Complex, challenging Parleys Canyon work hits halfway mark
This year's most complex Utah highway project replacing a huge, rotting pipeline beneath part of Interstate 80 in Parleys Canyon is now halfway complete, and on schedule for completion in October.
The Utah Department of Transportation marked the midway milestone Wednesday by allowing the news media to walk in some of the new 66-inch diameter pipe in the ground, and view the old rotted pipe it is replacing.
As I-80 was widened through the years, the pipeline ended up buried beneath the freeway in places complicating repair or replacement work.
To move the new pipe to the side of the freeway in the narrow canyon, "We have to trench through bedrock," said Robert Stewart, district engineer for UDOT Region 2. "In order to do that, we have to blast."
That's a challenge, officials say.
"Parleys is one of the most critical corridors we have" and needs to have most lanes open most the time "because it doesn't have any easy alternate routes," Stewart said. "So we've had to get really creative."
He said, "We drill to put charges right next to pavement. We get it all set up, close traffic for 15 minutes, set the charges off, make sure that everything is safe and that the roadway hasn't been damaged, and then open it up."
Precision is key, Stewart said.
"It's an amazing and precise process," and, "doing that in 15 minutes is a pretty short time."
The pipe handles drainage in the area, and overflow from Mountain Dell Reservoir. The old steel pipe was installed in the 1960s, and is at the end of its life, having rotted in many places. The new pipe is steel-reinforced concrete that has a design life of 100 years.
About two miles of pipe is being replaced "to prevent a more catastrophic failure in the future," Stewart said. Half that length is now complete on the $9.7 million project. Construction began in May and is scheduled to be completed in October.
"This is considered one of the most complex projects UDOT has this year because of all the elements of blasting, traffic control and avoiding closures," UDOT spokesman Adan Carrillo said.