September 4 - Buckner HeavyLift Cranes has used a Liebherr LR 11000 crawler and two LR 1600/2 cranes to build a huge retractable roof over the Arthur Ashe Stadium in New York, USA.

The three heavy-duty crawler cranes worked on site for ten months in order to complete the steel structure, so that the 2015 US Open could be held in the stadium this month. After the tournament has taken place, construction work will recommence, with the retractable roof scheduled for completion by 2017.

The Liebherr crawler cranes were a central feature of the planning and building of the structure, explained the crane manufacturer, with the space available at the stadium very constricted.

"The site was logistically challenging," explained Kevin C Long, project manager at Buckner HeavyLift Cranes. "A great deal of planning was required just for the assembly and disassembly of the cranes."

In addition to Buckner's three cranes, two Liebherr LR 1200 cranes and an LTM 1220-5.2 from Bay Crane Service were used on site as auxiliary cranes.

The restricted space and strength of the foundation soil also caused difficulties when planning the various hoists, added Liebherr.

"The maximum ground bearing pressure on site was our main concern," said Long. "But the Liebherr crawler cranes offer far better ground bearing pressures than the other cranes we considered. At the same time they also provide the lifting capacities and radii we needed. That meant that the cranes did not have to be moved so often which enabled us to save a good deal of time and money."