Repairs are underway to repair an Interstate 79 beam near Bridgeville that was damaged in a crash last month.

A nighttime crash during the week of Christmas is now causing major traffic backups every afternoon.

The damage left behind during the crash has led to a closed lane of the highway that isn't expected to reopen until the end of February.

We're talking about southbound Interstate 79 from the Carnegie exit to the Kirwan Heights/Heidelberg exit and the lane closing is unavoidable, impacting around 40,000 drivers every day.

As you're traveling south from Carnegie, drivers are forced into the left two lanes, but there's no sign of any issue at first glance.

PennDOT District 11 Executive Jason Zang said that a crash on Thoms Run Road in late December sent a truck slamming into the Interstate 79 bridge.

"The outside beam is knocked out of alignment," Zang said.

Looking at the point of impact head-on doesn't look too bad, but from the side, it's clearly curved.

"The steel is not supposed to be bent," Zang said, adding that it's bent much more than it appears.

Because the beam is bent, it's unable to bear the load it's supposed to.

"The beam is structurally compromised, so traffic cannot be on the beam until we make the repairs," Zang said.

The support steel behind the beam is also damaged and will need to be removed, refabricated, and replaced.

The beam itself will need to be carefully heated and straightened.

"You don't just go up there with anybody with torches and start going crazy," Zang said. "You have to do that carefully."

If crews aren't careful, the beam could become damaged worse than it already is.

The work is set to begin next week in the overnight hours and will last through late February with the lane on Interstate 79 closed around the clock until its finished.

The repairs are expected to cost around $400,000.