Civil Engineering Reference
In-Depth Information
3.14.6.2 Fiber Supplement Additive Method
V
u
¼
V
c
þ
V
b
ð
3
:
39
Þ
where V
c
is the concrete contribution to shear capacity, a combination of concrete
compressive resistance V
cc
, prestressing V
p
, and dowel resistance V
d
. The term V
b
is
usually the sole measure of the improved shear resistance due to
bers [
113
].
h
i
b
w
d
p
f
cu
V
u
¼
V
cc
þ
V
p
¼
0
:
4
þ
0
:
45
r
cpx
ð
3
:
40
Þ
V
b
According to Lim
V
b
¼
f
tu
b
w
d
ð
3
:
41
Þ
where f
tu
can be calculated theoretically as
ʷ
ʸ
·
V
f
·
τ
f
·
ʻ
f
according to Lim et al.
[
114
], where V
f
is the
ber volume fraction,
τ
f
is the
ber matrix interfacial bond,
ʻ
f
is the
ber aspect ratio, and
ʷ
ʸ
is
ber orientation factor.
V
b
According to Dramix Guidelines
Dramix guidelines [
115
]de
ned V
b
as:
V
b
¼
0
:
54f
ct
;
ax
R
t
bd
ð
3
:
42
Þ
where
R
t
is the ratio of the tensile strength before and after cracking and is given by
Nemegeer and Tatnall [
116
] as:
1W
f
k
f
180C
þ
W
f
k
f
1
:
R
t
¼
ð
3
:
43
Þ
ber content (in kg/m
3
) and
C
is a function of the anchorage effect
where
W
f
is the
of the
bers.
References
1. Fenwick, R.C., and T. Paulay. 1968. Mechanisms of shear resistance of concrete beams.
Proceedings of the ASCE 94(10): 2325
2350.
-
2. MC2010. 2012. Fib Bulletin 65
—
nal draft.
3. Minelli, F., and G. Plizzari. 2006. Steel bers as shear reinforcement for beams. In
Proceedings of the second
b congress, Naples, Italy.
4. Ju
66. Model Code
-
n, A., and K. Sobolev. 2007. The diagonal tension behavior of
ber reinforced concrete beams. Cement and Concrete Composites 29: 402
á
rez, C., P. Valdez, A. Dur
á
408.
-
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