Deviation Saddle Behavior and Design for Externally Post-Tensioned Bridges

R. J. Beaupre, L. C. Powell, J. E. Breen, and M. E. Kreger


This report is the second in a series outlining a major study of the behavior of post-tensioned concrete box girder bridges with post-tensioning tendons external to the concrete section. It presents the results of an experimental program in which ten very accurately sealed reinforced concrete models of typical tendon deviators were tested. Detailed instrumentation led to a very good understanding of the behavior of the various patterns of reinforcement in the deviators. The models included two very different patterns of detailing, several arrangements of tendon inclinations, and both normal and epoxy-coated reinforcement.

The report evaluates the results with respect to both simplified conventional analysis methods and strut-and-tie models. The results provide the basis for deviator design recommendations and several examples are presented to illustrate the practical use of these recommendations.

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