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Sixth Street Viaduct Replacement Project

The City of Los Angeles Bureau of Engineering’s $588 million Sixth Street Viaduct replacement project in Los Angeles will join the L.A. Arts District to Boyle Heights. The new bridge, to open later in 2022, replaces a 1932 structure that was retired due to seismic vulnerability and a rare chemical reaction in the cement supports. It is funded by the Federal Highway Transportation Administration and the California Dept. of Transportation, as well as city funds.

The new bridge, dubbed The Ribbon of Light, will include a 2,864‐ft‐long tied‐arch continuous concrete viaduct structure and a 193‐ft-long post‐tensioned, cast‐in‐place, reinforced concrete box girder structure at the west approach. Design was completed by HNTB and Los Angeles architect Michael Maltzan. Construction is led by contractors Skanska Stacy and Witbeck.

Atlas, through its acquired company Alta Vista Solutions, is providing quality management services, engineering assessment and evaluation for quality assurance and verification, materials engineering and investigations, structural steel inspection, testing and analysis, and source inspections.

“The project challenges have been significant,” says Bahjat Dagher, Project Manager with Atlas. Downtown traffic, dealing with Los Angeles River challenges, working over and under active rail lines operated by five agencies, and managing identified and unidentified utility conflicts top the list. Alta Vista Solutions, an Atlas company, has provided continuous support to the City of Los Angeles since 2017 dealing with typical and atypical construction, fabrication, and erection adversity. “We are grateful for the opportunity to provide our services that contribute to this first-class, high-quality structure that we can be proud of for generations to come” says Mr. Dagher.

“We have traveled to remote areas in California, as well as to states like Arizona, Utah, Ohio, Oregon, Missouri, and even Canada to perform source inspection and ensure the high standards of quality are met during fabrication. Our team of specialists help ensure that fabrication processes, welding, coating, material documentation, nondestructive testing and personnel certifications comply with contract requirements. Additionally, the team performs oversight assessment and verification of in-process quality control (QC) testing,” says Mr. Dagher. In addition, Atlas, through Alta Vista Solutions, provided batch plant inspections, field inspections and materials testing for the structural concrete which included the helical ramp and the ten pairs of unique arches. These remarkable features are what will make the Sixth Street Viaduct an iconic piece of the LA skyline.