Bond Behavior of 0.6-Inch Diameter Prestressing Strand at Two-Inch Grid Spacing in Fully Bonded High Strength and Normal Strength Composite Texas Type C Beams

This study examines the bond behavior of 1.524-cm (0.6-inch) diameter prestressing strands in fully bonded pretensioned prestressed concrete beams with high strength and normal strength concrete. The test beams were Texas Type C I-shaped sections with a complete deck added. Transfer lengths and development lengths were obtained for two beams (four ends) for each of the concrete strengths. The end slip for the fully bonded strands was measured for each beam at transfer (at the prestressing plant) and at testing (at Ferguson Structural Engineering Laboratory).

The study showed that bond behavior was excellent for all of the beams. The transfer and development lengths were short (less than AASHTO evaluations would predict) and no splitting occurred in the beam ends for any of the beams. End slip comparisons showed that the transfer end slips were very small (0.19 cm; 0.074-inch maximum) for all beams. The development length tests to flexural failure show that no general slip occurred and bond was not a problem for any of the beams. This development length was 183 cm (72 inches, less than AASHTO equation predicts), also indicating excellent bond behavior for 1.524 cm (0.6-inch) strand at 5.08 cm (2-inch) spacing.