Page 13 - Open-Access-May-2020

TECHNICAL PAPER

Each of Figures 10a to 10c compares the curves for specimens REFERENCES
with HSSCC and NSSCC jackets, for a particular percentage of
1. Bett, B. j., Klingner, R. E., and jirsa, j.O. (1988). “Lateral
jacket longitudinal reinforcement. It was found that the ultimate
load and the corresponding deflection increased by 48% and load response of strengthened and repaired reinforced
concrete columns”. ACI Structural Journal, 85(5), 499-508.
73%, respectively, even for the lowest amount of additional steel
of 0.38%. The initial stiffness for HSSCC and NSSCC specimens 2. Ersoy, U., Tankut, A. T., and Suleiman, R. (1993). “Behaviour
of jacketed columns”. ACI Structural Journal, 90(3), 288-
with a certain amount of steel was found to remain almost same,
because of the thin jackets. 293.
3. Rodriguez, M., and Park, R. (1994). “Seismic load tests on
reinforced concrete columns strengthened by jacketing”.
8. SUMMARY AND CONCLUSIONS
ACI Structural Journal, 91(2), 150-159.
The application of HSC as a jacket material to strengthen shear- 4. Fukuyama, K., Higashibata, Y., and Miyauchi, Y. (2000).
critical RC columns was examined in the present research. Two “Studies on repair and strengthening methods of
selected strengths of SCC equal to 69.1 MPa (high-strength) damaged reinforced concrete columns”. Cement and
and 43.7 MPa (normal-strength) were used to jacket 12 beam- Concrete Composites, 22(1), 81-88.
column specimens of shear span-to-effective depth ratio equal 5. Bousias, S. N., Spathis, A. L., and Fardis, M. N. (2007).
to 1.7. They had three different amounts of jacket longitudinal “Seismic retrofitting of columns with lap spliced smooth
tension reinforcement, 0.38%, 1.54% and 3.83%. There were no bars through FRP or concrete jackets”. Journal of
ties in the test regions to avoid their influence in shear capacity. Earthquake Engineering, 11(5), 653-674.
The details of materials used, specimen preparation, conducted 6. Vandoros, K. G., and Dritsos, S. E. (2008). “Concrete jacket
tests and test results are discussed in this paper. The salient construction detail effectiveness when strengthening RC
observations from the conducted tests and conclusions from the columns”. Construction and Building Materials, 22(3), 264-
study are as follows. 276.
7. Kaliyaperumal, G., and Sengupta, A. K. (2009). “Seismic
(a) Under single point lateral loading, the failure of all the
specimens were due to diagonal cracking of the jacket concrete retrofit of columns in buildings for flexure using concrete
jacket”. ISET Journal of Earthquake Technology, 46(2), 77-
as well as the inner concrete. This was as per the deliberate 107.
choice of designing the specimens for shear failure.
8. Kaliyaperumal, G., and Sengupta, A. K. (2014). “Seismic
(b) The use of HSSCC in the jacket indeed increased the shear behaviour of concrete jacketed columns in buildings”.
capacity of the retrofitted specimens substantially, based on the Proceedings of the Institution of Civil Engineers, 167(SB9),
increased diagonal cracking strength of the added concrete. 534-543.
There was no delamination of the jacket made of HSSCC under 9. Cheong, H. K., and MacAlevey, N. (2000). “Experimental
the static monotonic loads. For a member with ties, the diagonal behaviour of jacketed reinforced concrete beams”. Journal
compressive strength of the added concrete will be more with of Structural Engineering, 126(6), 692-699.
the use of HSSCC. 10. Altun, F. (2004). “An experimental study of the jacketed
reinforced-concrete beams under bending”. Construction
(c) The lateral load versus mid-span deflection behaviour and Building Materials, 18(8), 611-618.
curves of the specimens with two types of concrete revealed
that for shear-critical specimens, the stiffness of both the types 11. Chalioris, C. E., Papadopoulos, C. P., Pourzitidis, C. N.,
Fotis, D., and Sideris, K. K. (2013). “Application of a
remained almost the same. Hence, the use of HSSCC in thin reinforced self-compacting concrete jacket in damaged
jackets is not detrimental in attracting higher shear demand as reinforced concrete beams under monotonic and repeated
compared to the use of NSSCC. loading”. Journal of Engineering, Vol. 2013, Article ID
912983.
(d) The post-yield ductility of the jacketed specimens was
not evident in absence of the ties in the test regions. Other 12. Raval, S. S., and Dave, U. V. (2013). “Effectiveness of
various methods of jacketing for RC beams”. Procedia
specimens tested with ties showed limited ductility even under
shear failure [19] . Engineering, 51, 230-239.
13. Takiuti, A. R., Hanai, j. B., and Mirmiran, A. (2008).
The study can be further extended to test specimens under “Preloaded RC columns strengthened with high-strength
reversed cyclic loading using displacement controlled actuators, concrete jackets under uniaxial compression”. Materials
to investigate the degradation of strength for jackets with HSC. and Structures, 41(7), 1251-1262.

14 The IndIan ConCreTe Journal | MaY 2020