Aviv Carmel, general manager at Skyline Cranes & Technology Ltd in Israel, talked to Alex Dahm about the tower crane market in the country and his business there
A rapid increase in the height of buildings being developed in Israel has seen a whole new high-rise landscape emerge in the last decade. “The last ten years have seen a major evolution in the high rise construction field in Israel. It can be seen throughout the country but, especially, around the Tel-Aviv metropolitan area,” explains Aviv Carmel.
“The average building height grew from 13 storeys ten years ago to 25 storeys today. A 30 to 40 storey building was a rare sight at the time, whereas many of the high rise towers being built today in Israel are 40 or 50 storeys and it is expected to loom up to 80 storeys and above in the near future,” Carmel continues.
As a result the country’s tower crane population has almost doubled to around 1,400 units. Luffing jib tower cranes have become a major part of the scenery of the new urban Israeli sky line. The shift to higher-rise construction triggered a need to adapt and develop technological solutions and working methods, especially concerning matters such as engineering, quality of service, efficiency and cost.
On the Skyline
Skyline Cranes and Technologies was founded in 2004 by Baruch Parnes, Guy Parnes and Aviv Carmel. They have been part of the crane industry since the 1970s and 1980s, respectively. Today Skyline is a leading company in the field of tower cranes, both in the number and variety of cranes available, Carmel says. “Skyline holds the largest fleet of tower cranes in the country, numbering 187 units.” It also services about 400 of its client’s tower cranes.
“Skyline takes part in the market’s most complex and prominent construction projects, ranging from high-rise residential and office towers, shopping malls, private homes neighbourhoods, hospitals, parking lots, stadiums, defence industry structures and more,” Carmel continues.
The high-rise construction trend has had a significant effect on the tower crane industry in aspects of technological solutions and working methods, Carmel says. “It triggered the need to develop new, advanced technologies to lift heavy loads to considerable height, swiftly and with cost-effective performance, while preserving a high level of safety.” To this end, Skyline has several patents under its name in the field of tower cranes. It is the Israel distributor for Chinese manufacturer Yongmao tower cranes.
A project where Skyline implemented some of these developments was the construction of the Shachar Tower. The developers of this US$ 150,000,000 project were Tidhar and B.S.R Group and main contractor was Tidhar Construction.
“The contractor wanted us to reach a height of 212 metres - 57 floors (37 for offices and 20 residential), with a very limited working area and without limiting in any way the structure’s construction progress.”
The project started in 2013 and required five cranes: two units of Potain MC 310 for the underground parking area and for the first 18 floors of apartment building above it. Three luffing cranes were used for the tower of 57 floors that needed to reach a height of 212 m. One was a Yongmao STL230 while the others were a Potain MR 220 and an MR 225.
“To comply with the contractor’s demands and requirements we used two of the cranes to climb up out of the skin structure.” This was done using a special system of steel beams, developed and produced by Skyline. “It allows the cranes to be leveraged on the building’s concrete structure, leaving the skeleton below it totally free and clear to finish all cladding and indoor work needed immediately after the pass up to the next level.
Two other projects the company is involved in will rise between 180 and 200 m and will include a multi-storey underground parking lot, a vast commercial centre and 45 to 50 storeys of residential and office space. First is the $200,000,000 Alon Towers project for developer B.S.R Group. Contractors are Electra construction and Ashtrom Engineering. There are two 180 m towers, each of 45 levels, and a six storey underground parking lot.
The other scheme is the $250 million Midtown project of Canada-Israel Group being built by contractor Electra Construction. Its final height will be 200 m and each of the two towers will comprise 50 levels and seven-storey underground parking.
“For these projects we decided to climb on the towers’ concrete core structure using a unique folding steel structure with flexible joints. It is patented worldwide by Skyline and provides great advantage in terms of climbing efficiency and use of steel.”
On the two projects there are 15 tower cranes all owned and rented out by Skyline. There are 11 units of the 18 tonne capacity Yongmao STL230 with big winch drums and 1,030 m of cable. Then there are three Potain MC 310s and one Potain K4/56. Ten Yongmao STL230s are climbing up the building’s core using Skyline’s patented folding skin/core anchor beam system. It minimises the number of tower sections required because it stays the same and does not increase as the building rises and the crane gets higher. Each crane will need to be jacked up by between 11 and 13 climbing rotations to reach the final building height. Each climbing rotation will be carried out solely by Skyline jacking crews and will be done in full synchronisation with the site management, Carmel says.
In a similar way to other recent jobs, “we are planning on dismantling the last tower crane on each of these projects using a derrick. For example, at the A.B.C Tower we dismantled, down from a height of 140 m, a Potain MC 265 using a Terex Derrick CDK 83/12, combined with a Maeda MC 285 mini crane and a small special stiff leg derrick that was carried out at the end by using the building's internal elevators,” Carmel explains.
A major change that has emerged with the rise of these high rise projects is a demand, being fulfilled by Skyline, to have an “all inclusive” main tower crane contractor: “A company that can provide full scale solutions, optimised according to each project’s very specific needs. It begins by offering all resources, including an extensive choice of equipment from the tower crane rental fleet and a full range of other services - planning, erecting, dismantling, climbing, engineering, steel structure design and manufacturing - all from one supplier within a controlled budget,” Carmel concludes.