ASPIRE is a quarterly magazine published by PCI in cooperation with the associations of the National Concrete Bridge Council. The editorial content focuses on the latest technology and key issues in the Concrete Bridge Industry.
Issue link: http://www.aspiremagazinebyengineers.com/i/395356
PROJECT RAMP N-N OVER I-17 Rebuilding the gateway to northern Arizona in Cordes Junction by David B. Benton, Arizona Department of Transportation As a regular destination for motorists to the Flagstaff or Prescott region, the junction of I-17 and SR 69 has been described as the gateway to northern Arizona. But in recent years, the outdated Cordes Junction traffic interchange had started to show its age. Built in the early 1960s, the Cordes Junction traffic interchange carried far more traffic than it was designed to accommodate. With traffic volumes expected to double in the coming decades, the Arizona Department of Transportation (ADOT) began a daunting task in the summer of 2011 to redesign and rebuild the busy interchange—which is located approximately 65 miles north of downtown Phoenix—with minimal disruption to traffic. The solution was a reconstruction project that would transform the outdated intersection design and replace it with a modern interchange that could handle the increased traffic in the area. No longer would slower local traffic have to mix with high-speed highway traffic, causing congestion and safety concerns. Two years after construction started, ADOT completed the project on budget and on time in the summer of 2013. PROJECT CHALLENGES The junction of I-17 and SR 69 in central Arizona provides a vital link between the metropolitan Phoenix area to the south, the surrounding communities of Humboldt, Dewey, Prescott Valley, Chino Valley, and the city of Prescott to the north. Reconstruction of the Cordes Junction traffic interchange was a key project to ADOT to improve operational characteristics, geometrics, and safety at this interchange. The existing underpass (UP) at this traffic interchange, known as Cordes Junction TI UP, consisted of a four-span continuous steel girder bridge consisting of five girder lines with maximum spans of 86 ft 3¾ in. and 79 ft 3¼ in. skewed at approximately 31 degrees over northbound and southbound lanes of I-17. The bridge needed to be replaced with the reconstruction of the traffic interchange due to the inability to accommodate the future widening of I-17 and substandard vertical clearance and shoulder widths. In addition, it conflicted with improvements needed at the traffic interchange to facilitate a connector road to SR 69 and the community of Cordes Lakes, east of this location. PROFILE RAMP N-N OVER I-17 / CORDES JUNCTION, ARIZONA ARIZONA DEPARTMENT OF TRANSPORTATION, OWNER BRIDGE DESIGN ENGINEER: Arizona Department of Transportation Bridge Group, Phoenix, Ariz. PRIME CONSULTANT: HDR Engineering Inc., Phoenix, Ariz. PRIME CONTRACTOR: Vastco-Sundt Joint Venture: Vastco Inc., Chino Valley, Ariz., and Sundt Construction, Tempe, Ariz. POST-TENSIONING CONTRACTOR AND SUPPLIER: DWYIDAG-Systems International, Long Beach, Calif. BRIDGE DESCRIPTION: Two-span, 397-ft-long, cast-in-place, post-tensioned concrete box girder bridge STRUCTURAL COMPONENTS: Three-cell, cast-in-place concrete box girder with 14-in.-thick webs spaced at 11 ft on center, with 4-ft 6½-in.-long cantilever deck edges BRIDGE CONSTRUCTION COST: $182/ft sq AWARDS: Engineering Excellence Grand Award – American Council of Engineering Companies (ACEC) of Arizona 2013