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.

 

   

The Bridges of Chippewa County, Wisconsin (USA)

Cobban Bridge on the Chippewa River. Photo taken by Steve Conro in 2009, used with permission

The last of the three part Wisconsin bridge tour takes us to Chippewa County. With 62,415 residents according to the latest US Census survey, the county is part of the greater Eau Claire economic metropolitan area. While Chippewa Falls, with a population of over 13,000 inhabitants, is the county seat of Chippewa County, it is located approximately 15 km north of Eau Claire. Even sections of Eau Claire are located in Chippewa County. The county’s origin comes from the Chippewa River, christened by the Obijwe tribes.  There is a lot to see and do in Chippewa County, as it annually hosts the Northern Wisconsin State Fair and two music festivals near Chippewa Falls.  Seymour Cray, an inventor of the supercomputer, was born in the county seat, and a research center was created after him. And the Leinekugel Brewery Company got its beginnings in the county, even though the name itself is purely German.

Yet the county has its share of historic bridges to choose from, one will find some rarities, mostly inside the city limits of Chippewa Falls but also along the Chippewa River and Lake Wissota. This includes the Cobban Bridge, which is the last remaining Pennsylvania through truss bridge in the state. Yet one of the bridges, a railroad bridge, was a site of tragedy caused by an arsonist not respecting the rights of private property. This segment will be divided up into roadway and railway bridges, with the latter being commented by John Marvig, who visited the region this past May.  He, J.R. Manning, Bob Gile and Steve Conro provided the photos of the bridges for you to enjoy.

 

Roadway Bridges

Oblique view of the Cobban Bridge. Photo taken by Steve Conro in 2009, used with permission

1. Cobban Bridge

Location: Chippewa River just off Hwy. 178 at Cobban

Type: Two-span Pennsylvania Petit through truss bridge with 3-rhombus Howe lattice bracing and 45° heels

Built: 1908 by the Modern Steel Structures Company of Waukesha.

Dimensions:

Length of largest span: 241.2 ft.
Total length: 486.5 ft.
Deck width: 16 ft.

This bridge was originally constructed over the Yellow River between Eagle Point and Arthur Townships. With the construction of the hydroelectric power plant six kilometers from the bridge in 1916, the two townships agreed to relocate the bridge 25 kilometers upstream to its present spot over the Chippewa River.  It is the last of the bridge of its type in Wisconsin and one of the rarest you will ever see with two spans of the same truss design. It has become a point of attraction thanks to the state tourism board and given its pristine shape, it will remain in use for many years to come.

 

Barrel shot of the bridge. Photo taken by J.R. Manning in 2009, used with permission.

2. Bridge of Pines (Rumbly Bridge)

Location: Ravine on Erma Tinger Drive at Irvin Park in Chippewa Falls

Type: Three-span pony truss bridge

Built: 1907 by Wisconsin Bridge & Iron; Altered 1913 by Worden-Allen Co., both of Milwaukee

Dimensions: 146 feet long

The bridge was constructed in two phases. When the city of Chippewa Falls established the park in 1906, they contracted Wisconsin Bridge and Iron Company to build an arched Warren pony truss over Duncan Creek at the park’s main entrance. However, when the north addition was completed in 1913, that span was relocated and incorporated into a three-span system that would cross a deep ravine. The bridge today features the Warren truss as the center span with two Howe lattice approach spans- one on each end of the bridge. The structure is open to pedestrians and cyclists only.

Oblique view of the bridge. Photo taken by J.R. Manning in 2009, used with permission.

3. Central Street Bridge

Location: Duncan Creek on Center Street in Chippewa Falls

Type: Riveted Pratt through truss bridge with 3-rhombus Howe lattice portal and strut bracings

Built: 1934

Dimensions:

Length of largest span: 130.3 ft.
Total length: 134.8 ft.
Deck width: 29.9 ft.
Vertical clearance above deck: 13.7 ft.

This bridge is perhaps one of the smallest structures that can be found in Chippewa Falls, let alone in the county. One cannot see the bridge until right before crossing it. The bridge was one of many that were built during the Roosevelt Administration when the Works Progress Administration was established to put many unemployed people back to work. When it started in 1933, one in three Americans were unemployed, a figure that was reduced to 20% by the 1936 elections. The bridge is eligible to by listed on the National Register of Historic Places. Judging by its recent rehabilitation, that bridge will remain in use on the street for years to come.

 

Overview of the bridge as photographed by J.R. Manning. Picture taken in 2009, used with permission

Bridge 4: Spring Street Bridge

Location: Duncan Creek on Spring Street in Chippewa Falls

Type: Pony Rainbow Arch Bridge

Built: 1916 by the Iowa Bridge Company of Des Moines with James B. Marsh as engineer

Dimensions:

Length of largest span: 93.2 ft.
Total length: 110.9 ft.
Deck width: 20.0 ft.

The Spring Street Bridge is an example of a type of bridge one can still see on America’s rural roads today known as the Marsh Arch Bridge. Developed by James B. Marsh in 1911, these bridge types are classified by its pony or through arch design with reinforced concrete upper arch supported by vertical beams. It is unknown how many Rainbow arch bridges were built between 1911 and 1930, but over 100 of them still exist today, many to be found in Iowa and Kansas. The future of this bridge is questionable as plans are in the making to make this bridge serve one way traffic only for reasons that its 20 feet width is no longer suitable to today’s traffic needs.

 

Railroad Bridges

There were many rail lines that passed through Chippewa County, let alone the county seat of Chippewa Falls including two by Chicago and Northwestern Railroad (now owned by Union Pacific), one by the Soo Line Railroad (now owned by Canadian Pacific) and one by the now defunct Milwaukee Road. John Marvig is providing you with a couple key examples of railroad bridges you should visit while in the vicinity of Chippewa Falls

Overview of the bridge. Photo taken by John Marvig in May 2012, used with permission

Bridge 1: Lake Wissota Railroad Bridge
Built By: Soo Line
Currently Owned By: Canadian National Railway
Total Length: 185 Feet
Length of Largest Span: 80 Feet
Width: 1 Track
Height: 5 Feet (Estimated)
Main Type: Through Plate Girder
Date Built: 1910
Traffic Count: 4 Trains/day (estimated)
Link: http://pegnsean.net/~johnm/CN%20Lake%20Wissota%20Bridge.html

This bridge is located on the east side of Chippewa Falls.  It is along county road X (old WI-29).
This bridge is a fairly common Midwestern design.  But what makes it interesting is that it only goes over water.
But if you are going to access this bridge, be very careful.  The road next to it is extremely dangerous.  Traffic moves very fast, and there is a lot of it.

View of the Union Pacific Railroad Bridge on the south bank of the Chippewa River in Chippewa Falls. Ibid.

 Bridge 2: Union Pacific Chippewa River Crossing at Chippewa Falls
Built By: Chicago Northwestern Railway Company
Currently Owned By: Union Pacific Railroad
Total Length: 907 Feet
Length of Largest Span: 160 Feet
Width: 1 Track
Height: 15 Feet (Estimated)
Main Type: Quadrangular Through Truss (2-160’ and 2-100’ spans)
Approach Type: 3-100’ Deck Plate Girder and I-Beam Spans with Trestle approaches)
Date Built: ca. 1894, partially rebuilt 1993
Traffic Count: 5 Trains/day (Estimated)
Link: http://pegnsean.net/~johnm/Chippewa%20Falls%20Railroad%20Bridge.html
The northern most of all the bridges over the Chippewa River in Chippewa falls is this bridge.  There were once 4 bridges, now there is only two.  This one and the downstream bridge on the Soo Line.
This bridge was first built in about 1894 with trestle, 2-100’ truss spans, and 4-160’ truss spans.  But after the tragic events of July 21st 1993, the bridge looked forever different.
This bridge has lived a very tragic life.  First were the events of July 21st 1993.  A middle aged man walked to the second span from the west bank, and dropped a match on the wooden pier.  The pier had a very hot blaze, and the metal on the second span from the west bank expanded, causing the span to collapse.
After this event, a large scale investigation was carried out.  They found the man was upset by railroad traffic going by his house.  The Chicago Northwestern brought in 3 large deck plate girder spans from the nearby abandoned Lake Wissota Bridge.  These replaced the first 2 spans from the west bank.  Also added in was an additional I-Beam span at the west abutment, and another I-beam span between the current westernmost truss span and the easternmost deck plate girder span. Also, many people have been killed on this bridge.  This bridge is a landmark for Chippewa Falls.  I just wish I could have seen the full truss bridge.

View of the through truss spans in the background and the replacement spans from the former Lake Wissota bridge in the foreground. Ibid.

 

Photos of the fire on the railroad bridge on 21 July, 1993, which destroyed two of the original six spans. Photo courtesy of Bob Gile and can be accessed at http://www.kohlin.com

 

We hoped you enjoyed a tour of the three county region in western Wisconsin. While the state has lost a lot of its historic bridges over the course of 20 years, this area is one of only a few that has been bucking the trend and finding many creative ways of reusing the bridge for recreational purposes, should the structure no longer be able to accomodate today’s traffic. Each structure profiled in the three-article series has a unique value in terms of design and history, which has garnered attention by those wishing to keep the structures in tact for future generations. To close, I would like to ask you a favor when you visit one of these bridges next time, whether it is closer to home or far away: look at the structure closely and ask yourself: how did the structure get built and why, why is it here today, what stories can you find that relate to the bridge, and what can you do to save it for future generations. Chances are that nine times out of ten, you will receive at least one answer to each of the questions posed.

Click here to see the bridges of Eau Claire County and Dunn County.

Our next stop on the Chronicles Bridge Tour is Erfurt, Germany and with that, I would like to provide you with an introduction to a bigger series that is yet to come.

 

Special thanks to John Marvig for narrating the railroad bridges and providing the photos. Also thanks to J.R. Manning, Bob Gile and Steve Conro for their contribution of photos to this article.