The Lowry Avenue Bridge is a

steel Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistant ty ...

tied-arch bridge A tied-arch bridge is an arch bridge in which the outward horizontal forces of the arch(es) caused by tension at the arch ends to a foundation are countered by equal tension of its own gravity plus any element of the total deck structure such grea ...

over the

Mississippi River The Mississippi River is the second-longest river and chief river of the second-largest drainage system in North America, second only to the Hudson Bay drainage system. From its traditional source of Lake Itasca in northern Minnesota, it f ...

Minneapolis, Minnesota Minneapolis () is the largest city in Minnesota, United States, and the county seat of Hennepin County. The city is abundant in water, with thirteen lakes, wetlands, the Mississippi River, creeks and waterfalls. Minneapolis has its origins ...

, completed in October 2012.

History

The original structure was built in 1905 and utilized a 5-span

truss bridge A truss bridge is a bridge whose load-bearing superstructure is composed of a truss, a structure of connected elements, usually forming triangular units. The connected elements (typically straight) may be stressed from tension, compression, or ...

design. This bridge lasted 51 years until it became too weak to carry traffic. In 1958, five new truss spans were built in this location, using the same piers but raised 20 feet to allow navigation on the upper Mississippi River. This bridge was notable in that it had a steel grid deck where the river was visible directly through the mesh, as opposed to the (currently) more common concrete deck. Lead-based paint was removed from the bridge during a 2004 repainting effort and the steel grid deck was replaced in 2003. At this time, the bridge was expected to be replaced in the mid-2010s, and community meetings were held in 2007 to choose a design for the new span. However, the timetable to replace the bridge was accelerated as the condition of the 100-year-old piers deteriorated. During the 2004 repainting, engineers discovered that the pier 3 bearings (east side of navigation channel) had displaced roughly 11 inches east of their original location as a result of unexpected movement of that pier (west) towards the main river channel. Hennepin County contracted with Wiss, Janey, Elstner and Associates (WJE) to investigate and report on the cause and extent of damage. The consultant's report concluded that evidence suggested the pier underwent many years, perhaps 50, of creep deflection due to sustained lateral earth pressure at the foundation which was held in check by the bearing assemblies. The bearing assemblies ultimate strength was finally overcome sometime in 2004 which allowed the unrestrained and rapid movement of the pier. The structural engineers at WJE were unable to predict the magnitude of future pier displacements.

Hennepin County Hennepin County ( ) is a county in the U.S. state of Minnesota. Its county seat is Minneapolis, the state's most populous city. The county is named in honor of the 17th-century explorer Father Louis Hennepin. The county extends from Minneapol ...

, which owns and maintains the bridge, closed the bridge at 10:00 AM on April 25, 2008, due to safety concerns. Controlled explosions were used to demolish the bridge spans 14 months later on the morning of June 21, 2009. Construction of the $80 million replacement bridge began early 2010 and was opened for traffic on October 27, 2012, at a cost of $104 million. The bridge includes a protected, shared-use path on both sides for pedestrians and bikes.Johnson, Matt M.

References

External links

Animation of Replacement Bridge
{{Crossings navbox , structure = Crossings , place =

, bridge = Lowry Avenue Bridge , bridge signs = , upstream =

Canadian Pacific Camden Place Rail Bridge Canadian Pacific Camden Place Rail Bridge is a truss bridge that spans the Mississippi River in Minneapolis, Minnesota. This bridge is the official end of the navigable channel for river traffic. It is at mile 857 of the Upper Mississippi River ...

, upstream signs = , downstream = Northern Pacific-BNSF Minneapolis Rail Bridge , downstream signs = Bridges in Minneapolis Bridges over the Mississippi River Bridges completed in 1887 Bridges completed in 1905 Bridges completed in 1958 Road bridges in Minnesota Steel bridges in the United States Tied arch bridges in the United States Truss bridges in the United States 1887 establishments in Minnesota Shared-use paths in Minneapolis

History

See also

References

External links