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Building A Connection To Art
Like a runway from the heart of Chicago’s Millennium Park, spanning 620
feet across Monroe Street to the third-floor level of the Art Institute’s
new under-construction Modern Wing, a sleek steel pedestrian bridge is rising.
Drawing visitors from the park to the museum will be the new Nichols Bridgeway,
a slender blade of a bridge just 15 feet wide. Its curved, white-painted steel
underside resembles the hull of a boat or a racing shell. The floors will feature
textured aluminum planking, and steel railings will guide walkers as they enjoy
impressive views of Millennium Park, Michigan Avenue, and, appropriately, the
lakefront. Both the museum addition and the bridge were designed by architect
Renzo Piano and, as symbiotic works of art in themselves, are becoming striking
additions to the cityscape, while the new bridge is a pedestrian’s dream
in Chicago’s bustling downtown. Both the Modern Wing and the Bridgeway
are anticipated to open in spring 2009.
But setting the bridge on course required precise planning to accommodate
the tight site in a congested area downtown.
Planning for the bridge construction began in summer 2007, with groundbreaking
following in September. Danny’s Construction Company, Inc. of Gary, IN,
the steel erector, hired Central Contractors Service, Inc. of Chicago to supply
cranes for the project. Central was chosen for the job because of their knowledge
and experience in specifying the right equipment for a successful job. Central
is a member of the ALL Erection & Crane Rental Corp. Family of Companies,
North America’s crane rental and lift engineering leaders. ALL and Central
offer unmatched experience in lift planning and jobsite analysis and offer the
largest, most technologically advanced fleet. This “powerhouse” combination
provides cost savings, increased productivity, and improved safety to their
clients.
The Monroe Street/Art Institute section of the Bridgeway is composed of four
curved-bottom structural steel sections. The four sections were planned to
be prefabricated into maximum lengths and weights that could be erected utilizing
Central’s fleet of equipment. The sections, each with an average weight
of 100,000 lbs. and approximately 65 ft. long, were to be welded together as
each was lifted.
A 550-ton Grove GMK 7550 hydraulic all terrain crane from Central hoisted
the estimated total 200 tons of steel sections. A 40-ton Demag AC40 hydraulic
all
terrain was used to assemble the GMK 7550 and also served as an assist crane
to move shoring towers for the bridge.
“
The site is particularly tight and required exact dimensional layouts to allow
for erection of the bridge elements. Many times the clearances between the building,
the crane, and the bridge were within 1 foot,” says Linsenmann. “Central
met the challenges as we expected they would.”
John Martello, Central Contractors Service general manager, says, “Setting
these heavy steel segments across Monroe Street, on a rising plane ending 60
feet in the air at the entrance to the museum addition, was a challenging undertaking
because of the tight clearances. The crane had to be positioned as close as
possible to the bridge to achieve the desired operating radius of 79 feet.
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