Prepared by the Civil Engineeering Research Foundation.

This report describes the development and implications of a new concrete reinforcing bar with significantly improved bond strength. The increase in bond strength translates into a decrease in development and splice length, which in turn results in simplified connection details and an associated improvement in concrete placeability. Research demonstrated that increasing the relative rib height (the ratio between rib height and spacing) of the rebar from a typical level of 0.06–0.08 to a level of 0.12 can improve bond strength. As a result, the development length is reduced by 9–14% for confined reinforcement and 20% for all epoxy-coated reinforcement. In addition, it is expected that the reliability-based techniques used to develop the design expressions will result in more accurate design procedures.