Title: Investigation of the Parameters Influencing Bond Cracking

Author(s): E. L. Kemp and W. J. Wilhelm

Publication: Journal Proceedings

Volume: 76

Issue: 1

Appears on pages(s): 47-72

Keywords: beams (supports); bond (concrete to reinforcement); bond stress; cracking (fracturing);deformed reinforcement; dowels; embedment; reinforced concrete; reinforcing steels; shear properties; structural design; tensile stress.

DOI: 10.14359/6936

Date: 1/1/1979

Abstract:
The advent of large high tensile reinforcing bars has caused concern among engineers and stimulated research into the nature of bond and particularly the problem of longitudinal bond splitting. This recent research indicates that bond splitting is a complicated phenomenon involving interactions with shear and flexure and in-fluenced by cover, bar spacing, number of bars, specimen width, dowel forces, and other secondary effects. An extensive program has been carried out at West Virginia University to study, systematically, the various parameters influencing bond behavior in an effort to develop new design criteria at both the ultimate strength and working load stages. The paper is concerned with the central problem of longitudinal bond splitting. This phenomenon is discussed in terms of the parameters studied at West Virginia University, namely, bar cover and spacing, the influence of stirrups, and the bond/shear ratio. Based upon the current status of the research, tentative design criteria are presented for both the cracking and ultimate load limit states.