Alternate Vertical Shear Reinforcement in Prestressed Concrete Beams
The Texas Department of Transportation (TxDOT) commonly uses 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 were 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. Forty-three load tests were conducted on the eighteen specimens using four different load/support configurations. Load comparisons were made against AASHTO limits, and beam response comparisons were made against the standard TxDOT design. All of the beams had adequate shear and flexural strengths when compared to AASHTO limits and similar responses in terms of load/deflection curves, ductilities, failure modes, and crack sizes and distributions. A digital image analysis technique was developed and used to evaluate beam cracking.
Project PI: William R. Burkett