After dam breaches, overflow and watershed runoff washed away major sections of U.S. 34 through the Big Thompson Canyon in September 2013, Kiewit Infrastructure built a temporary road. Now the company, based in Omaha, Nebraska, is back building a permanent replacement.

"With Governor Hickenlooper wanting roads built back better, planning for resiliency in the roads is a huge component of this work," says Jared Fiel, Spokesperson for the Colorado Department of Transportation (CDOT).

The flow surges during the 2013 weather event exceeded a 500-year flood event, Fiel explains. The road, which provides access to Rocky Mountain National Park, also flooded in 1976. Kiewit did those repairs as well. Superintendent Max Chesnik worked on both projects.

In 2013, "the canyon section sustained widespread, massive damage," he continues. "Major sections of roadway were washed away completely, along with access bridges and retaining walls. In the narrows, much of the roadway and grade were undermined, washing out the pavement from below and exposing the wall support structures."

Temporary repairs were completed at a cost of $34 million and the highway was reopened to traffic in both directions on Thursday, November 11, 2013. CDOT and Kiewit worked from both the east and west ends of the canyon to assess and repair the damage and restore local access as quickly as possible. Employees worked seven days a week to get it done in 59 days, without an injury. Kiewit brought in 150 workers and 70 pieces of heavy equipment to rapidly complete the emergency repairs. However, not all of the fixes were made to normal CDOT standards, such as narrow shoulders or lower roadways.

"Emergency repairs were extensive and included removing debris, re-establishing shoulders and embankments, replacing damaged asphalt, filling washed out sections with concrete fill, repairing local access structures, and repairing damaged drainage structures," Fiel recalls. "Although the [emergency] work was done well, many sections of the road were actually below the grade of where the roads were before the flood."

Permanent Repairs

In June 2015, CDOT selected Kiewit to serve as the construction manager to make permanent repairs. The $250 million permanent repairs for the 21-mile section from Estes Park to Loveland, include removing and replacing much of the temporary asphalt, embankment fill, and temporary channel protection. The project will re-establish two 12-foot travel lanes and provide 6-foot shoulders. Crews also are re-vegetating, replacing guardrails and repairing fencing. Some of the roadway sections that were not destroyed, but experienced flood water overtopping the roadway, will be analyzed and possibly replaced.

"We are very appreciative of Colorado's congressional delegation that helped to push to get the Federal Highway Administration (FHWA) emergency fund backlog funded, which allows us the complete the whole project," Fiel says.

In December 2016, Senator Cory Gardner (R-CO) announced the final funding to the FHWA emergency relief account, which would allow CDOT to complete the rebuilding of U.S. 34 and other roads damaged in the 2013 floods.

Challenges to the Rebuilding

CDOT and Kiewit have overcome several challenges during construction. U.S. 34 is considered iconic to Colorado, Fiel says, and it was a challenge to design and construct it in a way to ensure it was safe yet maintained the aesthetics and closeness to nature residents are familiar with.

During this first phase of construction, Kiewit is blasting, excavating, and processing heavy rock. To make the roadway more resilient to future flooding, Kiewit is moving the roadway onto bedrock in many places, which necessitates the drill and shoot blasting work.

"One unique aspect of this project is the repurposing of rock material created by the rock excavation," says Jason Hagerty, Project Manager from Kiewit.

The first construction package requires the removal of approximately 300,000 cubic yards of rock. This amount is, roughly, 20,000 haul truck loads. All of this material is taken to the project's onsite rock processing plant. There it is sorted, crushed and repurposed into 4-inch minus road base, 12-inch riprap, 18-inch riprap and 24-inch riprap, which has been incorporated into the design of the project.

The material from the cuts is evaluated before it is transferred to the plant, the Kiewit team reported. The material must meet quality specifications before being repurposed. Throughout the night shift, haul trucks take the native rock material from the rock cuts to the plant, so that it can be processed the following day. Kiewit has a six-man crew running the rock processing plant, and an onsite quality team to inspect the riprap during the process and after that is produced.

Current equipment being used in the canyon includes 10 Caterpillar 740 Haul Trucks, a Caterpillar 390 Excavator, a Caterpillar 988 Loader, a Lippmann portable riprap plant, and a crusher and screening plant. Kiewit has a full time modeling team onsite that uses a variety of construction modeling software, including Trimble Business Center. These models are primarily used during the preconstruction services and planning phases.

The project is offering opportunities for young people interested in the construction industry. Kiewit has an extensive internship program and one college intern is working on the U.S. 34 project. The project also has an apprentice program for craft employees. Kiewit is required to train an apprentice for approximately 1,200 man hours and as of date the team is on track to do so.

Restricting Access

Another major challenge to the project was the need to restrict access to local residents on U.S. 34 for eight months to complete rock blasting, including removal of about 200,000 cubic yards of rock, and other work. Residents with permits can travel in or out from 6 a.m. until 8:30 a.m. and from 4 p.m. until 7 p.m. At other hours, residents and all commuters must take a detour route, U.S. 36, which takes about 15 minutes longer. CDOT opened the road during the winter holidays. The road is scheduled to reopen to regular traffic before Memorial Day.

Kiewit is coordinating with regulatory agencies such as Colorado Parks and Wildlife and the National Forest Service to ensure water quality is maintained, flood plains are not impacted and traffic control plans are coordinated. The company has had to prepare a stormwater management plan that explains how it will protect the Big Thompson River from construction materials. Plans include diverting water around the construction site by placing berms or barriers in the river, pumping water that may seep out of the area, but testing it and treating before releasing into the river.

The initial phase of the four-phase project is expected to wrap up by the end of the year with future packages currently scheduled through 2018.

 "Performing the permanent repairs, CDOT and Kiewit plan to provide the canyon corridor with a sense of protection - that their community and roadway is more resilient to future flood events, allowing them access to and from their home after a disaster," Hagerty concluded.