Monday, April 19, 2010
There are ten highway bridge spans across the Willamette River in Portland, connecting downtown with the eastside, and forming an important part of Portland's identity both economically, historically, and visually. The bridges standing today range in date from the 1910 Hawthorne Bridge to the Fremont, built in 1973. They represent a veritable "Who's Who" of American bridge engineers (David Steinman, Ralph Modjeski, Gustav Lindenthal and Waddell-Harrington…not to mention Joseph Strauss), They serve as a sort of one-spot shopping exhibit of bridge forms. There are deck trusses, vertical lifts, bascules, thru trusses, suspension and one of the longest tied-arch bridges in the country.
Portland, a growing and bustling city, has continually "messed" with its bridges, to lengthen their approach spans, to widen their decks, to keep them a vital part of an ever-changing transportation system that began to serve trains, trolleys and foot traffic, evolved (or contra-wise) to serve automobiles and buses, and now, once again, in some cases, again serves an electric powered trolley [MAX] along with cars, buses and bicyclists. One of the more recent changes involved the Morrison Bridge, built in 1958, and while that change was necessary to let Portlanders get across the river, it was determined to be an Adverse Effect under the Section 106 process. And, like all Adverse Effects, Multnomah County and the Oregon Department of Transportation had to develop a plan to "mitigate."
What they agreed to do, and what I am honored to be able to research and prepare on their behalf, is a National Register Multiple Property Submittal on the Willamette River Bridges of Portland. I have a little chart hanging in front of my computer, with each bridge's form, it's designer and "vital statistics" in an effort to keep them straight. So far it's only partially working but I'll get it eventually. I sure don't have any trouble remembering the St. Johns….an expensive, and comparatively under-used span that at least one historian termed a "mistake" from a financial standpoint. But it sure is a beautiful design.