By Euan Youdale21 June 2010
Dismantling a tower crane's counter jib, less than 1 m from the glass façade of the sixth and seventh floors of Jumeira's Wharf Tower 1 residential apartments in Dubai, called for precision lifts.
Al Faris used a 500 tonne Liebherr LTM 1500-8.1 wheeled mobile crane for the job. As well as minimising swing as the counter jib was released from the apex, it was also necessary to lift the jib above a second tower crane working just metres away, on the adjacent Wharf Tower 2. The LTM 1500-8.1 then had to slew the jib around to its transportation area.
The dismantling was further complicated by the restricted ground level area on which the LTM 1500-8.1 was based on. "The area constriction around the site meant the 'rig-up' was a most difficult aspect of the rental and time consuming," said Brian Green, Al Faris Rental.
The only available space was on the access ramp to the basement level of the adjacent Wharf 2, currently under construction. In addition to being uneven, the access gradient required different height settings on each of the crane's outriggers.
Featuring a three-section, 50 m long telescopic boom, the Liebherr LTM 1500 was configured with a 42 m high boom, a 56 m luffing jib and 165 tonne counterweight to provide an almost vertical boom setting.
With a crane capacity of 15.4 tonnes at a 68 m radius and a hook height of 60 m, the operator was able to lift and remove the counter jib with relative ease, said the manufacturer. The dismantled tower crane had been used during the construction of the podium of the recently completed 29-storey Wharf Tower 1.