Question: What is all the rock ground support construction along I-5 northbound, approaching the Portland Avenue exit?
The first construction enabled the parking of what seemed to be trailer containers parked close together.
Now there is additional rock construction just west of the original construction. What is all that for, and who utilizes it all? — David Lewtas, Tacoma
Answer: It’s all connected to the Washington State Department of Transportation’s efforts to widen I-5 to accommodate high-occupancy vehicle lanes in that area. To do that, they’re demolishing and rebuilding the Pacific Avenue and McKinley Way bridges.
According to WSDOT spokeswoman Claudia Bingham Baker, the original rock was placed there to create a support pad to hold portable water tanks, which, as you say, look like shipping containers.
The tanks are being used to treat stormwater runoff from the construction zone. It’s a temporary system only and will be dismantled after construction.
“The second set of rocks is being used as a basic roadway for construction equipment to access that area,” Bingham Baker said. “Crews need access because they’re building a biofiltration swale system there, which will be the permanent water treatment system once construction is done.”
If you want more information about the construction project, check out this WSDOT link: wsdot.wa.gov/projects/i5/ MStToPortland.