Closest to my camera above is the Memphis/Arkansas Bridge that is a significant historic bridge all on its own. However, what makes this setting even more unique is that this bridge sits right next to two even more significant historic bridges, the Frisco Bridge (railroad bridge in the middle) and the Harahan Bridge (or Big River Crossing that is farthest away from the camera above). Three historic cantilever truss bridges over the Mississippi River side by side by side with two of those bridges being nationally significant...there is no other historic bridge trio like this in North America.
The first bridge, the Memphis/Arkansas Bridge was built to provide a new crossing for vehicular traffic, replacing the two cantilevered vehicular traffic decks that are on the Harahan Bridge (or Big River Crossing). Harahan Bridge was designed by famous bridge engineer Ralph Modjeski. Although he had died by the time the Memphis/Arkansas Bridge was built, his firm, Modjeski and Masters was the engineering firm for it as well. Contractors for the bridge included the Harris Structural Steel Company of South Plainfield, New Jersey, the Virginia Bridge Company of Roanoke, Virginia (formerly the Virginia Bridge and Iron Company), and the Merritt-Chapman & Scott Corporation of New York, New York. Although this bridge carries heavy Interstate Highway traffic, it retains good historic integrity with no major alterations including the pedestrian sidewalks that remain on the bridge with original railings.
While the Frisco Bridge was designed by one of the greatest bridge engineers of the 19th Century, the Harahan Bridge was similarly designed by one of the 20th Century's greatest bridge engineers, Ralph Modjeski. As such, works by two of the greatest engineers of their respective centuries can be seen side-by-side. This affords a unique comparison between both engineering thinking, and also changing needs of two different periods in railroad history. The Harahan Bridge was designed to carry railroad traffic in between truss lines, and highway traffic on cantilevered decks outside of the truss lines. The construction of the Memphis/Arkansas Bridge ended the use of the Harahan Bridge for vehicular traffic. In 2016 however, a unique project converted the north vehicular deck into a pedestrian walkway named the Big River Crossing. This new walkway is unique because of its size, and also because it is rare for a railroad company to allow a public walkway to exist on one of their bridges. As might be expected, substantial fencing separates pedestrians from the railroad tracks. However, the truss is so large that despite the fencing, the walkway still offers excellent up-close views of the impressive details of the trusses. Another important aspect of the walkway is that despite addition of modern railing on the outside, the original riveted lattice railings for the vehicular deck were not removed. This helps convey the former vehicular usage of the deck, and also maintains the original appearance of the bridge. As part of the walkway, a modern full-color decorative lighting system was also installed, allowing for impressive light shows to bathe the entire bridge in a rainbow of animated colors. Note that if you visit this bridge in the evening and do not see the lights in operation, it may be due to a train or barge in the area, as this was a condition for the operation of the lighting system.
Finally, the Frisco Bridge is one of the most important historic bridges in the country, all on its own. It is one of the few surviving cantilever truss bridges that date to before 1900 in North America. Completed two years after the larger and more famous Forth Bridge in Scotland, this bridge is nevertheless significant in terms of American history as one of the earliest large-scale cantilever truss bridges. It is also the crowning achievement of engineer George Morison, who designed some of the first large-scale metal truss bridges in America, including many record-breaking spans. Most of his large-span truss bridges were simple spans however, so this cantilever truss bridge stands out as unusual among his bridges. Sadly, nearly all of Morison's bridges have been demolished, and even among those which remain today, not all are being preserved. Even this monumental, nationally significant historic bridge was as of 2016 facing the most significant alteration to its historic integrity since its construction in 1892: the entire western approach system was being demolished and replaced! While this does not affect the cantilever spans, this is regardless an alarming and disappointing outcome. The replacement of these spans is an unfortunate casualty of this bridge's remarkable status as a railroad bridge that continues, despite its age, to be used today by an enormous amount of railroad freight trains. As might be expected of such a large bridge, more than one notable engineer was involved with it, and many contractors fabricated and constructed the bridge. In addition to Morison, who was chief engineer, noted engineer Alfred Noble was resident engineer for the project. Union Bridge Company, Pencoyd Iron Works, and the Pennsylvania Steel Company all played a role in fabrication. The main superstructure contractor was Baird Brothers of Pittsburgh. There is 2,597 feet of the bridge that is composed of the cantilever through truss spans and the deck truss span is at the western end. The total length of the bridge including approaches is roughly 5,000 feet.
Historically, the Frisco Bridge was listed with the American Society of Civil Engineers (ASCE) as a Historic Civil Engineering Landmark in 1987. And the Memphis/Arkansas Bridge was listed on the National Register of Historic Places (NRHP) on February 16, 2001.
Three bracketed photos were taken with a handheld Nikon D7200 and combined with Photomatix Pro to create this HDR image. Additional adjustments were made in Photoshop CS6.
"For I know the plans I have for you", declares the LORD, "plans to prosper you and not to harm you, plans to give you hope and a future." ~Jeremiah 29:11
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