Repair work has resumed under a heavily-traveled Interstate 81 bridge in Binghamton after operations at the site were halted for a few weeks.

The span over Chenango Street has been sinking since its construction in 2013. The movement of the bridge had been closely monitored by the state Department of Transportation as engineers worked to assess the issue.

Chenango Street has been closed to traffic for nine months as efforts to fix the problem have been unsuccessful. The street closure was expected to last only three months.

According to the DOT, testing on the structure revealed the use of a sprayed-on concrete would not work for the "bridge retrofit" project.

The agency's engineers consulted with "national experts" to develop a different approach. The technique now being tried uses a product called "Speed Crete Red Line." The company that makes it describes it as "a rapid-setting, cement-based concrete and masonry repair mortar."

The new material has been applied to the sides of the bridge's precast concrete sections in recent days.

Both sidewalks under I-81 now are open for use by pedestrians and bicyclists.

Workers have been using jackhammer-type tools to break up the concrete that previously was put in place over Chenango Street.

The DOT is working to determine a target date for reopening the street that connects Binghamton's North Side neighborhoods.

The work to repair the sinking bridge was projected to cost $3.5 million. There's no revised cost estimate for the effort to extend the span's useful life.

Contact WNBF News reporter Bob Joseph: bob@wnbf.com. For breaking news and updates on developing stories, follow @BinghamtonNow on Twitter.