State highway officials said Monday they were awaiting results of soil testing to determine how long the emergency closure of an Interstate 65 bridge near Lafayette might continue.
Northbound drivers are facing lengthy delays on a 52-mile detour to get around the bridge over Wildcat Creek that was closed Friday for the second time in one week.
The only estimate that state highway Commissioner Brandye Hendrickson gave during a news conference was that the bridge would be closed for the "foreseeable future."
"We would hesitate to give any kind of timeline at this time," Hendrickson said. "It will probably be later in the week before we really get our arms around some of the more viable solutions."
Agency officials said they believed work by a contractor widening I-65 to six lanes in the area about 50 miles northwest of Indianapolis possibly disrupted an underground water feature, causing part of a bridge pier to sink about nine inches.
Crews began pile driving work nearby on Aug. 3 and that might have contributed to bridge bearings falling out, which caused the first closure of the bridge the following day, said Jeremy Hunter, bridge design manager for the Indiana Department of Transportation.
The bridge, which was originally built in 1968, was reopened Thursday after new steel supports were installed, but engineers spotted movement in a pier along the riverbank and closed the span again on Friday.
An inspector cited concern about piers in the bridge in 2005, saying that bearings at the top of the steel components that support the bridge deck had a significant tilt to the north that worsened when air temperatures fell.
Anne Rearick, the agency's bridges director, said she had not been notified of any additional settling of the pier since Friday's closure and that the primary concern was that a significant dig would develop in the bridge.
"Not that it would collapse, but that it would cause the bridge not to be rideable," she said.
The adjacent bridge for southbound traffic has remained open without any similar troubles being found during constant monitoring, highway officials said. No cost estimates for the bridge repairs have been made.
The official detour follows state highways from near Lebanon, around the west side of Lafayette and West Lafayette to link back up with I-65 north of the cities. Drivers have encountered slow traffic on the detour that has taken a couple hours or more to complete.
Crews installed temporary traffic signals along the route over the weekend in hopes of speeding up traffic flow.
Highway department spokesman Will Wingfield said the detour route was picked to use four-lane highways and keep traffic off city streets through Lafayette. He said it wasn't practical to divert northbound traffic to the southbound bridge over Wildcat Creek because traffic in both directions would be limited to one lane with a 35 mph speed limit.