Highway construction crews working in Nalley Valley are expected to pass a significant milestone Thursday, hoisting the last of the giant concrete girders that support the $300 million overhaul of the intersection of state Route 16 and Interstate 5.
The last of the girders, which will be lifted over South Tacoma Way, are the final puzzle pieces in the reconfigured network of elevated bridges and ramps that connect the two freeways.
Construction crews have been working on the project for more than five years.
“This is very significant not only for the project, but for the traveling public as well,” said state Department of Transportation spokeswoman Claudia Bingham Baker. “We’ve had many nighttime closures of state Route 16 to accommodate these girder lifts, and now those will be coming to an end.”
The last girders will help support new access ramps from Sprague Avenue to both directions of Interstate 5. The two ramps are scheduled to open in July.
Most of the roadway surface on the main portion of the new ramps has already been poured, Bingham Baker said. Work that remains is mostly electrical, including signals, lighting and ramp meters.
“We’re looking at opening up the ramps at the end of July,” Bingham Baker said, “but that won’t be the end of the work. After they’re open to the public, we’ll still have to do some demolition work on sections that the public is off of.”
When the new ramps open, the Department of Transportation will reconfigure the much-criticized Sprague Avenue interchange, which during the past three years of construction has forced drivers exiting Route 16 at Sprague to negotiate a tight 90-degree turn at the top of the exit.
Work on the Nalley Valley interchange was divided into two separate construction projects — westbound and eastbound.
The first phase of the project, a $184 million job that realigned the westbound half of the interchange, took 2½ years and was completed in June 2011. That phase included building 10 bridges, pouring 48,000 cubic yards of concrete and sinking 77 supporting piers as much as 70 feet deep.
Crews now are just three months away from completing work on the eastbound elements of the interchange, which included relocating the eastbound mainline of Route 16, building seven bridges and constructing the Sprague ramps.
Rob Carson: 253-597-8693