Thursday, August 21, 2014

NW Melinda & Maywood

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Today's installment in the ongoing bridge project takes us to Portland's West Hills, at the hairpin intersection of NW Melinda Ave. & Maywood Drive, not far from NW 23rd. We're here because of an unusual arched concrete structure that supports Maywood as it climbs sharply from the intersection. I ran across it in the 2013 Oregon's Historic Bridge Field Guide, Part 4 -- the guide's alphabetical by county, and Multnomah County falls in part 4 -- which calls it the "NW Maywood Dr Semi-Viaduct" and describes it:

Nine 13-ft reinforced concrete frame spans with an arched façade
The significant aspect of this relatively simple structure is the arched façade on the frame spans which give the bridge the appearance of a Roman aqueduct. It is unknown why this sort of bridge would have been constructed in this neighborhood. Along the road underneath the viaduct is a large amount of stone masonry that may be the remnants of the previous bridge or roadway.

Thanks to the library's Oregonian database, we can answer some of the open questions in the state's description of this sorta-bridge. The aforementioned stone masonry was likely part of an early 20th Century retaining wall, which collapsed on December 21st, 1932. The article says the wall had been there for nearly 20 years. A pair of photos in the next day's paper show it really was an enormous landslide, and it's surprising that no deaths or injuries were reported. Melinda Ave. was reopened the day of the slide, but Maywood was out of commission for an extended period of time. A full year later the city still hadn't gotten around to repairing it despite residents' repeated pleas. The city eventually had to appropriate an extra $8000 for the replacement viaduct; budgets must have been very tight during the Depression. I assume that money went to build the present structure, which was completed in 1934. I don't have references for why it looks the way it does; I imagine that after all the delays and handwringing they felt they should build something that looked (and was) solid and reassuring. Or maybe it was just the contemporary style at the time. I'm not really sure about that part.

As for the present structure, it's 80 years old this year, vastly outliving its predecessor. The city's 2011 bridge inventory gives it a sufficiency rating of 59.6 out of 100, meaning "not deficient", but also notes it has a posted weight limit, gives its condition as "poor", and says it ought to be replaced at some point.

There's one other detail here, something I only realized after I looked at the map for a while and couldn't figure out what looked wrong. Melinda Avenue is apparently one of the very few roads in the city that runs east-west but is designated an avenue. There are quite a few avenues that aren't straight, but this is the only one I know of that is basically straight and runs east-west. I'm only asserting "one of the very few", though, because I haven't looked for other examples, and looking for them seems like it would be incredibly tedious. Tedious even by my usual standards, which is saying a lot.

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