AASHTO Journal, 26 June 2015
The Oklahoma Department of Transportation turned to a fellow state DOT for specialized help, after a section of the rain-saturated Arbuckle Mountains gave way and unleashed boulders onto part of Interstate 35 in southern Oklahoma’s Murray County.
The rock slide occurred June 18 and closed part of north-south I-35, but no one was injured. ODOT said its crews and contractors worked to reopen one lane of northbound traffic by June 21, “using a crossover that moved one [lane] of traffic in each direction to the southbound lanes.”
On June 24, ODOT said in an “I-35 Corridor Update” that the agency had “been working tirelessly to develop a plan to reopen all lanes of I-35 in the Arbuckle Mountains south of Davis following the rock slide.”
It explained that agency engineers “brought experts from the Colorado Department of Transportation and construction contractors to the site to help develop a plan of action for removing the current rock slide and stabilizing the rock face to prevent further slides.”
Colorado’s DOT not only deals with steep Rocky Mountain terrain as a normal course of business but had recent experience with a natural disaster that included washouts from extreme weather. It had to deal in 2013 with severe storms that produced flash floods, wiped out many roads and bridges and took months to repair.
For the I-35 project, ODOT said its recommendation “includes removing the unstable rock mass with blasting, specialized equipment and hand tools, before placing rock bolts through the formation to finalize the stabilization. An estimated 15,000 to 20,000 tons of fallen rock will have to be removed and surface repairs will be made to the highway.”
That plan would exceed the executive director’s $750,000 contracting authority, so ODOT said it would seek approval of the state Transportation Commission for an expedited contract.
Meanwhile, it said the speed limit in that slide zone is 50 mph, and warned users of the route not to expect a quick fix. “Drivers are urged to continue to expect congestion and delays in the upcoming weeks, especially during peak travel times and holidays,” it said.
The agency also noted that “I-35 is narrowed to one lane in each direction just north of SH-29 near Wynnewood and in Ardmore for ongoing bridge rehabilitation work.”
So it said drivers of passenger cars and trucks that wish to avoid that whole corridor can divert to US-81 to the west or US-69 to the east.