The Big “I”

Project Detail

The Big “I” in Albuquerque, New Mexico was the largest capital works project awarded in New Mexico and involved the reconstruction and expansion of nearly 2 miles of the existing Interstate 25 and Interstate 40 interchange through central Albuquerque. Features of the reconfiguration included increased auxiliary merge distances; smoother, straighter roadways leading to improved performance; addition of interior and exterior shoulders; and fewer motorist weaves or lane changes due to the elimination of left-hand on/off ramps.

Project Highlights

Fifty-five bridges were built as part of the project including 33 concrete girder bridges, four structural steel girder bridges, 10 rehabilitated bridges, and eight new precast segmental fly-over bridges, which have become the trademark of the project because of their magnificent arcs. At 80 feet tall and more than 2,800 feet long, the I-25 southbound to the I-40 eastbound bridge includes 206 individual segments and is the longest bridge in the state of New Mexico.

Major items of work included 4 miles of sound wall; 111 lane-miles of paving; 16 miles of bridge beams; 154 miles of the conduit; 29 miles of concrete barrier wall; 4 miles of drilled shafts; 7.5 million pounds of rebar; 5 million pounds of structural steel; and 70 miles of utility work.

  • The Big “I" is the largest transportation project ever constructed in New Mexico.
  • The project including 33 concrete girder bridges, four structural steel girder bridges, 10 rehabilitated bridges, and eight new precast segmental fly-over bridges.
  • The design was completed in about 18 months and the construction in 24 months.
  • The geometry of the project consists of an assortment of horizontal and vertical curves that winds the ramps through the intersection with a minimum radius of 182.5 meters.
  • The segmental ramps contain two different cross-sections, for a double-lane and for a single-lane ramp.
  • The box sections are 2.790 meters deep and measure 12.914 m wide for the double-lane and 9.914 m wide for the single-lane ramps.

Client: New Mexico Department of Transportation

Location: Albuquerque, New Mexico

Area: 2,800 feet long

Finished: 2002

Value: $237 million

Remarks: The Big-I area design capacity is 400,000 cars per day. The project included the construction of 45 new bridges and 111 miles of road reconstruction over the two-year duration of the project.


The Big-I reconstruction project involved various construction projects on the I-25 and I-40 interchange in Albuquerque, New Mexico. The Big-I was originally designed to service around 40,000 vehicles a day. However, approximately 300,000 vehicles a day used it before the reconstruction project.

The Big I project contains the first segmental structures in the state of New Mexico. The project is being built for the New Mexico State Highway Transportation Department and will add eight precast segmental ramps to the busy and vital I-25 and I-40 interchange in Albuquerque. The eight precast ramps are part of the 55 bridges included in the two-year schedule.

the challenges

Due to the proximity of the precasting yard adjacent to the site, the segment lengths were adjusted for both the pier segments and typical segments to maximize the segment weight and reduce the number of segments. Typical segment lengths were increased from 3.0 meters to 4.0 meters for the double-lane segment and from 3.6 meters to 4.5 meters for the single-lane segments. The pier segments designed as split-pier segments were modified to be cast as a single unit. By increasing the segment lengths and weights the number of segments was reduced from 822 to 662 segments, eliminating 160 segments from the critical path of precasting.

project goals

By 2000, the 40-year old Big I interchange was experiencing traffic volumes nearly ten times what it was built to handle. Furthermore, the interchange had several obsolete features, such as left-hand exit ramps and quick weaves. The new Big I is a five-level stack interchange capable of accommodating 400,000 vehicles a day.

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