Basic HTML Version
630
IBRACON Structures and Materials Journal • 2012 • vol. 5 • nº 5
Fatigue lifetime of a RC bridge along the Carajás railroad
rescence and infiltration, as shown in Figure 6. In the transition slab
were not observed gaps, being therefore in satisfactory conditions.
The design of the structure according to the available information
in the calculation history was performed using the compressive
strength of concrete corresponding to 18.0 MPa. For the founda-
tions, was admitted concrete with compressive strength of 15.0
MPa and land with admissible stress of 0.8 MPa. The criteria used
were based on the NBR 6118 : 1978 [3] to be the design code at
the time of preparation of the project.
In this last inspection were inspected areas of the upper face (0.3
mx 0.3 m), where it was possible to remove the gravel ballast, and
bottom face of the deck slab with the aid of a stair, as shown on
Figure 7, and the existence of cracks was not verified on these
surfaces. In Figure 8, it can be seen that the support devices of the
abutment E1 shows no visible abnormalities, only natural strains
that the progression of cracking is an indication of symptomatic
occurrence of a defect, it is believed that in this case, the cracks
are the result of shrinkage of the concrete at early ages and that
the differences could be related to the methodologies of measure-
ment of these lengths. Efflorescence due to the dissolution of the
compounds of the cement paste were also observed, according to
Cascudo [2], infiltration, surface segregation and insufficient rein-
forcement coatings in concrete beams. On the crossbeams were
also observed efflorescence and moisture stains. Generally, the
stringers and crossbeams have satisfactory integrity, as shown in
Figure 5.
During the inspection of the deck a heavy cracking pattern with ef-
florescence was noticed. On the stringers the presence of short or
damaged drains led to the occurrence of moisture stains. Already
on the side cantilevers were observed cracks with and without efflo-
Figur�������u���r��������������i���ru������i������������ri�g�r
Figure � � �ater infiltration and
stains under the deck slab
Figure � � ��a� concrete surface
preparation for instrumentation