Highway 243 Bridge
MN-243/WI-243 Saint Croix River Crossing
Osceola, WI

Highway 243 Bridge

• Structure ID: NBI: 6347 (MN), B48022400000000 (WI).
• Location: River Mile 45.5.
• River Elevation: 683 Feet.
• Highway: MN-243, WI-243
• Daily Traffic Count: 7,330 (2003).
• Bridge Type: Steel Truss Deck.
• Length: 674 Feet.
• Width: 31 Feet, 2 Traffic Lanes.
• Navigation Channel Width: Non-Navigable.
• Height Above Water:
• Date Built: Opened 1953, Rebuilt 1980.
Claim to fame: Wisconsin Trunk Highway 243 is the shortest trunk highway in the state at 3/10 of a mile, connecting the bridge to Trunk Highway 35 on the east side of the river.

The Saint Croix River is much more calm here than upstream at the US-8 Bridge. The channel is wider and more shallow, while the river itself flows through a wide valley rather than being confined between walls of rock.

The Highway 243 bridge gained some additional fame after the I-35W bridge collapse in 2007 due to the bridge being one of the few remaining deck truss bridges. A deck truss has a metal lattice work of cross members, with the roadway being built on top of the truss. The deck truss is considered to be an obsolete style of bridge. The reasons include that they are fracture critical (ie, non-redundant, which means that any one piece breaking can result in the entire bridge failing), they are very hard to inspect (the structure is under the road rather than above the road), they are easily damaged by road salt (which can leak though cracks in the deck and cause the steel to rust), and finally, truss bridges are far more costly to maintain.

The Highway 243 bridge was inspected shortly after the I-35W disaster, and it receives routine inspections every other year. The bridge is not considered to be deficient, so it is not being considered for replacement anytime soon.


Highway 243 Bridge

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Photo and text by John A. Weeks III, Copyright © 2005, all rights reserved.
For further information, contact: john@johnweeks.com