Flexural design of GFRP bar reinforced concrete beams: An appraisal of code recommendations

Comportamento de vigas de concreto armadas com barras de GFRP

“…Por outro lado, um grande aumento na taxa das barras de FRP aumenta ligeiramente o momento resistente das vigas de concreto superarmadas com barras de FRP, mas reduz bastante sua flecha após a formação da primeira fissura. Saleh et al (2019) ensaiaram oito vigas de concreto armadas com barras de GFRP de seção retangular e de 100 mm x 150 mm x 2400 mm de dimensões, nas quais se variaram a taxa da armadura longitudinal (0,5%, 1,0% e 2,0%) e a resistência do concreto à compressão (47 MPa ou 66 MPa). Observou-se que as vigas dimensionadas como superarmadas, conforme o guia ACI 440.…”

“…Ainda segundo Saleh et al (2019), as recomendações de projeto sobre vigas de concreto armadas com barras de GFRP inseridas no guia ACI 440. 1R-15 (2015) e na norma CAN/CSA-S806-12 (2012) conduziram a valores conservadores em termos de carga de ruptura e flechas no meio do vão na ruptura das vigas superarmadas, embora superestimaram estes valores para as vigas subarmadas e balanceadas.…”

Fracture monitoring of steel and GFRP reinforced concrete beams using acoustic emission and digital image correlation techniques

“…GFRP-RC beams have been reported to exhibit higher load-carrying capacity, higher crack width, and deflections as compared to steel-RC beams. [16][17][18][19][20] Due to the relatively lower modulus of elasticity of GFRP bars as compared to steel, GFRP reinforced beams exhibit linear-elastic behavior up to failure, unlike steel-RC beams which undergo noticeable yielding before failure. [16][17][18] Due to lack of ductility, the margin of safety factor for the design of GFRP-RC flexural member is much higher than that for steel-RC flexural members.…”

“…[16][17][18] Due to lack of ductility, the margin of safety factor for the design of GFRP-RC flexural member is much higher than that for steel-RC flexural members. 19,20 Therefore, to avoid catastrophic failure in the form of rupturing of GFRP reinforcement, it is recommended to design GFRP-RC beams as over-reinforced to facilitate failure by concrete crushing. 14,15 Due to the brittle mode of failure in GFRP reinforced structures, it is essential to have effective means to evaluate the integrity of GFRP reinforced structural members using appropriate non-destructive tools which can give an early and prior indication of damage initiation much before it is visible to the naked eye.…”

“…Various researchers have compared the performance of GFRP‐RC beams with steel‐RC beams. GFRP‐RC beams have been reported to exhibit higher load‐carrying capacity, higher crack width, and deflections as compared to steel‐RC beams 16–20 . Due to the relatively lower modulus of elasticity of GFRP bars as compared to steel, GFRP reinforced beams exhibit linear‐elastic behavior up to failure, unlike steel‐RC beams which undergo noticeable yielding before failure 16–18 .…”