Saturday, November 22, 2014

MLK/Grand Ave. Viaduct


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The next installment in the ongoing bridge project is only sort of a bridge, but it's right in town and convenient to get to, so I figured I'd include it. Starting a few blocks south of the Hawthorne Bridge, MLK and Grand Avenues travel on a raised viaduct until near the Ross Island Bridge, crossing over a large industrial area and several railroad lines (as well as the upcoming MAX Orange Line). The current viaduct opened in 2011, replacing a circa-1937 viaduct designed by Conde McCullough, the state's well-known chief bridge engineer during that era.

I'd vaguely intended to go walk across the old viaduct before it was too late, but I never quite got around to it. Which is a shame, because it would have made for some interesting photos. This was one of the main highways into Portland before Interstate 5 went in, so the old viaduct was a high profile project and it was built with some interesting architectural details, including the (mostly unused) grand staircases around the bridge piers. McCullough's Yaquina Bay Bridge in Newport has similar staircases, but it's not clear why they were deemed necessary here, since this has long been an industrial area without a lot of pedestrians. The new viaduct doesn't have similar stairs, probably for ADA or bike reasons since it does have ramps in a couple of spots.

I've been told that there was once a great view of downtown Portland from the old viaduct, before the view was blocked by the ugly Marquam Bridge in the early 1960s. That was well before my time, but it reminds me of when the KOIN Center blocked the view of Mt. Hood from the Vista Tunnels. There was a lot of public unhappiness about that, but Portland doesn't have strong regulations protecting specific views like that, so legally there wasn't much anyone could do about it. There are number of vintage photos of the old viaduct on the net if you're curious about it, such as these four photos from AncientFaces.com

(Note that the old viaduct is often referred to as the "Union Avenue viaduct", that being the old name of MLK before the street was renamed in the 1980s. For what it's worth, the city of Tacoma has or had a similar-looking Union Avenue Viaduct dating to about the same era.)

By the early 2000s the old viaduct was sagging and cracking, and the state decided it had to be replaced, not repaired. Unfortunately the replacement effort took twice as long and cost three times as much as planned, largely due to building on unstable ground. Turns out the whole SE industrial area is built on a former wetland area, which was filled in with old sawdust from the enormous sawmills that once stood here. Historical accounts refer to an enormous mountain of sawdust here back when the mills were in operation; a Cafe Unknown article includes a photo showing sawdust hills on the waterfront as late as 1940. In some areas there is reportedly a 66' deep layer of sawdust below ground. That's feet, not inches. I find that hard to imagine, but news accounts insist it's true.

Some items on the new viaduct and its long and complicated genesis:

So what's it like to walk across the semi-shiny new viaduct? Not great, I'm afraid. There's a sidewalk, obviously, but you're obviously on the side of a highway here: Heavy, fast-moving traffic, with lots of trucks. I didn't see any other pedestrians or even bikes while I walked across, and the collection of road garbage along the sidewalk indicates they don't come by and clean it very often. Which is disappointing considering this is a new structure. If the city of Portland had built it, rather than ODOT, there would at least be modern bike lanes, and maybe a guardrail between traffic and the sidewalk. Although it would have also been even more expensive, and the city could easily have failed to get the job done at all.

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