Title: Bond Performance of Reinforcing Bars Embedded in High-Strength Concrete

Author(s): Atorod Azizinamini, Mark Stark, John J. Roller, and S. K. Ghosh

Publication: Structural Journal

Volume: 90

Issue: 5

Appears on pages(s): 554-561

Keywords: bond stress; development length; high-strength concrete; reinforcing bars; splice length; Structural Research

DOI: 10.14359/3951

Date: 9/1/1993

Abstract:
Because of the lack of test data, ACI 318-89 building code requirements imposed an arbitrary upper limit of 10,000 psi (69 MPa) on specified compressive strength of concrete f c that may be used in calculating tension development length and tension splice length. A research study was conducted to evaluate the bond performance of reinforcing bars embedded in high-strength concrete. Twelve beam splice specimens using No. 11 reinforcing bars and concrete with compressive strengths exceeding 14,000 psi (97 MPa) were tested. The effect of several variables on bond capacity in high-strength concrete is discussed and a failure hypothesis explaining the observed behavior during the experimental phase of the study is presented. Additionally, it is concluded that the current trend in ACI of making the splice length longer to compensate for having small cover and spacing may not be an effective approach. A better approach could be to provide a minimum amount of transverse reinforcement.