Naperville carillon tower undergoes 'structural forensics' test this week
The scaffolding and fencing Riverwalk users will see this week around Moser Tower in Naperville are not a sign of the structure's imminent demise, nor of any significant city spending on measures to fix its issues with deterioration.
It just will mean a period of testing is set to begin to help officials determine the best way to address structural problems identified at the 18-year-old tower that contains the Millennium Carillon.
A consultant's report last spring found cracked and deteriorating concrete and corroded steel supports that could decrease the stability of the 160-foot-tall tower.
Now, under a $148,000 contract with consultant Engineering Resource Associates of Warrenville, four subcontractors are set to start a 10- to 14-day detailed assessment of the tower's construction, materials and strength, said Jan Erickson, Riverwalk administrator.
"They call it structural forensics," Erickson said. "It's a little bit more than just a simple assessment."
Riverwalk users still will be able to walk or jog past the base of the tower near Rotary Hill, but the autoplay function that sets the carillon bells chiming throughout the day will be interrupted.
During the study, subcontractors with specialties in construction, engineering, architecture and materials testing will remove small samples of concrete and grout to send to labs for evaluation, said Bill Novack, director of transportation, engineering and development for the city.
Results will provide potential repair solutions, as well as the life expectancy and cost of the solutions. Engineering Resource Associates will compile the results into a new study, expected to be complete this summer.
When results of the first study were released last year, the city aimed to make a decision on the carillon's future in time for money for fixes to be set aside in this year's budget.
Cost estimates for options identified in the study -- such as tearing down the tower, conducting basic maintenance, completing some structural repairs or enclosing the base of the tower to prevent future corrosion -- ranged from $600,000 to $3.75 million.
But after hearing news of the tower's structural woes, experts from across the country offered a range of techniques to address them and potential solutions.
Instead of deciding right away whether to fix or raze the iconic bell tower beloved by some and berated by others, the city took a step back.
Officials with the Riverwalk Commission, which oversees the carillon and Moser Tower, hosted a tour of the spire for several experts in August, and Engineering Resource Associates subcontracted with four of them to perform the upcoming testing.
"At this point, it's really a matter of collecting additional information so that good decisions can be made in the future," Erickson said. "I'm hopeful that we will gather the information we need to move forward."