Why do the existing Cass Street Bridges in La Crosse include a tied arch structure next to a through truss, and the plans for the new Red Wing Bridge include a tied arch bridge alternate, while the new Winona Bridge is planned to be built using a concrete box girder design along with rehabilitation of the existing bridge?
Since the existing Winona Bridge is eligible for the National Register of Historic Places, several agencies were required by federal law to work together in studying new bridge options while considering impacts to the existing historic bridge. The project falls under the full oversight of the Federal Highway Administration, the agency responsible for compliance with federal laws regarding the protection of historic resources (Section 106 and Section 4(f)).
Through collaboration between FHWA, MnDOT, and the State Historical Preservation Office, the historic review process resulted in the recommendation to build the new bridge using the concrete box girder design as the other two bridge types considered (tied arch and cable stayed) were deemed to have detrimental visual impacts to the preservation of the existing Winona iconic historic truss. Cost and migratory bird issues were also considered.
See these links for more information about the Historical Review processes on the Winona Bridge Project:
Conversely, the existing Cass Street Bridges spanning the Mississippi River in La Crosse were built and rehabilitated over ten years ago. At that time, the existing through truss bridge was not eligible for the National Register of Historic Places, established by the National Historic Preservation Act of 1966. Therefore, the new bridge type was not required to follow the Section 106 requirements of the NHPA, which requires federal projects to consider historic preservation in planning and decision making. Stated another way, the new bridge was eligible to be a tied arch, because visual impacts from the new bridge type (in relation to the existing bridge) were not required to be considered from the historical context of the NHPA. Therefore, although in a setting similar to Winona, the new Cass Street Bridge was allowed to be a tied arch design, while the Winona Bridge wasn’t due to its historic standing.
For the Red Wing Bridge project, the existing Mississippi River Bridge (called the "Eisenhower Bridge") was built in 1960 and is also not NRHP eligible. Since the Eisenhower Bridge in not NRHP eligible, the context of this river crossing corridor differs from the Winona crossing and existing bridge. However, the Trunk Highway 63 Bridge over Trunk Highway 61 in Red Wing is NRHP eligible. Similar to the Winona Bridge Project, the Red Wing Bridge project will need to follow Section 106 requirements of the NHPA, requiring consideration of historical preservation in planning and decision making for the project, in relation to the historical impacts to the Trunk Highway 63 Bridge over Trunk Highway 61 as that bridge is also included in the proposed project scope. Read more about the Red Wing Bridge Project.