Access to Whittier was the subject of at least 12 studies before the Alaska Department of Transportation and Public Facilities (ADOT&PF) commissioned HDR in 1992 to produce a final study. Among the options considered in that study were higher capacity rail alternatives, a new highway tunnel and highway roads across the mountains. Based on a comprehensive analysis, the most practical and cost effective alternative was to combine the highway and railway traffic in the same tunnel. Designed to allow automobiles to drive directly over the track area, the tunnel saved tens of millions of dollars compared to the cost of widening the tunnel to allow the roadway to be separated from the track.
Completed in June, 2000, the $80 million Anton Anderson Memorial Tunnel is the longest rail and highway tunnel in North America and the first dual-use tunnel in the U.S. Special features of the tunnel include:
- A computerized traffic control system that regulates both rail and highway traffic to ensure cars and trains are not in the tunnel at the same time. Traffic control, video monitoring and emergency response systems are integrated to ensure safety.
- The first U.S. tunnel to combine portal and jet ventilation.
- The first use of safe houses spaced at 1,600-foot intervals to provide emergency shelter for travelers, along with pull out areas to be used for disabled vehicles and railroad double stack trains.
- An innovative design of 1,800 precast concrete panels with embedded railroad tracks for the road surface. The highway surface within the tunnel is long wearing concrete for reduced long-term maintenance costs.
After the concept of a multi-modal railroad and highway tunnel was agreed upon by the authorizing agencies, work got underway on the environmental impact study (EIS), engineering development, the procurement process and document preparation. A team of nationally recognized experts in design-build law, tunneling, ventilation and railroad signal systems was assembled by HDR (with assistance from Parsons Brinkerhoff, Latchel and Assoc. and Wickwire Gavin) to develop the request for proposal and performance specification to select a design-build contractor.
In June, 1998, Kiewit Construction Company with Hatch Mott MacDonald as their lead design firm was awarded the contract as the design-build contractor for the tunnel. HDR continued to coordinate the project through the construction process, ensuring that the design met the performance specification and assisting ADOT&PF with construction management.
Under design-build, as one component of the project was being designed, another was being built, allowing accelerated completion of the tunnel. The project required more than 50 separate design-construction tasks to be integrated into the overall project.
Since rail passenger traffic is ten times heavier during summer, installation of the track/roadway panels occurred during the winter months. Weekly scheduling meetings were held with the Alaska Railroad to allow a maximum of four six-day work windows and six four-day windows between January and May. The narrow tunnel workspace required innovative construction techniques, such as using a rail-mounted gantry crane system to set the panels on the prepared course bed. Following panel placement, the long strings of rail were installed. Use of this system allowed excavation and grading operations to continue simultaneously with panel placement.
Designers and contractors were challenged by severe weather conditions, with temperatures reaching minus 40o
F, winds up to 150 mph, as much as 40 feet of snow a year, and a major series of avalanches that cut off access to the project site for nearly a week. The tunnel’s portal structures, used to house the 300 hp portal fans and emergency equipment, were designed as an A-frame capabile of withstanding avalanches and the heavy snow loads common to the area.
Since its completion, the Whittier Access Project has earned the 2001 Outstanding Civil Engineering Achievement (OCEA) Award, which is the highest award given by the American Society of Civil Engineers, along with these other national honors:
- The 2001 Grand Award from the American Council of Engineering Consultants.
- The Outstanding Heavy/Highway Project and Outstanding Design Project honors from the F.W. Dodge Awards program.
- The American Association of State Highway and Transportation Official’s Total Program Excel Award for Public Involvement with a Consultant.
- The American Road and Transportation Builders Association’s 2000 Globe Award for Environmental Excellence.
- The 2000 Excellence in Construction Award from the Associated General Contractors of America.
- The 2001 Best Project – Public Sector over $15 million from the Design Build Institute of America.
WHITTIER ACCESS PROJECT FACTS
Project Name: Anton Anderson Memorial Tunnel.
Location: Whittier, Alaska.
Contracting Agency: Alaska Department of Transportation and Public Facilities (DOT&PF)
Lead Consultant: HDR.
Design-Builder: Kiewit Construction.
Purpose: Convert a railroad-only tunnel into a multi-modal railroad and highway facility for use by both trains and automobile traffic.
Tunnel Characteristics: Total Length 2.5 miles (4km), 16-ft. tunnel width, 11-ft. 8-in. roadway, 3-ft. sidewalk, and 21-ft. tunnel height.
Tunnel Surface: Tunnel walls are natural rock. Road surface is precast concrete panels with embedded railroad tracks. Majority of the tunnel roof is constructed with chain link mesh to catch any loose rocks that may work loose over time. Less stable sections of the tunnel were rock bolted and/or shotcreted.
Special Features: Longest combined rail/highway use tunnel in North America. First highway or rail project in Alaska to use the design-build process. First use of a combination of portal and jet ventilation fans in the U.S. Alaska’s first toll road. Innovative, fail safe computerized control system that regulates both rail and vehicle traffic. The tunnel was designed to operate in minus 40o
F temperatures and extreme wind conditions.
Funding: A major portion of the $57 million design/build project was funded by the Federal Highway Administration (FHWA) under Special Experimental Project No. 14 (SEP-14 – Innovative Contracting). Alaska was one of 20 states and the District of Columbia with design-build projects approved or underway under SEP-14.
Design-Build Concept: According to the Federal Highway Administration (FHWA): "The design-build concept allows the contractor maximum flexibility for innovation in the selection of design, materials and construction methods. With design-build procurement, the contracting agency identifies the end result parameters and establishes the design criteria. The prospective bidders then develop design proposals that optimize their construction abilities. Submitted proposals can be rated by the contracting agency on factors such as design quality, timeliness, management capability and cost and these factors may be used to adjust the bids for the purpose of awarding the contract. By allowing the contractor to optimize its work force, equipment and scheduling, the design-build concept opens up a new degree of flexibility for innovation…From the contracting agency’s perspective, the potential time savings is a significant benefit. Since the design and construction are performed through one procurement, construction can begin before all design details are finalized." In the case of the Whittier Access Project the Alaska Department of Transportation and Public Facilities estimated that the project saved 12 to 16 months in time over a conventional design-bid-build contract and was completed on time and on budget.
