Analysis of alternative ductile fiber-reinforced polymer reinforcing bar concepts

Abstract

Steel-reinforced concrete structural components are often associated with significant maintenance costs as a result of reinforcement corrosion. To mitigate this problem, fiberreinforced polymer (FRP) bars have been used in place of traditional steel reinforcement for some applications. The non-ductile response of typical FRP bars is a concern, however. To overcome this problem, hybrid ductile FRP (HDFRP) bars have been developed for use in concrete flexural members with resulting ductility indices similar to sections reinforced with steel. In this study, five different HDFRP bar concepts are analyzed and compared in terms of ductility, stiffness, and relative cost. Of primary interest is the effect that the number of materials used in bar construction has on performance. Reinforced concrete beam and bridge deck applications are considered for analysis. It was found that all HDFRP-reinforced flexural members considered could meet code-specified strength and ductility requirements for steelreinforced sections, although service load deflections were approximately twice that of steelreinforced sections of the same depth. In general, ductility increased, and overall material cost decreased, as the bar material layers increased from 2 to 4. The 4-material continuous fiber bar approach was found to be most promising, with high ductility as well as relatively low cost.

Flexural performance of hybrid GFRP-Steel reinforced concrete continuous beams

“…Therefore, there is a need for a new method of construction to avoid such problems; that is durable, cost effective, and exhibits some ductility. A number of methods have been suggested to improve ductility, including hybridization of different types of fibrous material [5][6][7][8] and combining steel reinforcement with composite materials to make a rebar with an inner steel and an outer FRP [9][10][11][12][13]. These attempts were not practical to be implemented in the construction industry due to the high cost and complexity of manufacturing process.…”

Flexural behaviour of hybrid (FRP/steel) reinforced concrete beams: a review

“…To imitate steel's bilinear stress-strain conduct, an alternative technique for enhancing the suppleness of FRP-RC constructions is to employ a composite composed of various fibre types. More of scholarly studies [66][67][68][69] have been done to explore the characteristics and performance of these bars. Harris et al [66] investigated hybrid FRP reinforcing bars formed of Aramid braiding around a core of carbon fibres in their investigation.…”

“…However, it is worth noting that the hybrids possessed only half the modulus of elasticity when compared to steel bars. In order to ascertain the optimal hybrid polymer bar, a series of experiments were conducted by Behnam and Eamon [69] wherein five distinct versions were investigated. The researchers conducted an assessment on the rigidity and malleability of the bars and determined that steel-reinforced sections including hybrid fibre bars as flexural elements exhibited satisfactory levels of both strength and ductility [69].…”

Justification of the Rationality of Use of Composite Reinforcement in Low-Rise Construction

“…Гибридные армирующие стержни имеют различный состав: включают как непрерывные армирующие волокна, так и рубленое волокно с полимерной матрицей; имеют сердечник из стали или стеклопластика; включают углеродные, стеклянные и/или арамидные волокна. Показано, что сокращению затрат на производство стержня в сочетании с коррозионной стойкостью и устойчивостью к динамическим нагрузкам способствует конструкция со стальным сердечником (8 мм), с оплеткой из непрерывных арамидных и стеклянных волокон, с рубленым углеволокном в полимерной матрице, что позволяет использовать преимущества всех материалов в работе арматуры [11]. Для повышения прочности связи волокнистой компоненты с матрицей применяют различные способы модификации [12], в том числе плазменную активацию для лучшей адгезии высокопрочных волокон к смоле [13].…”