AECOM to Head Up Design of New $1.4B Seattle Bridges

AECOM has been picked as the lead designer for two parallel bridges that will replace a 1960s-era structure over the Portage Bay in Seattle, Washington. The infrastructure consulting firm will be part of a design-build team led by construction and development company Skanska.

The Washington State Department of Transportation’s SR 520 Portage Bay Bridge and Roanoke Lid Project, with $1.375 billion in funding, aims to replace the 60-year-old current four-lane bridge, which the WSDOT says “could collapse in a severe earthquake.”

The new bridges – one for eastbound traffic and the other for westbound – are set to be completed in 2031.

The planned landscaped freeway lid will include approximately three acres of neighborhood open space and new local and regional non-motorized trails.

AECOM said commuters will have access to new ramps, seismically resilient structures and improved connections to transit, local streets, and local and regional shared-use trails.

“This vital project will not only improve mobility along one of Washington State’s most congested routes but support new, vibrant public spaces thanks to its innovative lid design,” said Mark Southwell, chief executive of AECOM’s global Transportation business. “Our team will leverage their integrated expertise across the built environment to meet the project’s holistic objectives, supporting both improved mobility and a connected, livable local community.”