Characterization of Steel Wire– and Carbon/Glass Hybrid Fiber–Reinforced Polymer Bars in Compression

Abstract

This paper reports on the compressive properties of a new steel wire– and carbon/glass hybrid fiber–reinforced polymer (S-CG HFRP) bar. The influence of the carbon and glass fiber volume proportion (Vc/Vg), steel wire replacement ratio (Vs), fiber volume ratio (Vf), fiber arrangement, and ratio of the unbraced length to the bar diameter (Lu/d) on the compressive behavior of the S-CG HFRP bars was experimentally investigated. The failure mechanisms were analyzed, revealing that the failure mode changed from fiber microbuckling to fiber macrobuckling with an increase in Lu/d. Adding steel wires resulted in a decrease in the compressive modulus of the S-CG HFRP bars. The compressive strength of the S-CG HFRP bars was not effectively improved by adding steel wires or carbon fibers and was governed by the Lu/d ratio. The results showed that the compressive modulus and strength of the S-CG HFRP bars were approximately 90% and 28% of their tensile modulus and strength, respectively. Finally, the relationship between the compressive and tensile properties of the S-CG HFRP bars was established. Simplified empirical equations were proposed to estimate the compressive strengths of S-CG HFRP bars with different Lu/d ratios.