Noisy demolition work in south Ashland that began late Wednesday and diverted Interstate 5 traffic overnight will continue for another five nights, transportation officials said.

Noisy demolition work in south Ashland that began late Wednesday and diverted Interstate 5 traffic overnight will continue for another five nights, transportation officials said.

Crews are using highly pressurized water to remove decaying concrete on the deck of the I-5 overpass at Exit 14.

The night work is necessary to lessen impact on I-5 traffic, which is being detoured because of debris being blasted onto the freeway's northbound lanes, said Oregon Department of Transportation spokesman Gary Leaming.

Four motors powering two hydro-blasting mills are causing most of the noise, said Leaming. People in homes and motels nearby can also feel the ground vibrating from the equipment, he said.

Leaming and other ODOT officials canvassed the area Monday, advising motel owners to book their guests in rooms farthest away from the bridge, he said.

"I think it's going to get some folks' attention," Leaming said Wednesday. "People are going to notice some vibration or a low hum depending on where they live, because of the night work."

Residents in the nearby Oak Knoll neighborhood said they couldn't feel any vibration when crews were running the hydro mills on Monday and Tuesday afternoons. Then, crews were blasting the concrete away from the portion of the old bridge above the freeway's eastern shoulder.

Oak Knoll resident Josh Harris, 18, whose home is one of the closest to the bridge, said he could hear "a little hum" from inside, but it wasn't too bad.

A few doors farther away, Janine Bishop said she couldn't hear anything from her home when crews were running the hydro mills.

But two residents who live on Tolman Creek Road behind Albertsons said the noise generated by the demolition equipment is unbearable.

"It sounds like a 747 taking off," said Sheri Anderson. "I couldn't even hear the TV playing inside my house ... the ground was just vibrating."

Jill Gilbert, who lives near Anderson, said she complained to ODOT about the noise earlier this week.

"I totally understand that we have to listen to road work machinery sometimes, but this is just so obnoxious," Gilbert said. "I can't believe they're going to be working at night. It's too noisy for that."

Dennis Steers, a public service representative from ODOT, said the department looked at the possibility of jack hammering the concrete away, but said it would take about 10 times longer than using hydro-blasting and would likely be just as loud.

Though the hydro mills are covered with sound-dampening material, Leaming said, "they're just really loud."

The compressors within the hydro mills blast water from a nozzle mounted on a small tractor with up to 36,000 pounds of pressure per square inch to eat through about five inches of remaining concrete.

"It blasts the concrete right down through the rebar and onto the ground," said Steers. "It works great "… water cut the Grand Canyon, so we know it's a pretty good cutting agent."

Steers said the high-pressured water blasting through the concrete also contributes a considerable amount of noise to the operation.

Jennifer Burkett, manager of the nearby Windmill Inn, said she could hear the bridge demolition from the front desk of the motel on Monday and Tuesday, but that no guests complained.

She said the noise shouldn't be a problem in the rooms not facing the bridge, and that the motel isn't having a problem booking guests into those rooms.

Estar Travis, who worked the front desk at nearby Best Western Windsor Inn Tuesday, said she could hear the demolition work from her desk, but that no guests had complained.

The Best Western is also booking guests in rooms farther away from the bridge, she said.

Because of the erratic debris that is being scattered onto the road below during demolition, I-5 traffic is being diverted over the off- and on-ramps at Exit 14.

The freeway's northbound lanes will be closed from 7 p.m. to 7 a.m. today through Friday, Leaming said.

Starting on Saturday, Pennsylvania-based contractor Rampart Hydro Services will begin working over the freeway's southbound lanes, resulting in similar closures and detours, Leaming said. That work is expected to be completed by Tuesday morning, he said.

Rampart, which was sub-contracted the demolition job by the project's primary contractor, Oklahoma-based Concrete Enterprises, may take Sunday night off, Leaming said.

The crews may need Wednesday and Thursday to demolish the deck above the freeway's western shoulder, said Steers, but that work will be done during the day.

After the demolition work is completed on one side of the bridge, crews from Concrete Enterprises will likely begin rebuilding it as demolition crews work on the other side, Steers said.

"No reason to wait around," Steers said. "We want to get this thing done."

ODOT officials originally planned to have repairs to the old span wrapped up in April, but the rotting deck wasn't discovered until January, and additional work to replace it will extend the project likely until the beginning of September, said Leaming.

The costs added to the $9.4 million art deco-style bridge since discovering the rotten deck are about $500,000, Leaming said.

"It surprised everybody when they exposed the rebar," said Steers.

The original plan for the project was for the contractor to widen the bridge by about two traffic lanes, which has been done since work started in mid-2010, and to scrape off and pour a new surface layer of concrete above the rebar embedded beneath the road.

That plan went south when the crews revealed the rebar and realized the existing deck couldn't be salvaged, said Leaming.

"It's a big hurdle for us," he said. "We appreciate people's patience through this ... it's necessary work."

Inspectors from ODOT didn't take core samples of the bridge before opening the project for bidding, but they usually don't in this area, according to the ODOT website.

Leaming said the decomposition of the concrete and rebar was "rare," and "usually not the case" on bridges in the Rogue Valley.

Core samples of bridges near the coast are commonly taken by ODOT inspectors, its website says, because the bridges are in a chloride-producing salty environment, which is known to corrode concrete and steel.

"However, because of what we found at Exit 14, ODOT is revisiting that practice for the future rehabilitation of western Oregon bridges," the website states.

Reach reporter Sam Wheeler at 541-499-1470 or email swheeler@dailytidings.com.