In Indiana, crews test I-65 northbound bridge repairs

| Thursday, August 20, 2015

The hourlong detour on Indiana I-65 near Lafayette that’s costing you time and money is high priority on the state’s list of immediate fixes. Specialized crews have been on site this week testing the solution for bridge pier settlement where I-65 northbound crosses Wildcat Creek.

Structural engineers monitoring the riverbank pier noticed the pier settling and tilting, and ordered the bridge closed on Aug. 7. The full closure of the northbound lanes created an hourlong detour.

Here’s what InDOT says happened to cause the bridge to sink.InDOT awarded an $82.8 million design-build contract in January to Walsh Construction Co. of Crown Point to widen and rehabilitate I-65 from State Road 38 to State Road 25 in Lafayette. Construction crews drove steel piles into nearby soils to widen the existing piers and sheet piling to work below the Wildcat Creek waterline.

According to InDOT, 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 reviewed preliminary designs over the weekend, and continue to review new information. Specialized geotechnical construction crews mobilized on site Sunday evening, and began installing a test micropile near the pier on Monday.

Walsh Construction Co. plans to install steel casings, grout and high-strength, small-diameter micropiles through the footers of the existing pier and deep into the soil. The process involves drilling steel casings through the water-tight soils, injecting grout to fill and densify the sandy soils below, and then installing the micropiles.

Test pile installation is expected to be completed Thursday; then the grout must cure for three days. Crews will test how the micropile distributes load to the adjacent soils before finalizing the designs to repair the bridge.

Micropiles have been used effectively to stabilize other bridge piers around the country. Walsh estimates the repairs will be completed and I-65 northbound reopened between Lebanon and Lafayette by mid-September.

Detour
I-65 northbound merges to one lane and is diverted onto U.S. 52 at Exit 141 north of Lebanon. The northbound lanes are closed to all traffic between U.S. 52 and State Road 25 (Exit 175). The I-65 southbound lanes remain open within the work zone.

Related article:
Hour detour: I-65 north bridge near Lafayette, Ind., closed for another month

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