Title:
Confinement Model for Concrete Columns Reinforced with GFRP Spirals
Author(s):
Priyank P. Sankholkar and Chris P. Pantelides
Publication:
Symposium Paper
Volume:
327
Issue:
Appears on pages(s):
8.1-8.18
Keywords:
Axial load; Axial Strain; Compressive strength; Confinement model; Concrete column; Ductility; Fiber reinforced polymer; Glass fibers; Hoop Strain; Spiral
DOI:
10.14359/51713328
Date:
11/1/2018
Abstract:
Confinement of concrete using glass fiber reinforced polymer (GFRP) spirals was evaluated using small-scale concrete cylindrical specimens with a 254 mm (10 in.) diameter and 762 mm (30 in.) height under concentric axial compression. The contribution of longitudinal GFRP bars to confinement was excluded by using wood dowels as longitudinal reinforcement to maintain a constant spiral pitch. Thus, concrete confinement was provided exclusively by the GFRP spiral. An ultimate hoop strain of 1.0 to 1.5% was achieved for the GFRP spirals of well-confined small-scale concrete specimens. Expressions were developed for the confined compressive strength and ultimate axial compressive strain of concrete confined with GFRP spirals. The resulting confinement model is compared to axial column tests of reinforced concrete columns with GFRP spirals and GFRP longitudinal bars from the present study and the literature. This research investigates confinement of concrete obtained purely due to GFRP spirals. The contribution of the vertical reinforcement to confinement was avoided by using wooden dowels which did not provide appreciable strength under compression. In addition, this research investigates the ultimate tensile hoop strain of GFRP spirals. The equation derived for the confinement of concrete and axial strain of confined concrete can be used for design; additional research should be carried out for columns with a larger diameter and greater height than the columns used in this research.
Related References:
ACI (American Concrete Institute). (2014). “Building Code Requirements for Structural Concrete and Commentary.” ACI Committee 318-14 Farmington Hills, MI.
ACI (American Concrete Institute). (2012). “Guide test methods for fiber-reinforced polymers (FRPs) for reinforcing or strengthening concrete structures.” ACI Committee 440.3R-12 Farmington Hills, MI.
ACI (American Concrete Institute). (2008). “Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures.” ACI Committee 440.2R-08 Farmington Hills, MI.
ASTM (American Society for Testing Materials) (2005). “Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens.” ASTM C39, ASTM International, West Conshohocken, PA.
ASTM (American Society for Testing Materials) (2016). “Standard Test Method for Tensile Properties of Fiber Reinforced Polymer Matrix Composite Bars.” ASTM D7205, ASTM International, West Conshohocken, PA.
Afifi, M., Mohamed, H., and Benmokrane, B. (2013a). “Strength and axial behavior of circular concrete columns reinforced with CFRP bars and spirals.” J. Compos. Constr., 04013035 doi: 10.1061/(ASCE)CC.1943-5614.0000430
Afifi, M., Mohamed, H., and Benmokrane, B. (2013b). “Axial capacity of circular concrete columns reinforced with GFRP bars and spirals.” J. Compos. Constr., 04013017. doi: 10.1061/(ASCE)CC.1943-5614.0000438
Afifi, M., Mohamed, H., Chaallal, O., and Benmokrane, B. (2014). “Confinement model for concrete columns internally confined with carbon FRP spirals and hoops.” J. Struct. Eng., 04014219. doi: 10.1061/(ASCE)ST.1943-541X.0001197
Afifi, M.Z., Mohamed H.M., Benmokrane B. (2015). “Theoretical stress–strain model for circular concrete columns confined by GFRP spirals and hoops.” Engineering Structures, 102, 202-213.
Canadian Standards Association (CSA). (2012). Design and construction of building components with fiber reinforced polymers, CAN/CSAS806-12, Rexdale, ON, Canada.
De Luca, A., Matta, F., and Nanni, A. (2010). “Behavior of full-scale glass fiber-reinforced polymer reinforced concrete columns under axial load.” ACI Struct. J., 107(5), 589-596.
De Luca, A., Nardone, F., Matta, F., Nanni, A., Lignola, G. P., and Prota, A. (2011). “Structural evaluation of full-scale FRP-confined reinforced concrete columns.” J. Compos. Constr., 112–123. doi: 10.1061/(ASCE)CC.1943-5614.0000152
Hadi, M.N.S.. Karim, H., and Sheikh, M.N. (2016). “Experimental investigations on circular concrete columns reinforced with GFRP bars and helices under different loading conditions.” J. Compos. Construction, 1-12. doi: 10.1061/(ASCE)CC.1943-5614.0000670
Hales, T.A., Pantelides, C.P., and Reaveley, L.D. (2016). “Experimental evaluation of slender high-strength concrete columns with GFRP and hybrid reinforcement.”
J. Compos. Constr., 04016050. doi: 10.1061/(ASCE)CC.1943-5614.0000709
Karim, H., Sheikh, M.N., and Hadi, M.N.S (2016). “Axial load-axial deformation behaviour of circular concrete columns reinforced with GFRP bars and helices.” Constr. Build. Mater., 112, 1147-1157.
Lam, L., and Teng, J.G. (2003). “Design-oriented stress-strain model for FRP-confined concrete.” Constr. Build. Mater., 17(6-7), 471-489.
Mander J. B., Priestley, J. N., and Park R. (1988). “Theoretical stress-strain model for confined concrete.” J. Struct. Eng., 114(8), 1804–1826.
Mohamed, H., Afifi, M., and Benmokrane, B. (2014). “Performance evaluation of concrete columns reinforced longitudinally with FRP bars and confined with FRP hoops and spirals under axial load.” J. Bridge Eng., 04014020. doi: 10.1061/(ASCE)BE.1943-5592.0000590
Maranan, G.B., Manalo, A.C., Benmokrane, B., Karunasena, W., and Mendis, P. (2016). “Behavior of concentrically loaded geopolymer-concrete circular columns reinforced longitudinally and transversely with GFRP bars.” Eng. Structures, 117, 422-436.
Pantelides, C.P., Gibbons, M.E., and Reaveley, L.D. (2013). “Axial load behavior of concrete columns confined with GFRP spirals." J. Compos. Constr., 305-313. doi: 10.1061/(ASCE)CC.1943-5614.0000357
Tobbi, H., Farghaly, A.S., and Benmokrane, B. (2012). “Concrete columns reinforced longitudinally and transversely with glass fiber-reinforced polymer bars.” ACI Struct. J., 109(4), 551-558.