Hurricane Katrina will long be remembered for the toll it took on the United States’ infrastructure. But nature also took its wrath out in another, much less publicized location.
On May 19 and 20 five mud and debris slides severely damaged Beartooth Highway (Highway 212), a two-lane road that connects Red Lodge, MT, with Yellowstone National Park.
According to the Montana Department of Transportation’s (MDT) Web site, this road is essential to the livelihood of Red Lodge because 200,000 tourists travel it from Memorial Day to Labor Day every year. (The road closes each winter because of excessive snow and adverse winter conditions). As a result, Congress approved up to $20 million on June 9 to clear the debris and reconstruct the road.
According to Gregg Teets, business development manager of Kiewit Western Co. of Littleton, CO, the project’s general contractor, “the two-day rainfall event caused mud, rock and trees on the mountain to give way, destroying some parts of the road, leaving a ribbon of asphalt supporting tons of debris.”
“MDT estimated that there was more than 500,000 tons of debris that flowed down from the mountainside,” Teets added. “The project became an emergency repair design-build contract to rebuild and reopen the road within 16 weeks.”
The road was so inundated with debris and obstructed, the 13 locations with damage could only be surveyed by helicopter.
Included in the project’s scope of work was how to access the damaged areas and how to proceed with the cleanup and repair. Teets pointed out that the 13 damaged sites spanned a 12-mi. (19.3 km) stretch with elevations ranging from 5,700 to 11,000 ft.
Addressing the project head on, Kiewit Western and its team surmounted the first project challenge: gaining access up and down the entire road. To accomplish this, “We excavated into the debris and cut a safe passage consisting of a single 12-mile lane up and down the road. A hydraulic excavator and articulated trucks were used during this. The terrain was steep and the work area was limited,” Teets said.
The next step was to access the damage and develop a plan of action. Teets said that because Kiewit Western was awarded a design-build contract, “We put together 13 task force teams, one for each damaged site, to access the damage at each site and develop a plan of action for each site.
“Once a preliminary plan was developed, we staged the work at 65 percent, 90 percent and 100 percent completion. MDT had to buy into each stage, with plans for the debris removal and road reconstruction approved at the 65 percent stage. Next, work was performed in a top-down fashion. This meant starting the debris removal and repairs from the top of the decimated areas,” Teets said.
Project challenges were encountered along each step of the project, he noted, adding that the first of these was “he unknown geological conditions.” To determine the geological conditions, “We excavated as soon as possible, doing geologic surveys on the fly.”
Teets said the abbreviated construction season —Memorial Day through Labor Day — necessitated a fast-track schedule.
“This required an immediate mobilization of equipment and a specialized labor working 24-hours a day, seven days a week for a 16-week work period. This meant pre-planning and teaming up with local contractors and engineers.”
Before the contract was awarded, he said Kiewit Western had 15 engineers and 25 workers ready to start work on day-one along with 15 semi-trucks, two excavators, 16 articulated dump trucks and two bulldozers.
Another project challenge was that both design-build and the emergency pace of the work was new to the client. The solution was to conduct “on-site training on the design-build process for the project’s design engineers, construction workers and the client,” Teets explained.
“These training sessions took place daily, weekly and on an as-needed basis,” he added.
Reconstruction, required restabilizing the road. This was done by building five mechanically-stabilized earth walls ranging in height up to 25 ft. (7.6 m). The tallest, according to MDT’s Web site, “is currently the largest one installed in North America.”
Each of these walls consists of a gabion basket with rock fill, Teats said.
In addition to these walls, the project required installation of a new drainage system, which consists of culverts and an under-drainage system.
“We redesigned the drainage system to help prevent this from happening in the future,” he said.
An interesting note about the project is the contract’s incentive and disincentive clause, which called for an incentive of $38,000 per day for each day the project was completed ahead of schedule and $38,000 per day for each day the project was behind schedule. The result is that Kiewit Western Co. completed the project “seven days ahead of MDT’s most optimistic deadline,” Teats said.
Kiewit Western received its incentive. And, by using the design-build method of project delivery, saved $5 million over MDT’s $20 million estimate and brought the project in for $15 million.
“The project team completed the project more than 25 percent under budget and a week ahead of the first and most optimistic of three scheduled deadlines,” Teets said.
According to Teets, a debris removal and road construction project of this magnitude required the use of 30 over-the-road dump trucks; 25 pickup trucks for use by construction crews, designers and construction staff members; six Caterpillar 735 articulated end dumps; six track backhoe/excavators, including Caterpillar 330s, 345s and JD 450s; four personnel lifts; three front-end loaders, including Caterpillar 966s and 980s; six track dozers, including Caterpillar D6s and D8s; two track-mounted rock drills; one 84-in. (213.4 cm) compactor; one asphalt paver; two rollers; one motorgrader; one portable screening plant; and one portable office complex.
MDT man-hours for this project exceeded 12,000; the contractor’s workforce put in more than 37,000 hours of work. Design hours, according to MDT’s Web site, totaled 9,000. MDT also calculated trucking totaled 12,000 hours, excavators totaled 3,000 hours, loader hours also totaled 3,000 hours, and bulldozer hours totaled 1,800.
Project highlights included 92,000 cu. yds. (70,339 cu m) of rill and shoot rock excavation; 6,000 sq. ft. (557.4 sq m) of mechanically stabilized earth walls; 4,700 tons (4,264 t) of asphalt paving; 15,000 sq. ft. (1,394 sq m) of rock retention wall; 19,600 tons (17,781 t) of road base; 4,100 lineal ft. (1,250 m) of guard rail; and 1,300 cu. yds. (994 cu m) of structural concrete.