Resolving Bond Challenges in Reinforced Concrete and Masonry Structures

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The existence of bond, otherwise described as strain compatibility between the reinforcement and the surrounding cementitious materials, is one of the fundamental assumptions used in the analysis of reinforced concrete and masonry members, and influences member ductility as well as shear and flexural response. An accurate assessment of bond is therefore necessary to ensure proper detailing of the reinforcement, and so the safety and economy of reinforced concrete and masonry structures. Though masonry is one of the oldest building materials, research in this area has been quite minimal. As a result, some aspects of design codes lack consistency and are not rationally-based. A case in point is that the requirements for the development and splicing of reinforcement, as provided by the U.S. masonry standard, are significantly more conservative than those provided by the Canadian standard, particularly for larger bar sizes. It is hypothesized that bringing the lessons learned from 100+ years of study of bond in reinforced concrete to masonry research will allow for a rationalization of these two sets of standards and a re-evaluation of code provisions. This will be based on a unique and comprehensive experimental program which will include the development of analytical relationships to verify the hypothesis of this study. Furthermore, recent bridge collapses and exposés on the state of the nation's infrastructure have highlighted the need for proper evaluation techniques for existing structures. Historical reinforced concrete structures may have been built with plain reinforcement, or deformed bars that do not conform to modern standards. It is hypothesized that the bond performance of these bars differs from that of modern deformed bars. Experimental and analytical work is required to reach the goal of improving evaluation techniques for practicing engineers. Three M.Sc. students and three Ph.D. students will participate in the proposed research. These students will be trained in an area that is strategically important to Canada's economy.