Measurement Based Revisions for Segmental Bridge Design and Construction Criteria

C. L. Roberts, J. E. Breen, and M. E. Kreger


This report is the second and final in a series reporting the field study of several spans of San Antonio "Y" project. San Antonio "Y" project is a major urban viaduct comprising segmental concrete box girders post-tensioned with a mix ofinternal and external tendons and erected using span-by-span techniques.

The instrumentation program targeted areas ofsegmental design and construction which are still uncertain due to lack oflaboratory and field data or are still debated by designers and constructors. The targeted areas of uncertainty were:
(1) Prestress losses in external tendons,
(2) Distribution ofstresses across flanges,
(3) Thermal gradients and their effects,
(4) Behavior ofsegmental joints,
(5) Heavy end diaphragm behavior,
(6) Deviator behavior,
(7) Behavior under construction and live loads, and
(8) Thermal gradients during match casting.Each topic is presented in an individual chapter which includes a literature review, a description ofthe instrumentation system, presentation ofthe results, analysis and comparison with current design methods, and recommendations for improvement ofcurrent design and construction criteria.

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