Next
week’s issue of Engineering News Record will officially recognize Chicago’s
lakefront crown jewel – Millennium Park – as by far the world’s largest green
roof. The park’s green roof area of 99,127 square meters dwarfs by far the
second place contender – Frankfurt International Airport, in Germany – which at
80,000 square meters is really an aggregation of several smaller terminal
buildings.
Millennium
Park has several features beyond size to distinguish it from the other green
roof projects honored in the ENR July 9 issue. It isn’t just a roof – it provides
chair and lawn seating for 11,000 concertgoers who listen to the Grant Park Symphony
and other groups performing in the Frank Gehry ornamented Pritzker Pavilion’s
outdoor concerts all summer long. The roof includes 2.5 acres of native
Illinois plants in the Lurie memorial garden. There’s a mirror surfaced bean
shaped sculpture named “Cloudgate” by Anish Kapoor reflecting the skyline and
street wall along Chicago’s famed Michigan Avenue, and a delightfully fanciful
Crown family memorial fountain featuring the faces of animated anonymous Chicagoans
spitting cool water for children and adults to splash in when the weather
reaches this week’s hundred degree highs.
The
park was the brainchild of former Mayor Richard M. Daley, who managed to put
together a coalition of generous corporate and very well heeled private donors
to fund about half its total cost, which ran around half a billion dollars by
the time the park roof was completed. One of the first public/private
partnership construction projects in the city, ultimately completed by Chicago
based general contractor Walsh Construction, the donors of the rooftop
enhancements formed a tax exempt organization to contract for and pay for their
part of the job, then made a tax deductible gift to the City of both the funds
to pay for construction of their enhancements and their contracts with Walsh to
build them.
Fieldwork
by the tradesmen who put up the Crown Fountain’s Jaume Plensa designed twin 50
foot high glass block towers housing the multiple projectors which create the “spitting
images” of Chicago citizens, those who assembled the Kapoor Cloudgate sculpture
and then polished it to a mirror finish, and those who erected the intricate
free form aluminum Frank Gehry panels adorning the Pritzker Pavilion was so
highly skilled and unique to the trades involved that Walsh Construction
published a coffee table picture book of progress photos from the project heralding
the dedication of these tradespeople. The title of that book, handed out to
folks involved in building and paying for the project: “Better Than Perfect.”
According
to the forthcoming article in ENR, green roof construction in the U. S. and
Canada grew 115% between 2010 and 2011. American Society of Landscape
Architects Executive Vice President Nancy Somerville touts the economic
incentives for green roofs: “Green roofs have a higher cost up front, but the
payback over time is significant,” she says, “not just in energy savings. It’s
protecting your roof membrane – you can skip one or two or three roof
replacement cycles.”
None
of the big green roofs presently under construction around the nation and the world
even comes close to the size of Millennium Park, and even if a bigger one were
to be erected, it is quite doubtful any green roof built in the foreseeable
future could ever rival Chicago’s crown jewel in accessibility to the public, scenic
grace, or entertainment value. Chicago’s visionary politicians, business people
and philanthropists who contributed their money and their genius to design and
creation of Millennium Park have undoubtedly left their city a legacy which
will stand the test of time.
