Bridge Talk presentation clarifies dates, answers questions from community members regarding bridge demolition, construction

The monthly Bridge Talk presentations that have been offered in Lansing by the Iowa Department of Transportation (DOT) since the beginning of the bridge replacement project over the Mississippi River at Lansing took on some added interest for the August meeting.

With that Thursday, August 14 meeting being the first such public meeting since the July 14 announcement by the DOT that the Black Hawk Bridge will be closed and demolished at some point this fall in order to safely complete the new bridge construction, and also following the not fully official reporting of more specific closing and opening dates associated with the project from earlier in the week, Thursday’s meeting was moved from its typical Meehan Memorial Lansing Public Library location to the Kerndt Brothers Community Center in anticipation of a larger attendance, which ended up at approximately 50 individuals from Lansing and the surrounding area.

With many of the monthly Bridge Talk presentations being hosted by Iowa DOT District 2 Engineer Clayton Burke, who is the project manager for the Mississippi River bridge project, he was joined at Thursday’s presentation by Brennan Dolan, a Cultural Resources Team Lead for the Iowa DOT who had been a familiar face in the early stages of the project. Both Burke and Dolan offered insight and further clarification into the processes and decisions made in regard to the new bridge placement location, including the required compliance with Federal guidelines such as the National Historic Preservation Act and the National Environmental Policy Act, as well as the construction processes used, and ultimately the impact some of those construction processes ended up having on the Black Hawk Bridge that forced the recent decision to close and demolish the existing bridge in order to be able to complete the new bridge construction in a safe and timely manner.

More detailed specifics of most of those points discussed by the DOT tandem at Thursday’s meeting were previously published from a one-on-one interview with Burke that was printed in the July 23, 2025 edition of The Standard.

NOT EVERYTHING IS CONTROLLABLE
One thing Dolan wanted to further elaborate on in regard to the project and its current status was the amount of planning, analysis and research that did go into the project and the work that was required to try and offer the best possible scenario for successfully carrying out the original plan of constructing the new bridge while being able to keep the adjacent existing bridge open to traffic.

“One of the things that I would want to underscore in this discussion would be the amount of geotechnical work that did go on as we were moving through the preliminary designs to the final design; that factored prominently into the construction documents that we prepared and the methods that the contractor would bid their construction abilities on,” he explained. “It’s probably not hard to foresee that it’s not possible to control all of those variables. And that really does paint the picture as to the decision of where we’re at. Obviously, putting safety out in front; as an agency, that’s a core value for us - it has to be.”

But, he emphasized that no amount of working and planning can fully control or fully account for the simple dynamics of the river and what truly lies underneath its surface.

“It really just speaks to the dynamic nature of the bend in the river and the really, really deep depth you have to get to in order to reach bedrock here,” Dolan furthered. “If you recall, for those of you who were present back in 2017 and 2018 at those first few public meetings we were kicking off, that was when we started doing geotechnical work and, I’ll never forget, we got the data from our first core, and it was 126 feet to get down to anything that was even relatively solid underneath the sand - and that’s an eye-opener. So, very complex in terms of the geotechnical, the geology underneath the river and the shifting elements there, and that, again, paints the picture in terms of the situation we are in today.”

PLANNING AGAINST THE UNKNOWN
In furthering that sentiment of how testing and planning don’t always win out over the forces of nature and elements simply unseen and unknown, Burke shared how the thorough testing of driving pile near the piers of the existing bridge for the completion of the adjacent pier of the new bridge did not show any concerning impact. However, further necessary steps in the construction process that involved smaller piling further away from the existing bridge surprisingly did show impact that was not anticipated but ultimately pushed safety parameters over the brink of being acceptable.

“What we found was that the construction of the pier in the middle of the river had a very minor influence on the existing bridge; it was minor enough that we could get the deep foundations into place and keep the bridge open,” Burke shared. “But when we got to the temporary shoring towers - which are steel towers that will come up out of the river and support the truss as we erect it from pier to pier, those are smaller pipe pile that go down to bedrock, and we did not anticipate that those would have influence on the existing bridge after the testing we had done. But, for whatever reason - 17 feet away, so even further away (than the testing or the new pier pilings), they still had influence on the bridge and we had another emergency shut-down when the sensors picked up more movement.”

In reference to that most recent bridge closure in May of this year, Burke explained that a thorough analysis was conducted to determine the safety level of the bridge after that latest motion was detected by the bridge’s monitoring system. He outlined how the engineering team simulated every part of the Black Hawk Bridge into a “finite element model” for a computerized analysis, determining that the existing bridge is ultimately safe in its current status but that further pile driving necessary for construction of the new bridge could easily render it very unsafe and could not be continued with the existing bridge in place.

“They used a computer program and put every single member and every connection in that model, and then they moved the pier in that model and figured out how stressed some of the members got,” Burke outlined. “They could use that to tell us that it’s safe in its current condition that is out there today, and they could also use that to tell us that you don’t have room to move it anymore. It’s not safe to keep going, it’s not safe to keep driving this piling. You guys need to shut it down and demolish it first before you continue with the new bridge. So, that’s where we took the recommendation. Like Brennan (Dolan) said, safety is one of our core values - it’s number one. It was an incredibly difficult decision. I personally pushed it, and I didn’t want to accept it at first. I wanted to keep doing more analysis, I wanted to keep pushing that structures group and squeeze another two to three inches (of bridge movement) out of there, and it just came to the point where it wasn’t safe, and we had to do something to shut it down.”

DATE CLARIFICATIONS
With that closure and demolition recommended, Burke explained how the next step is to get a demolition plan completed and approved. “That plan details every step as to how we are going to remove the decking, remove the rails, remove some stringers underneath the decking, and then attach explosives and implode the structure from the sand span over into Wisconsin,” Burke detailed. “It’s a very detailed plan and it has to be done right to be done safely, so it takes time to put together.”

Burke also addressed the October 15 bridge closing date that had initially been reported on by Radio Iowa coverage of the August 12 meeting of the Iowa Transportation Commission. When asked about that reported closure date prior to Thursday’s Bridge Talk meeting, Burke had explained that the information presented to the Commission by Iowa DOT Highway Division Administrator Tony Gustafson out of Ames was information that would be “different than what we would typically present to the public” due to the fact that “the dates mentioned do not contain any contingency, and are the earliest possible if everything goes absolutely perfect.”

At Thursday’s Bridge Talk, Burke furthered his explanation of that October 15 date being the absolute earliest possible date for closure. He noted that with so many agencies involved in the approval process of the required demolition plan, there are many factors that need to fall into place.

“That is the earliest we could possibly get it through with the minimum review times,” he noted of that October 15 date. “That’s not the date that we’re saying that we are going to close it, that’s just our internal date that’s kind of gotten out there. We can’t possibly move faster than that October 15 date. So, it could be later, depending upon the review of that demolition plan and how that process moves forward. We can’t know how fast that process is going to go. So, that’s where we’re at in setting up the demolition.”

A March 2027 opening of the bridge had also been reported by Radio Iowa out of that Iowa Transportation Commission meeting. Burke again cautioned that date would involve a “perfect” scenario, noting prior to Thursday’s meeting that “an opening in March of 2027 is also idealistic. We would need two very mild winters, no flooding, and no construction delays in order to be able to meet that date. A more realistic opening date to communicate to the public would be mid-2027.”

He further confirmed at Thursday’s meeting that “with our construction efforts and looking at the minimum timeframe of getting that bridge built, we’re looking at sometime in mid-2027 right now. So, it is a two-year timeframe.”

To read the full article, pick up the Wednesday, August 20, 2025 print edition of The Standard or subscribe to our e-edition or print edition by clicking here.