Influência da ancoragem na resistência à flexão de vigas reforçadas com mantas de PRFC

Abstract

PBuscando avaliar a influência da ancoragem na resistência à flexão de vigas reforçadas com mantas de Polímero Reforçado com Fibra de Carbono (PRFC), foram analisados os resultados experimentais de 126 ensaios presentes na literatura e de uma série inédita, ensaiada pelos autores, com 4 vigas de concreto armado. São avaliados os parâmetros que afetam o desempenho e a resistência das vigas, e discutidos os critérios de dimensionamento do fib Bulletin 14 (2001) e ACI 440-2R (2008). Observou-se que, mesmo com dispositivos auxiliares na ancoragem do PRFC, falhas prematuras são possíveis, e também que ambas as recomendações teóricas conduzem a estimativas a favor da segurança, porém excessivamente conservadoras nos casos onde a ancoragem da manta de PRFC é feita adequadamente.

Adhesion, strengthening and durability issues in the retrofitting of Reinforced Concrete (RC) beams using Carbon Fiber Reinforced Polymer (CFRP) – A Review

“…CFRP strengthening of beams The observed failure modes of concrete beams reinforced with CFRP sheets have been reported by Teng et al (2003) and further analyzed by Ferreira et al (2018). They reported three typical failure modes: (1) tensile failure of the CFRP when its tensile strength is lower than the applied load; (2) debonding of the reinforcement at the laminate-concrete interphase; and (3) a cohesive failure of the concrete and there is separation of the reinforcement together with a layer of concrete.…”

“…The second mode of failure is attributed to a lack of anchorage of reinforcement, excessive cracking of the beam or faults in the bonding. Again here, failure of the adhesive bond strength may be cause by normal stresses at the end of the CFRP strip, where a stress singularity is known to exist [Leung, 2001 The analysis of the strengthening of a concrete beam with a CFRP layer loaded in bending presented by Ferreira et al (2018) considered that the ratio of the reinforced beam framework is equivalent to the addition on the initial reinforcement ratio with the contribution from the reinforcement (see figure 3).…”

Influencia de variables experimentales en las propiedades mecánicas de los concretos reforzados con fibras de acero (SFRC) en experimentos de degradación por cloruros: revisión bibliográfica y análisis estadístico

“…Although reinforcing bars are still the most widely used for this purpose, the use of fibers has had a significant boom in recent decades, generating what is known as steel fiber reinforced concrete (SFRC). , the fibers improve the tensile properties of concrete, fatigue resistance, impact resistance, and toughness and help control cracking (Behbahani & Nematollahi, 2011;Kaur et al, (2012), Ferreira et al, 2018Zhang et al, 2020). SFRC is used, for example, in tunnel lining, highway construction, and buildings prone to earthquake damage (Berrocal, 2015;Marcos-Meson et al, 2019;Zhang et al, 2020).…”