Name that bridge type: A mystery bridge made of salt.

Photos taken in October 2011

Our next mystery bridge is also one whose bridge type is to be identified. But before mentioning anymore about it, let us clarify what this bridge is all about. First of all, it is not made of salt, nor was there salt used in building the structure.  After all, salt and steel do not mix as the former eats away at the latter when used for any purpose, which includes deicing the roads to ensure that no cars slide around and cause accidents. Second of all, the bridge is located over a river whose Sorbian name means “salt”, and it is in a (former East) German city that prides itself on the commodity that was once treated like gold during the Medieval era. The city still mines salt along the river today and markets products made from salt, but not as much as about 300 years ago at the latest.

Going back to the bridge itself, this was found by chance while touring this river in 2011 and 12 respectively. It is one of the oldest bridges over the river in this salt city, whose construction dates back to the 1880s. It used to serve a railroad leading to an industrial district on an island that was in service until shortly after German Reunification in 1990. While the rail line and the bridge were both abandoned when the manufacturing company went out of business, the city bought the line and later converted it into a bike trail, while at the same time, the bridge was rehabilitated and received a color of green for its color, which can still be seen while biking along the river today.  The design of the bridge however reveals one of the truss designs that eventually made its way to the United States even before the time of its construction, where one can see many examples today in the New England states, Pennsylvania  and Texas. This despite the fact that: 1. The truss bridge type was developed and patented before 1860 with the earliest example known to be built in Mainz and 2. The truss bridge type was developed by two different engineers, one of which led the efforts to build one of the key landmarks in Pittsburgh in 1883, which still exists today. The design resembles a parabolical, lens-like shape, resembling a combination of a suspension and an arch bridge, supported by diagonal truss beams. It resembles that of the Prince Albert Bridge in England, which was built by I.K. Brunel in 1859.   The design was later modified by another American engineer in the 1890s even though that design never bore fruit.

The bridge was one of the first to introduce welded and riveted connections, instead of pinned connections. Pin connections meant that truss beams are connected with a series of eyebars, nuts and bolts. They’re easy to assemble and reassemble. Yet the riveted connections imply that the beams are joined by gusset plates, where they slide into place and bolted shut by bolts. Welded connections do not require gusset plates but the beams are welded together, either with or without the use of bolts. With the exception of the riveted connections between the end posts and the upper chords, much of the bridge’s connections were welded, supported by bolts. Surviving World War II, the bridge represents one of the earliest surviving examples of bridges built with these connections.

Keeping this in mind, here are some questions for you to consider and answer:

  1. What is the name of the bridge, and where is it located?  To help you, please refer to sister column The Flensburg Files and the Christmas market series to help you. You can access the Files by clicking here.
  2. What truss bridge type is mentioned here?
  3. What do you know about the bridge’s history?  A murder of a well-known politician occurred on this bridge but he was dignified as a prominent figure by the East German Socialist Party (SED) during the Cold War. A plaque can be found on the trusses, which can be seen while crossing the bridge today.

Put your thoughts and guesses in the comment section both here as well as on the facebook page.  The answers will be revealed when a bridge tour of this salt city is given, which will be later in the summer, after the tour of the bridges in Schleswig-Holstein is completed.  Speaking of that state, the next article takes us back to the Grand Canal, where one will have a look at 10 finest bridges with over 130 years of history with it.

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