Roots Group – working on behalf of Saudi Bin Ladin Group (SBG) – is using the cranes in the construction of what will be the tallest building in the world.
The Jeddah Tower, also known as the Kingdom Tower, will stand 1,001-metres high when complete. London’s Shard, by comparison, stands a mere 309.6 metres.
The skyscraper will be the centre of a new district, being built along the Red Sea in Obhur, north of Jeddah. The building, designed by Adrian Smith + Gordon Gill Architecture, will house apartments, offices, shops and a hotel.
The pack of Wolffs on the project currently consists of 12 type Wolff 7532 saddle jib cranes, which are used primarily for moving loads on the ground and for construction of the podium at the base of the tower. Also in operation is a type Wolff 355 B luffing crane with a 40m jib and a maximum lifting capacity of 28t. It is positioned in the triangular-shaped core of the tower, forming the focal point of the Y-shaped building floorplan. A second Wolff 355 B is to be set up in the near future.
Both luffing cranes are on 48-metre high towers and are raised step by step with the building, by means of an internal climbing procedure. This will take them to a height of approximately 580 metre. They “jump” between 12 and 15.5 metres higher with every climbing step.
The next phase of the construction should see one of the luffing cranes moved to a platform at a height of 538 metres, where it will work on the outside of the building with an anticipated hook height of 734 metres. It is then planned to disassemble it again and reassembled it at 630 metres above sea level, to achieve its expected ultimate hook height of almost 800 metres.
Erecting and operating the two luffing cranes at a height of several hundred meters presents a special challenge with the high wind speeds that can prevail at these heights. This is where the tower combination consisting of the internal climbing tower segment KSH 23 and the HT 23 tower elements come into play. Their sturdy construction of high-strength steel is designed to protect against distortion, while at the same time saving space as they measure only 2.3 by 2.3 metres.
"Our Wolff 355 B cranes are impressive on these sites due to their very high working speeds of up to 185 m/min and a hook path of 920m," said Habib Mikati, managing director of WolffKran ISS in Dubai. "They also have significant lifting capacities when compared with the competition for the compact working radius relevant for this project."
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