A LIEBHERR 355 HC-L 12/24 Litronic luffing jib crane was used to place the crescent on the Makkah Clock Royal Tower, the second tallest building in the world, in Makkah, Saudi Arabia, at a height of more than 600 m.

The last crane to be used on site, with a hook height of 618 m, played a key role in the installation of the golden crescent moon – proof of the great performance capacity of the crane from Liebherr, says a spokesman for the Liebherr Group.

The Makkah Clock Royal Tower stands at the heart of the Abraj Al Bait Complex, and accommodates a first-class hotel over 76 storeys. The crescent is partly accessible by foot, and includes a viewing platform at a height of 558 m.

“At night, when the faithful are called to prayer, the crescent opens and searchlights send beams of light 10 km into the sky,” says the spokesman.

The gilt crescent crowns the building at a height of 601 m. “The assembly of the crescent, made up of five segments – each weighing 12 tonnes and with a diameter of 23 m – was an extremely tough challenge,” says the spokesman. “The prefabricated parts were lifted one by one by a second Liebherr luffing jib crane onto a platform at a height of 393 m, where the valuable individual components were pre-assembled.”

The Liebherr crane positions the crescent at the tip of the tower.

A huge advantage for assembly work was the horizontal load path available at the push of a button as well as load holding without engagement of the hoist gear brake, he explains. “Jib movements were automatically regulated by means of the hoist gear control in such a way that the load hook travelled on a horizontal path. The preassembled components
were carried aloft on the hook of the 355 HC-L to the tip of the building where they were optimally positioned to create the finished crescent moon,” the spokesman adds.

The 355 HC-L 12/24 Litronic luffing jib crane was assembled as an inside climbing crane at a building height of 390 m, and then went into action. After completing four climbing stages to a height of more than 400 m, the luffing jib crane was placed on an inserted foundation frame. Over the various stages of construction, the 355 HC-L demonstrated its adaptability outside the building, and climbed in further increments as an outside climbing crane in step with the building up to the end hook height required (618 m).

Using the 500 HC tower system, the luffing jib crane had a tower height of more than 150 m. In order to remain stable and work safely at this enormous height and under the prevailing conditions, the tower was guyed up to four times to the tapering tip of the building. The upper two guying points formed an elaborate spacious truss structure, since at this point a gap of more than 15 m had to be bridged between the crane tower and the building.

Over the past 10 years, some 30 Liebherr luffing jib cranes of the HC-L series with load moments from 160 to 355 m tonnes have been hard at work on the site. The facade, including the top structure with the crescent moon at the tip, was completed right on schedule before the start of Ramadan last August.

Liebherr is one of the world’s leading manufacturers of construction machinery and an acknowledged supplier of technically innovative user-oriented products and services in numerous other fields. The Liebherr Group’s holding company is Liebherr-International in Bulle, Switzerland, which is entirely owned by members of the Liebherr family.