Instrumentation Systems for Field Study of Segmental Box Girder Bridges

This report is the fust in a series reporting the field study of several spans of the San Antonio "Y" Project. The San Antonio "Y" Project is a major urban viaduct comprising segmental concrete box girders post-tensioned with amix ofimemal and external tendons and erected using span-by-span techniques.

This report describes the development ofthe instrumentation systems which were installed in the field project. The major systems were:
1. External post-tensioning tendon forces,
2. Span deflections and segment deformations,
3. Concrete temperatures,
4. Concrete strains,
5. Reinforcing steel strains,
6. Joint openings,
7. Bearing movements, and
8. Solar radiation.

A comprehensive literature review ofeach system was performed and the mostpromising systems were tested in the laboratory and in the field. Recommendations on the best system for each type ofmeasurement were made, and the systems were installed in four spans ofthe San Antonio "Y" Project. Also in this report the performance ofeach system in the field is evaluated and recommendations for future field studies are presented.