Alternate vertical steel reinforcement in prestressed concrete beams.

摘要

The Texas Department of Transportation (TxDOT) commonly uses normal strength concrete (NSC,) and high strength concrete (HSC) prestressed I-beams to construct bridges. Currently, TxDOT permits the substitution of welded wire fabric (WWF) for the traditional, 60-ksi, steel shear reinforcement, but load tests are needed to verify the behavior. WWF stirrups consist of deformed, vertical, cold-drawn wires anchored by a pair of smooth horizontal wires that are attached to the stirrups by electrical resistance welds.; Sixteen full-scale TxDOT Type “A” I-beams that were 36-feet long were cast in matching pairs using four different shear reinforcement details: beams with traditional steel bar details, beams substituting WWF for traditional bars on a bar-for-bar basis, beams with a simplified (uniform size) WWF detail, and beams with an equal-strength WWF detail using 80-ksi steel in lieu of 60-ksi. Five load tests were conducted on each pair of beams. Ten beams were NSC with an average compression strengths of 6,000 psi, and six beams were HSC with an average compression strengths of 10,000 psi. All of the beams had adequate shear strength when compared to AASHTO limits and similar responses in terms of load/deflection curves, ductilities, and crack patterns.