Bond Strength of Grade 100 Reinforcing Steel

Abstract

The bond strength of Grade 100 ASTM A 1035 reinforcing steel manufactured by MMFX Technologies Corp. is evaluated with respect to bond strength equations found in ACI 318-05 and ACI 408R-03. Test specimens are fullscale beam-splice specimens tested in four-point bending to create a constant moment region over the length of the splices. Specimens differed with regard to the level of confinement provided by transverse reinforcement, concrete cover and bar spacing, concrete compressive strength, and bar size. Sixty-nine specimens were tested at three universities - North Carolina State University, the University of Texas at Austin, and the University of Kansas - of which 64 failed in bond and are included in this report. The results indicate that the development length equation found in ACI 318- 05 is not suitable for the design of unconfined or confined splices without the use of a modification factor. The development length equation found in ACI 408R-03 is suitable for analysis purposes for both unconfined and confined splices.