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307 IBRACON Structures and Materials Journal • 2012 • vol. 5 • nº 3
P. P. NASCIMENTO | R. B. GOMES | L. L. J. BORGES | D. L. DAVID
on the interfacial zone of each column, thus improving the model’s
monolithic behavior and preventing their failure by uncoating of the
strengthening concrete.
The P1 model with cross-section of 120 x 250 mm represents the
original model in conventional concrete. Column P2 is a monolithic
reference model; its final section is 155 x 250 mm, identical to the
reinforced column. The remaining columns were strengthened with
a 35 mm thick layer of SCC on the compressed face. Figure 2
shows the characteristics of the transversal sections of the col-
umns assayed. The original longitudinal reinforcement of all col-
umns (Figure 3) is composed of four ribbed straight bars with a 10
mm nominal diameter (As = 314 mm2, ρ=1.05 %). Figure 4 shows
the tension curve x strain of 10 mm diameter bars. The shear rein-
forcement is made up of 5 mm stirrups whose spacing measures
100 mm in the central area and 50 mm near the model’s edges (fy =
662 MPa, ey = 2.91 mm/m, Es = 225.3 GPa). P6A column is identi-
between connectors influence the columns’ failure loads and es-
pecially their failure modes.
2. Experimental program
The experimental program included tests on nine columns whose
measurements are shown in Figure 1. These models of tests and
the test arrangements are similar to those carried out by Adorno
(2004), Araújo (2004), Omar (2006), Nascimento (2006) and Sahb
(2008). The columns were cast in two phases. In the first phase, six
models were shaped, two of which were used as non­strengthened
reference columns. The remaining columns (second phase) were
strengthened with SCC on the compressed face. Their initial ec-
centricity decreased; therefore, the original load application posi-
tion was maintained. To ensure bonding between strengthening
concrete and substrate, connectors were used in various positions
Figure 3 – Detailing of original column reinforcements (mm)