Civil Engineering Reference
In-Depth Information
Fig. 5.3
Veri
cation of curtailment for near-surface-mounted CFRP strips
(
p
a
r
b
L
?
τ
bLd
?
?
l
bL
?
0
:
4
0
:
0015
?
l
bL
?
0
:
95
for
l
bL
115 mm
4
?
p
a
r
F
bLRd
a
r
70
b
L
?
τ
26
:
2
0
:
065
?
tanh
l
bL
115
?
0
:
95
for
l
bL
>
115 mm
?
4
?
bLd
(5.5)
To determine the bond capacity, Equation 5.5 also requires the bond strength
τ
bLd
of the
near-surface-mounted CFRP strip, which according to Equation 5.6 is found from the
result of the minimum of the concrete bond strength and the adhesive bond strength:
1
γ
BE
?
min
τ
bGk
?
α
bG
τ
bck
?
α
bc
τ
bLd
(5.6)
For concrete strength classes C20/25 and higher and the strengthening systems currently
on the market, the bond strength of the adhesive according to Equation 5.7 governs:
s
q
f
Gtk
f
Gck
?
f
Gtk
τ
bGk
k
sys
?
2
?
f
Gtk
2
?
f
Gck
?
f
Gtk
(5.7)
In this equation the bond stress is expressed in terms of the shear strength of the
adhesive, which according to the Mohr-Coulomb failure criterion is given by the tensile
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