Take a drive along Interstate 205 between Southeast Mill Plain Boulevard and Northeast 18th Street, and it’s plain to see that a remodel is coming. Heavy equipment, work crews and unfinished foundations line the corridor.
What’s less clear is what the final result will look like. But that will change by the end of this summer.
“The next two months, you’re really going to see it take shape,” said Brad Clark, a design and construction engineer on the project.
The Washington State Department of Transportation is building a new interchange that will connect I-205 with 18th Street. The $40.6 million project will add a “half-diamond” interchange at that spot, with ramps only to the south of 18th Street. An offramp will allow northbound freeway traffic to exit directly onto 18th Street; an onramp will send vehicles from 18th Street to I-205 heading south.
Currently, there aren’t any interchanges on I-205 between Mill Plain and state Highway 500 — a stretch of about two miles. WSDOT hopes the end result improves congestion, safety and connectivity in the area, Clark said.
Crews are largely focusing on walls at this point in the process, he said, and shaping the foundations that will eventually support the new ramps. One of those ramps, the southbound ramp onto I-205, will be carried in part by a 525-foot bridge. That structure will be a major focus of the project next year, Clark said. The entire effort is expected to wrap up in the fall of 2016, according to WSDOT.
The work has already shifted the alignment of I-205 in the area. That will make room for new lanes that will stretch much farther than the current ramps. Southbound traffic wanting to get off I-205 at Mill Plain, for example, will exit near 18th Street and follow an extended ramp alongside the freeway.
The project will also alter the character of 18th Street itself, adding a roundabout to the west of the freeway. The feature is something WSDOT has included in several recent projects.
“It just helps keep traffic flowing,” Clark said of the roundabout, which will connect directly to one of the ramps. “It keeps everybody moving.”
The project won’t, however, replace the 18th Street bridge over I-205. But crews are completing seismic upgrades to the structure and another nearby bridge at Northeast Ninth Street, said WSDOT spokeswoman Tamara Hellman.
WSDOT has already fielded numerous questions from neighbors and motorists about the project during its early stages of construction, Hellman said. Answering those inquiries and keeping people informed is a big part of any major undertaking, she said.
“We want to show the work and show what we’re doing to get to the final product,” Hellman said.
The 18th Street interchange is a companion project to an earlier effort that remade the convergence joining I-205, Mill Plain Boulevard and Northeast 112th Avenue. It’s the last major project in Clark County that was funded by a pair of gas tax packages approved by the Washington Legislature in 2003 and 2005.
Meanwhile, WSDOT has used excess material from the 18th Street site to quietly prepare for another project on its wish list. Crews have hauled much of that dirt to a state-owned property near Northeast 54th Avenue and state Highway 500. WSDOT hopes to eventually build a new interchange at that intersection, which is now controlled by a traffic signal. But that project is unfunded, Hellman said.
At 18th Street, this year’s work will also include some paving by the end of the summer, Clark said. The project is being led by main contractor Cascade Bridge LLC of Vancouver.
