Signs of deterioration on the concrete frames of the Mitchell Park Domes have been evident for more than 22 years, according to documents released by the county executive’s office this week.
The Domes have been closed since Feb. 5 — a week after a piece of fallen concrete was discovered on the floor of the desert dome — prompting renewed scrutiny of the nearly 50-year-old conservatory’s structural integrity.
An engineering survey of the Domes completed in 1994 by Graef, Anhalt, Schloemer and Associates, Inc., a Milwaukee engineering firm that later became Graef USA, found evidence of deterioration in each of the Domes’ precast concrete frames.
At the time, Graef project panager Kenneth Grebe and project engineer Cynthia Minshall recommended “updating the structural condition” of the Domes and urged the county to perform regular maintenance to preserve what they saw as historically significant structures.
“The Domes were designed using concepts which advanced the state-of-the-art of conservatories and construction,” Grebe and Minshall wrote in the report. “Ideas developed from construction of the Domes have been studied and utilized on other projects throughout the country. It is a unique structure that must be maintained if future generations are to enjoy it.”
Grebe is now chief operating officer of Graef USA.
Though budget records indicate the county has spent $700,000 on temporary repairs, maintenance and engineering studies since late 2013, years of deferred maintenance extending back to the mid-1990s have driven up the cost of a total replacement or complete renovation of the Domes to an estimated $65 million to $75 million.
The Domes will be closed for at least three months while county officials, including County Executive Chris Abele and Parks Director John Dargle, work with engineers to install a temporary fix that will prevent more concrete from falling. In the meantime, Abele is seeking public input on the future of the Domes.
A public hearing will be held on Feb. 24 at 6 p.m. in the greenhouse complex on the east side of the Domes.
See a recent look inside the Domes from WISN-TV Channel 12, media partner of BizTimes Milwaukee.
