Distinctly Montana Magazine

W W W. D I S T I N C T LY M O N TA NA . C O M 59 e dawn of the automobile age demanded changes in bridge technology to accommodate the new mode of transportation. e automobile was the primary reason for the legislature's creation of the Montana State Highway Commission in 1913, which also mandated the formation of a bridge department two years later. e new department soon standardized bridge designs for steel, reinforced concrete, and timber bridges. In August 1915, the commission oversaw its first bridge project, across the Bitterroot River near Florence. Sixty-eight bridge projects followed over the next year. e highway commission's bridge department designed bridges for automobiles, not wagons. THE NATURAL PIER BRIDGE In 1917, the Lord Construction Company built a steel truss bridge across the Clark Fork in Mineral County. e bridge crosses the river about a mile northwest of Alberton on the South Frontage Road at the head of the spectacular Alberton Gorge. It consists of two Warren truss spans with the center pier resting on a natural rock outcrop in the scenic river canyon. Warren trusses, are characterized by the "W" configuration of the struc- tural members when viewed from the side. ey also identify it as a highway commission-designed structure. e bridge was once an important part of the Yellowstone Trail, an early 20th-century interstate highway, in western Montana. Like the Dearborn River High Bridge, the MDT rehabilitated the Natural Pier Bridge sev- eral years ago. It represents innovative design and making the best use of the landscape at hand. THE CARTER BRIDGE It's hard to take a bad photograph here. e Carter Bridge crosses the Yellowstone River four miles south of Livingston on Secondary Highway 504, the old highway to Yellowstone National Park. e adjacent Carter Bridge Fishing Access Site provides a place for photographs of the structure. Built in 1921, the bridge is an adaptation of a design developed by Great Falls architect George Shanley for the 10th Street Bridge in that city. Concrete bridges became more common on Montana's roads in the 1920s. Concrete combined function, durability, and aesthetics to provide a more streamlined structure that was also pleasing to the eye. e highway department built only a few large open spandrel arch bridges, like the Carter Bridge. All could be found in areas of scenic beauty to enhance the motoring experience for Montanans and tourists. Natural Pier Carter Bridge

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