Title: Pullout Tests on High Strength Reinforcing Bars

Author(s): Phil M. Ferguson, John E. Breen, and J. Neils Thompson

Publication: Journal Proceedings

Volume: 62

Issue: 8

Appears on pages(s): 933-950

Keywords: bond strength, cracking, development length, high strength steel, pullout test, reinforced research

DOI: 10.14359/7730

Date: 8/1/1965

Abstract:
Pullout tests using unsymmetrical specimens with spirals around the bars are reported on # 14s and # 18s bars in comparison with # 7 bars, all of ASTM A431 steel. The longer specimens developed high steel and bond stresses even though loaded end slip was large. Loaded end slip varied approximately in proportion to bar diameter but the length of embedment had little influence on the f, developed at a loaded end slip of 0.010 in. Rather than consider crack width as twice this loaded end slip, direct observations on beams are recommended OS more reliable. Unloaded end slip was not significant except in top cast bars. These top bars slipped at the unloaded end at relatively small loads, even before splitting started in some cases.