Two bridges spanning the Mississippi River — one connecting Minneapolis and Saint Paul, and a similar bridge crossing the river a mile and a half upstream — exhibit design characteristics reflecting significant changes in how people move across bridges throughout our cities.
The Saint Paul-Minneapolis structure joining East Lake Street and Marshall Avenue was built in 1989, and its design conforms to its basic traditional main function of carrying motor vehicles along the main road bed, with relatively narrow passageways for walkers and runners. A pair of vehicular lanes run both directions. Each walkway width is six feet.
The upper stream Franklin Avenue Bridge in Minneapolis, officially the F.W. Cappelen Memorial Bridge, was completed in 1923. At the time of its completion, the reinforced concrete open-spandrel arched structure, was the longest concrete arch in the world. The bridge originally carried streetcars, which were removed in the 1940s. F.W. Cappelen also designed the nearby Prospect Park Water Tower (popular name is the Witch’s Tower) in 1913 in a public park at the city’s highest elevation.
By 1970, the Cappelen Bridge was in such poor shape that it had to be closed down. The bridge was stripped down to its main arches and rebuilt from 1971 to 1973. During rebuilding design, structural engineers calculated that the original bridge was vastly overbuilt, and needed only half as many vertical supports, and many supports were removed, lending the structure a more streamlined design. During the rebuilding, the horizontal beams were built wider with a four-lane deck and wide sidewalks. The railings design was obedient to standard issue Department of Transportation standards in which aesthetics was not a high priority.
In 2015 – 2017 the bridge’s top structure was re-built on its existing arches to accommodate change of people movement. The now recognized growth of walking and bicycle traffic induced traffic engineers to re-evaluate bridge re-design.
The width changes of both East and West motor vehicular lanes assisted how both evolved movement modes actually function. The new bridge design maintains the original overall width. Wider approach aprons at both bridge ends allow cars to ease into the main East and West traffic lanes, which taper to be narrow enough to permit single travel paths, seeming to induce slower movement. But the main feature provides ample walking and bicycle lanes on both sides of the motorway, giving auto travel and pedestrian use equal widths. This work included rebuilding some of the railing minimally ornamental details lost in the 1970s reconstruction
The F.W. Cappelen Bridge is listed on the National Register of Historic Places.