This report describes the design, instrumentation, construction, and test set-up of two high-strength concrete prestressed
The girder specimens were constructed to evaluate prestress transfer length, prestress losses, flexural fatigue, ultimate
flexural strength, and ultimate shear strength. Each test girder was a 132.75-foot long, 46-inch deep, Minnesota
Department of Transportation (Mn/DOT) 45M girder section reinforced with 46 0.6-inch diameter 270 ksi prestressing
strands. The 28-day nominal compressive strength of the girders was 10,500 psi. Each girder was made composite with
a 9-inch thick, 48-inch wide composite concrete deck cast on top with a nominal compressive strength of 4000 psi.
Girder I used a concrete mix incorporating crushed limestone aggregate while Girder II utilized round glacial gravel
aggregate in the mix with the addition of microsilica. In addition, the two test girders incorporated two different end
patterns of prestressing--draping versus a combination of draping and debonding--and two different stirrup
configurations--standard Mn/DOT U versus a modified U with leg extensions. More than 200 strain gages were
imbedded in each girder during construction. Other reports present flexural and shear testing results.
Kielb, Jeffrey; French, Catherine E.; Leon, Roberto T.; Shield, Carol K..
Instrumentation and Fabrication of Two High- Strength Concrete Prestressed Bridge Girders.
Minnesota Department of Transportation.
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