The Mottville Bridge is the longest example of a curved chord through girder bridge (commonly called concrete camelback bridges) in Michigan, and with three spans, it is also the only multi-span example, with all other surviving examples being single span. The spans of the Mottville Bridge are each examples of the 90 foot plan, which was the largest span size included in the set of state standard plans for this bridge type. The bridge also has not been altered from its original design and appearance, giving it an extremely high level of historic integrity, increasing the significance of the bridge. The bridge is also noteowrthy for being located at a historic crossing. The fourth bridge to span the St. Joseph River at Mottville, remains of the substructures from one of the previous bridges can be seen north of the bridge.
The Mottville Bridge is also significant for its aesthetic value. The design of a single 90 foot concrete camelback span is beautiful in its own right, with its curve, pierced openings, and inset rectangles that are carefully designed to have a pleasing appearance. However the unique repetition of the sweeping arches as seen in the three span Mottville Bridge gives the bridge another level of beauty that is truly unlike any other bridge.
The Mottville Bridge has been bypassed by a modern vehicular bridge and the historic bridge was restored for non-vehicular use. The abandoned highway alignment west of the bridge was converted into a small park, and interpretive signage describing the bridge was posted in this park.
The community of Mottville recognizes and and appreciates the treasure they have. A sign welcoming visitors to Mottville on M-103 has a logo with the bridge on it and it also reads "Home of the Longest Camelback Bridge in Michigan." The bridge is also prominently featured on their website.
The Mottville Bridge, and indeed all of Michigan's 90 foot concrete camelback spans should be considered to have national historic significance, since these spans exceed the national average maximum length for concrete through girder bridges (either curved or straight chord) by 30 feet, since most states only built through girder bridges up to 60 feet. In addition, Michigan's 90 foot spans, including those seen on the Mottville Bridge are perhaps the most beautiful and architecturally well-designed of any concrete through girders in the country.
Among all the examples of this bridge type that should be preserved, the Mottville Bridge would certainly be at the top odd the list, and indeed this priceless structure has been preserved, fortunately. However, the apparent consensus on the part of the various county road commissions and MDOT was that the other few multi-span examples that were once extant in the state were not worth preserving, despite their extremely high levels of historic significance and aesthetic value. This extremely poor view appears to be the result of a lack of vision and poor planning on a part of these highway agencies. One by one they have all been demolished, leaving the Mottville Bridge standing today as the only remaining multi-span camelback bridge in Michigan. This is most unfortunate, since Michigan might be thought of as the camelback bridge capital of the country, since no other state built so many camelbacks, and the few camelbacks that other states built rarely if ever exceeded 60 foot spans or came in a multi-span configuration.
All of Michigan's surviving curved chord through girders should be considered historically and technologically significant. The bridges are historically significant because they represent a unique and innovative design developed by the Michigan State Highway Department in its earlier years of bridge construction.
The bridges should be considered technologically significant as well. By incorporating a curve into the design, Michigan State Highway Department not only increased the efficiency of the design, they also greatly increased the aesthetic value of the bridges. The graceful curves of this bridge type, complemented by architectural details such as inset rectangles and pierced openings, make them among the most aesthetically pleasing of bridge types ever encountered. Straight chord through girder bridges are generally considered among the more plain and less visually appealing types of historic bridges. The aesthetic qualities of the curved girder bridge, those qualities being an integral and functional part of the bridge and not a decorative facade, should be considered to be a technologically significant feat: an extremely effective union of function and form.
Also, the 90 foot plan concrete camelbacks, including the Mottville Bridge are all noteworthy on a national level because they are among the longest spans seen in concrete through girders throughout the country. They represented the maximum potential of the bridge type, which had a short life because it was limited as a practical structure type in terms of span length and deck width. Most concrete through girders (including the small number of curved chord examples outside Michigan) throughout the country appear to have been limited to no more than 60 feet. With their 90 foot spans, Michigan's 90 foot plan concrete camelbacks push beyond this number considerably.
Information and Findings From Michigan Historic Sites Online
The US-12 St. Joseph River Bridge crosses the St. Joseph River in Mottville Township at the west edge of the Village of Mottville. It is situated at a historic river crossing, the fourth bridge to span the St. Joseph River at Mottville. The bridge is a two hundred and seventy foot long, reinforced concrete, camelback-arch bridge composed of three ninety foot long and twenty-two foot wide spans resting on concrete piers and abutments. The bridge is constructed using massive concrete reinforced steel girders, providing the structure with its distinctive arches. The interior of each arch is pierced with five openings occurring above a series of paired, recessed panels, which provide a decorative effect complementing the bridge's sweeping concrete arches.
Statement of Significance
The US-12 St. Joseph River Bridge is the largest surviving reinforced concrete camelback bridge in Michigan. Camelback bridges such as this one were built from a standardized plan provided by the Michigan State Highway Department under the supervision of its bridge engineer, C.A. Melick. Built in 1922, the present bridge is the fourth to cross the St. Joseph River at Mottville.
MOTTVILLE BRIDGE The Great Sauk Trail, which connected Detroit, Chicago and Green Bay, Wisconsin, crossed the St. Joseph River at a shallow spot in this vicinity. Responding to the westward migration of pioneers, the federal government surveyed the trail and converted it into the Chicago Road (presently U.S. 12) in 1825. The first Chicago Road bridge to cross the river near Mottville was a substantial timber structure constructed in 1833-1834 by contractor Hart L. Stewart. A pile-supported bridge replaced it in 1845. In 1867, Mahlon Thompson and Joseph Miller built a covered Burr arch truss. The ruins of its stone-block abutments are visible upstream from here. This three-span camelback bridge was built in 1922. In 1990, U.S. 12 was rerouted over a new bridge. The camelback bridge is now used for foot traffic. SIDE TWO Constructed in 1922, this three-span, 270-foot-long bridge is the longest Michigan example of a reinforced concrete camelback bridge. These bridges are found primarily in Michigan and Ontario, Canada, and the Mottville Bridge is an excellent example of this design. It was built by contractors Smith and Nichols of Hastings under the direction of State Bridge Engineer C. A. Melick. The Michigan State Highway Department pioneered the use of standardized designs for concrete bridges. By the early 1920s the department had established standardized plans for camelback spans of 50, 60, 70, 75 and 90 feet. This bridge contains three identical 90-foot spans. It was preserved as an engineering landmark by the Michigan Department of Transportation when the present U.S. 12 bridge was erected.
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