Civil Engineering Reference
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4.5
τ
fl
Holzenkampfer
(fctm= 2 MPa)
4
3.5
3
Fracture Energy
G
f
2.5
2
1.5
1
0.5
S
fo
S
fl
0
0
0.1
0.2
0.3
0.4
Bond Slip mm
FIGURE 5.20
Holzenkampfer model for bond shear stress-slip of externally bonded FRP
to concrete.
k
b
is a geometry factor:
b
b
b
f
2
−
b
b
1
3
f
k
=
1.06
≥
1.0
with
≥
(5.93)
b
f
1
+
400
C
1
and
C
2
are coefficients needing to be calibrated from test results:
0.64
2
C
C
=
=
1
forCFRPstrips
(plates) and
2
b
,
b
f
, and
t
f
are in mm, and
E
f
and
f
ctm
are in MPa.
For
l
b
<
l
b
,max
, the ultimate force to be anchored is
l
l
(
)
b
b
NN
=
2
−
(5.94)
fa
fa
,max
l
l
b
,max
b
,max
According to Equation (4.25) of FIB Task Group 9.3,
M
bh
cr
f
≈
ctm
2
/6
Thus
f
≈=
f
0.62
f
in MPa
ctmr
c
(5.95)
=
7.5
f
in psi
c
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