(Ft. Rock Tunnel | Photo Courtesy of Century West Engineering)
The community of Sunriver prides itself on the miles of paved pathways that keep pedestrians and bicyclists separated from vehicle traffic. This includes grade-separated crossings where pathways and roads intersect. Until recently, these pathway under-crossings were narrow, had steep approach and exit grades and did not feature adequate drainage facilities, resulting in flooding in several locations. The Sunriver Owners Association (SROA), the organization that maintains the road and pathway systems within the community, has prioritized the replacement of these tunnels to improve safety and create a more inviting environment for multimodal users.
To date, two tunnels have been replaced and a third new tunnel was built on Abbot Drive as part of the roundabout project completed in 2019. SROA approached the first tunnel as a standalone design-bid-build project using a pre-cast structure. While this solution yielded an attractive finished product, it was cost-prohibitive to recreate. After hiring a contractor, Marcum & Sons (M&S), for the Abbot Drive/Beaver Drive roundabout construction, the Abbot tunnel was added to the scope of work to minimize construction impacts as compared to completing the roundabout and tunnel as separate projects. This required Century West Engineering, SROA’s design consultant for the roundabout project, to work quickly and collaboratively with M&S and SROA to complete plans and brainstorm construction solutions.
“Although the project was established as a design-bid-build effort, our engineering team worked alongside M&S’s crew in what effectively felt like a design-build team,” says Century West Project Manager, Tom Headley. “We shared a common definition of success to bring this significant safety improvement into service ahead of schedule and under budget. I’m glad to say we succeeded.” Construction of the Abbot tunnel was a success that the entire team was confident could be carried forward to replace the remaining ten tunnels in Sunriver’s pathway system. In 2021, SROA asked Century West to complete a Pathway Tunnel Evaluation Report that reviewed each location for accessibility, frequency of use, traffic loads, detour complexity, stormwater issues, site access and geotechnical conditions, among other considerations. SROA will use this information to prioritize locations with the goal of completing one tunnel project per year.
Using the Report, the tunnel leading into Fort Rock Park was chosen as the 2022 project due to flooding concerns. Up to two feet of standing water had been observed in the tunnel after large storm events. Early discussions between SROA, M&S and Century West explored options to improve on the project process. “We knew there had to be a more cost-effective way to build these tunnels,” says Brian Marcum, owner of M&S. “Working with Century West and our structural teaming partner, Shayne Tennis of Tennis Engineering, we decided to formalize the design-build project structure with Century West. After carefully reviewing options with SROA, the team decided on a cast-in-place tunnel concept that could be built quickly and economically.” The result is a wide, attractive pathway undercrossing with an associated stormwater collection and detention system. Collaboration between team members even resulted in saving a large Ponderosa pine, consistent with Sunriver’s Tree Protection Plan. “Every member of this team is responsive and solutions-oriented,” says SROA’s Public Works Director Mark Smith. “I have so much confidence in each of them and know that they are working to provide Sunriver with the most efficient project so that we can get all of these tunnels built.”
The Sunriver community is highly supportive of the tunnel rehabilitation program, and the M&S and Century West team is committed to working together to provide innovative and cost-effective design and construction solutions to SROA for years to come.
Tom Headley is Century West’s project manager for their work at Sunriver, both with SROA and the Sunriver Airport. He lives and works in Bend and is committed to improving infrastructure in Central Oregon. His other local clients include Bend Municipal Airport, the City of Bend and Deschutes County.
