I-69 Black Ankle Bridge
On I-69, the Black Ankle bridge near Koleen, Indiana spans over 2,000 feet of seasonal wetland areas. This presented a challenge because the sets of piers and caps supporting the massive bridge was originally set on poor soil. imi supplied the concrete for this massive Indiana Department of Transportation (INDOT) project.
Project Overview
The challenge on a bridge of this size is ensuring the concrete supports the massive weight across the entire span. Any concrete poured within a measured space of five feet or more is considered mass concrete by INDOT engineering specifications. For this project, that included all of the footings, caissons, stem walls, piers, caps, and beams. Special consideration is needed when pouring mass concrete. If the inner temperature at the core of the concrete exceeds tolerance ratios based on the ambient temperature, the concrete will produce thermal cracks. It is critical that the delivery temperature of the concrete not exceed 70 degrees. The imi quality control team used a chilled water mix to keep the temperature of the concrete between 60 and 63 degrees upon delivery. Each load was checked as it entered the construction site. As ambient temperatures rose, the imi team used ice and adjusted the water accordingly. Fly ash was also added to the mix to keep heat hydration to a minimum without compromising strength.
imi provided over 20,000 yards of concrete for the mass pours of the understructure of the Black Ankle bridge. That included 60 piers and 10 pier foundations. imi also supplied 2,000 yards for the bridge deck.
This project was awarded an Outstanding Concrete Achievement Award from the Indiana Ready Mix Concrete Association for infrastructure – bridge construction.
