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IBRACON Structures and Materials Journal • 2012 • vol. 5 • nº 5
Flexural strengthening of reinforced concrete beams with carbon fibers reinforced polymer (CFRP) sheet
bonded to a transition layer of high performance cement-based composite
the tangential stresses for the strengthening, among instrumented
points, using the eq. 1.
(1)
r r
)i(
)1i(
)i(r
)1i(r
r
t E
s
s
ε
ε
τ
where:
t
r
= is the tangential stress;
e
r
= is the strain in the strengthening;
s
i
= relative position of the extensometer;
E
r
= modulus of the strengthening;
t
r
= thickness of the strengthening.
Figure 1� � �istribution o� normal an� tangential stresses in the beam V1C
normal stress
tangential stress
A
B
In the Figures [13] and [14] are presented the profiles of normal
and tangential stresses along the strengthening of the beams V1C
and V2C, respectively, for loads of 25%, 50%, 75% and 100% of
the ultimate load. From the general analysis of these figures it is
possible to verify that the maximum values of normal stresses were
recorded in the central region of the beams. In the beams V1C and
V2C the maximum value of normal stresses occurred at 213 mm
of the middle of span and was recorded through strain gauge 18.
On the other hand, a general examination of tangential stresses
points out that the maximum values occurred in the region of the
shearing span. With the increase of applied load to the beams, it
is verified that the maximum values of tangential stresses tend to
dislocate in the direction to the strengthening end. In the beam
V2C, up to 50% for the failure load, the maximum value of tan-
Figure �� � �istribution o� normal an� tangential stresses in the beam V2C
normal stress
tangential stress
A
B