“Let’s Talk Bridges” meeting updates community on Blackhawk Bridge progress

Monthly public meetings will take place at the Lansing, IA, library

By Steve Van Kooten

“When you have a bridge of this caliber and complexity, it draws some of the best people in the nation to it,” Clayton Burke, Iowa Department of Transportation (DOT) Project Manager for the Blackhawk Bridge, said. “Certain designers are excited because they get to design a steel through-truss cantilever bridge. You draw this crowd of people you don’t see every day.”

At the Nov. 9 “Let’s Talk Bridges” meeting held at the Meehan Memorial Lansing Public Library in Lansing, IA, Burke addressed a crowd of more than twenty people as he ran down the list of capable hands on board the project.

First, there was Robert Magliola designing the bridge. Burke said, “I believe he kept this as his last project before going into retirement.” Then, Burke listed Greg Hasbrouck, with Parsons along with Magliola; Al Nelson from HDR, who reviewed the design; Paul Axtel, with Dan Brown and Associates, developed specifications for the project’s drill shafts; and Jim Hauber, from the DOT, who assisted to bring the project to fruition. Each of them were respected names in their field. 

These were nationally recognized names with a list of accomplishments and accolades long enough to cross the bridge and back.

Structure Rating

Burke spoke to the audience and fielded questions about the project. Burke stated the bridge, completed in 1931, had seen a slow but persistent degeneration, which resulted in a lower Structure Rating as time pressed on. A typical bridge has a design life of 100 years; however, in the 30’s this standard was not in place.

“It’s really impressive how this bridge has maintained a high-enough structural rating to stay in service,” Burke said. The DOT uses the Structure Rating to determine the service eligibility and needs for bridges. “The DOT watches it and monitors it, then we can forecast.”

By the early 2000’s, the forecast wasn’t promising: repairing the bridge, even with “extensive rehab,” would only give the bridge 26 years of additional service life, according to a feasibility study began in 2004, and the ability for the bridge to bear over-sized loads and heavier commercial traffic has become a concern. The alternative, Burke said, made more sense: “You could spend a little more and get 100 years of life out of it.”

That alternative was to construct a whole new bridge.

Road Closures

In the audience, one listener asked about traffic closures during the bridge’s construction. Previous statements made by IowaDOT had claimed “five weeks to five months,” according the audience member.

Burke stated original estimates by the DOT were approximately a month for the bridge to be closed to through traffic. As the design process went on more obstacles and variables were encountered that extended the closure window. The solution, Burke said, was to construct the road in sections to keep the road open as much as possible. “That will extend the time it takes to complete the roadway, but it allows people to continue to use the crossing.”

Burke stated the estimated time the crossing will be closed and detoured will be two weeks.

Advancements

The new bridge will improve upon the existing bridge’s design to update its functionality. 

Among the design issues are a tight turn on Iowa 9 in Lansing, a 21’ deck that is narrow for two lanes of traffic, no shoulders on either side of the deck, steel grate that makes traveling across the bridge rough and a 650’ navigation channel that is difficult for barges to pass through.

Solutions to these problems include an updated intersection at Iowa 9 to allow for safe truck travel, a 40’ deck that will allow for an eight foot shoulder on each side of the a 20’ thoroughfare, a concrete deck to make travel over the crossing smoother and a 750’ navigation channel for barges.

Two protective structures, called “dolphins,” will be removed as the replacement bridge will be made using 11.5” shafts designed for barge impact, which will make the dolphin structures used to rebuff barges unnecessary.

Money and Time

Burke stated the bridge had a bid cost of $124 million, significantly less than the original estimate of $140 million for construction costs. As of the meeting the project’s indirect costs, which can include everything from inspections, renderings and other “soft” costs incurred, had totaled $10 million. The original estimate listed total indirect costs at approximately $160 million for the entire project.

Benchmarks for the project include the installation of support shafts starting in a southern part of the project, called Pier 3, by early January. From there work on supports will continue through February.

“The goal is to install them in the winter when there isn’t as much barge traffic,” Anden Lovig, Construction Engineer, said. Travis Konda, Project Manager with the HNTB Corporation added that low water level in the cold weather would help as well.

A large portion of construction will be done through 2024. The replacement bridge will become fully functional in 2027, and the original bridge will then be removed.

Project leaders for the Blackhawk Bridge will hold a meeting on the second Thursday of each month to provide updates to the public. The next meeting is scheduled for Dec. 14. Future meetings are expected to include informational sessions and demonstrations of equipment, discoveries and educational presentations about the mechanical, environmental and progress elements of the project as it moves forward. 

For more information about the project visit iowadot.gov/lansing-bridge and the project’s Facebook page. Questions can also be sent to library@lansing.lib.ia.us.

Articles in the Boscobel Dial and Waukon Standard contributed to this article.