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IBRACON Structures and Materials Journal • 2012 • vol. 5 • nº 3
P. T. C. MENDES | M. L. T. MOREIRA
|
P. M. PIMENTA
Figure 20 – Variation of minimum, medium and maximum longitudinal compressive stress in the top
of the slab versus
ρ
for (B-S) and (SOL) models, in cracked section, modulus of elasticity 0.5.E ,
c
with impact, caused by {DEAD}, {DEAD +
φ
.TB360} and {DEAD +
φ
.TB450}, with reinforced corrosion
6413
4436
4284
3041
6442
4551
4345
3149
6444
4778
4416
3321
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
DEAD-
ρ
3-TOT
DEAD+
φ
.TB360-
ρ
3-TOT
DEAD+
φ
.TB450-
ρ
3-TOT
DEAD-
ρ
3-0,6L1
DEAD+
φ
.TB360-
ρ
3-0,6L1
DEAD+
φ
.TB450-
ρ
3-0,6L1
DEAD-
ρ
3-0,0L1
DEAD+
φ
.TB360-
ρ
3-0,0L1
DEAD+
φ
.TB450-
ρ
3-0,0L1
σ
c
(kN/m
2
)
VARIATION OF THE MÍN, MÉD E MÁX COMPRESSIVE STRESS
WITH CORROSION IN THE REINFORCEMENT -
ρ
3=2,68% -
φ
=1,26 - TOP OF THE SLAB- CRACKED SECTION - (B - S) AND
(SOL) MODELS - 0.5EC - (kN/m2)
(SOL)-
ρ
3-TOT-MAX
(B-S)-
ρ
3-TOT-MAX
(SOL)-
ρ
3-TOT-MED
(SOL)-
ρ
3-TOT-MIN
(SOL)-
ρ
3-0,6L1-MAX
(B-S)-
ρ
3-0,6L1-MAX
(SOL)-
ρ
3-0,6L1-MED
(SOL)-
ρ
3-0,6L1-MIN
(SOL)-
ρ
3-0,0L1-MAX
(B-S)-
ρ
3-0,0L1-MAX
(SOL)-
ρ
3-0,0L1-MED
(SOL)-
ρ
3-0,0L1-MIN
for major worries. For the new bridges, the requirements to their
durability require the adoption of concrete with very high character-
istic strength, which for the same levels of solicitations ensures a
greater security reserve.
In relation to the tensile stress in reinforcement, on observe as ex-
pected a significant variation by the effect of cracking. The effect
of the variation of the modulus of elasticity from E
c
to 0.5.E
c
in the
cracked section, is not significant. The complete corrosion of the
inferior layer of the reinforcement (L-1), with the reduction of the re-
inforcement ratio ρ
3
= 2.68% in 20.9% raises the maximum stress
value in the bars in 13.9% for the modulus of elasticity of concrete
E
c
and in 29.4% considering a reduction in the modulus of elasticity
of concrete to 0.5.E
c
.
From distributions of the stresses on the bars of the reinforce-
ment in (SOL) model in the cracked section, one could con-
clude that an inadequate positioning of the deformation sen-
sors in the reinforcement might not capture a real situation of
the stresses on the bars, on the occasion of load tests or in the
monitoring of the structures. This numerical finding suggests
the realization of laboratory and field tests that sensors are ad-
opted in all bars of the reinforcement of a same section, being
adopted details of the execution that induces the occurrence of
cracking in this section.
5. References
[01] MENDES, P. T. C.. Contribuições para um modelo de
gestão de pontes de concreto aplicado à rede de
rodovias brasileiras. Tese (Doutorado). Escola
Politécnica da Universidade de São Paulo, São Paulo,
2009.
[02] ASSOCIATION FRANÇAISE DE GÉNIE CIVIL –
AFGC. Concrete Design for a Given Structure Service
Life. April, 2007. Paris, France.
[03] ASSOCIAÇÃO BRASILEIRA DE NORMAS
TÉCNICAS. NBR 6118: Projeto de Estruturas de
Concreto - Procedimento. Rio de Janeiro: ABNT,
2007.
[04] ASSOCIAÇÃO BRASILEIRA DE NORMAS
TÉCNICAS. NB 6: Carga Móvel em Pontes