The Improvement of Reinforced Concrete Column Capacity with External Confinement.
(B. Teknologi)
The Improvement of Reinforced Concrete Column Capacity with External Confinement
Keywords: column, compressive strength, external confinement, modulus of elasticity, steel rings, strain
Safitri, Endah; Mediyanto, Antonius
Fakultas Teknik UNS, Penelitian, BOPTN UNS, Hibah Bersaing, 2012
Geographical condition of Indonesia is located right above the tectonic plates (the Indo- Australian,
Eurasian, and Pacific), crossed by two seismic lines (Circum Pacific and Trana Asiatic Earthquake Belts),
and traversed paths Ring of Fire Java / Sunda Trench, that has become one of the countries with the risk
of a large earthquake. Earthquake mitigation are steps that have to be taken to reduce loss of life and
property, by design of earthquakeresistant structures that have high ductility. One of the way to improve
the ductility is the restraint of reinforced concrete elements. The collapse of the structural column is very
significant in terms of economic and human safety, therefore it is necessary to design the bottom of the
column design to achieve high ductility.
This study aims to determine the effect of the use of ring of steel as external confinement on the
compressive strength, modulus of elasticity and strain of concrete and steel ring. If a is the width of the
steel ring and b is the distance between the rings, then with a variety of ratios a / b on a wide range of
constant and b is a constant, it will get the optimum value of the ratio a/b. Specimens are concrete
cylinders with 30 cm high and 15 cm diameter. At the constant a of 40 cm used a variation b of 90, 47,
and 25 cm with ratio of a/b is 0.444; 0.857 and 1.6 respectively. In the constant b of 40 cm used a
variation of 73, 45, and 28 cm with ratio of a/b is 1.833; 1.125 and 0.7 respectively.
The larger ratio of a/b get the higher compressive strength of concrete. The increase in compressive
strength of concrete for the variation ratio of a/b 40/90 (0.444), 40/47 (0.851), and 40/25 (1.600)
respectively is 97.368%, 151.974% and 200%, while the variation ratio of the a/b 28/40 (0,700); 45/40
(1,125) dan 73/40 (1,825) respectively is 151.316%, 165.789% and 192.105%. The increase in the
modulus of elasticity of concrete for the variation ratio of a/b 0/90 (0.444), 40/47 (0.851), and 40/25
(1.600) respectively is 5.221%, 59.836% and 132.651%, while the variation ratio of a/b 28/40 (0,700);
45/40 (1,125) dan 73/40 (1,825) respectively is 80.511%, 19.829% and 2.632%. In the ring width (a)
constant, maximum concrete strain occurrs in the a/b ratio = 40/25 = 1.6% with an increase of
1020.272%, while the distance between the ring (b) constant, maximum concrete strain occurs at the a/b
ratio = 73/40 = 1.825% with an increase of 1178.029%.
The Improvement of Reinforced Concrete Column Capacity with External Confinement
Keywords: column, compressive strength, external confinement, modulus of elasticity, steel rings, strain
Safitri, Endah; Mediyanto, Antonius
Fakultas Teknik UNS, Penelitian, BOPTN UNS, Hibah Bersaing, 2012
Geographical condition of Indonesia is located right above the tectonic plates (the Indo- Australian,
Eurasian, and Pacific), crossed by two seismic lines (Circum Pacific and Trana Asiatic Earthquake Belts),
and traversed paths Ring of Fire Java / Sunda Trench, that has become one of the countries with the risk
of a large earthquake. Earthquake mitigation are steps that have to be taken to reduce loss of life and
property, by design of earthquakeresistant structures that have high ductility. One of the way to improve
the ductility is the restraint of reinforced concrete elements. The collapse of the structural column is very
significant in terms of economic and human safety, therefore it is necessary to design the bottom of the
column design to achieve high ductility.
This study aims to determine the effect of the use of ring of steel as external confinement on the
compressive strength, modulus of elasticity and strain of concrete and steel ring. If a is the width of the
steel ring and b is the distance between the rings, then with a variety of ratios a / b on a wide range of
constant and b is a constant, it will get the optimum value of the ratio a/b. Specimens are concrete
cylinders with 30 cm high and 15 cm diameter. At the constant a of 40 cm used a variation b of 90, 47,
and 25 cm with ratio of a/b is 0.444; 0.857 and 1.6 respectively. In the constant b of 40 cm used a
variation of 73, 45, and 28 cm with ratio of a/b is 1.833; 1.125 and 0.7 respectively.
The larger ratio of a/b get the higher compressive strength of concrete. The increase in compressive
strength of concrete for the variation ratio of a/b 40/90 (0.444), 40/47 (0.851), and 40/25 (1.600)
respectively is 97.368%, 151.974% and 200%, while the variation ratio of the a/b 28/40 (0,700); 45/40
(1,125) dan 73/40 (1,825) respectively is 151.316%, 165.789% and 192.105%. The increase in the
modulus of elasticity of concrete for the variation ratio of a/b 0/90 (0.444), 40/47 (0.851), and 40/25
(1.600) respectively is 5.221%, 59.836% and 132.651%, while the variation ratio of a/b 28/40 (0,700);
45/40 (1,125) dan 73/40 (1,825) respectively is 80.511%, 19.829% and 2.632%. In the ring width (a)
constant, maximum concrete strain occurrs in the a/b ratio = 40/25 = 1.6% with an increase of
1020.272%, while the distance between the ring (b) constant, maximum concrete strain occurs at the a/b
ratio = 73/40 = 1.825% with an increase of 1178.029%.