| Summary: | Colum reinforcement is essential in a structure. When a column is weak, it
will cause total failure to the structure. This study examined the behavior of column
reinforced with mortar jacketing method and wire netting. The objective of this study
was to identify the contribution of the reinforcement to the shear strength and column
ductility.
Four column specimens were made. They consisted of one original column
(as comparison) in square shape of 150 x 150 mm, and 700 mm height and
foundation plate in 1200 x 700 mm with 250 mm thickness and three specimens in
same dimensions and strengthened by mortar jacketing to become column with round
section in 220 mm diameter and 730 mm height. Longitudinal reinforcement and wire
netting in 1.7 mm diameter and consisted of small squares of 25 mm x 25 mm with 1
layer strengthening (KP-1). Two layers (KP-2), and 3 layers (KP-3) were used as the
mortar jacketing. Sika Grout 215 New was used as the filler. Loading type used was
constant axial and cyclic lateral to simulate earthquake by using the displacement
control method.
Results of this study showed that in KP-1, KP-2 and KP-3 reinforced column,
their lateral load capacities increased by 90.263%, 101.985%, 124.196%,
respectively, than the average original column (KA-1). Addition of wire netting for
KP-1, KP-2, and KP-3 showed general increase of displacement at a maximum
lateral load in compare to the original column (KA-1). Drift ratio at maximum
load at KA-1 was 2.07%. As for KP-1dan KP-3, the maximum loads were 2.52
% and 2.924%, respectively. However, the drift ratio of KP-2 was 1.192%, or
smaller than 1.50%. The stiffness values obtained from the tests for KA-1, KP1,
KP-2 and KP-3 were 3.92 KN/mm, 9.04 KN/mm, 9.01 KN/mm, and 8.14
KN/mm, respectively. Ductility factor (µ) of KA-1, KP-1, KP-2, and KP-3 were
5.451, 6.273, 3.938, and 6.667, respectively. Thus, more netting wire showed
increasing ductility, except for KP-2 which had the smallest ductility in compare to
other specimens. Based on the test results and the regulation of ACI 374.1-05.200,
the reinforced column could be used for structures with maximum R (response
modification factor) of 6.
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