Plymouth Avenue Bridge
Encyclopedia
The Plymouth Avenue Bridge is a segmental bridge
that spans the Mississippi River
in Minneapolis, Minnesota
. It was built in 1983 and was designed by VanDoren-Hazard-Stallings. The construction of this bridge was unique, for it was the first segmental concrete girder bridge built in Minnesota. This method of design uses a "form traveler" that shapes the concrete as it is built out from the piers. This avoided the use of falsework
and avoided impeding river traffic. The concrete is also engineered to be salt-resistant by the use of post-tensioning. Tubes run through the concrete structure carrying strands of cable. With tension on the cables, the structure is designed to be under compression. This prevents cracks and hinders the intrusion of salt water. Since then, other bridges in Minnesota have used this construction method, including the I-35W Saint Anthony Falls Bridge in Minneapolis, the Wabasha Street Bridge
in downtown St. Paul and the Wakota Bridge
in South St. Paul
.
The original bridge was a wooden Howe truss design, built in 1873. This was built when Minneapolis, then only on the west side of the river, consolidated with the city of St. Anthony, on the east side of the river. As part of the merger, Minneapolis (the western city) agreed to build two bridges, one upstream of the Hennepin Avenue Bridge
and one downstream. That bridge was replaced in 1886 with an iron truss bridge
. It was remodeled in 1913 and then raised in 1953 for more clearance. As a result of deterioration over the years, the bridge was closed in 1981 because the floor beams were rusted.
On Friday, October 22, 2010, the Plymouth Avenue Bridge was closed indefinitely "as a precaution, pending further investigation after a routine inspection discovered corrosion on cables that run through the bridge." The bridge was reopened to foot traffic on Thursday, January 6, 2011 after engineers determined that the bridge was safe for pedestrian use. Use by vehicular traffic will not be allowed until corroded cables can be replaced, a project that is expected to take place late in 2011.
Segmental bridge
As its name implies, a segmental bridge is a bridge built in short sections , i.e., one piece at a time, as opposed to traditional methods that build a bridge in very large sections...
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 Minneapolis, Minnesota
Minneapolis, Minnesota
Minneapolis , nicknamed "City of Lakes" and the "Mill City," is the county seat of Hennepin County, the largest city in the U.S. state of Minnesota, and the 48th largest in the United States...
. It was built in 1983 and was designed by VanDoren-Hazard-Stallings. The construction of this bridge was unique, for it was the first segmental concrete girder bridge built in Minnesota. This method of design uses a "form traveler" that shapes the concrete as it is built out from the piers. This avoided the use of falsework
Falsework
Falsework consists of temporary structures used in construction to support spanning or arched structures in order to hold the component in place until its construction is sufficiently advanced to support itself...
and avoided impeding river traffic. The concrete is also engineered to be salt-resistant by the use of post-tensioning. Tubes run through the concrete structure carrying strands of cable. With tension on the cables, the structure is designed to be under compression. This prevents cracks and hinders the intrusion of salt water. Since then, other bridges in Minnesota have used this construction method, including the I-35W Saint Anthony Falls Bridge in Minneapolis, the Wabasha Street Bridge
Wabasha Street Bridge
The previous bridge was an iron cantilever deck-truss bridge, which was an advanced engineering feat at the time. That bridge was listed in the National Register of Historic Places in 1989...
in downtown St. Paul and the Wakota Bridge
Wakota Bridge
-External links:***...
in South St. Paul
South St. Paul, Minnesota
South St. Paul is a city in Dakota County, Minnesota, immediately south and southeast of the city of Saint Paul, Minnesota. It is also southeast of West St. Paul, Minnesota. The population was 20,160 at the 2010 census. It is notable as one of the historic major meat packing cities in the United...
.
The original bridge was a wooden Howe truss design, built in 1873. This was built when Minneapolis, then only on the west side of the river, consolidated with the city of St. Anthony, on the east side of the river. As part of the merger, Minneapolis (the western city) agreed to build two bridges, one upstream of the Hennepin Avenue Bridge
Hennepin Avenue Bridge
The Hennepin Avenue Bridge is the structure that carries Hennepin County State Aid Highway 52, Hennepin Avenue, across the Mississippi River in Minneapolis, Minnesota at Nicollet Island. Officially, it is the Father Louis Hennepin Bridge, in honor of the 17th-century explorer Louis Hennepin, who...
and one downstream. That bridge was replaced in 1886 with an iron truss bridge
Truss bridge
A truss bridge is a bridge composed of connected elements which may be stressed from tension, compression, or sometimes both in response to dynamic loads. Truss bridges are one of the oldest types of modern bridges...
. It was remodeled in 1913 and then raised in 1953 for more clearance. As a result of deterioration over the years, the bridge was closed in 1981 because the floor beams were rusted.
On Friday, October 22, 2010, the Plymouth Avenue Bridge was closed indefinitely "as a precaution, pending further investigation after a routine inspection discovered corrosion on cables that run through the bridge." The bridge was reopened to foot traffic on Thursday, January 6, 2011 after engineers determined that the bridge was safe for pedestrian use. Use by vehicular traffic will not be allowed until corroded cables can be replaced, a project that is expected to take place late in 2011.