By Roger Thompson

We’re gearing up for the fourth weekend full closure of the SR 520 bridge this month. Wait. What? Another closure?

The main reason streets or highways are closed to traffic for construction is so crews can get the work done more quickly, more efficiently, and more safely with fewer disruptions to motorists. Sometimes crews can perform their work by closing just part of a road. Other times, it’s necessary to shut down a highway entirely – again, to get the work done more quickly, efficiently, and safely.

In other words, get in and get out!

Another reason is to take advantage of the longer daylight and good weather we often have in Western Washington during the summer. It’s great for backyard barbecues – but it’s also great for getting a lot of outdoor construction done. Especially when it involves pouring concrete or placing asphalt. And there’s a whole lot of that going on with the SR 520 Bridge Replacement and HOV Program.

During June’s four weekend closures of SR 520, crews are pouring some 2,000 cubic yards of concrete to build the roadway deck for the new West Connection Bridge on Lake Washington (it will connect the new floating bridge with the highway’s existing lanes in Seattle). Other crews, working around the clock during the four closures, are placing asphalt for the new, six-lane highway being built on SR 520 between Evergreen Point Road and I-405.

Crews use a closed SR 520 highway and a barge as work platforms to pump concrete for the roadway deck of SR 520’s new West Connection Bridge.

Another reason for having four weekend highway closures in a five-week span is the pressing nature of the SR 520 construction schedule. Urgency is driving our weekend closures for the highway’s  Eastside Transit and HOV Project. Our contractor crews are in the home stretch of completing the Eastside’s improvements, including new transit stops in the highway’s median, lidded overpasses, roundabout interchanges, direct-access ramps for buses and carpools, and a dedicated transit/carpool lane in both directions. All this work is critical to opening the improved Eastside segment of SR 520 later this summer.

A paving crew places asphalt on the highway’s new six-lane Eastside corridor.

Crews also are working to complete the West Connection Bridge in a couple of months so that other crews can move forward with the next phase of building the new floating bridge: anchoring into position and joining together the bridge’s massive concrete pontoons, building the roadway deck, then, in early 2016, connecting it to the fixed-bridge structures on either side of Lake Washington and opening the new road to traffic.

Did we need to schedule four full-weekend closures in such a short time frame? Unfortunately, yes. The fact is there is never a good time to shut down a highway. But summer, as noted earlier, is when certain highway work can best be done. With so many community festivals, sporting events and other popular weekend happenings in the greater Seattle area, the number of “available” weekends for highway closures gets whittled down pretty fast.

More SR 520 closures will be needed this summer as we proceed with all this construction. Check our SR 520 Highway Closures page for the latest in closure information.

By Bart Treece

The name of the game is to keep traffic moving safely. But when there are several construction and maintenance projects that need to get on the road, the job gets complicated.

There really isn’t a “good” time to close part of entire stretches of highway in a large metropolitan area. However, the work needs to get done. Much of it is important for maintaining and preserving our aging infrastructure, like replacing bridge expansion joints (pdf 937 kb) on I-5 or patching the deck of the Ship Canal Bridge. Ignoring these issues would eventually mean unscheduled emergency closures that could impact your regular route to work. We all saw how badly traffic was snarled when a damaged joint needed repairs ASAP last week. This is why we try to schedule these closures when it affects the least amount of people, at night if possible. Some projects need more time, such as when there’s concrete involved which needs time to cure before its strong enough to hold the weight of hundreds of thousands of vehicles. That leaves the weekend, when fewer folks hit the roads.

The white board where closures are initially coordinated with large Seattle events and holidays

Looking at only weekends, we try to avoid four during the summer: Memorial Day, Fourth of July, Seafair and Labor Day weekend. This adds up to a whole month without weekend closures because we know those are big travel times. We’re now left trying to juggle projects on competing corridors, such as SR 520 and I-90 or SR 99, I-5 and I-405. It doesn’t take a traffic engineer to know that closing lanes in the same direction on north/south or east/west routes at the same time would be a very bad thing. Also add into the mix that there are several events including Mariners, Sounders, Husky and Seahawks football game traffic we try to take into consideration. We can’t forget weather, which isn’t always predictable in the ‘Pugetopolis’ region. The threat of liquid sunshine can push a weather-sensitive project back to another weekend.

With projects on every major route planned this summer, there’s not that many weekends left. When possible, we try to combine work to avoid spreading project impacts further along than needed.