The Blackhawk bridge that connects Lansing, Iowa and Rural Wisconsin will not survive to see its completion of its completion, as the transport agencies of the two states have decided to close and demolish the structure almost a year before the initially planned.
Built privately in 1931 in piles of shallow wood and managed by states for the last 70 years, the 1,702 feet long steel through the Truss bridge is the only crossing along a 70 -mile stretch of the Mississippi River. The original plan requested to keep the bridge open until after Kraemer North America completed a new 1,724 wider crossing, which is only 75 feet away.
However, since the construction began by the end of 2023, the Old Bridge has twice experienced enlarged closures, both the result of the structural movement that exceeded the safety thresholds. Repeated displacement problems have had an undulating effect on the construction activity of the new bridge, promoting the expected date of completion of the project from 2026 to 2027.
Although the existing bridge was considered to be reopen safe after the second instance of excessive movement this past May, another Wiss engineering analysis, Janney, Elstner Associates and extensive discussions between the state’s dumps and Kraemer determined that closing and demolition offered the best approach to guarantee a safe and timely construction of the replacement bridge.
“In addition, we refined the analysis, more supposes had made our engineering consultant on the state of the existing structure and the pre -existing tensions in the various members,” says Clayton Burke, responsible for the Iowa Dot project. “The decision was reduced to the uncertainties in the cases we should make and the risk of failure if any of these cases were wrong. It was determined that we had pushed ourselves to the point that we could without risk the public, the workers, the navigation channel and the railway.”
From analysis and exhaustive inspection, the points have determined that the existing bridge can be safely in its current condition, while the planning of the demolition is underway, adds Burke. The final closure is expected this fall.
The head of the Kraemer project, Aaron Rosenbery, says that the center of the old bridge and the eastern extensions will be eliminated by controlled demolition. The rest of the portions, including Span 1 and Western Cantilever, will be deconstructed for the piece to protect an active railway line and adjacent buildings on the Iowa side and to minimize river traffic interruptions.
While the battery driving for the temporary traffic towers is suspended until after the end of the demolition, Kraemer continues the final results for the new bridge concrete batteries. In a change in the original construction plan, the steel erection will be west on the east from the side of the Iowa. The construction of Cantilever de Piers 2 and 3 will be used above half of the new navigation channel 750 feet wide, with the final line – a preambled 334 feet in length – to be lifted from a barge and placed in its place.
In the meantime, the project team is using Old Bridge in recent weeks to investigate alternative river crossing opportunities to support companies, institutions and travelers during what could be up to two years of construction. The study options include the restoration of a water taxi service offered during the previous closures. The points are also working to minimize the construction and other interruptions in the detours of the road.
