1- Department of Civil Engineering, Faculty of Engineering, University of Shahahb Danesh
2- Assistant Professor, Department of Civil Engineering, Faculty of Engineering, Islamic Azad University of Malayer ,eng_mahdi2005@yahoo.com
3- Department of Civil Engineering, Faculty of Engineering, University of Qom
4- Department of Civil Engineering, Faculty of Engineering, University of Shahab Danesh
2- Assistant Professor, Department of Civil Engineering, Faculty of Engineering, Islamic Azad University of Malayer ,
3- Department of Civil Engineering, Faculty of Engineering, University of Qom
4- Department of Civil Engineering, Faculty of Engineering, University of Shahab Danesh
Abstract: (120 Views)
Bars with standard hooks in tension are often used to anchor reinforcing bars where concrete dimensions element are not sufficient to provide the required development length for straight reinforcement. In previous researches, concrete breakout failure was the predominant failure mode of hooked bars. Closely-spaced hooks provide a lower strength per hooked bar than more widely-spaced hooked bars because the area of the breakout surface is reduced for the more closely-spaced bars. The effects of fy of bars, spacing, and confinement by ties or stirrups have been updated to reflect test results, in 25.4.3.1 of ACI 318-19. In this formula, The confining reinforcement factor ψr is based on test results reported by Ajaam et al. (2018). Base on ACI 318-19 definition, Ath is total cross-sectional area of ties or stirrups confining hooked bars. Therefore crossties are not included in the relationship. The purpose of this study is to expand the understanding of the behavior of confinement effect of crossties on development length bars with 90 degree bent hooks in tension. In this study, 3 simulated beam-column joints were tested as a continuation of previous work by Ajaam et al. (2018). The results of this experimental study show that the ACI318-19 provisions underestimate the contribution of confinement by crossties on the development length bars with 90 degree bent hooks in tension.
Article Type: Original Research |
Subject:
Civil and Structural Engineering
Received: 2024/04/9 | Accepted: 2025/03/11
Received: 2024/04/9 | Accepted: 2025/03/11
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