Analysis and Structural Benefits of High Performance Concrete for Pretensioned Bridge Girders

The maximum lengths for simple span pretensioned composite girders were investigated analytically using concrete strengths varying from 6 to 15 ksi, and prestressing strands of 0.5, 0.5 modified and 0.6 diameter. Both AASHTO and NU (developed by the University of Nebraska) sections were investigated. Girder spacings were varied from 5 to 11 feet. Use of the 0.6 diameter strand was more efficient and provided maximum spans, up to 40% greater than 0.5 diameter strand. The strength of the deck did not significantly affect the maximum span, and the strength of the girders at release affected maximum span length more at lower design strengths than at strengths greater than 12 ksi. Overall, the use of 0.6 strand with concrete strengths up to 13 ksi may be used to provide more efficient prestressed concrete bridge girders.