Friday, May 31, 2013

Baltimore & Ohio Railroad Bridge #463

Baltimore & Ohio Railroad Bridge #463

As I mentioned recently, I have a bunch of bridge photos from my brief trip to Cleveland last year, and I'm starting to think maybe I ought to post some of them. (By now you may have noticed this isn't really an up to the minute, breaking news sort of blog.) So here are a few photos of the Baltimore & Ohio Railroad Bridge #463, a former railroad bridge on the Cuyahoga River in downtown Cleveland, just north/downstream of the ginormous Detroit-Superior Bridge. It hasn't functioned as a bridge in quite some time, but apparently it's considered iconic now and they're keeping it around in a permanently raised state. People more pedantic than I (and yes, they exist) might want to argue whether it still counts as a bridge, if it's permanently open and no longer bridges anything. I'm going to punt on that and call it an unanswerable philosophical question, and go ahead with this post on the grounds that I have photos of it, and it sure looked like a bridge when I took these photos. Cleveland Memory quotes the book Bridges of Metropolitan Cleveland about it:

The next movable bridge on the river is known as Bridge No. 3. This bridge is also a B. and O. Railway Bridge. Built in 1956, it is a record-making, jackknife located just north of the Detroit-Superior Viaduct. It replaced a Scherzer rolling lift bridge that had a main span of 161 feet. The present structure has a main trunnion bascule span of 255 feet long and a clear channel distance of about 231 feet. It carries a single track on the 22-foot width of the trusses. There is a vertical clearance of about 23 feet from the top of the track to the bottom of the counterweight when in the lowered position. The substructure consists of two concrete piers with 30-inch steel caissons and 10-inch pipe piles. This bridge is an outstanding example of a single-track, jackknife bascule bridge. In this peculiar type, each rail is supported directly upon the lower chord of the truss. When the bridge is opened, the span pivots around one end. The weight of the bridge is balanced by a weighted lever arm supported by the tower located at the fixed end of the bridge. When in open position he lever arm folds against the upright truss -- hence the name "jackknife". However, J.A.L. Waddell, in his monumental work Bridge Engineering, dubbed this type as a "freak" and dismissed it as "defunct"." (It was first used in 1845 at Manchester, Massachusetts.)
Baltimore & Ohio Railroad Bridge #463

Thanks to the magic of the interwebs, the full text of Waddell's 1916 book is also online. Waddell was no fan of the jackknife bascule design, and described it thusly:

Jack-knife or folding bridges were a freak design that passed out of existence more than a decade ago. Two of them were built in Chicago but they proved to be so light and vibratory and were so continually out of order that they were soon removed. Each half of a jack-knife bridge consists of two steel towers, from the top of which are suspended by tie-rods the two leaves of the floor. These are hinged together at their point of junction, and when the draw is to be opened this point rises, the other ends of the leaves move downward, and each half of the floor assumes the position of an inverted V. In this position a portion of the space between the piers is left free for the passage of vessels; and it was claimed that "the raised floors form effective guard gates." Unfortunately, though, the said guards are badly placed, as there is left in front of each of them a big opening in the floor for animals and vehicles to fall into.

Concerning this type of structure in 1897 the author wrote thus in his "De Pontibus":

"The jack-knife or folding bridge is a type of structure which is not at all likely to become common. There have been only two or three of them built thus far, and they have been often out of order; moreover, considering the size and weight of bridge, the machinery used is powerful and expensive. The load on the machinery while either opening or closing the bridge is far from uniform, and the structure at times almost seems to groan from the hard labor. The characteristic feature of the jack-knife bridge is the folding of the two bascule leaves at mid-length of same when the bridge is opened. The loose-jointedness involved by this detail is by no means conducive to rigidity, nevertheless these structures are stiffer than one would suppose from an examination of the drawings. The Canal Street Bridge, Chicago, is of this type; and its design is illustrated in "Engineering News" of December 14, 1893."

Anyone desirous of learning more concerning this defunct type of movable bridge is referred to "Engineering News", Vol. 25, page 486, and Vol. 30, page 480.

Sadly I haven't found an online archive of century-old Engineering News issues yet, though, so the trail seems to end here. Which is a shame since I'd like to see a description of the design by someone who's not completely dismissive of it. I ought to point out that this bridge was built in 1956, forty years after Waddell declared the design "defunct". So I'm not certain that we can take his opinion as gospel in this case, despite his considerable resume in the bridge business. His firm, Waddell & Harrington, was involved in the aforementioned Detroit-Superior bridge, as well as several here in Oregon: The Interstate Bridge, the Hawthorne, the Steel Bridge, the Sandy River Bridge in Troutdale, and the Union Street Bridge in Salem, among others. They seem to also be behind the OR-99 Columbia Slough bridge, and the 12th Avenue Viaduct over Sullivan's Gulch / I-84 (about which there's a post on the way, sooner or later).

Baltimore & Ohio Railroad Bridge #463 Baltimore & Ohio Railroad Bridge #463 Superior Viaduct

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