DENVER -- If you drive elevated Interstate 70 at night, you're going to notice a lot more construction work in the next 2 1/2 years.

The Colorado Department of Transportation is going to rebuild about 60 expansion joints on the stretch of highway between Brighton and Colorado boulevards.

The major construction project will lead to overnight lane closures, sometimes one, sometimes two lanes.

"The expansion joints allow the bridge to expand or contract," said C-DOT bridge engineer Mark Leonard. "The concrete in those areas is (crumbling) due to moisture."

Leonard said work crews will soon begin opening up the bridge deck, tearing out the old joints and using new concrete and rebar to rebuild the joints.

He said it's going to cost $21 million and that if the repair work isn't done the joints could fail.

"We'd have to close the bridge," Leonard said. "There are already several areas underneath where we've had to shore up the joints. We would need more and more of those 'til we reached a point where we would need to shut the bridge down."

CDOT spokeswoman Mindy Crane said 140,000 vehicles travel on the busy highway.

"We get a lot of truck traffic and a lot of commuters," Crane said. "There's no way we could shut down the highway completely and get the work done more quickly."

Crane told 7NEWS that the contractor will soon begin working seven nights a week, closing one lane down at 8 p.m. and the second at 10 p.m.

She said all lanes will reopen by 5:30 a.m.

"It's going to be a long project," Crane said. "We just ask for a lot of patience. Slow down through the work zone and be safe."