A three-step process is being used to evaluate bridge crossing alternatives and select a preferred project alternative for the Osceola Bridge. This process begins with identifying a reasonable range of build concepts, including a no-build alternative. Each step will refine the alternatives through quantitative and qualitative environmental analysis. Each step looks at the remaining alternatives at a progressively greater level of detail. The outcome of the third step is the identification of a preferred alternative, which is the alternative that will proceed into final design and ultimately construction for the Hwy 243 Osceola Bridge project.
Bridge concepts will be evaluated using the criteria outlined in the Alternatives Evaluation Criteria document. Initial criteria include Bridge Condition and Structure Robustness. Additional criteria include bikeability/walkability, Social, Economic and Environmental considerations, and other factors like constructability and ability to reduce traffic impacts during construction.
There were eight concepts screened in step 1. Four of these initial concepts were removed after the first screening for not meeting the project criteria. The step 2 analysis will look at these remaining 4 concepts and further develop them into alternatives. The 4 alternatives will then be screened based on the secondary criteria of bike and pedestrian considerations, as well as social, economic and environmental considerations.
The results of the Step 2 analysis indicated that there was not adequate information at this level of design to differentiate among the Build Alternatives to justify eliminating any of them. Therefore, the three Build Alternatives considered in Step 2 are recommended for further evaluation in Step 3:
Build alternative B, existing alignment
Build alternative C, north alignment
Build alternative D, south alignment
Step three in the review process is currently underway
The project team is currently in step three, which involves extensive evaluation of the three remaining alternatives including a more detailed and refined assessment of the road design and structure. The team will consider geology, trails and road width and the impacts to the St. Croix River, the Wilke Glen Cascade Falls area and area bluffs. A visualization will be created for each of the three alternatives.
Once step three evaluation is complete, another public meeting will be held to share the results and gather input from the public and regulating agencies on the recommended preferred alternative.
Concepts considered in step 1
A total of eight project concepts were considered in step 1 of the process. These alternatives are included on the map below. Descriptions follow.
No-Build Alternative: The No-Build Alternative (or “do nothing” alternative) includes routine bridge maintenance activities on the existing Hwy 243 Bridge. The existing bridge deck, superstructure, and piers would be left as-is.
Build Concept A: Concept A includes removal of the existing Hwy 243 bridge deck and superstructure and replacement with a new deck and superstructure. The existing bridge
piers would remain-in-place and be re-used with the rehabilitation concept.
Build Concept B: Concept B includes removing the existing Hwy 243 Bridge and constructing a new bridge and approach roadways along the existing alignment.
Build Concept C: Concept C includes constructing a new bridge parallel to the existing Hwy 243 bridge. The new bridge would be built to the north of the existing bridge. The existing Hwy 243 Bridge would be removed following construction of the new bridge.
Build Concept D: Concept D includes constructing a new bridge crossing parallel to the existing Hwy 243 bridge. The new bridge would be built to the south of the existing bridge. The existing Hwy 243 Bridge would be removed following construction of the new bridge.
Build Concept E: Concept E includes constructing a new bridge crossing north of the existing Hwy 243 bridge and realigning Hwy 23 on the Wisconsin Side to connect to the existing 2nd Avenue. The existing Hwy 243 Bridge and approach would be removed following construction of the new bridge.
Build Concept F: Concept F includes constructing a new bridge crossing along an entirely new Hwy 243 alignment between MN Hwy 95 and WI Hwy 35 outside of the Village of Osceola. The existing Hwy 243 Bridge would be removed following construction of the new bridge.
Build Concept G: Concept G includes constructing a tunnel under the St. Croix River along the existing Hwy 243 alignment from Minnesota to Wisconsin. The existing Hwy 243 Bridge would be removed following construction of the tunnel.