This bridge seemed like a rare example where Missouri and Illinois did exactly what they should with an extremely important monumental large river bridge. They built a new bridge next to the historic bridge, but then instead of demolishing the bridge, they left the historic bridge standing, and even rehabilitated the bridge and allowed it to carry eastbound traffic, while the new bridge carried westbound traffic. This solution saved money, preserved history, and increased the capacity of the crossings. Opportunities for this type of preservation occur all the time, but usually the owners choose to demolish the historic bridge, no matter that potential benefit there might be. However, a couple decades down the road, as of 2013, Illinois Department of Transportation has proposed to demolish and replace this historic bridge. The bridge is not in bad condition, could be easily rehabilitated, and combined with the westbound bridge provides ample traffic lanes for vehicles. It is unclear why the preservation commitment that seemed to once exist for this bridge appears to have disappeared. This is an exceedingly rare design of bridge, a beautiful community landmark, and is associated with a famous engineer. It was built to last, and is deserves to be preserved for decades to come.
The bridge was designed by Strauss Engineering Company, a company ran by famous engineer Joseph B. Strauss. Many people associate Strauss as the engineer for the Golden Gate Bridge, but the real history and heritage of Strauss is actually in Chicago as a movable bridge engineer. Much like with the Golden Gate Bridge, when Strauss undertook the project to build the Quincy Memorial Bridge, he appears to have attracted the attention of Chicago contractors that he likely had worked with on previous projects.
The Quincy Memorial Bridge is an extremely unusual and significant bridge due to its extremely large non-cantilever continuous truss spans. It is a continuous modified Warren truss. It is nearly a trapezoidal truss, except that the top chord changes its angle slightly towards the ends of the bridge, barely allows it to be a polygonal Warren. It is unusual because most bridges of this size were built as cantilever bridges. However, the Quincy Bridge is not cantilevered, it is just continuous.
The bridge is also significant as one of a rapidly shrinking number of big river historic bridges in the country.
HistoricBridges.org currently only has introductory coverage for this bridge, with a small set of overview photos only for this bridge. HistoricBridges.org intends to revisit this bridge in the future to fully photo-document the bridge with a full set of detail photos.
Information and Findings From Missouri's Historic Bridge Inventory
Superstructure: steel, rigid-connected, continuous
Baltimore through truss, with multiple-span deck girder and stringer
Discussion of Bridge
Early 20th century motorists wishing the cross the Mississippi River at Quincy faced two options: riding the ferry that traversed the river in the warm-weather months, or crossing on the vehicular runways cantilevered from the sides of the CB&Q railroad bridge. With neither alternative especially palatable, the local citizenry boosted for a highway bridge at this point off-and-on for years. Plans to build the bridge finally began to coalesce in 1927 with the formation of the Quincy Memorial Bridge Company, a consortium of local business interests. The corporation proposed to build a highway bridge at Quincy and pay for its construction through tolls levied on bridge users. To design the immense structure, the Quincy Memorial Bridge Company hired the Chicago-based Strauss Engineering Corporation-the civil engineering firm later responsible for the design of the Golden Gate Bridge. As delineated by Strauss, the proposed bridge extended 1256 feet, with two 628-foot, rigid-connected Baltimore through truss spans carried continuously over a center concrete pier in the river's channel. The Kelly-Atkinson Construction Company, also of Chicago, was contracted to build the bridge's approaches and erect the superstructural steel; the Foundation Company of New York would build the 36 river piers. Construction on the bridge proper commenced on June 15, 1928, with construction of the river piers began in September. Laborers worked on the concrete piers despite massive floodwaters along the Mississippi in November 1928 and again in March 1929. Carrying the cantilevered weight of both main spans, the center pier was the most critical. Men in a pneumatic caisson excavated almost 118 feet below the river's surface to found the center pier on bedrock. The substructure was completed in September 1929. Steelworkers erected the multiple beam and truss spans in 1929-30, assembling the last of the superstructural steel by March 1, 1930. The Quincy Memorial Bridge was opened ceremoniously to traffic on June 16, 1930. It remained under the aegis of the Quincy Memorial Bridge Company as a toll crossing until the construction bonds were retired in 1945. Ownership of the bridge was then transferred to the states of Missouri and Illinois, and the bridge was made toll-free. In 1982, the St. Louis Bridge Construction Company was hired to reconstruct the bridge's deck. The original concrete floor was removed at that time and replaced with a steel grid deck. Other than this, the Quincy Memorial Bridge remains essentially unaltered. Bridges over the Mississippi River comprise some of America's longest examples of vehicular truss construction. With over 400 miles fronting on the great river, Missouri possesses several notable Mississippi River bridges. Seven of the state's longest crossings over the Mississippi are included in the statewide bridge inventory, all of which are considered eligible for the National Register. The Quincy Memorial Bridge is historically significant because it served as a pivotal transportation link between Illinois and Missouri on a major interstate highway, and it had a major impact on the socioeconomic development of northeastern Missouri. Featuring an unusually configured continuous truss design and multiple girder approach spans, the bridge ranks among Missouri's most monumental examples of steel truss construction-a superlative, well-preserved example of its type.
Bridge Considered Historic By Survey: Yes
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