Omaha Road Bridge Number 15
Encyclopedia
Omaha Road Bridge Number 15 is a swing bridge
that spans the Mississippi River
in St. Paul, Minnesota.
It was built in 1915 by the Chicago, St. Paul, Minneapolis and Omaha Railway
(Omaha Road), though it, and the line from St. Paul to Mendota, was jointly owned with the Chicago, Milwaukee and St. Paul Railway.
The bridge was designed by I.F. Stern of Chicago. It is unusually shaped, because the swing span is asymmetrical. According to local legend, the original bridge design had equal length spans on either side of the center pivot. Once the bridge was completed, the owner of the property on the south side of the river did not want the swing span crossing his land. In response, the owner removed most of the south end of the swing span and added a concrete counterweight to compensate for the lost material.
Legends aside, the reason for the "bobtail" configuration of the bridge is that the section of the river deep enough for navigation at that point is not wide enough to accommodate a full-sized swing bridge. The counterweight is necessary to keep both ends of the bridge in balance over the center pier, which is near the right descending bank. While the legend may be an appealing one, it cannot withstand the fact that no qualified bridge engineer would lavish the material and effort required to build a swing span over land.
The bridge forces barge traffic heading up river to cross over to their respective port (south) shore of the river, while those heading downstream are able to maintain their normal traffic pattern.
An earlier bridge in this location, built in 1869, was a wooden Howe truss design. This was one of the original 15 bridges spanning the Mississippi River. The first bridge was an 8-span drawbridge, but much of the superstructure had to be replaced in 1877 because of decay in the original pine chords.
Swing bridge
A swing bridge is a movable bridge that has as its primary structural support a vertical locating pin and support ring, usually at or near to its centre of gravity, about which the turning span can then pivot horizontally as shown in the animated illustration to the right...
that spans the Mississippi River
Mississippi River
The Mississippi River is the largest river system in North America. Flowing entirely in the United States, this river rises in western Minnesota and meanders slowly southwards for to the Mississippi River Delta at the Gulf of Mexico. With its many tributaries, the Mississippi's watershed drains...
in St. Paul, Minnesota.
It was built in 1915 by the Chicago, St. Paul, Minneapolis and Omaha Railway
Chicago, St. Paul, Minneapolis and Omaha Railway
The Chicago, St. Paul, Minneapolis and Omaha Railway or Omaha Road was a railroad in the U.S. states of Nebraska, Iowa, Minnesota, Wisconsin and South Dakota. It was incorporated in 1880 as a consolidation of the Chicago, St. Paul and Minneapolis Railway and the North Wisconsin Railway,. The...
(Omaha Road), though it, and the line from St. Paul to Mendota, was jointly owned with the Chicago, Milwaukee and St. Paul Railway.
The bridge was designed by I.F. Stern of Chicago. It is unusually shaped, because the swing span is asymmetrical. According to local legend, the original bridge design had equal length spans on either side of the center pivot. Once the bridge was completed, the owner of the property on the south side of the river did not want the swing span crossing his land. In response, the owner removed most of the south end of the swing span and added a concrete counterweight to compensate for the lost material.
Legends aside, the reason for the "bobtail" configuration of the bridge is that the section of the river deep enough for navigation at that point is not wide enough to accommodate a full-sized swing bridge. The counterweight is necessary to keep both ends of the bridge in balance over the center pier, which is near the right descending bank. While the legend may be an appealing one, it cannot withstand the fact that no qualified bridge engineer would lavish the material and effort required to build a swing span over land.
The bridge forces barge traffic heading up river to cross over to their respective port (south) shore of the river, while those heading downstream are able to maintain their normal traffic pattern.
An earlier bridge in this location, built in 1869, was a wooden Howe truss design. This was one of the original 15 bridges spanning the Mississippi River. The first bridge was an 8-span drawbridge, but much of the superstructure had to be replaced in 1877 because of decay in the original pine chords.