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IBRACON Structures and Materials Journal • 2012 • vol. 5 • nº 5
V. J. FERRARI | J. B. DE HANAI
the intensity and the application speed of loads and displacements.
The beams were subjected to displacement-control of the actuator
piston with the imposition of a rate of 0.007 mm/s. The actuator re-
mained attached to a metallic beam of great stiffness, part of a reac-
tion porch at the beam center. Strain gauges were attached to the
steel reinforcements and strengthening to obtain strain profile. A data
logger was used to read and record the values given by the strain
gauges, load cells and linear variable displacement transducers
(LVDTs). The nomenclature and scheme for positioning the instru-
mentation of beams are indicated in Figure [10].
4. Test results
4.1 Failure modes
As expected, the mode of failure of the beam V1A was of exces-
sive deformation for the longitudinal reinforcement, followed by
high deformations in the compressive concrete.
The failure of the beam V1C (Fig. 11-a) began from the appearance
of a crack at the strengthening end (P=117 kN). The propagation
of this crack developed in horizontal direction and strengthening
debonding with the entire layer of concrete from the reinforcement
cover along the shearing span.
The mode of failure of the beam V2C (Figure [11-b]) was different
from the observed for the beam V1C. Although it has appeared a
crack at the strengthening end when the applied strength was 141
kN, it did not propagated horizontally and the debonding process
for the strengthening by the rupture of concrete layer was avoided.
In the beam V2C the failure was originated from a section locat-
ed in the shearing span and near to the application of concen-
trated load. The appearance of a flexural/shearing crack and the
development of its opening with the increment of load, cause the
strengthening debonding through the cement composite interface
with the epoxy adhesive until its nearest end. A thin layer of micro-
concrete remained jointed to the sheet.
Ta�le � � Properties of the CFRP
Epoxi adhesive
Comercial name
Sikadur 330
Colour
Part � � �hite / Part B � gray
Tensile strength
30MPa (7 days)
Tensile strain
9�
Bending modulus
3,800 MPa
Tensile modulus
4,500 MPa
Moisture
4�1 � ��B (�eight)
Consumption
2
1.0 a 1.5kg/m
Carbon fibers sheet
Comercial name
SikaWrap � 300C
Weight
2
2
300g/m ± 15g/m
Thickness
0.166mm
Density
3
1.79g/cm
Tensile strength
3,900 MPa
Elastic modulus
230 GPa
Failure strain
15�
Figure � � ���emati� of t�e f�e�ura�
test of beams