Monday, July 16, 2012

Celebration In Ceylon

Ceylon Covered Bridge as seen in 2010, notice the supports underneath.

When I saw the Ceylon Bridge in late 2010, I realized that the span would need to be rehabilitated in the near future to ensure it's existence for another century and beyond. At first glance the bridge didn't look that bad, but a closer look underneath revealed a different story. Cribbing and other supports had been installed to support a sagging lower chord and floor system. I would learn shortly after that plans were already in the works to restore the bridge, and just over a year later that work would begin. So when I made a return visit Saturday to see a community celebrate the restoration of it's iconic piece of history, I saw a bridge ready to survive for generations to come.

Originally referred to as the Baker Bridge and constructed in 1879, it replaced another smaller pony type span that was built in 1860. The earlier structure was likely not sturdy enough to withstand the floods on the Wabash. Yes, the Ceylon Covered Bridge has the distinction of being the last covered bridge standing to have spanned the iconic state river of Indiana. I say that in past tense only because many years back the river decided to change course and left the bridge spanning an often dry depression. The new bridge sits a few hundred feet to the East and the old one sits in a roadside park. Only when the Wabash floods does this back-channel see a significant amount of water. In this years drought it sits over a mere puddle or two at best. A future endeavor might include finding a way to introduce water under the bridge on a year-round basis.

Despite it's High-and-dry status, It is still a wonderful sight to see the lone survivor of the Wabash standing proud!

Monday, April 23, 2012

Old vs. New... You decide

Just this past Saturday I had the opportunity to visit an historic bridge that had been relocated to a new trail and saved. The Cool Creek I'll call it, was dismantled and saved from demolition in Randolph County in 2005. The little riveted Warren pony truss found favor with a group from Carmel that decided it would fit perfectly into their plans for the new Greyhound Trail. The nearly hundred year old span would have ended up as scrap had it not been for the fortuitous decision made to give it a new life.
Trails are becoming trendy not only in Indiana, but across the nation. Even as the economy has struggled for the past several years, the funding for these pedestrian pathways has seemed to stay rather steady. And "Railbanking" of abandoned railroad corridors means that the future seems bright for even more trails in the coming years. As these trails are planned out and developed, a decision must be made when the obstacle of crossing a stream is reached. The common or what I like to call the "No thought needed" choice has been to order a prefabricated built-to-order span from one of several companies that manufacture them. These Mail Order Bridges...or MOB's as us Bridgehunter's like to call them, all have a rather similar look and lack any real character that make them unique. They are a quick and easy solution that to me ranks right up there with the likes of Instant Mashed Potatoes. They might look real at first, but upon further investigation they are nothing more than an imposter or a "wannabe". Fortunately, there is an alternative that is becoming popular not only in Indiana but across the country. Taking an historic metal bridge that might otherwise find the junkyard and adapting it into the blueprints is becoming as trendy as the trails themselves. A good selection of these bridges are available, and most are unique in one way or another. Often the trail might have to be adapted to accommodate a specific structure, but this only enhances the significance of the bridge and helps to expand the heritage that it brings to the trail. The bridge in Carmel features some unique signage that shows photos of the bridge in it's original location, and the steps taken to get it moved to where it now resides. It also talks about the former interurban route that ran on much of the land that now makes up this trail. So not only do the pedestrians on this trail get exercise for their bodies, but they get a unique history lesson that helps to stimulate their minds... A really neat combination if you ask me!
So, what does it take to make these old spans a common choice for future trails? It takes educating people about about the fragile link to our transportation heritage that can be broken if these bridges are lost. It takes a willingness by organizer's and official's to explore the possibilities of obtaining one or more of these unique structures, rather than just settling for something that looks like it came out of a cookie cutter. The costs are surprisingly similar in most cases, but the outcomes can be drastically different. And the process of obtaining one of them can leave a lasting impression on more than just the community it will serve. More than once I have heard of teary-eyed folks traveling to visit the bridge that formerly spanned the stream of their hometown. A little piece of history can go a long way. Along with Dr. James Cooper, I have helped to create a list of abandoned bridges across the state of Indiana. These spans range from very small pony trusses to some rather impressive multi-span through trusses. Many of these structures might just be available for relocation to a park or trail near you. Pulling these beautiful trusses out of the weeds and bringing them back to life is a dream come true for me. So Old vs. New... I know what my choice would be!

Saturday, March 3, 2012

Spanning The Industrial Revolution

This is the last of two posts that talk about the materials used in Indiana's historic bridges. From iron to steel in the last half of the nineteenth century, to concrete in the early twentieth century.

It only seems natural that the two earlier forms of bridges made of stone and wood would someday be emulated with man-made materials that would attempt to capture the benefits of their predecessors while offering improvements in strength and durability.

Truss bridges would be the first to experience this phenomenon, as the labor-intensive hand hewn wooden beams were replaced with components formed from cast and wrought iron, and later of steel. The benefits were numerous indeed...from allowing for larger and longer span that didn't require a roof and siding to protect the trusses from the elements, to components that could be manufactured in a factory and easily assembled at the site. This allowed for mass production of bridges that would help to improve the transportation infrastructure as a whole.

Where wooden trusses were limited to a handful of "trusted and true" types, the introduction of metal allowed for designers to experiment and look for constant improvements to reduce weight and save materials. Wood had definite limitations in form that was easily solved within it's metal counterpart. Although wooden covered spans would continue to be built on occasion into the 1920's, their heyday had pretty much passed by the early 1880's.

Warrick County can likely lay claim to the oldest metal bridge in the state.

The earliest metal spans started appearing in Indiana by the late 1860's, with Warrick County's 1869 Boner Road Bridge the oldest survivor today. This is a rare example of a Bowstring truss that was popular only into the 1880's. Thomas and Caleb Pratt's truss, on the other hand, would enjoy a popularity that would not be exceeded by any other type to come along. The Pratt truss was found in pony and through trusses and would also be transformed into many other variations over the course of it's existence. The Whipple truss was a Pratt that featured verticals that extended across more than one panel to allow for much longer spans with less weight. When designers looked to reduce material even more, the Camelback and Parker versions of the Pratt were introduced that featured polygonal upper chords. And when the railroads were looking for even stronger versions of the Pratt, they found that sub-dividing the panels within the trusses would give them what they needed. The Baltimore and Pennsylvania trusses were the results of their efforts.

A limited number of metal truss bridges remain in Indiana today. Sadly, the last quarter of the twentieth century saw about two-thirds of these remaining spans obliterated. Now we are scrambling to save the best examples of what remain, and fortunately Indiana is now one of the better states at working to accomplish this.

Dearborn County's incomparable Laughery Creek Bridge, the only triple-intersection Pratt truss remaining today. Often referred to as the "Triple Whipple".

The introduction of concrete would have even a bigger impact on the future of bridge building that has continued to this day. Concrete first appeared in the sub-structures of wooden and metal spans at about the turn of the century. Cut stone abutments were expensive and often cost more than the bridge superstructure. Concrete had actually been used by the ancient Romans in many of there structures but the technology was basically "lost" for centuries until the mid-1700's. Just why it's use in bridge building wouldn't surface for almost another 150 years is uncertain. It would quickly become evident that concrete abutments and piers offered great savings over their stone siblings.

It didn't take long for designers to discover that concrete could be used for much more than substructures. Concrete by nature is very strong when in compression but falls short under the stress of tension. Reinforcing bars (better known as rebar) were added to the concrete to give it the tensile strength needed for Indiana's first concrete arches. Although a couple pre-1900 examples may survive, large scale construction would begin in the first decade of the twentieth century. Arches were the first type of concrete span to appear, perhaps an emulation of the stone arches that were built in the previous century. But much like the metal trusses to the wooden ones, concrete spans would evolve past the arch design and take on many shapes and sizes even into modern day.

Many wonderful examples of historic concrete bridges remain in the state today, and like the metal trusses some are enjoying a revival through rehabilitation and continued use. Although moving a concrete span is rather impractical compared to a truss bridge, it is hoped that creativity can help to save the best survivors.
Wayne County's Teetor Bridge dates to 1912. A rehabilitation has been proposed.

I started writing this way back in December and I thank you all for your patience between this and my last one. Sometimes family and work constraints can distract one from the other pleasures of life.