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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
4.2 Loads
In the Table [5] are showed the values of cracking load (P
f
), of lon-
gitudinal reinforcement yield load (P
y
) and beams failure load (P
u
).
The presence of strengthening increased the first crack load of the
strengthened beams. The increment was of 19.8% for strengthened
RC beam and 66.2% for the beam V2C. In relation to the beam V1C,
the cracking load of beam V2C was increased by 38.8%.
The presence of strengthening increased also the load necessary
for the longitudinal reinforcement yield. This occurs because the
Figure �� � �o�en��ature and positioning of the strain gauges and LVDT´S
str.1 e 2
str.3 e 4
Strain gauges locations:
Strain gauges in the concrete and reinforcement
0.0 mm
1 2
1600 1600
1600
1600
4 3
2250
5
11 12
27702690 2490
2610
14 13
9 10
2890 2850
2930
2970
8 7
Strain gauges in the strengthening
2370
15
18 19
1818 1600
2034
2250
17 16
reference
number of strain gauge
support
A
0.0 mm
1600
1600
21 20
support A
support B
str.6
str.5
transd.1
transd.7
transd.3
transd.4
transd.5
transd.2
transd.6
6
2970
22
950 350
23
str.23
str.2
1
str.20
str.19
str.22
16
9 8
15 14 13
7
10 11 12
str.17
str.18
transd. = transductor
str. = strain gauge
reference
support
A
number of strain gauge
Figure 11 � Fai�ure modes of beams V1C and V2C