There are many benefits associated with making simple-span precast concrete girders behave as continuous members. A simple connection to cause this behavior uses the longitudinal steel in the deck to resist the negative moment in the girders at the support. Any positive moment at the support caused by secondary effects (for example, creep, shrinkage, or thermal gradients) is resisted by either strand or bars extended from the ends of the girders and cast within a continuity diaphragm. This study compares the performance of two different connections used in the positive-moment region of full-depth, 5-in.- deep (1140 mm) precast concrete bulb-tee (PCBT) girders. The two connections use extended, 1�?2-in.- diameter (12.7 mm) prestressing strands bent at 90 degrees and extended No. 6 (19M) reinforcing bars bent at 180 degrees, which were cast into a continuity diaphragm. A conventionally reinforced concrete deck was applied to the tops of the girders. Both two-span systems were tested to determine their initial positive cracking moments, the integrity of the connections under cyclic loads, and their ultimate positive moment capacities. When subjected to similar loading conditions, he connection made with the mild reinforcing bars performed better than that made with prestressing strand.
