Crane Rental Corp in tandem lift
By D.Ann Shiffler04 August 2009
Orlando, Florida, USA-based Crane Rental Corporation (CRC) performed a unique lift when it was hired to remove a fallen chimney stack at a paper mill in Georgia. The 100 foot (30 m) stack had fallen unexpectedly and the 68,000 pound (31 tonne) load was balanced between the old plant and new boiler house more than 160 feet (49 m) up.
After laying out and analyzing the situation, CRC decided that two cranes would be used to provide maximum control of the stack as it was hoisted out.
The first crane was a Manitowoc Model 18000 crawler crane with a Max-ER wagon rigged with 300 feet (91 m) of #55 boom, 110 feet (34 m) of #79A jib, 492,000 pounds (223 tonnes) of counterweight, 320,000 pounds (145 tonnes) of carbody weight, and 772,000 pounds (350 tonnes) of wheeled counterweight on a 59 foot (18 m) wagon. The second crane was a Grove GMK7550 wheeled telescopic mobile with 179 feet (55 m) of main boom, a 161 foot (49 m) luffing jib and 264,500 pounds (120 tonnes) of counterweight. Both cranes were erected within five days of being given the order.
The Model 18000 worked at a 290 foot (88 m) radius and the Grove 7550 worked at 155 feet (47 m). CRC's rigging crews attached rolling blocks, spreader bars, and 60 feet of 1 1/2 inch (18 m of 38 mm) cables to choke the stack.
The stack was removed without incident. Several other stacks and some miscellaneous equipment was removed and replaced while the cranes and crews were on site.