Gulf Construction Online - Liebherr tackles UAE landmarks

Cranes

Liebherr cranes ... on the Landmark Tower.

Liebherr tackles UAE landmarks

Liebherr cranes rise to the occasion for two extraordinary projects currently under way in Abu Dhabi.

01 August 2009

LIEBHERR has put gigantic machines to work on two extraordinary projects in the UAE capital Abu Dhabi – the 329-m-high Landmark Tower and the Yas Marina Hotel on Yas Island.
Three Liebherr luffing jib cranes are working round-the-clock for the joint-venture main contractor Al Habtoor-CCC, on Abu Dhabi’s second tallest tower to complete the ‘tight’ 40-month contract on schedule.
At the top of the 72-storey tower, a concave steel structure – 52-m high and reducing to 7.3 m height on the opposite side of the roof – will be installed in-situ with an external climbing Liebherr 160HC-L 8/16 Litronic luffing jib crane being used for lifting the two to 10-tonne elements. In order to undertake lifting duties for the structure, a distance of 52 m from the last tie-in to the cranes slewing platform was specified to ensure an acceptable ‘over-standing’ height.
“Liebherr was the only crane manufacturer able to meet this requirement which also included a 7 m radius as a result of the curved face of the steel structure,” says a spokesman for company.
In total, the external climbing crane, featuring a 500 HC mast to accommodate the final free-standing 52 m, will use nine tie-ins at 34 m intervals. Each incorporates six tower sections. In erecting the rooftop steel frame to support the cladding, the Liebherr crane will be used to speed and simplify the process of lifting elements weighing up to 6 tonnes up to the pool area on the 67th floor.
“Luffing jib cranes were chosen by the contractor for their speed in operations in narrow sites allowing simultaneous lifting and lowering,” he says. “Above 150 m heights, luffing jibs become faster than conventional tower cranes particularly with Liebherr’s two fall winch system, considered the fastest in the world with speeds of up to 338 m/min; allowing 20 per cent more load cycles.”
On this project, all three cranes feature modified hoist drums from seven to 10 layers of wire to accommodate the full height two-fall operation. With a six-tonne load, the Liebherrs can lift at speeds of 0 to 39 m/min and have a lowering speed of 244 m/min.
The 72-storey tower includes a four-storey office/retail/lobby area extending beyond the main tower footprint of 2,600 sq m and reducing to 2,400 sq m as the east and west facades reduce. The tower sits over five levels of basement car parking, for approximately 1,000 cars.
Two Liebherr 280 EC-H12 tower cranes were used for construction of the basements and levels One and Two of the podium. One, with a 65 m jib length and a maximum 12-tonne lifting capacity featured an erected hook height of 45 m, which includes 17 m on the bottom basement level. The second crane has a 70 m jib length and a 43 m hook height from ground level.
Today, both cranes continue to perform crucial lifting duties. Because the external luffing jibs cannot reach the road, the first tower crane is used to unload trucks, placing steel in the rebar fabrication yard for final lifting by the luffing jibs to the top of the tower.
Both tower cranes also unload electromechanical units for storage in the basement levels plus finishing materials such as cement and marble for placement close to the hoists.
Above the ground level, the tower rises upwards from the middle of the site. Mechanical areas of the tower – each of which comprises several levels of mechanical plant – are located on the sixth and seventh and 36th and 37th floors, plus the 66th, 68th to 72nd floors. Level Seven also forms the ‘springing’ point for two large canopies on either side of the building, which extends over the offices and podium spread below.

F1 race circuit
Meanwhile, a Liebherr LTM 1500-8.1 500-tonne mobile crane is engaged on the Yas Marina Hotel, which is centrepiece for Abu Dhabi’s F1 Grand Prix circuit. The five-star hotel will ‘straddle’ the track, making it the only hotel in the world to have a Formula One track running through it. Comprising two towers clad in a ‘glazed cloak’, the hotel includes 499 bedrooms and suites. It will also feature a Michelin-starred restaurant and other leisure facilities and an underground car park deck for 200 cars. Both hotel towers are linked with a bridge at Level One with executive lounge facilities being constructed within the bridge deck.
The LTM 1500 is playing a key role in the construction of the bridge spanning the 5.5-km-long race circuit, lifting and positioning the 72-tonne steel shrouds and 24-tonne aesthetic ‘shroud’ cladding.
The 500-tonner is part of the UAE rental specialist Al Faris’ Liebherr fleet, which comprises more than 130 models, including four 500-tonne models and a new LTM11200-9.1 1,200-tonne crane. Al Faris is recognised as one of the largest crane rental fleets in the Middle East with more than 320 mobile cranes.
The LTM 1500 has a maximum lift capacity of 500 tonnes at a 3 m radius. Its seven-section, 84-m telescopic boom is the world’s longest telescopic boom in its class. Lifting capacities are increased due to the jib suspension. The lattice jib, reaching heights of up to 91 m, extends the operating range of the unit to 145 m hoisting height and 108 m reach. Work started on the Yas Marina hotel in February and main contractor Al Futtaim Carillion is confident of meeting the September completion date.