The Big Walker Mountain Tunnel sneaks up like a ghost on motorists traveling Interstate 77 through Virginia’s Appalachian Mountains. Big Walker Mountain is the first mountain along the interstate that crews could not snake the road around – so motorists have been driving through it for 46 years.
They’re now traveling on a fresh ribbon of SM-12.5E asphalt, as the RS&H Transportation-Construction Management Practice has wrapped up a paving project in the 4,720-foot tunnel. The RS&H team was able to mill, pave and stripe both lanes of the southbound tunnel in just two nights.
The tight timeline was just one of the challenges the team faced.
“Space was tight and safety was made a priority,” said Jason Gamble, who served onsite as RS&H’s Inspector Trainee. “Everyone watched out for one another since escape routes were very minimal with all the equipment, trucks, and construction traffic traveling through while paving operations were performed.”
Virginia State Police diverted all traffic into a slow roll through the northbound tunnel. The slow roll method was utilized to slow traffic in order to allow workers time to place traffic control devices. The traffic followed the law enforcement officials into the diverted traffic pattern, which was then maintained by channelizing devices. Meanwhile, the T-CM team solved one puzzle after another in the southbound tunnel.
Vibratory rollers could not be used inside the tunnel due to the potential of damaging existing water lines inside, so all rolling had to be done by the static method. Due to height restrictions inside the tunnel, larger dump trucks bringing in the asphalt from the nearby plant couldn’t enter. Instead, larger trucks dumped their payload into a shuttle buggy set up just outside the tunnel where the asphalt was then transferred into smaller dump trucks on the paving train inside.
“With everybody’s assistance and hard work the asphalt temperature was monitored and placed within its recommended placement temperature range,” Gamble said. “The (asphalt) fumes were a bit annoying at times, but overall ventilation was kept up to the best of its ability.”
Gamble worked with other inspectors from different consultant firms on the project, including A. Morton Thomas & Associates and MBP. The Virginia Department of Transportation (VDOT) Bristol District also had representatives on site. Kristy Plummer in the RS&H Abingdon, Va., office led the efforts to acquire the project work.