Development Length of 0.6-Inch Prestressing Strand in Standard I-Shaped Pretensioned Concrete Beams.

摘要

The use of 0.6 in prestressing strand at a center-o-center spacing of 2 in allows for the optimal implementation of High Strength Concrete (HSC) in precast, prestressed concrete bridge superstructures. For this strand configuration, partial debonding of strands is a desirable alternative to the traditional method of draping to alleviate extreme concrete stresses after prestress release. Experimental evidence suggests that existing code provisions addressing the anchorage of pretensioned strands do not adequately describe their behavior. In addition, the anchorage behavior of partially debonded strands is not fully understood. Results are reported from a research study to determine the anchorage behavior of 0.6 in strands at 2 in spacing in full-size, plant-cast AASHTO Type I I-beams. The use of pull-out capacities and strand draw-in measurements to predict the anchorage behavior of prestressing strands was also examined. Along with recommended design procedures for anchorage of prestressing strand, a review of the evolution and shortcomings of existing code provisions is presented.