|Crews secure a girder section that will support the|
new westbound SR 522 Snohomish River Bridge.
Widening SR 522 between the Snohomish River Bridge and US 2 in Monroe is a massive undertaking with a lot of moving parts. All along a four-mile stretch of SR 522, crews are blasting rock, building bridges, digging ponds, constructing walls and hauling out dirt to make way for two new lanes. And that’s not all. In the next year, before construction wraps up in 2014, they’ll also build a new roundabout, a noise wall and a wildlife undercrossing.
The most herculean undertaking of all is the creation of a new 1,700-foot-long Snohomish River Bridge that will carry westbound SR 522 across the river. Crews reached a major milestone last week – though daily drivers might have missed it entirely. Well below the sight of drivers on the existing highway, behemoth girders arrive daily, one by one. Crews are working steadily to piece together the new bridge, one girder at a time.
The first of 49 steel girders arrived Nov. 1, after an overland journey that began in Libby, MT, at Stinger Welding. The last leg of its journey took it up I-5 and east on US 2 to the SR 522 interchange, where it picked up a WSP escort. Each of the next 48 girders will make a similar journey to their final destination above the Snohomish River.
But getting the girders to the project site isn’t as simple as it seems. Once the trucks arrive at the existing bridge, crews have to get the girders down the steep embankment to the work area below the bridge. The solution: A temporary off-ramp. Crews took out a section of guardrail and on a rainy Tuesday night, built a temporary ramp from westbound SR 522 to the ground-level work area. They covered it with steel plates to keep the truck tires from sinking in and give the big semis some extra traction. Using brief overnight rolling slowdowns, the girders roll down the ramp and are unloaded before the trucks head back out on Tester Road.
Crews are using an army of cranes to set the first batch of girders this fall. Each assembled girder ranges in length from 150 to 305 feet and weighs between 30,000 and 55,000 pounds – and those are the small ones. The smaller girders will form the backbone of the eastern end of the bridge – primarily over land – on the north side of the river.
But the real action will come next spring, when the massive, river-spanning girders arrive on scene. These girders will be even longer and heavier than the girders we’re setting now. Crews will use huge steel rollers to launch the girders up, out and over the river, where crews will secure them between piers in the river.
Even though drivers might not see a difference as they pass by the project area each day, these girders are good news. It means that we’re one step closer to opening two new lanes of SR 522 by fall 2014. Crews pushed hard this summer to complete the piers during a limited in-water work window. Their efforts meant the girder setting – what’s known as “critical path work” in WSDOT lingo – could start right on schedule.
If you’re a westbound passenger, you might be able to catch a glimpse of the new bridge coming together as you approach the Snohomish River. For the rest of you, we’ve updated our Flickr set with photos of the work.