Experimental characterization of pier caps for light-rail aerial structures.

摘要

The results of the instrumentation and year-long study of distressed areas of pier caps from aerial structures are presented. These aerial structures support dual tracks for a light-rail transportation system. The pier caps are cast-in-place reinforced concrete. They support pre-cast, prestressed girders. Both, Texas Department of Transportation U54B U-beams, and American Association of State Highway and Transportation Officials Type IV I-beams are used. The distressed areas are vertical and inclined cracks across the tops and faces of the pier caps. The objectives of the research are to characterize the behavior of the pier caps and make recommendations for repair and further study. Instrumentation was completed with strain, crack propagation, and crack detection gages. Measurements were made of static and dynamic conditions. Pier-cap surface temperatures were monitored with negative temperature coefficient thermisters.