Bridge decks supported by adjacent precast, prestressed concrete beams have become increasingly popular in recent years due to their ease of construction, shallow superstructure, and aesthetic appeal. In New York State prior to 1992, such structures were built by placing a number of precast beams alongside one another and connecting them through 12 in. (0.305 m) deep grouted keyways called shear keys to transfer shear forces across the structure. After the grout hardens, the beams are transversely posttensioned and a composite, cast-in-place deck is poured over them. Prompted by the frequent appearance of longitudinal deck cracking over these partial-depth shear keys soon after construction, full-depth shear keys with more transverse tendons were adopted in 1992. A follow-up study evaluated the performance of this new full-depth shear key/transverse tie system. Results indicate that this method has reduced the frequency of shear key related deck cracking.
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