A 34 storey roof extension16 November 2015
A Potain MR 415 crane has been erected on top of an existing building in Chicago to overcome space restrictions in the US city.
James McHugh Construction erected the luffing tower crane at Block 37 in Chicago, to assist with the construction of a 34-storey, 690-unit apartment building on top of the existing five-storey complex.
Lifting work began in June 2014, with James McHugh hiring a 26.5USt Potain MR415 from Central Contractors (Central), based at Cleveland, Ohio and part of the All Family of Companies.
Paul Urbanski, sales manager at Central, said: "The MR 415 was initially erected on 11 tower sections so that its jib would clear the historic Cadillac Theatre, which is just across the street, when it was stowed.
"With a lack of space below for a spread foundation, the crane was tied in at the 5th floor - a height of 78ft -- during the initial assembly to reduce the foundation reactions."
The crane was first used to lift 20ft-tall steel trusses, weighing up to 40USt, which were erected on the existing roof to support the additional construction. The Potain was then used to lift construction materials of up to 10USt.
A 550USt Grove GMK7550 with 121ft of luffing jib was used to assist the erection of the Potain crane, and was used again with a fixed jib to disassemble the crane in September.