The 'Little I' Gets a Makeover

By K. Robert Wendel

The 1960s-era Coors Boulevard / Interstate 40 interchange in Albuquerque has seen better days.

Originally designed to handle 75,000 vehicles a day, the explosive growth of the city's west side is severely taxing the old interchange with more than 140,000 cars a day.

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But things are changing. Albuquerque-based Twin Mountain Construction is the general contractor on a $91 million project to rebuild the interchange. The job is also known as Albuquerque's "Little I" and is part of Gov. (Bill) Richardson's Investment Partnership, or G.R.I.P., which allocated $1.6 billion for new road construction.

Twin Mountain was also the contractor on the city's other "I," the "Big I," the reconstruction of the I-40/I-25 interchange in the heart of Duke City.

When the Coors Boulevard/I-40 interchange is completed in summer 2006, transportation officials said the new interchange would resemble the "Big I" project.

"We are building a directional interchange, so any direction you want to go has its own designated ramp," said engineer Tom Virding, the design manager for the Albuquerque office of Parsons Transportation Group, an engineering firm.

"Our goal is to keep traffic moving, and the whole key is the free flow of vehicles."

Work on the design-build project started in December with initial earthwork.

The state chose the design-build method to shave 18 months of construction time off an original 36-month schedule.

The project features eight bridges, including two pedestrian bridges over I-40.

Seven bridges are precast concrete box girder bridges, but designers went with steel on the longest and highest bridge. The steel bridge is 60-ft. high and approximately 850 ft. long.

"Steel was the best option due to the curvature of the bridge and the length of the span," Virding said. "A cast-in-place bridge would work, but that's a lot more false work and a fair amount of time. We wanted to minimize the disruption of traffic and felt steel was the optimum material to use." >>

Poor soils led to heavy foundation engineering, with all of the bridge structures sitting on caissons and pilings 20 ft. to 120 ft. deep. The majority of the bridges are one lane, but a south-to-east ramp features two lanes. More than 8,000 cu. yds of concrete will be used on the structures, and crews will excavate more than 400,000 cu. yds of material.

Plans call for the addition of two lanes, one for acceleration and the other for deceleration, in each direction, with three travel lanes in each direction. Crews will also widen the median for a possible future transit route. The project includes 5,000 lin. ft. of sound wall between 10 ft. and 12 ft. high. The extra lanes give drivers a chance to speed up or slow down when entering or exiting the freeway.

The interstate roadbed is 10 in. of asphalt on top of an 8-in. base. The ramps and bridges get a 7-in. asphalt top. In all, crews will place 125,000 tons of base course and nearly 140,000 tons of hot mix.

Traffic planning is a key aspect of the project. Contractors wanted to keep the traffic patterns consistent so drivers wouldn't get confused. The project is also one of only three river crossings between east and west Albuquerque, so controlling congestion was important.

"We designed the detours to keep people in the same traffic patterns, even during construction," said Twin Mountain project director Kevin Swaving.

"For the most part, drivers won't be seeing a new interchange every month. We think we have a pretty clean traffic control plan."

Swaving credited the local police and New Mexico Department of Public
Safety for increased patrols in the area. Officers have written more than 2,000 speeding tickets since the project started, with all the tickets bringing double fines for violating work zone speed limits.

As with many other New Mexico road projects, architectural features are important. Plans call for textured sound walls and retaining walls and the pedestrian bridges feature aesthetic art elements created by local sculptor Karen Wank. The entire aesthetic mimics the natural landscape of the city's west side, from structures to landscape.

"One of the goals is to have an aesthetically pleasing interchange," Swaving said. "We are making sure the designs are integrated throughout the project, such as the wing walls and sound walls."