Two arches and a pier were taken out and replaced by a Warren truss bridge between 19 to allow commercial traffic through the then recently constructed Upper Lock and Dam. The bridge's width was increased by cutting the top walls back a foot in 1925 to accommodate larger train cars. Riders had dramatic views of the area as they crossed into and out of the city.ĭrainage modifications and some reinforcement occurred between 19. At its peak, the bridge supported eighty-two passenger trains a day. In 1885, with the completion of the city's new Union Depot, also commissioned by Hill, the Stone Arch Bridge was heavily used by passenger trains. The bridge was commonly used in letterhead and advertising materials, and it was frequently photographed, often in conjunction with the neighboring Industrial Exposition Building and Washburn and Pillsbury mills. The Stone Arch Bridge was called "Hill's Folly" during its construction, but once complete, it became a recognized and admired symbol of Minneapolis. It was the only structure Hill commissioned to which he attached his name, on a plaque on one of the arches. Hill took a personal interest in the bridge and spent lavishly to make it more durable than its contemporaries. Three men and one horse died during the bridge's construction, which was tragic but a low number of fatalities for the time. All of its stones were placed using ropes, pulleys, horses, and men. It was a masonry construction of stone from local sources, with granite from Sauk Rapids for the pilings, limestone from the riverbank for the fill, magnesium limestone from Mankato and Stone City, Iowa, for the facing, and marble from Bridgeport, Wisconsin, for the trim. No new technology was used to build the bridge, despite its innovative design. The bridge stretched 2,100 feet long and twenty-eight feet wide-enough width for two tracks to run side by side. Achieving the curve as designed required twenty-three arches varying in size from forty to 100 feet wide. Anthony Falls, and the fragile stone underlying the area.
Smith designed the bridge with a curve due to the site's physical restrictions, which included pre-existing buildings, St. Hill commissioned the Stone Arch Bridge in 1881 to carry freight and passengers to and from Minneapolis on his St. Ashlar stone can also be used to make flat arches, in which the joints are either joggled or rebated.Built over the course of twenty-two months in 18, the Stone Arch Bridge across the Mississippi River in Minneapolis is a feat of engineering and a reminder of the importance of rail traffic in the late nineteenth century. For determining the wedged shapes of voussoirs, it is preferable to set out the arch on a level platform, marking on it the key-stone and voussoirs along with radial mortar joints.
#Stone arch full#
Up to depth of 60 cm, the voussoirs are made of full thickness of the arch. In this type, the stones are cut to proper shape of voussoirs, and are fully dressed, set in lime or cement joints with proper bed joints. For greater depths (thickness), rubble stones are laid in two rings in alternate course of headers and stretchers. Upto a depth of 37.5 cm, these arches are constructed in one ring. They are also used as relieving arches, over wooden lintels. Rubble arches are used upto spans of 1 m. These arches are made of rubble stones which are hammer dressed, roughly to shape and size of voussoirs of the arch and fixed in cement mortar. Rubble masonry arch is comparatively weak and is used for comparatively inferior work. Classification Based On Material And Workmanshipĭepending upon workmanship, stone arches are of two types: (i) Rubble arches, and (ii) Ashlar arches.
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