Drivers on eastbound state Route 16 will encounter nighttime detours and delays over the next several weeks as work crews lift 83 massive concrete girders into place on top of new support piers in Tacoma’s Nalley Valley.
Construction crews have spent the past three months building the concrete piers that will support overhead roadways connecting eastbound Route 16 with both directions of Interstate 5, as well as new I-5 connectors from the Sprague Avenue overpass.
Starting Monday night, they’ll be setting in place the precast girders that will span the piers and form bases for new roadway surfaces. The girders are 9 feet tall and measure from 104 feet to 190 feet in length. They weigh from 130,000 pounds to 240,000 pounds each.
Lifting the girders into place is going to mean occasional nighttime road closures of surface streets and the eastbound Route 16 mainline through the middle of August, according to the state Department of Transportation.
“For safety, you pretty much have to stop traffic as you’re flying these things through the air to put them in their ultimate place,” said Neal Uhlmeyer, the department’s project engineer.
The construction work is part of a $500 million project intended to streamline the complex intersection of I-5 and Route 16, the busiest in Pierce County.
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. The 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 more than halfway through work on the eastbound elements of the interchange, a $125 million job expected to take until May or June 2014 to finish.
The girders being used on the job were manufactured by Tacoma’s Concrete Technology Corp. They’ll be trucked to the job site, Uhlmeyer said, either onto the closed mainline of Route 16 or surface streets. From there, giant cranes will hoist them from the truck beds to the tops of the piers.
At the widest point of the new roadways, the stretch between Center Street and South Tacoma Way, 11 of the girders will be placed side by side to support the road deck.
The road decks will be constructed by placing wood floors across the girders and pouring concrete over them, Uhlmeyer said.
The largest girders — those 190 feet long — will be used to build spans across South Tacoma Way and Center Street, Uhlmeyer said.
Rob Carson: 253-597-8693