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WSDOT SR 520 Replacement Program

Transforming Puget Sound Commutes with Precision and Care

The SR 520 Bridge Replacement Program is a multibillion-dollar initiative by the Washington State Department of Transportation to enhance safety, reduce congestion, and improve mobility across .

Key components include the world’s longest floating bridge, HOV lanes, and a bicycle/pedestrian path, all designed with environmental stewardship and community engagement in mind.

This project will boost mobility between Seattle and the Eastside while setting new standards for sustainable infrastructure development. We’re providing extensive Quality Assurance (QA) testing and inspection services throughout the corridor.

Key Contributions:

  • QA Testing and Inspection: Mobilization and daily operation of on-site testing laboratories for soils, aggregates, and concrete at each project site. QA data management and reporting, supported by multiple teams of inspectors and testers.
  • Pontoon Fabrication Plant Support: Atlas assisted with the start-up of the Quality Assurance Program, including the on-site satellite materials testing laboratory for high-strength concrete production and materials tracking documentation.
  • Environmental and Materials Tracking: Atlas supports environmental stormwater management and materials tracking to ensure contract compliance.

Atlas ensures that all QA processes adhere to strict contractor schedules, providing round-the-clock support with 25 inspectors/testers working in 24/7 shifts to meet project milestones efficiently.

Specific Segments:

  • SR 520 Pontoons Construction ($515 Million): Implemented Quality Assurance Program for high-strength concrete production and materials tracking.
  • SR 520 Floating Bridge and Landings ($850 Million): Provided material laboratory testing services, special inspections, and multi-shift QC inspections.
  • SR 520 Eastside Transit & HOV Project ($434 Million): Managed QA documentation, environmental work plans, and special inspections.
  • SR 520 West Approach Bridge North ($264 Million): Provided initial environmental inspections and stormwater management.