How Granite Construction Restored Access to Denali National Park

The Pretty Rocks Landslide has been measurably active since the 1960s, if not long before. And for the last decade, it has been moving with markedly increasing speeds, making conventional roadway reconstruction impossible and threatening one of the nation’s most treasured destinations. When it cut off access to nearly half of Denali National Park in 2021, the challenge was more than simply repairing a damaged road.

For Granite Construction, the solution was the Polychrome Area Improvements Project, a federally funded effort to restore safe, reliable access along Denali Park Road by constructing a 475-foot bridge that completely spans the active landslide. Working alongside the Federal Highway Administration and the National Park Service, Granite is delivering a permanent infrastructure solution designed for one of the most geologically complex construction sites in the U.S.

“The project centers on constructing a single-span steel truss bridge across the Pretty Rocks Landslide — an actively moving section of terrain that has made a significant portion of the park inaccessible since 2021,” said Todd Keller, vice president of business development for Granite. “Its primary mission is to reconnect visitors to the western half of the park while delivering a long-term, resilient transportation solution that performs reliably in one of the most remote and environmentally sensitive locations in the country.”

The project aligns closely with Granite’s mission of delivering infrastructure solutions that support resilient communities. In this case, that mission extends beyond transportation. Restoring access will reopen some of Denali’s most iconic destinations to visitors while supporting tourism, improving safety and providing a durable replacement for a roadway that had become increasingly difficult to maintain.

Engineering Around a Problem That Won’t Stop Moving

From the beginning, the project team recognized that success would depend on designing for the landscape rather than trying to control it.

Instead of rebuilding the roadway across unstable ground, engineers developed a bridge that spans the landslide, transferring structural loads to stable ground beyond the moving terrain. Ground improvement measures — including micropiles, anchors and specialized stabilization systems — provide additional support where needed, while thermosyphons help preserve permafrost conditions that contribute to long-term ground stability.

“The bridge was designed to span the unstable area entirely, avoiding reliance on shifting ground,” Keller said. “Rather than treating these challenges as obstacles, the team approached them as design drivers, resulting in a solution tailored specifically to the site conditions.”

The project team’s objectives extended beyond restoring traffic. They sought to create infrastructure capable of withstanding changing environmental conditions while minimizing impacts within the federally protected national park. Equally important was demonstrating how collaborative project delivery could improve decision-making on highly complex infrastructure work.

Collaboration Changed the Delivery Strategy

One of the project’s defining decisions came before construction even began.

“Given the remote location, unknown geotechnical situation and constrained terrain, it was clear bid-build presented too much risk to a contractor,” Keller explained. “Granite presented the idea of moving forward with the construction manager/general contractor (CM/GC) method, which the owner agreed to.”

This delivery model brought Granite into the design process early, allowing the contractor, owner and design team to collaboratively refine engineering solutions, manage risks and optimize construction sequencing before work began. 

That early collaboration proved invaluable throughout the project, particularly as the team balanced constructability, environmental stewardship and the realities of working in one of North America’s most isolated construction environments.

Building in Alaska’s Wilderness

Constructing major infrastructure inside Denali National Park presented logistical challenges that few highway projects encounter.

In remote projects like this, logistics become as important as engineering. Every construction activity had to be planned around transportation limitations, weather conditions and environmental protections, with little margin for unexpected delays during Alaska’s short construction window.  

“The team established worker camps, staged materials carefully and sequenced work to align with limited seasonal access and transportation constraints,” Keller said.

Digital Technology Guides Precision Construction

Digital modeling became especially important during planning for the bridge launch, one of the most technically demanding phases of construction.

Rather than erecting the bridge directly over the landslide, crews assembled the steel truss on one side of the crossing before incrementally launching it into position using a specially designed “launch nose.” Once the launch nose reached the opposite side, the main truss followed, sliding across the gap in a carefully controlled operation.

“The teams built up to the launch over the course of two work seasons,” Keller said. “The launch itself, sending a 475-foot-long truss across hundreds of feet of empty air, demanded incredible planning.”

Detailed digital simulations allowed engineers to model every stage of the launch before construction began.“It required close coordination across designers, engineers and field crews, supported by detailed digital modeling to simulate each stage of the process,” Keller said.

“The alignment of planning and execution in such a remote environment reflects the strength of the team’s collaboration and shared commitment to delivering a successful outcome.”

Sustainability Through Long-Term Resilience

While the Polychrome Area Improvements Project was not designed around a formal sustainability certification, environmental stewardship influenced nearly every project decision.

Construction activities were carefully planned to minimize disturbance within the protected park, while efficient material staging reduced unnecessary transportation impacts. The result is infrastructure designed not only to perform for decades but also to reduce future maintenance needs and repeated disturbances within the surrounding landscape.

Restoring More Than a Road

Once access is restored, visitors will once again be able to reach the western portion of Denali National Park, areas that have remained inaccessible since the landslide disrupted travel five years ago.

Improved access also supports the regional economy, where tourism remains a critical driver for local communities and businesses. At the same time, replacing an increasingly unstable roadway with a permanent bridge improves safety for both park visitors and maintenance personnel while reducing the need for ongoing emergency repairs.

Lessons for Future Infrastructure

For Keller, one of the project’s greatest successes lies in the lessons it offers the broader construction industry. “Early collaboration is critical,” he said. “Engaging contractors during design leads to more constructable and resilient solutions. Collaborative contracting methods like CM/GC provide opportunities for innovation that go beyond traditional delivery methods.”

He also pointed to digital technology as an increasingly important project delivery tool. “Modeling and simulation can significantly improve planning for complex construction activities. Projects in dynamic environments must be designed and executed with flexibility in mind. Especially in the context of a constrained work season in a place like Alaska, this kind of adaptability is a huge advantage.”

Granite expects the project to reinforce several long-term priorities, including expanded use of collaborative delivery models, increased investment in digital modeling and continued focus on resilient infrastructure solutions.

The Polychrome Area Improvements Project demonstrates how innovation, thoughtful planning and strong partnerships can solve extreme challenges. By designing around an evolving landscape, Granite is restoring more than a roadway — it’s reconnecting a national park while setting a new benchmark for infrastructure built to thrive in extreme conditions.