Many studies on fiber reinforced polymer composite bars, as a substitute for reinforcing bars, have been conducted to solve corrosion of steel in reinforced concrete structures since 1960s’. However, FRP Bars have a lower elastic modulus than steel rebar as a structural component of concrete structures. Material properties with brittleness fracture and low elastic modulus can be improved by combining cheaper steel than carbon or aramid fibers. In this study, prototypes of FRP Bars with inserted steel wires (i.e., “FRP Hybrid Bars”) were developed and their tensile performance was compared depending on the proportion and diameter of steel. The FRP Hybrid Bars were made by dividing them into D13 and D16 according to the diameter and proportion of inserted wires: GFRPs were combined with wires having different diameters of 0.5 mm, 1.0 mm, and 2.0 mm in the proportion of 10%, 30%, 50%, and 70%, respectively. As a result of tensile tests, the elastic modulus of FRP Hybrid Bars were improved as 20% - 190% in comparison with the fully GFRP Bars.
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 Seo, D.W., Park, K.T., You, Y.J. and Kim, H.Y. (2013) Enhancement in Elastic Modulus of GFRP Bars by Material Hy-bridization. Engineering, 5, 865-869. http://dx.doi.org/10.4236/eng.2013.511105
 Korea Institute of Construction Technology (KICT) (2004) Design and Construction Technology for Concrete Structures Using Advanced Composite Materials: FRP Rebars and Grids (in Korean). Interim Report Submitted to the Korea Research Council of Public Science and Technology.
 ASTM. D 3916 (2002) Standard Test Method for Tensile Properties of Pultruded Glass-Fiber-Reinforced Plastic Rods. http://news.cnfrp.net/file_dir/2012-12/20121221100040.pdf