QATAR crane rental company United Equipment has provided a solution for construction of Doha’s 59-storey Silhouette Tower, following a change of contractor, by installing a new Liebherr self-climbing tower crane on the 47th-storey, ensuring significant cost and time savings.

Contractural disagreements between the owner and contractor on the 59-storey tower resulted in the stopping of construction at the 52nd storey, the removal of construction equipment and the appointment of a new contractor, Redco Construction. Two tower cranes tied to the outside of the tower had previously been used to ensure complete coverage of the tower’s footprint. Replacement tower cranes required a three-month delivery time and costly installation.

Considerable time and costs were, therefore, saved with the solution provided by  United Equipment.

In providing total technical support, United Equipment proposed that a Liebherr self-climbing 160 HC L8/16 Litronic luffing crane be fitted into the tower’s existing core shaft with braces on the 47th and 49th floors.

With the existing lift shaft too small to incorporate the crane’s mast, a 2.3 m by 2.3 m hole was cut through the slab between the two lift shafts.

Using a specially fabricated steel frame supported by slab beams on the 47th and 49th floors and further positioned through the lift shafts, the luffing jib crane was successfully installed, ensuring considerable cost savings with a single crane to cover the tower’s ‘footprint’ and a virtually immediate start.

On the 52nd floor, the crane will be further jacked to allow construction up to the final height of 220 m.

The 160 HC L8/16 Litronic was chosen for its ability to be easily fitted within the shaft and high-speed lifting capability. Featuring a high-speed single rope winching system offering a maximum 8-tonne lifting capacity, the crane is able to lift loads of 2.4 tonnes at 183 m/min; 4 tonnes at 110 m/min and 400 kg at 338 m/min.