Behavior of Circularized Hollow RC Columns under Different Loading Conditions
Publication: Journal of Composites for Construction
Volume 21, Issue 5
Abstract
One of the methods for strengthening square concrete columns is shape modification. The method involves modification of the column cross section from square to circular by bonding concrete segments and then wrapping the column with fiber reinforced polymer (FRP). This paper investigates experimentally the applicability of the shape modification (circularization) for square hollow reinforced concrete (RC) specimens under different loading conditions. Five groups of four hollow RC specimens made from normal strength concrete were cast and tested. The specimens in the first group were RC hollow specimens, which served as reference specimens. The corners of the specimens in the second group were rounded to 20 mm and wrapped with two layers of carbon FRP (CFRP). The specimens in the third group were circularized and wrapped with two layers of CFRP. The specimens in the fourth group were bonded with one CFRP strap longitudinally on each side and then circularized and wrapped with two layers of CFRP. The specimens in the fifth group were wrapped with one layer of CFRP and then circularized and wrapped with two layers of CFRP. The results show that circularization increased the strength and ductility of the hollow specimen. Transverse wrapping with CFRP mainly improved the performance of the specimens under concentric axial loadings, while the longitudinal CFRP straps mainly improved the performance of the specimens under eccentric axial loading.
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Acknowledgments
The authors would like to acknowledge Mr. Richard Gasser and Mr. Ritchie McLean of the Structural Engineering Laboratory at the University of Wollongong for their help in testing the specimens. The second author acknowledges the Iraqi Government and the University of Wollongong for the support of his Ph.D. scholarship.
References
ACI (American Concrete Institute). (2011). “Building code requirements for structural concrete and commentary.”, Farmington Hills, MI.
Alsayed, S. H., Almusallam, T. H., Ibrahim, S. M., Al-Hazmi, N. M., Al-Salloum, Y. A., and Abbas, H. (2014). “Experimental and numerical investigation for compression response of CFRP strengthened shape modified wall-like RC column.” Constr. Build. Mater., 63, 72–80.
ASTM. (2010). “Standard test methods for determining tensile properties of fiber reinforced polymer matrix composites used for strengthening civil structures.” ASTM D7565:2010, West Conshohocken, PA.
Bisby, L., and Ranger, M. (2010). “Axial-flexural interaction in circular FRP-confined reinforced concrete columns.” Constr. Build. Mater., 24(9), 1672–1681.
Chaallal, O., and Shahawy, M. (2000). “Performance of fiber-reinforced polymer-wrapped reinforced concrete column under combined axial-flexural loading.” ACI Struct. J., 97(4), 659–668.
Colajanni, P., Fossetti, M., and MacAluso, G. (2014). “Effects of confinement level, cross-section shape and corner radius on the cyclic behavior of CFRCM confined concrete columns.” Constr. Build. Mater., 55, 379–389.
CSA (Canadian Standards Association). (2006). “Canadian highway bridge design code.”, Rexdale, ON, Canada.
Fam, A. Z., and Rizkalla, S. H. (2001). “Confinement model for axially loaded concrete confined by circular fiber-reinforced polymer tubes.” ACI Struct. J., 98(4), 451–461.
Faustino, P., Chastre, C., and Paula, R. (2014). “Design model for square RC columns under compression confined with CFRP.” Compos. Part B., 57, 187–198.
Fitzwilliam, J., and Bisby, L. A. (2010). “Slenderness effects on circular CFRP confined reinforced concrete columns.” J. Compos. Constr., 280–288.
Foster, S. J., and Attard, M. M. (1997). “Experimental tests on eccentrically loaded high-strength concrete columns.” ACI Struct. J., 94(3), 295–303.
Hadi, M. N., and Widiarsa, I. B. R. (2012). “Axial and flexural performance of square RC columns wrapped with CFRP under eccentric loading.” J. Compos. Constr., 640–649.
Hadi, M. N. S. (2006a). “Behaviour of FRP wrapped normal strength concrete columns under eccentric loading.” Compos. Struct., 72(4), 503–511.
Hadi, M. N. S. (2006b). “Comparative study of eccentrically loaded FRP wrapped columns.” Compos. Struct., 74(2), 127–135.
Hadi, M. N. S. (2007). “Behaviour of FRP strengthened concrete columns under eccentric compression loading.” Compos. Struct., 77(1), 92–96.
Hadi, M. N. S., and Le, T. D. (2014). “Behaviour of hollow core square reinforced concrete columns wrapped with CFRP with different fibre orientations.” Constr. Build. Mater., 50, 62–73.
Hadi, M. N. S., Pham, T. M., and Lei, X. (2013). “New method of strengthening reinforced concrete square columns by circularizing and wrapping with fiber-reinforced polymer or steel straps.” J. Compos. Constr., 229–238.
Harries, K. A., and Carey, S. A. (2003). “Shape and ‘gap’ effects on the behavior of variably confined concrete.” Cement and Concrete Research, 33(6), 881–890.
Kusumawardaningsih, Y., and Hadi, M. N. S. (2010). “Comparative behaviour of hollow columns confined with FRP composites.” Compos. Struct., 93(1), 198–205.
Lam, L., and Teng, J. G. (2003). “Design-oriented stress-strain model for FRP-confined concrete in rectangular columns.” J. Reinf. Plast. Compos., 22(13), 1149–1186.
Li, G., Maricherla, D., Singh, K., Pang, S.-S., and John, M. (2006). “Effect of fiber orientation on the structural behavior of FRP wrapped concrete cylinders.” Compos. Struct., 74(4), 475–483.
Li, J., and Hadi, M. N. S. (2003). “Behaviour of externally confined high-strength concrete columns under eccentric loading.” Compos. Struct., 62(2), 145–153.
Lignola, G. P., Prota, A., Manfredi, G., and Cosenza, E. (2008). “Unified theory for confinement of RC solid and hollow circular columns.” Compos. Part B, 39(7–8), 1151–1160.
Moran, D. A., and Pantelides, C. P. (2012). “Elliptical and circular FRP-confined concrete sections: A Mohr-Coulomb analytical model.” Int. J. Solids Struct., 49(6), 881–898.
Pantelides, C. P., and Yan, Z. (2007). “Confinement model of concrete with externally bonded FRP jackets or posttensioned FRP shells.” J. Struct. Eng., 1288–1296.
Pham, T. M., Doan, L. V., and Hadi, M. N. S. (2013). “Strengthening square reinforced concrete columns by circularisation and FRP confinement.” Constr. Build. Mater., 49, 490–499.
Priestley, M. J. N., and Seible, F. (1995). “Design of seismic retrofit measures for concrete and masonry structures.” Constr. Build. Mater., 9(6), 365–377.
Rochette, P., and Labossiere, P. (2000). “Axial testing of rectangular column models confined with composites.” J. Compos. Constr., 129–136.
Saadatmanesh, H., Ehsani, M., and Jin, L. (1997). “Seismic retrofitting of rectangular bridge columns with composite straps.” Earthquake Spectra, 13(2), 281–304.
SA (Standards Australia). (1999). “Methods of testing concrete.”, Sydney, NSW, Australia.
SA (Standards Australia). (2007). “Metallic materials—Tensile testing at ambient temperature.”, Sydney, NSW, Australia.
SA (Standards Australia). (2009). “Concrete structures.”, Sydney, NSW, Australia.
Sheikh, M. N., and Légeron, F. (2014). “Performance based seismic assessment of bridges designed according to Canadian Highway bridge design code.” Can. J. Civ. Eng., 41(9), 777–787.
Sheikh, M. N., Vivier, A., and Legeron, F. (2007). “Seismic assessment of hollow core concrete bridge piers.” Proc., 9th Canadian Conf. on Earthquake Engineering, Canadian Association for Earthquake Engineering, Ottawa, 1631–1640.
Silva, M. A. G. (2011). “Behavior of square and circular columns strengthened with aramidic or carbon fibers.” Constr. Build. Mater., 25(8), 3222–3228.
Tan, K. H. (2002). “Strength enhancement of rectangular reinforced concrete columns using fiber-reinforced polymer.” J. Compos. Constr., 175–183.
Taylor, A. W., Rowell, R. B., and Breen, J. E. (1995). “Behavior of thin-walled concrete box piers.” ACI Struct. J., 92(3), 319–333.
Yan, Z., and Pantelides, C. (2006). “Fiber-reinforced polymer jacketed and shape-modified compression members: I—Experimental behavior.” ACI Struct. J., 103(6), 226–234.
Yan, Z., and Pantelides, C. P. (2011). “Concrete column shape modification with FRP shells and expansive cement concrete.” Constr. Build. Mater., 25(1), 396–405.
Yazici, V., and Hadi, M. N. (2009). “Axial load-bending moment diagrams of carbon FRP wrapped hollow core reinforced concrete columns.” J. Compos. Constr., 262–268.
Yeh, Y. K., and Mo, Y. L. (2005). “Shear retrofit of hollow bridge piers with carbon fiber-reinforced polymer sheets.” J. Compos. Constr., 327–336.
Information & Authors
Information
Published In
Journal of Composites for Construction
Volume 21 • Issue 5 • October 2017
Copyright
©2017 American Society of Civil Engineers.
History
Received: Jul 7, 2016
Accepted: Dec 30, 2016
Published online: Mar 16, 2017
Discussion open until: Aug 16, 2017
Published in print: Oct 1, 2017
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