Performance Comparison of Hooked Plain and Deformed Bars in Concrete

• Published in: ACI structural journal Vol. 118; no. 5; pp. 91 - 99
• Main Authors: Vors, Bjorn E, Feldman, Lisa R
• Format: Journal Article
• Language: English
• Published: Farmington Hills American Concrete Institute 01.09.2021
• Subjects: Bars; Bars (Engineering); Beam-columns; Bearing capacity; Concrete construction; Dynamic testing; Failure modes; Geometry; Materials; Mechanical properties; Reinforced concrete; Testing; Yield stress; Canada
• ISSN: 0889-3241; 0889-3241; 1944-7361
• DOI: 10.14359/51732864

Ninety-and 180-degree hooked plain and deformed bars were tested in beam-column specimens. Six replicate specimens were tested for each bar type and bend angle to evaluate whether differences in the reported quantitative results were statistically significant. Statistically significant differences were identified in the maximum normalized tensile resistance between 90-degree hooked plain and deformed bars, 180-degree hooked plain and deformed bars, and 90-and 180-degree hooked deformed bars. Side and front face blowout were visually identified as the primary failure modes for specimens containing 90-and 180-degree hooked bars, respectively, with tail kickout noted as a secondary failure mode in select specimens containing 90-degree hooked bars. The influence of bearing capacity of concrete in advance of the bend region resulted in no statistically significant differences between displacements of the hooked bars at the maximum tensile resistance for the range of concrete strengths investigated in this study. Keywords: anchorage; beam-column joint specimen; bond and development; deformed reinforcement; hooks; plain reinforcement; reinforced concrete.