SR 99 Aurora Bridge Fence project delayed, but still on track

by guest blogger Greg Phipps

If you’ve been paying attention to our Aurora Bridge Fence project in Seattle, I can understand if you’re a little confused.

Initially, we expected construction would start this January. Then the start was delayed to February, then, March and April and May. But at the start of April, we learned that construction would start much earlier, on April 21. Now it’s early May and we’re still waiting to start. Why the delays? The best way to explain it is the story of Plan A, Plan B, and Plan C.

Plan A – “The Buggy”
Last fall Massana proposed to install the fence using equipment stationed on the bridge’s sidewalk. This became known as the “buggy”. The buggy would run on rails and was equipped with ladders and work platforms that extend out over the bridge railing and down to the outside of the bridge.

We expected the buggy to be ready in January, but WSDOT bridge engineers were concerned about the buggy’s weight and worked with Massana’s engineers for several months to ensure it met strict safety standards. The safety review process took longer than we expected, but by the end of March we were ready to move forward with the buggy. Bridge buggies don’t come off the shelf, though; they must be custom built and this one would be ready in late spring. While the delay was frustrating, we believed it was worth it. Working on the sidewalk meant daytime work with few lane closures and the added benefit of reducing construction noise effects.

Our bridge engineers also required that Massana install extra supports underneath the sidewalk for extra support. This work would start about a month earlier, on Monday, April 19, and at night until the buggy showed up. News of the start of construction appeared all over local TV, newspapers, radio and blogs and even on the website of England’s most popular newspaper, the Daily Telegraph.

Then we got the bad news. Just 10 hours before construction was to start Massana told us they were abandoning the buggy plan. Turns out the manufacturer of another sidewalk buggy (yes, there’s more than one) raised a patent issue. So it was on to Plan B.

Plan B – Exit the Buggy, enter the Hydra Platform
Massana had a backup plan -- the Hydra Platform, and they’d be ready to go on Wednesday night, April 21.
This was a true bad news/good news scenario. The bad news was the Hydra Platform was much bigger than the buggy and would require closing two lanes on the bridge. Crews would also work at night for the duration of the project. Working at night helps keep traffic moving during the day, but the tradeoff is construction noise while people are trying to sleep. The good news was that we wouldn’t need to add the supports under the sidewalk and could start fence work 4-5 weeks earlier than we expected. Even better, tests of our contractor’s equipment indicated the work would not be nearly as loud as we expected. Things were looking up, or so we thought.

That Wednesday, Massana told us that there was a problem with the Hydra Platform. Once again work was postponed.  We waited a week and on April 28, discovered that the problem was bigger than we thought. The Hydra Platform didn’t have enough clearance with its outriggers extended to reach the work area. So what’s Plan C?

Plan C – Two custom-built work platforms.
Massana is now building two bridge access platforms customized to work on the Aurora Bridge.  Massana says they will be delivered in early June and then assembled on site. Construction on the bridge would start a few nights after that.  The two platforms will allow multiple crews to work on the bridge at the same time, speeding up fence construction.

While Massana is waiting for these platforms they are taking some additional steps that should save time so that they can complete the fence on schedule.

  • Before the new rig shows up, they plan to work from under the north and south ends of the bridge using a boom lift (aka cherry picker). This work will likely start sometime in May after obtaining permission from the city of Seattle.
  • Secondly, they plan to do a portion of the fence assembly off site instead of during fence installation.