With much of its foundation now in place, the Salmon Creek Interchange Project is looking up — on Tuesday, about 40 feet up.
Construction crews are hoisting concrete girders to form the skeleton of a new bridge over the northern convergence of Interstate 5 and Interstate 205. A half-dozen of the massive girders were placed upon support pilings and crossbeams on Tuesday.
Evidence of the job’s scale was more than visual. As a pair of cranes slowly lowered one 120-foot-long girder into position, a steady screeching sound carried across the project site.
“That’s the brake in the crane,” said Allen Hendy, a project manager with the Washington State Department of Transportation.
The work is part of a $133 million effort to remake the busy junction of I-5 and I-205. The final phase now under construction will add a new bridge carrying Northeast 139th Street up and over the two freeways. One main goal of the project is to improve safety and relieve congestion on nearby Northeast 134th Street. Extending 139th Street adds another east-west corridor through the area.
On Monday, crews began setting the 34 girders on three sections of the new bridge, a process that’s expected to wrap up next week. The girders are 110 to 150 feet long, and weigh up to 63 tons each, according to WSDOT.
But that’s just the first batch — a total of 133 girders will eventually carry the bridge in nine sections over the freeways.
For now, the process doesn’t directly affect freeway traffic. Work is happening to the west of I-5, where there’s no existing roadway yet. That provides ideal conditions for crews to bring equipment and materials into and out of the project area, Hendy said.
“The access to this site is phenomenal when it comes to building a bridge like this,” he said.
The girders themselves arrive by truck from Tacoma. Each is carried on a rig with two drivers: one in the truck itself, another steering a specially designed trailer under the load. The deliveries will cause temporary delays on local roads as crews bring the girders onsite, according to WSDOT.
Later this spring, girder-setting above I-5 and I-205 will mean complete closures of both freeways, but never both at the same time. Even now, WSDOT cautions motorists to avoid rubber-necking or otherwise becoming distracted while passing the highly visible project.
“There’s a lot of responsibility on drivers to be mindful of their surroundings and stay focused on the road,” said WSDOT spokeswoman Heidi Sause.
Once the girders are in place, additional concrete and rebar will form the bridge deck itself, said Ron Phillips, superintendent with lead contractor Max J. Kuney Company. That will happen gradually, he said, as the rest of the supports take shape.
The Salmon Creek Interchange Project is a joint effort between WSDOT and Clark County. Earlier phases built a new park-and-ride lot, improved local roads and expanded the freeway. The project is schedule for completion in 2014.