Mystery Bridge update: The Horn’s Ferry Bridge and others

Photo courtesy of Luke Harden from the historic collections

Also: Another potential Mystery Bridge in Marion County gone by floods.

With plans wrapped up for the Historic Bridge Weekend and the events to take place in Marion County, combined with the plan to pay a loving ode to another historic bridge in Germany, a couple people brought the Horn’s Ferry Bridge up to my attention. Fellow pontist Luke Harden found an old postcard of the bridge when the entire structure was open to traffic. However, have a look at the photo above with the photos below. What differences can you see there?

Horn’s Ferry Bridge in the 1980s when it was open to bikes and pedestrians. Photo courtesy of Larry Brown

 

 

 

Oblique view of the spans after being converted to observation deck. Photo taken in August 2011

The difference on the through truss span is obvious: the first photo showed a pin-connected truss bridge with M-frame portal bracings. The second and third photos showed the same bridge but with riveted connections. Yet even more obvious was with the northernmost span, the pony truss. There, the top photo showed a Pratt or Howe pony truss span with pinned connections whereas the second photo showed a riveted Warren pony truss bridge.

Looking at the facts so far, the present northernmost spans were erected in 1929 by Wickes Construction Company of Des Moines. The extension of the bridge was necessary for flooding was undermining the northern abutment causing the potential for the Camelback through truss span to collapse. Yet this concern was raised as far back as 1915 by the county, which had advocated two additional spans to alleviate the problem. The river was channeled but reports indicated that the two additional spans were added in 1929. The question is:

Did the older spans exist before 1915 or between 1915 and 1929? By answering this question, we will have a better idea when the present spans, now serving as an observation deck were built. If the spans existed in 1929, the next question is:

When were the present spans built if the older spans were built in 1929? This is important because it would undermine the argument that standardized truss bridges were introduced in 1913, which phased out pin-connected truss bridges in favor of riveted truss bridges.

Any information? Please send it to Jason Smith at the Chronicles at flensburg.bridgehunter.av@googlemail.com and the information will be revealed then.

Sadly, one of Marion County’s bridges disappeared as it was wiped away. Why?

Mystery Bridge over White Breast Creek gone due to flooding.

Located over White Breast Creek at 92nd Avenue, the bridge’s aesthetical features made it a treat to see, as seen in a pic taken by a person travelling by bike. Records show that the bridge was located here in 1947 and was built ca. 1899. Yet more information is needed to determine where the bridge originated from and who built it.  Sadly, according to locals, floodwaters took the structure out last week. More on the bridge will come, but if you have any information on this bridge, you know where to find the source for information. ;-)

 

 

 

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