The Alaska Department of Transportation is seeking bids for rockfall-prevention work just past 6-Mile Zimovia Highway in an area known as The Bluffs and prone to rocks breaking off from the hillside and landing in the right of way.
The work is scheduled for this summer.
Bids were due Jan. 9. The work will include drilling and installing into the rock face more than 300 linear feet of bolts, each at least 25 feet long and grouted in place. The job also will include clearing work at the top of the slope.
An engineer’s estimate puts the expected cost for the project at between $250,000 and $500,000, according to state bid documents. Work is expected to be completed by October.
If the bids on this summer’s Zimovia Highway work come in low enough, the state has asked contractors to provide a quote for an additional 275 linear feet of rock bolts and clearing work at a second site, about half a mile farther down the road.
The rockfall-mitigation work planned for this summer is not related to November’s deadly landslide, which occurred five miles farther out from town along the highway.
This summer’s work is the latest phase in an ongoing and yearslong project to address what was recognized as a chronic problem along the highway. Dozens of rockslides occurred in a short stretch of the road between 2007 and 2019, the Sentinel reported in 2021.
A rockfall in 2021 at 8-Mile “drew our attention” to the stretch of roadway, state Transportation Department officials said after that incident. The department identified three specific areas for rock work between 5.5-Mile and 8.5-Mile, “to reduce the frequency and severity of rockfalls,” the department said in 2021.
The work is covered by funding through the U.S. Department of Transportation’s Highway Safety Improvement Program, a spokeswoman for the Alaska Department of Transportation told the Alaska Beacon news site last month.
The Wrangell locations are among several in a statewide program that identified rockfall-prone sites, a state DOT official said in 2021.
The work involves breaking off loose rocks from the hillside, using either pry bars or maybe inflatable air bags that would be wedged into tight spaces and expanded to dislodge loose rock, state officials said.
No blasting is planned for the Wrangell work, to avoid any risk that it would further destabilize the rock slope, they said.
Rock bolting literally bolts rocks together, to hold them in place.
Vegetation clearing is also part of the work. The roots of trees and shrubs can expand crevices, allowing water to seep into the rock and, after freezing and expanding, loosening and breaking apart the rock above the highway.
The Alaska Beacon contributed reporting for this story. The Beacon is an independent, donor-funded news organization. Alaskabeacon.com.
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