Title: Pullout Tests on High Strength Reinforcing Bars
Author(s): Phil M. Ferguson, John E. Breen, and J. Neils Thompson
Publication: Journal Proceedings
Appears on pages(s): 933-950
Keywords: bond strength, cracking, development length, high strength steel, pullout test, reinforced research
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.