Making a Case for Hybrid GFRP-Steel Reinforcement System in Concrete Beams: An Overview

Abstract

Ageing concrete infrastructures are known to be facing deterioration, especially regarding the corrosion of their reinforcing steel. As a solution, glass fibre-reinforced plastic (GFRP) bars are now considered a reinforcement alternative to conventional steel, and design codes now exist for designing GFRP-RC structures. However, there is a need to improve on addressing the limited plastic yield in GFRPs. Consequently, it is suggested that a hybrid steel–GFRP RC system can enhance the mechanical performance of flexure beams up to the required standard and, at the same time, address the durability concerns of steel-only RC beams. This overview presents the studies conducted to enhance the performance of hybrid GFRP–steel RC beams by reviewing the analytical models proposed to improve the various aspects of reinforcement design. The models consider mechanical effects such as ductility, crack width, flexure and shear, and the physical effects such as thermal stability when exposed to the temperature. Though the evidence reviewed supports the viability of the hybrid GFRP–steel reinforcing system to address ductility, much is still required in the area of research, as highlighted in the future outlook.

On the Factors That Determine the Bond Behaviour of GFRP Bars to Concrete: An Experimental Investigation

“…However, the proposed measures are too complicated, impractical or expensive to apply to existing structures. The construction industry, therefore, requires new solutions that are easy to adopt into construction practice and are not prohibitively expensive [12].…”

“…Recognising these limitations of steel in RCs, fibre-reinforced polymer (FRP) is attracting attention as a suitable replacement for steel [13][14][15]. Among the FRP variants, GFRP stands out with a high strength-weight ratio and is economically favourable [12,16] compared to carbon fibres, which are stronger but more expensive, and basalt fibres, which have better fire resistance but limited availability. Basalt-fibre-reinforced polymers (BFRP) also met the functional requirements as a potential replacement for steel, but the non-renewable geologic source rules it out as a sustainable replacement.…”

Global Resistance Methods for the Design of Fiber-Reinforced Concrete (FRC) Beams with Material Nonlinear Finite Element Analysis

“…Additionally, GFRP bars demonstrate a notable decline in their mechanical properties under relatively high temperatures [16,17], posing unique challenges in fire-prone environments. To enhance the ductility and overall performance of GFRP-reinforced beams, the concept of hybrid reinforcement, comprising steel and GFRP bars, has been proposed [18][19][20][21][22]. This innovative approach capitalizes the inherent strengths of both materials, striking a balance between corrosion resistance and ductile behavior, thus elevating the reliability of structural elements.…”

Special Issue “Reinforced Concrete: Materials, Physical Properties and Applications Volume II”

“…Reference [8] also addressed the issue of reinforcing steel in terms of corrosion. It is known that aging concrete infrastructure is susceptible to destruction primarily for this reason.…”