Luffer working over 300 metres high in Dubai

Erected on an undercarriage, a Raimondi LR213 luffing jib tower crane is currently operating at a significant height of 322 meters with a 50 metre jib and a tip load of 3.3 tonnes in Dubai, UAE.

The tower crane is working on a 75 storey construction project. (Photo: Raimondi)

Marking a new region-wide milestone, the crane is aiding construction of a 75 storey residential building.

Substantial site planning was involved to use the existing undercarriage, a type of steel base.

“With the deployment of the luffing LR213, Raimondi continues to demonstrate a presence on Dubai’s most relevant jobsites. This development underscores Raimondi’s steadfast commitment to innovative engineering and providing tailored solutions for the most demanding construction challenges,” said Wael Hasan, general manager at Raimondi Middle East.

The confined jobsite location, coupled with intricate technical challenges and contractor requirements, demanded a precision approach for machine deployment.

Foundation challenge

Tasked with replacing a previously installed crane after the building had already reached a height of 100 meters, the Raimondi team faced the complexity of working with a pre-existing foundation.

The pre-existing foundation imposed restrictions on base loads, due to the existing raft and its maximum allowable limits.

Typically, crane foundations are designed based on reaction forces provided by the crane manufacturer. In this case, Raimondi’s engineers had to reverse the process, adapting the crane’s setup to comply with predetermined limits.

“To achieve this, we used a 6x6 base and progressively removed ballast blocks at each climbing stage, ensuring the base reaction remained within the studied allowable load limits. This adjustment was critical for maintaining stability while adhering to the site’s structural limitations,” Hasan explained.

In addition, to fulfil client requirements and project specifications, the Raimondi Applications Department redesigned the load curve to accommodate lifting needs at a final height exceeding 300 meters.

Structurally, the crane was assembled using GR5S mast elements, incorporating two longer 11.8 metre sections and 100 smaller 2.95 metre segments. To stabilise the crane at its towering height, 12 bracings were installed.

One of the most challenging aspects of the deployment involved collar positioning.

Site-specific requirements meant there had to be several revisions to collar placement, each involving extensive calculations and detailed adjustments.

“The complexities of this deployment demanded an extraordinary level of innovation and adaptability, highlighting Raimondi’s expertise in addressing unconventional challenges,” said Hasan.

Crane removal

With dismantling procedures expected to commence in the coming weeks, Raimondi Middle East operations team has planned the jack-down of the crane to 50 metres, after which it will be fully removed with the use of a mobile crane.