I-90 Mississippi River Bridge

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I-90 Mississippi River Bridge
Aerial View of the area looking south, with Lock and Dam No. 7 in the foreground
Carries	4 lanes of Interstate 90
Crosses	Mississippi River
Locale	Dresbach, Minnesota to La Crosse, Wisconsin
Maintained by	Wisconsin and Minnesota Departments of Transportation
ID number	B-32-0045 (Wisconsin), 9320 (Minnesota)
Design	Plate girder bridge
Longest span	450 feet (137 m)
Total length	2,490 feet (759 m)
Width	67.3 feet (21 m)
Clearance below	62 feet (19 m)
Opening date	October 1967
Coordinates	43°51′28″N, 91°17′57″W

Ground level view of the I-90 Bridge looking east

The I-90 Mississippi River Bridge is a plate girder bridge that connects La Crosse, Wisconsin to rural Winona County, Minnesota. It is an automobile bridge that traverses the Mississippi River, and is part of the Interstate 90 route. The railing consists of solid concrete; the steel structure is painted a dark green. There is another automobile crossing a few miles south of this bridge; the Mississippi River Bridge, a combination of two bridges, along with the La Crosse West Channel Bridge connect La Crescent, Minnesota and La Crosse, Wisconsin.

Although the current bridge has no weight restrictions and operates at an acceptable level of service, there are number of problems with the bridge and surrounding roadways:

The deck is deteriorating, the most pressing issue in the short term.
The bridge is of an obsolete, non-redundant structural design similar to that of the Hoan Bridge in Milwaukee, which suffered a substantial structural failure. After the Hoan Bridge incident, the I-90 Mississippi River Bridge was hurriedly inspected and found to be in satisfactory condition, but concern about the basic steel structural design remains.
A lack of standard shoulders inhibits emergency responses to incidents on the bridge and does not provide enough room for disabled vehicles to get out the traffic lanes.
There are issues with the the interchange on the Minnesota side, including a curve on the main travel lanes that is sharper than desirable for an interstate, a confusing design, and congestion on some of the ramps.
There are capacity problems at the Dresbach Rest Area on the Minnesota side, which currently has only limited room for expansion. Compounding the problem, it is currently accessable from the eastbound direction, even though it is intended for westbound traffic only.
There are no provisions for bicyclists and pedestrians on the bridge.

[edit] Potential rehabilitaton or replacement

This article or section contains information about a planned or proposed future bridge.
It may contain information of a speculative nature and the content may change dramatically as the construction and/or completion of the bridge approaches, and more information becomes available on it.

In 2006 Mn/DOT commissioned a study on ways to rectify some or all of these issues. Some of the options that were presented included:

Replacing the deck only, estimated cost $23 million
Widening and rebuilding the existing structure with either additional piers or strengthening the foundation, estimated cost $40-$58 million
Building a new westbound girder bridge and converting the existing bridge to eastbound only, estimated cost $63 million
Building a new girder bridge, extradosed bridge, or cable stayed bridge, and demolishing the existing one, estimated cost $59-$71 million

Selecting a preferred alternative will take further studies, but it should be noted that the least costly option that would address the non-redundant design of the existing bridge is $58 million, while the least costly total replacement option is $59 million. There are also a number of concepts for rebuilding the interchange on the Minnesota side, depending on whether the bridge is rebuilt or replaced. Complicating construction will be the proximity to steep bluffs and an active railway on the Minnesota side, proximity to the La Crosse Municipal Airport, which could limit the height of any towers, and barge traffic, which restricts where piers may be placed. Construction is currently planned for 2013.

[edit] See also

[edit] References

Costello, Mary Charlotte (2002). Climbing the Mississippi River Bridge by Bridge, Volume Two: Minnesota. Cambridge, MN: Adventure Publications. ISBN 0-9644518-2-4.
I-90 Bridge near Dresbach study (2006). Retrieved on March 30, 2007.