“We have marine ports on the north and south sides at Seattle and Tacoma, and this will benefit both and also the Sea-Tac Airport,” says Andrey Chepel, the SR 509 Completion Project Construction Manager. “It will also be helpful for folks living south of the airport.”
The SR 509 Completion Project will connect the Port of Seattle with warehouse and industrial centers, reduce congestion, improve airport access, and promote regional economic growth. About 40 percent of the jobs in Washington have a connection with trade.
“The Puget Sound Region is home to important manufacturing and distribution centers,” Chepel says. “This provides benefits to moving freight between those centers and regional ports.”
“They worked together to make this project happen and secured the funding necessary to complete the project.” Chepel says. “We engaged the stakeholders to right-size the project.”
Besides the SR 509 Completion Project in King County, the other project in the Gateway Program – funded together by the state legislature in 2015 – is the SR 167 Completion Project in Pierce County. Together, they are expected to increase access to Interstate 5, Seattle-Tacoma International Airport, and the ports of Tacoma and Seattle, by establishing a north-south alternative to I-5.
Funding for the Puget Sound Gateway Program came from the state’s Connecting Washington, $1.56 billion, and Move Ahead, $423 million, transportation funding packages; local contributions of $130 million; tolling revenue of $180 million; and $73.6 million from an INFRA federal grant.
The state estimates the Puget Sound Gateway Program will produce more than $5 billion in economic activity and deliver $379 million annually in taxes.
SR 509 project will construct three miles of new expressway from SR 509’s terminus near the Sea-Tac Airport to I-5; add new I-5 ramps; improve interchanges; and build several new bridges and a new Veterans Drive tunnel under I-5. The project required additional right-of-way through residential and business areas and vacant land.
The department divided the SR 509 project into stages: Stage 1a, being managed by Sound Transit, as part of the Federal Way Link Extension project they are building in the same area; Stage 1b, the first Washington State Department of Transportation (WSDOT)-administered contract; and Stage 2. Stages 1a and 1b are under construction.
Kiewit, headquartered in Omaha, Nebraska, received the Stage 1a contract. The work entails building a new SR 99 bridge over the future SR 509 Expressway, constructing retaining walls, earthwork, and noise walls.
“Because of our partnership and willingness to work together and be good stewards of taxpayers’ money, Sound Transit built some scope that made sense, such as shared noise walls and a retaining wall, earthwork, and a bridge,” Chepel says.
The team proposed a flyover above I-5, rather than an I-5 underpass for traffic exiting northbound I-5 to the new SR 509 Expressway. It created an easier maintenance of traffic plan and also saved money. The flyover will have concrete girders, supported by drilled shafts.
“The design-build method also provides for early cost certainty, which was helpful given this inflationary environment we are in,” Chepel adds. Additionally, “It provides schedule certainty… and provides a best value for the project.”
Crews began construction in fall 2021 and are building the first mile of the extension of the four-lane SR 509, new ramps and interchanges, and a bridge.
“It’s a fun project,” Chepel says. “It’s a good project to work on.”
Crews will build the first mile of the extension of SR 509. The greenfield location creates no interference with existing traffic.
Additionally, the team is making improvements along the 10-lane I-5, building an open-cut tunnel at Veterans Drive, adding new ramps, installing sound walls and widening a concrete girder bridge over SR 516. These improvements, especially the tunnel, will require shifting traffic to different lanes. Tunnel work is expected to begin this spring.
“This project has every possible piece of highway scope,” Chepel reports. “A tunnel, bridge, different noise walls and retaining walls, massive earthwork and some improvements to local streets. It makes you want to come to work every day.”
Atkinson Construction is using GPS and total stations. WSDOT flies drones monthly to monitor construction progress and also uses it for public education efforts.
As with most construction projects in 2021 and 2022, this one experienced issues with the supply chain, labor shortages and COVID-19 precautions.
Crews will install an intelligent transportation system with electronic variable tolling. It is expected to enhance safety and reduce congestion.
Stage 1b is scheduled for completion at the end of 2025.
WSDOT expects to issue a request for qualifications in 2023 and for Stage 2 to finish by the end of 2027.
“We really are building this project right now,” Chepel says. “It’s finishing what was started many decades ago and finally bringing improvements to communities out there today. That is exciting.”