The MN Historical Society notes that this was a complex bridge to build due to the rail lines, street car lines, and existing auto traffic that could not be interrupted. This bridge was totally rebuilt from the arches up in the 1989.
The secondary arch spans consist of five individual concrete arches, while the main span has only 2 individual arches. The reason is the rainbow style arch, which extends above the roadway. There was no way to add more arches above the roadway without using up much of the width of the roadway. As a result, engineers designed a steel structure that sits under the main span to help support the roadway over the main span.
