The northbound bridge on Interstate 65 over Wildcat Creek in Tippecanoe County on Wednesday, August 5, 2015. Photo Provided

The northbound bridge on Interstate 65 over Wildcat Creek in Tippecanoe County on Wednesday, August 5, 2015. Photo Provided

Chris Morisse Vizza and Dylan Peers McCoy, Journal and Courier

The "foreseeable future."

That's about as specific as Indiana Department of Transportation officials were willing to get Monday when asked how long northbound Interstate 65 would have to remain closed while the damaged bridge over the Wildcat Creek is repaired.

As of now, officials said more analysis and study needs to be done before a reopening date can be determined.

INDOT Commissioner Brandye Hendrickson asked for drivers' patience because she said she knows "the full closure of a major interstate is understandably frustrating and difficult to bear."

Hendrickson said a repair and reopening timeline may be available later this week, when officials can "really get our arms around some of the more viable solutions."

What caused the bridge to drop 9 inches last week while construction crews worked to widen it has not yet been determined, pending further tests. Officials believe soil conditions and an underground artesian spring, in conjunction with construction work on the bridge, caused the structure to settle or sink into the ground, necessitating its closure.

But officials said they are confident that the southbound span can continue to remain open because construction crews have not observed the same instability on that bridge. They added, however, that workers are "constantly monitoring" the southbound bridge to detect any adverse changes.

INDOT is collaborating with Purdue University to install monitoring methods that include real-time technologies that track vibration, temperature and brittleness of the steel, officials said.