Impact of Large 0.7 Inch Strand on NU-I Girders

Authors

Maher K. Tadros Ph.D., P.E., University of Nebraska - LincolnFollow
George Morcous Ph.D., University of Nebraska-LincolnFollow

Date of this Version

2011

Document Type

Article

Citation

Report SPR-P1 (08) P311 Final Report 26-1120-0038-001

Comments

Copyright 2011 Mid-America Transportation Center

Abstract

The NU I-Girder series uses a unique cross-section and high-strength concrete to achieve longer spans. The objective of this project was to develop the quality control and design criteria required to introduce 0.7 inch strands at 2 in. spacing in NU I-Girders. Compared to 0.5 inch strands, only 1/2 of the total number of strands would be needed. This would result in immediate labor savings in precast concrete product costs. More importantly, having the ability to introduce almost twice the prestressing force, compared to 0.5 inch strands, and 135% of the prestressing force, compared to 0.6 inch strands, could result in a significant increase in the span capacity of the current Nebraska Department of Roads (NDOR) NU I Girder without having to modify the sections or acquire new forms.