The Robert Street Bridge is a masterpiece of urban architecture. It leapfrogs through downtown St. Paul, carrying five lanes of Robert Street across train tracks, a railroad bridge, 2nd Street, and the Mississippi River. Built in 1926, this arching concrete structure was surely an engineering challenge in its day, but the resulting design fits beautifully into its surroundings.
The bridge was built to replace an earlier wrought-iron wagon bridge, which had opened in 1885, as St. Paul was just a small but growing city on the banks of the Mississippi. That bridge cost one million dollars—a huge sum at that time. It took 60 years to pay for it, which was 20 years longer than it lasted. By the 1920s, it was overwhelmed with streetcar and automobile traffic. The city simply needed a larger bridge.
Building of the new bridge began in 1924. A temporary bridge at Jackson Street helped manage traffic congestion in the area during the two years of construction. Engineers had worked hard to design a bridge that would meet all the requirements that the location demanded. The bridge needed to be high enough for river boat and barge traffic, yet low enough to meet the low grade south of the river without having too steep of grade (as required by street cars). It had to be high enough for trains to pass under, yet it had to match the height of Kellogg Boulevard.
These limitations determined the exact location of nearly every pier. The resulting bridge design is a combination of three open-spandrel barrel arches, four open-spandrel rib arches, and a rib through-arch (rainbow arch) for the main span.
When the Robert Street Bridge opened in 1926, perhaps the most striking feature was the main span. The monumental rainbow arch, constructed of reinforced concrete, rises 30 feet above the roadway, allowing greater clearance for boats in the navigation channel below.
The design is functional, indeed, but also aesthetically pleasing. The shape of the arches is enhanced by the modern architectural detailing of the concrete itself, which was designed to catch sunlight and shadow. The bridge’s clean and elegant lines are complemented by concrete medallions and fluted detailing on the bridge’s piers, elegantly shaped floor beam ends, and an art deco railing.
The Robert Street Bridge is truly a landmark that serves as a gateway for motorists as they enter St. Paul. Luckily, it has been maintained over the years, including receiving a new bridge deck in the 1980s. With continued attention, it will remain one of our historic bridges for future generations.
Reinforced Concrete with Multiple Arches
Tolz, King, & Day
Five Lanes of Robert Street
The Robert Street Bridge is named after early St. Paul settler, Captain Louis Roberts, who was a French Canadian river boat captain and businessman in the early days of the city.