Development length on concrete with bundle bars

• Published in: IOP conference series. Materials Science and Engineering 2018-11, Vol.434 (1), p.12197
• Main Author: Walujodjati, E
• Format: Article
• Language: English
• Subjects: Bars; Bond stress; Bonding strength; Concrete; Concrete structures; Design factors; Pull out tests; Reinforced concrete
• ISSN: 1757-8981; 1757-899X; 1757-899X
• DOI: 10.1088/1757-899X/434/1/012197

The Development Length is an essential factor in the design of reinforced concrete structures. On the other hand, reinforced concrete allows the existence of bundle bars as one of the solutions in overcoming dimensional limitations. However, the use of bundle bars causes some of the reinforcing surfaces not to be covered with concrete, resulting in bond strength between the reinforcement and the concrete will reduce. So, it is necessary to research how far the development length on the concrete with bundle bars, can achieve the desired performance. The methodology used with Pull Out on concrete cylindrical test objects with bundle bars and single bar. Variations in the development length are given to 100 mm, 125 mm, and 150 mm. Gradual loading until a break occurs. Pull Out test results indicate a caesarean movement from the loaded end to the free end. The variation in the development length given appears to affect the greater load tensile requirements of the bundle bars compared with the single bar. This can be seen from the amount of bond stress generated which tends to decrease with increasing length of the development length.