This bridge is slightly shorter than the Freeport Bridge, and at the time of demolition was considered the third longest historic bowstring truss span in the country. The bridge retains good historic integrity, having served vehicular traffic for 137 years. Over this large period of time, only one significant alteration occurred on the superstructure, which was that one vertical member was replaced. It appeared that the substructure had been redone at some time.
The bridge includes typical Wrought Iron Bridge Company bowstring details as outlined in the original patent. The top chord is a Keystone column. Sway and portal bracing are latticed. Some verticals are latticed, while other verticals are made of built-up star-members (cruciform members). There are cast iron connection assemblies on the bridge, including a six point intersection assembly for the truss web. Original fishtail style floorbeams remain on the bridge. The floorbeam caps are cast iron and include a decorative star design. Unusual etch marks on edges of the metal on the keystone column top chord at rivet points appear to have been some sort of measurement aid, the exact purpose of which is unknown.
Lee J. Bjerke P.E., Winneshiek County Engineer commented that contrary to what was previously thought, the bridge did not always cross the Turkey River, but originally spanned the Upper Iowa River until 1939, when it was replaced relocated to the Turkey River in 1941.
As if Iowa's insane amount of flooding that seems to plague the state in 2010 and the past few years which in 2010 resulted in the collapse of two bowstring truss bridges was not bad enough, this bridge was demolished and replaced.
The demolition of this bridge represents one of the most historically significant bridges ever to be demolished since HistoricBridges.org was founded in 2003. The third largest span of its kind remaining in the country, an example of one of the rarest and oldest types of metal bridge in the country, and nearly completely unaltered from its original construction, the loss of this bridge is beyond devastating to the transportation heritage of the United States. As important as preserving any remaining examples of this type of bridge is, no amount of bridge preservation can ever fill the void left by the loss of this bridge. All that can be done now is to preserve what's left in the hope that at least part of this loss can be mitigated.
The collapse of two bowstring truss bridges and the demolition of a third in a mere single year in Iowa shows that Iowa is on a path to losing its recognition as the iron bowstring capital of the country.
The demolition and replacement of this nationally significant 137 year old iron bowstring truss bridge is also perhaps one of the most perfect examples of how hopelessly and completely broken and wasteful the surface transportation funding system in the United States really is.
Winneshiek County originally planned to replace this bridge in Summer 2010, but was going to relocate this historic bridge to a park/trail setting near Decorah where it would sit as an exhibit, similar to the aforementioned Freeport Bridge. While, this preservation solution may initially seem less appealing that rehabilitating the bridge in place or placing it over a river for non-motorized use, this solution would not alter the original design and high level of historic integrity the bridge enjoys. It was also a relatively low cost preservation option. Also, there was no reason why in the future, the bridge could not have been moved again and fully restored if a more functional preservation solution became available.
So, you thought a nationally significant 1870s iron bowstring was going to be preserved? You thought wrong. Even as a low-cost preservation solution, the final estimated cost for relocating the bridge came in higher than the county expected. Also, in-house funds at the county level were extremely tight, especially with the economic downturn that started in 2008.
Logic would suggest that if funds were tight and the economy was either in recession or recovering from a recession, plans to replace this rural bridge with a new bridge might be canceled and a less expensive repair or rehabilitation solution for continued light vehicular use of the bowstring might be devised. However, the United States surface transportation funding system at the federal level and often the state level as well provides far more funding assistance for projects which demolish and replace a bridge, than those projects that would fund the repair or rehabilitation of a bridge. Further, next to zero historic bridge targeted funds are available for the rehabilitation of a historic bridge unless the bridge can be described as a "wooden covered bridge." As such, although the Little Church Road Bridge had far more historic significance and was also much older than the majority of surviving covered bridges, no funding was available for it. As such, less county funds were needed to demolish and replace the bridge, and from the county perspective it was cheaper to destroy the third largest bowstring span in the country and replace it with an ugly slab of concrete, even though a repair or rehabilitation for light vehicular use would likely have cost far less combined total tax payer dollars.
This system of funding, which essentially rewards local agencies for deferring maintenance and letting their bridges deteriorate by providing them with funding for demolition and replacement of structurally deficient bridges, while at the same time discouraging the repair and rehabilitation of bridges is why the United States has perhaps the most wasteful surface transportation funding system on Earth and perhaps beyond. Not only has it resulted in costly replacements taking place when repair or rehabilitation is feasible or less costly, it has increased the number of bridges with serious structural deficiencies being on today's roadways. Worst of all, it has resulted in the senseless destruction of countless numbers of our nation's beautiful historic bridges. Only with a system so broken and wasteful would an economic downturn result in the demolition of a nationally significant historic bridge, when a repair and rehabilitation project could have preserved the bridge and also cost less money.
How should a proper surface transportation funding system work? Take a look at Europe, especially the United Kingdom and France. Citizens of these countries must either laugh or shake their heads in disbelief when they look at the roads and bridges of the United States. There are bridges that are hundreds of years older than historic bridges in the United States, and these ancient European bridges are in far better condition and continue to be used for vehicular traffic. Why? Simply because they are maintained. Europeans enjoy bridges that are in better structural condition, and they enjoy the continued and unthreatened existence of their historic bridges. Also, many countries, particularly Germany, have greater protection for historic bridges, making it more difficult to proceed to a demolition project for a bridge, particularly extremely rare nationally significant bridges like Iowa's Little Church Road Bridge.
Organizations such as AASHTO, ASCE, and other agencies might often seem at odds with historic bridge preservationists because these agencies often seem to be fighting to get more money from the federal government, money that is usually used to demolish and replace historic bridges. However the reality is that both these organizations and those historic bridge preservationists who are properly informed actually share the same goal: getting additional federal funding for surface transportation with the goal of improving the condition of our roads and bridges. However, the difference is that preservationists place a greater emphasis on getting increased and more flexible funds for use on bridge maintenance, repair, and rehabilitation, and that these funds should be more readily available than demolition and replacement funds. There should also be expanded flexibility for the use of such funds on bridges, even when these repairs might not bring a bridge up to 21st Century AASHTO guideline standards, particularly for those many bridges that are historic and are located in locations with low traffic volumes. HistoricBridges.org believes that such reform could lead to reduced overall cost to maintain the nation's roads and bridges. It would encourage agencies to put more money into routine maintenance and repair, thus increasing safety and reducing the number of instances where inconvenient bridge closures would be required for costly total structure replacement.
Bowstring truss bridges are sometimes called bowstring arch bridges because they have similarities to both structure types. Beginning with Squire Whipple's Whipple Arch Bridges, such as the Ehrmentraut Farm Bridge, the bowstring truss bridge is the bridge type that began a transition away from wood and stone and began to make metal a common bridge building material. It also began a period of experimentation until a good bridge form was developed, leading to a gradual standardization of bridge design. During this period, numerous bridge companies all experimented with metal, trying to design the best bridge. Each company had their own distinctive bowstring design, including unique and creative design details. These designs were often patented. Most bowstring truss bridges were built in the 1870s. Also during this time, cast iron was still used in addition to wrought iron for the construction of bridges, so many bowstrings built during this period include details such as connection assemblies that are made of cast iron. By the 1880s, bridge companies decided that the pin-connected Pratt truss was a better structure type, and construction of bowstring bridges sharply dropped after 1880. Because of the period in which Iowa was first being settled, a much larger number of bowstring truss bridges were built in the state than in other states. As a result, even today, Iowa has more historic bowstring truss bridges than any other state, although the number of bridges statewide is under 20, a very small number. However, a number of states do not have even a single historic bowstring truss within their borders. As such, while bowstring truss bridges are very few in number in Iowa, they are extremely rare on a national scale. It is imperative that each surviving bowstring in the county be preserved to protect this key period in bridge building history.
Historic American Engineering Record created a large and very informative historical overview and context for Iowa's bridges, and it is offered here by HistoricBridges.org in convenient PDF format for easy printing or offline viewing. The HAER source for the documents composing the PDF is here.
In its discussion about a single bowstring bridge, Historic American Engineering Record included a detailed description of the Wrought Iron Bridge Company and a general history and discussion of its bowstring truss bridges in general. HistoricBridges.org has clipped this section for convenient viewing in PDF format. The HAER source for the documents composing the PDF is here.View Bowstring Arch Bridges of Iowa, An Online Book By Michael Finn (PDF)
Michael Finn has composed a concise and detailed overview of Iowa's beautiful historic bowstring bridges. It has been made available for free by Iowa Department of Transportation.View Historic American Engineering Record's Structural Analysis of Iron Bowstring Bridges (PDF)
Historic American Engineering Record created a large and very informative structural analysis of how bowstring truss/arch bridges function. Everything from basic discussion of the engineering behind the bridges to advanced mathematical equations are available. The HAER source for the documents composing the PDF is here.
Information and Findings From Iowa's Historic Bridge Inventory
Discussion of Bridge
Among the Winneshiek County bridges included in Iowa's
historic bridge inventory is this 12-panel bowstring through arch. The structure
crosses Turkey River south of Festina in southern Winneshiek County. The
wrought iron arch dates to 1873. In the spring of that year Washington Township
citizens presented the county bridge commissioner with a request for a permanent
bridge over the Turkey River. The commissioner, after reviewing the petition,
agreed that there was a justifiable need for a crossing at this location,
but decided to delay action owing to the county schedule, already replete
with new bridge construction. Soon thereafter the bridge over the Turkey
River was evidently approved by county officials and let out to bid. The
structure was fabricated and erected by the Ohio-based Wrought Iron Bridge
Company, often contracted by Winneshiek County, for an undisclosed amount
of money. The truss's bridge plate reveals that the firm completed the bridge
the same year. Excluding a deck replacement in 1978, the Turkey River Bridge
continues to carry local traffic in virtually unchanged condition.
Bridge Considered Historic By Survey: Yes
This bridge is tagged with the following special condition(s): Keystone Columns
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