Limited space, lifts weighing several tonnes and a world first: Two new Liebherr luffing jib cranes are currently raising a 48-storey office building in the centre of Singapore.
Internal climbing systems have been a successful part of high-rise building construction for a number of years now. What makes the Singapore project a world first is that the two 710 HC-L cranes are using a 24 HC 1000 tower system to climb up on the inside.
The cranes started work in November 2020. Back then, the cranes belonging to the fleet of the Kim Soon Lee company were assembled freestanding at a tower height of around 40 metres. The Central Boulevard Towers are being built right next to the historic “Lau Pa Sat” building, also known as “Telok Ayer Market.” One of the two new towers will be approx. 241 metres in height. It’s for this part of the project that the two 710 HC-Ls, with jib lengths of 40 and 45 metres, are being used.
Fewer climbing stages, less downtime
The two cranes will reach their maximum tower height of 245 metres in just ten climbing stages. This is made possible by a 57 metre-high tower.
“The number of times a crane has to climb impacts how long the downtime is for customers,” says Liebherr Tower Cranes project manager Eric Konijn, stressing the advantages of this solution. “We were able to offer our customer a solution with ten climbing stages, which saves them valuable time and consequently money.” One climbing stage takes about two hours, so the cranes stand still for as short a time as possible. In addition, there are significantly fewer storeys to reinforce, which also has a positive impact on cost efficiency.
Due to the amount of guying that is legally required, and the resulting significantly increased costs, having the cranes climb completely on the outside of the building wasn’t a viable option. Plus, there isn’t enough space on site to use exterior climbing cranes.
Lifts of up to 30 tonnes
The high-performance Liebherr 710 HC-L model was chosen because of the tight conditions on site, and the project’s heavy load and handling capacity requirements. The 710 HC-L has a maximum lifting capacity of 64 tonnes and is the largest luffing jib crane Liebherr offers. It can easily lift and precisely position the pre-cast concrete parts, weighing up to 30 tonnes, which are needed for the skyscraper’s construction.
When completed, the 48-storey tower will accommodate office and retail space. The Central Boulevard Towers project also includes a second tower, which is 16 storeys high. One of the highlights is an urban “sky park” with green spaces. Small recesses are to be incorporated into the greenery as meeting areas, and the park will also include a jogging track for employees to do laps on.
The two luffing jib cranes will be working on this site, which borders on high-traffic roads, for several more months. They will continue climbing skywards section by section, watched over by the city’s skyscrapers. When they reach their maximum height, they will tower over the surrounding high-rises.
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