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HNTB Effort Earns Top National Award in Annual Showcase of World’s Best Engineering Efforts

WASHINGTON, D.C. — The new Sixth Street Viaduct Project in Los Angeles on Tuesday won the 2023 “Grand Conceptor” Award signifying the year’s most outstanding engineering achievement.

The project was honored at the 57th Annual Engineering Excellence Awards Gala (EEA)—a national juried competition awards ceremony sponsored by the American Council of Engineering Companies (ACEC).

Hosted by noted comedian Ross Shafer, Tuesday night’s EEA Gala honored 179 outstanding engineering achievements from the U.S. and worldwide.

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Designed by HNTB of Los Angeles, the Sixth Street Viaduct is a 3,500-foot tied arch bridge locally called the “Ribbon of Light.” The structure re-establishes a critical thoroughfare between L.A.’s historic Boyle Heights on the east side with the Downtown Arts District on the west.

Paying homage to the original double-arched 1932-era predecessor closed for demolition in 2016, the new viaduct features ten pairs of sculptural 30-and 60-foot concrete arches. Each arch is supported by an innovative seismic isolation system designed to withstand a 1,000-year seismic event. It also is the largest bridge project in the history of Los Angeles.

The project will also include a new 12-acre public park running below the bridge, accessible by multiple stairways and a monumental helical bike ramp currently under construction.

The project joins a prestigious list of recent Grand Conceptor Award winners, including the Moynihan Train Hall (New York, NY, 2022), Copperhill Watershed Restoration (Ducktown, Tennessee, 2020); and the SR 520 Floating Bridge Replacement (Seattle, 2017).

Other 2023 Engineering Excellence Award winners are:


  • Frederick Douglass Memorial Bridge Project, Washington, DC, AECOM
  • I-74 Corridor over the Mississippi River, Bettendorf and Davenport, IA and Moline and Rock Island, IL,  Benesch & Modjeski and Masters
  • Hugh K. Leatherman Terminal, North Charleston, SC, HDR
  • Clear Creek Canyon Park, Gateway Segment; Golden, CO; Muller Engineering
  • PAE Living Building, Portland, OR, PAE
  • Delta’s New Terminal C at LaGuardia Airport, Queens, NY, STV/Satterfield & Pontikes (Joint Venture)
  • Climate Pledge Arena, Seattle, WA, Thornton Tomasetti


  • NASA Langley Measurement Systems Laboratory, Hampton, VA, AECOM
  • Jane Byrne Interchange, Chicago, IL, AECOM & TranSystems (Joint Venture)
  • City Walk BHAM, Birmingham, AL, Barge Design Solutions
  • Towerside District Stormwater Management System, Minneapolis, MN, Barr Engineering
  • I-295 over Veranda Street Bridge Replacement, Portland, ME, HNTB
  • Reconstruction and Rehabilitation at the Verrazzano-Narrows Bridge, Brooklyn to Staten Island, NY, HNTB, WSP USA (Joint Venture)
  • City of Billings Nutrient Improvements, Billings, MT, HDR
  • I-579 Urban Open Space Cap, Pittsburgh, PA, HDR
  • SEA International Arrivals Facility, Seattle, WA, KPFF
  • Chatham Park Water Recovery Center, Pittsboro, NC, McKim & Creed
  • 100 Vandam Street, New York, NY, Severud Associates
  • Navajo-Gallup Water Supply Project, Councelor, NM, Souder, Miller & Associates
  • Bridging Kentucky, Frankfort, KY, Stantec, Qk4 and AECOM
  • Seapoint Industrial Terminal Complex, Savannah, GA, Terracon
  • Merchants Bridge Main Span Trusses & East Approach, St. Louis, MO,TranSystems
  • 66 Hudson Boulevard – The Spiral, New York, NY, WSP USA

For further information about the 2023 ACEC Engineering Excellence Awards program, contact Alan D. Crockett at 202-682-4301 or by email at




Resource Type

Press Release

Topic Area

Awards, Engineering Excellence Awards


June 15, 2023

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