Cobban Bridge To Be Replaced: Truss Bridge’s Future Unknown

CHIPPEWA FALLS, WISCONSIN-  Imagine this situation for a second: You have an old but very unique historic bridge with a history that binds two communities together. After being built 120 years ago, it was relocated to its present site during its 20th year and remains in use until structural problems force the county to close the bridge and plan its replacement. The bridge is located near a bike trail that used to be a railroad line connecting the two communities. While the public is really attached to the bridge, the county insists on building a new bridge at its current site because the cost for even restoring the bridge is far more than just tearing it down and replacing it. Because of its history and unique design, the bridge is listed on the National Register of Historic Places, which makes funding for restoring the structure easier to achieve than it is when removing it using federal funds. Yet funding for restoring the bridge is hard to find. What do you do?

Do you:

  1. Proceed to tear the bridge down and replace it?
  2. Get a second opinion about the cost of evaluating the bridge and find ways to fix the bridge for continued use?
  3. Build a bridge alongside the sturcture and convert the old bridge into a pedestrian crossing?
  4. Build a new bridge at its original site but find constructive ways to relocate the bridge or use part of the structure- especially along the bike trail?

In the case of the Cobban Bridge, a two-span Pennsylvania through truss bridge spanning the Chippewa River southwest of Cornell in western Wisconsin, the situation is very precarious, for the historic bridge, considered eligible for the National Register of Historic Places because of its history and unique design, has met the end of its useful life as a vehicular crossing. Yet costs for restoring vs. replacing the bridge have forced county officials to look at other options apart from rehabilitating the bridge in place or building a new structure alongside the old one. In other words, the bridge cannot remain in its current place and must go.

Since August 2, the bridge has been shut down to all traffic including pedestrians, and talks are underway for securing funding for the bridge’s removal in place of a new strucure. This also includes looking at options for reusing the bridge, which when looking at the drone video, it’s a real beauty:

Yet inspite of its beauty, the Cobban Bridge will most likely have to make its third move in its lifetime, unless financial support for reconstructing the bridge at its current location combined with constructing a new bridge alongside the structure is realized, not just on the government level but also from the private sector.

When the bridge was first built in 1908 by the Modern Steel Structures Company, based Waukesha, the two-span Pennsylvania through truss bridge was over the Chippewa River between the townships of Anson and Eagle Point. The bridge was christened the Yellow River Bridge even though it was located one mile north of the Yellow River itself. Replacing the iron bridge built years before, the structure had the same features as the one at its present location: it was made of steel, had pinned connections, overhead V-laced strut bracings and a three-rhombus Howe lattice portal bracings with 45° heel bracings. Ten years later, as part of the plan to construct a dam along the river near Chippewa Falls (and subsequentially inundate the crossing upstream), the bridge was relocated 15 miles downstream to cross the same river between Cornell and Jim Falls near the village of Cobban. The bridge has been in service since then- all 486.5 feet in length; each span, being identical and having a length of 241 feet.

Despite this, planning has been in the works to replace the Cobban Bridge, even though the two-span Pennsylvania through truss bridge is not only the last one of its truss type left in the state, but it is the only multiple-span bridge of its kind in the country! Inspections and estimates have revealed that restoring the bridge to be reused even for pedestrian purposes would be $13-14 million. A report presented by a well-known bridge builder, AECOM (whose regional office is based in Stevens Point in northern Wisconsin) revealed that replacing the bridge on a new alignment would cost $11 million, up from an estimated $7.2 million that was figured in March 2016. If delayed until 2025, the price would be lowered from $12.9 million to $8.6 million at the site where the bridge is located. Tearing the bridge down would cost $1.6 million. Established as a conglomerate in 1990, AECOM has its headquarters in New York but dozens of offices throughout the country as well as Europe. While its specialty is designing and building state-of-the-art buildings and modern bridges, for restoring historic bridges, its only focus has been on stone arch bridges, which included Grobler’s Bridges in South Africa and the Railroad Viaduct over the Neisse in Görlitz, at the German-Polish border. County officials and supporters of the Cobban Bridge are dissatisfied with the results provided by AECOM. Yet all parties have agreed to one thing, if the bridge is unsafe, then something has to be done about it.

Because of its design and historical integrity, the bridge is elgible for listing on the National Register of Historic Places, which means environmental and cultural impact surveys (especially those in connection with Section 106 of the Preservation Laws) are to be undertaken before any work on replacing the bridge was to commence. According to Marilyn Murphy, who has started a facebook page on Saving the Cobban Bridge and has over 2000 followers, the surveys are already underway. As the project will require federal money, state and local authorities are mandated to allow the surveys be undertaken to determine the impact of replacing the Cobban Bridge, while looking at alternatives for reusing the bridge. Several other agencies have been involved in looking for options for the bridge, including the Texas-based Historic Bridge Foundation, as well as the Chippewa County Historical Society. The key variable that is known, according to Murphy, is that the county would like to relieve themselves of legal responsibilities for the bridge and would gladly like to give the bridge to any third party member wishing to take responsibility for maintaining the structure, including its relocation.

So with the bridge available for the taking, what options are available for the Cobban Bridge?

In the interview with the Bridgehunter’s Chronicles, Murphy presented a long list of possibilities for reuse. This includes using portions of the bridge along the Old Abe Bike Trail, which runs along the Chippewa between Lake Wissota and Brunet Island State Parks, relocating one or both spans back to the original Yellow River site, using one span for a state park, or even purchasing parts of the dismantled span (boards or beams) as remembrances. However, as mentioned earlier, there is interest in keeping the two spans in its original spot- a practical and most logical choice, yet two variables are lacking: funding and expertise. Funding because it is likely that regardless of ownership- be it through the state with the Department of Natural Resources (which owns the Old Abe Bike Trail), private-public partnership or simply pure ownership- funding will need to be found mostly through private sources, including donations from companies and citizens. This would be needed to renovate the bridge to make it a viable crossing for pedestrians and cyclists and incorporate it into the bike trail. Expertise would mean looking at companies that have restored bridges like this for recreational use, and there are enough both in-state as well as out-of-state to go around. Even if the bridge is to be relocated again, these two variables are going to be key in order for the bridge to live on.

What needs to be done in order to prevent the demise of the Cobban Bridge?

We know that the bridge has been declared off limits for all traffic, including pedestrians and cyclists- at least until the environmental impact and cultural surveys are completed, which can take 6-12 months or more to complete (including alternatives for reusing the bridge both in place and elsewhere).  Without that there is no federal funding that can cover 80% of the costs for the bridge. There has been a lot of public support and sentiment towards the Cobban Bridge and ways to save and reuse the structure, yet the approach of doing-nothing is not an option. This was already seen with the Wagon Wheel Bridge in Iowa, and its neglect, combined with vandalism and the lack of maintenance resulted in the “Triple GAU” consisting of arson, collapse and in the end, the removal of the remaining structure in 2016. There are a lot of ideas for reusing the bridge- be it in place or at a different location (even in segments), and the county is ready to hand over the keys that will unlock the gates that have closed off the structure since August, forcing travelers to detour to crossings at Jim Falls and Cornell. Yet, like with the Green Bridge in Des Moines, Iowa, which has been reopened since the end of last year, a group or alliance will be needed that will take over ownership and assume full responsibilities of the bridge and assure that it is safe for use. And speaking from experiences of others, the going may be tough at the beginning, but after a series of fundraisers and other events to help restore and reuse the bridge, the Cobban Bridge may have another life beyond that of horse and buggy, the Model T and lastly, the Audi.

 

If you would like to help restore and/or reuse the Cobban Bridge, you can visit its facebook page (here) and contact Marilyn Murphy at this address: mjmurphy1970@gmail.com. She’s the main contact for the bridge and can also provide you with some other contact information of others involved with the project. She and her husband Jim were nice enough to provide some pics of the bridge for this article.  The Chronicles will keep you posted on the latest on the Cobban Bridge and the steps that will be needed on the structure’s future, regardless of which direction it is taken.

 

   

Leave a Reply