Imagine stumbling across 363,000 tons worth of concrete pontoons in the free section of Craig’s List.  Would you build a floating island? A massive version of Stonehenge?  Perhaps stack them on top of each other for a 33 story condo complex?

Well this is your chance to show off your idea for what our state should do with these massive blocks of concrete.  Come up with a brilliant idea, create a shiny and compelling poster to describe it, and you might win $3,000.  Head over to RETHINK REUSE for details.

520 Bridge, Wikimedia

22 Replies to “What Would You Do With the Old 520?”

  1. I suggest they just sink them in place. Each new bridge will require replacement every 50 or so years, so in about 3 or 4 hundred years of doing that, we’d just need to pave the last layer and be done with it.

  2. Will they fit through the Ship Canal? Is it feasible to tow them out to deeper water and sink them for use as reefs?

      1. The current pontoons look to be about 60ish feet wide, so they’d fit through the locks pretty easily (80’x 825′ dimensions). The Montlake Cut is significantly wider, 125 feet or so.

    1. I would assume the answer is yes. They likely cast them elsewhere, and brought them through the locks in the first place. I believe the new pontoons are being cast on one of the islands.

      1. They’re being cast in Aberdeen (Gray’s Harbor), and floated in. Check out the Popular Mechanics article for details here.

      2. Here’s a picture of the original Lake Washington sinking bridge going through the locks. Note the RR bridge in the background is still functioning but for a number of the pontoons it was a one way trip. I can’t find the photo but I seem to remember that for later bridges the pontoons were wider than the locks so they had to partially sink one side and float them through tipped up at an angle. Wish I could find that photo.

  3. I would turn them into a massive floating park…disconnect the floating parts and shift them north maybe a couple of hundred yards and hook them up to the land with some ramps so people could ride their bikes right into the water…or sit on benches and picnic on a sunny day.

    It would be like SeaFair when they close I-90.

    Then maybe I would run a gondola from each side of the lake so you could transport your bicycle. This would give everyone without a boat a chance to “get out on the lake”.

  4. 4th runway at SEA anyone? No, how about a giant concrete mushroom that could be used as a sports arena? Maybe float them up to Kenmore and recycle for use building the Seattle section from Montlake to I-5.

  5. Make them into a big square, fill the tops with dirt, anchor it, add plants and connect to the new bridge. Water source for the plants shouldn’t be tough, since Lake Washington is fresh water. There’s enough flotation available that you could even have some trees.

  6. Connect a segment to madison and the new 520 bridge bike path, for a bike path highway to downtown (and a flat route around broadmoor).

  7. Place them from Magnolia to Bainbridge Island for a test to see if we can eliminate the need of ferries from Seattle. This would reduce pollution and bring need transit corridor from the Olympics to Seattle. This is possible and it should be looked at.

    1. The floating part of the current SR 520 bridge wouldn’t even reach halfway across. Plus you’d kill the ports since it’d be blocking Puget Sound.

  8. I almost never respond to questions like this selfishly (hah!) so I’m going to indulge myself this time. If they’re still seaworthy for light use, build a super-wide pedestrian/bike/skating bridge from Sand Point to Kirkland.

    I like Matt G’s floating trees. It even rhymes.

  9. Of course, any of the ideas that involve bridges over Lake Washington or other significant water bodies would be way too expensive and would only compound our problems with maintenance costs.

    Therefore I’m in favor of a precariously-balanced floating version of Stonehenge.

  10. JUST TO MAKE SEAFAIR THAT MUCH MORE RED, WHITE AND BLUE…

    SINK ‘EM AS REEFS ALL AROUND SEATTLE AS BATTLESHIPS FIRE THEIR MAIN GUNS… SUPER HORNETS DROP SMART BOMBS… ORIONS FIRE HARPOONS… :-)

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