2019 CSCE Annual Conference - Laval (Greater Montreal)

2019 CSCE Annual Conference - Laval (Greater Montreal) Conference

Long-Term Deflection of Reinforced Concrete Beams

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Mr. Ziad Elaghoury, Western University (Presenter)
Dr. Michael Bartlett, University of Western Ontario

This paper critically evaluates methods for computing long-term deflections due to creep and shrinkage described in the 4th Edition of the Cement Association of Canada Concrete Design Handbook. It also presents a mechanics-based approach for computing incremental deflections due to creep and shrinkage. The accuracy of both methods in predicting the total deflection of concrete beams under sustained loads is quantified by investigating test-to-predicted ratios. The method presented in the Concrete Design Handbook was found to be unconservative, with test-to-predicted ratios as large as 1.4, but can be improved by using more conservative creep coefficients and ultimate shrinkage strains. The mechanics-based method was found to yield accurate and slightly conservative test-to-predicted ratios of 0.82-0.92.