Shear Behavior of Pretensioned High-Strength Concrete Bridge I-Girders

Due to the optimization of I-girder shapes for maximum flexural efficiency and increasing use of high-strength concrete (HSC), shear strength control of member design is becoming more common. AASHTO Standard Specifications require that Vs not exceed 8 bwd (fc¢ in psi), otherwise the section web must be widened or the depth increased. On the other hand, AASHTO LRFD Specifications require a maximum shear limit of 0.25fc¢bwdv. The difference between the two limits may be as high as 100%. The purpose of this research is to theoretically and experimentally establish a limit on shear capacity before member size must be increased. Full-scale experiments have shown that the limit on shear capacity specified in the LRFD Specifications can be reached. A key factor is anchorage of the longitudinal flexural reinforcement at the member end.