l
bL
x
cr
t
=
2
a
L
;
t
389
:
29
200
=
2
50
239
:
29 mm
As in Section 4.5.4, the effective bond length and the bond strength of the externally
bonded reinforcement result from the boundary values of the bilinear bond stress-slip
approach
s
L0k
,
τ
L1k
according to DAfStb guideline part 1 annex RV K 1, which are
l
bL,max
=
251.08mm and
f
bLk,max
=
241.30N/mm
2
. Using these figures it is possible to
determine the bond length and associated ultimate strain in the strip required for
verifying the end anchorage:
l
bL
;
lim
0
:
86
?
l
bL
;
max
0
:
86
?
251
:
08
215
:
93 mm
f
bLk
;
max
E
Lm
241
:
30
170
1
:
40 mm
=
m
The available bond length
l
bL
=
239.39mm is greater than the bond length
l
lbL,lim
=
215.93mm and so the strain in the strip as well as the associated slip can be calculated
using the following equations:
ε
a
LRk
;
lim
ε
0
:
985
?
0
:
985
?
a
LRk
a
LRk
;
lim
l
bL
239
:
29 mm
ε
1
:
40 mm
=
m
?
ε
s
Lr
l
bL
a
LRk
239
;
29 mm
0
:
213 mm
l
bL
l
bL
;
lim
;
lim
0
:
213 mm
239
:
29
215
:
93
?
1
:
40
0
:
246 mm
First of all, the bond coef
cient of the reinforcing steel must be determined in order to
calculate the strain in the reinforcing steel. To do this, the variables
κ
b1k
=
2.545,
κ
b2k
=
1.0,
κ
b3k
=
0.8 and
κ
b4k
=
0.2 according to DAfStb guideline part 1 Tab. RV 6.1
are chosen for ribbed reinforcing bars and good bond conditions:
s
f
κ
b2
cm
κ
bsk
κ
b1k
?
2
:
545
κ
b4
E
s
?
ϕ
κ
b3
?
E
L
?
t
L
t
28
1
:
0
0
:
0036
0
:
8
?
p
?
6
0
:
2
200 000
?
:
5
170 000
?
1
:
4
?
The depth of the compression zone is also required. This is calculated below in
simpli
ed form according to DAfStb guideline part 1 annex L 1:
s
"
#
d
L
h
α
s
?
ρ
s1
?
d
s1
h
2
x
α
L
?
ρ
L
α
s
?
ρ
s1
α
L
?
ρ
L
α
s
?
ρ
s1
2
?
α
L
?
ρ
L
?
h
?
43
?
10
2
1000
?
160
0
:
0028
A
s1
b
?
h
4
:
ρ
s1
A
L
b
?
h
140
1000
?
160
ρ
L
0
:
00088
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