IN DEPTHMarch 2017

Brierley Associates is part of a great team of engineers who are inspecting transportation tunnels statewide for the Colorado Department of Transportation (CDOT). Stantec Consulting is the team leader who directly works with CDOT engineers to operate their asset management software for tunnel inspections. Gannet Fleming has a long history with transportation tunnel inspections. Brierley Associates provides expertise in tunnel design and construction.

Numerous tunnels in the United States were constructed in two distinct periods of highway expansion. The first period took place during the 1930s and 1940s as part of the Great Depression era public works programs. The second occurred during development of the Interstate Highway System throughout the 1950s and 1960s. Based on preliminary information obtained from an initial tunnel inventory conducted jointly by the Federal Highway Administration (FHWA) and the Federal Transit Administration (FTA), more than 350 highway tunnels have been identified in the United States. Approximately 40% of these tunnels are more than 50-years old; and approximately 5% of these tunnels already exceed 100-years of service. Age and increasing tunnel traffic are among the factors that support the need for routine inspections to help ensure that tunnels on public roads remain in safe condition.

In 2012, the Moving Ahead for Progress in the 21st Century Act (MAP-21) went into effect. It recognized that the safety and security of the Nation’s highway tunnels is of paramount importance. The Federal Highway Administration FHWA developed the National Tunnel Inspection Standards (NTIS) to ensure that tunnels continue to provide safe, reliable and efficient levels of service for the traveling public. NTIS is based on successful implementation of the past bridge inspection programs and tunnel research efforts.

CDOT Tunnel Inspection and Asset Management ServicesDavid Kwietnewski, PE

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In late 2015, the CDOT inspection team, which included David Kwietnewski of Brierley Associates, was one of the early groups to receive NTIS training and certification for tunnel inspection. Using the established federal manuals, Specifications for the National Tunnel Inventory (SNTI) and Tunnel Operation Maintenance Inspection and Evaluation (TOMIE), the inspection and asset management team collaborated to create the Colorado Inventory and Inspection Manual (C-TIIM) which is tailored to CDOT requirements and the unique occurrence of unlined tunnels.

Data collected during tunnel inspections is entered into a database that is used to forecast maintenance and rehabilitation funding and efforts. Additionally, all data generated will be maintained in the National Tunnel Inventory (NTI) which provides information for a data driven, risk based approach to asset management and investment decisions.

Tunnel inspections began in 2016 with four weeks in the Eisenhower and Johnson Tunnels on Interstate 70 beneath the Continental Divide, bypassing the historic Loveland Pass with a summit elevation of 11,990 feet above sea level. Finishing out the year the team inspected the Wolf Creek Pass Tunnel and the Veterans Memorial Tunnels. The 2017 inspection season includes more than 10 tunnels on state and federal roads plus another 12 that are off of state and federal roads. Other Brierley team members involved with this program are Co-Project Manager - Becky Brock, Mohamed Gamal, Sean Bailey and Josh Zimmermann.