Construction crews drove steel piles into nearby soils to widen the existing piers and sheet piling to work below the Wildcat Creek waterline.
The piles pierced the water-tight soils to a sandy layer with water under pressure. Sand and/or water percolated up from beneath the bridge pier, causing it to tilt. Structural engineers monitoring the riverbank pier noticed the pier settling and tilting, and ordered the bridge closed on Aug. 7 in the interests of safety.Here's how the repairs will be made to restore the structural integrity of the bridge:
Engineers and soils experts with INDOT, Walsh and the Federal Highway Administration have identified the solution is to install high-strength, small-diameter steel casings with rods and grout, known as micropiles, through the footers of the existing pier and deep into the soil. Micropiles have been used effectively to stabilize other bridge piers around the country.The bad news is that it will take at least until mid-September for the repairs to be completed, resulting in a more than one month closure of that section of the northbound lanes of I-65. The 9-mile detour adds about 25 minutes to the northbound commute. INDOT does not know yet how much the repairs will cost and who is accountable for the cost of those repairs.