Page 164 - Riem-Vol6_nº3

509 IBRACON Structures and Materials Journal • 2013 • vol. 6 • nº 3
F.M. ALMEIDA FILHO | M. K. EL DEBS | A.L.H.C. EL DEBS
measured value showed a minimal stress presented in the steel
bar surface. This assumption shows that the beginning of the de-
velopment length was being used resisting the slip, while the other
points on surface help only with a minimal amount of stress, dis-
tributed in it.
For the high strength concrete, both numerical models (with 10 and
16 mm steel bars) showed similar behavior, also observed in the
previous series. However, at failure an increase of bond stress at
the end of the development length was observed. This behavior
may be explained by the nature of the model’s failure, occurred by
the steel bar yielding.
5. Conclusions
The presented paper describes the numerical and experimental investi-
gation performed to evaluate the bond strength. Beammodels based on
the Rilem recommendation were used, comparing ordinary concrete and
self-compacting concrete of same compressive strength. The numerical
approach was based on finite element method, using Ansys® software.
According to the results, the following conclusions can be made:
1. The beam models with self-compacting concrete and ordinary
concrete produced similar results, with a small advantage for
the ordinary concrete;
Figure 14 – Comparison between the test results from the strain gages and the numerical result
Figure 15 – Stress distribution on the steel-concrete interface for the beam models
0 2 4 6 8 10 12
-30
-25
-20
-15
-10
-5
0
Concrete elements
Contact elements
Measurement points
S tr ess (c on cr ete ) (M P a )
-80
-70
-60
-50
-40
-30
-20
-10
0
10 mm steel bar
S tr ess (c ont a ct ) (M P a )
0 2 4 6 8 10 12 14 16 18
-30
-25
-20
-15
-10
-5
0
Concrete elements
Contact elements
Measurement points
S tr ess (c on cr et e) ( MP a ) -30
-20
-10
0
16 mm steel bar
S tr ess (c on ta c t) (M P a )