Shang High
July 2007
Jonathan Robson visits the cranes at the top of the world’s third tallest skyscraper
There can be hardly one among Shanghai’s 19m people that hasn’t noticed the cranes sitting at the top of the World Financial Center in Pudong district’s Liujiazhui area in Shanghai, China. At this height, nobody can read the name Favelle Favco emblazoned on the machines; with their cabs 390m up in April this year, these cranes are, with the three Favcos on the Burj Dubai tower, some of the highest-reaching tower cranes in the world.
The height of the building is emphasised by its design: it begins as a square footprint at ground level but tapers to a wedge at its top.
When complete in 2008, the 492m tall, 101 storey building (plus three levels below grade) will just top Kuala Lumpur’s Petronas Towers (452m), but not Taiwan’s 509m-high Taipei 101, currently the world’s tallest skyscraper.
The mixed-use 381,000 sq m development will contain offices, a hotel, shops and a conference venue. It was designed by Kohn Pedersen Fox Associates for Japanese developer Forest Overseas, a wholly-owned subsidiary of Mori Building. Construction of the building was begun in 1997, but the Asian financial crisis prevented the building rising above its completed foundations for years.
A resurgence of anti-Japanese feeling rose against the building’s design, which had included a large round hole in the top of the building. Despite pleadings from Mori that the design was based on the traditional ‘moon gate’ commonly found in Chinese garden design, it was felt locally that the image towering over Shanghai's central financial district was closer to the rising sun of the Japanese flag.
In 2003, Mori announced new financial and architectural plans that call for a rectangular hole at the top, and construction began anew.
The site today
Each of the two cranes perched on the building core is an internal climbing M900D diesel hydraulic luffing tower crane with a 56m tower and a 55m boom. A Caterpillar C-15, 515 HP diesel engine raises the 32t line pull at 140m/min (light load of approximately 6t) and by August this year it will be lifting loads above the 91st floor: a maximum height of 407m. The cranes have a maximum lifting load of 64t with two falls of rope at 19.2m radius, although, according to Ted Hsieh, Favelle Favco’s representative in Shanghai, the average load on the site is about 20t with columns weighing up to 50t. The cranes themselves weigh 263t including 80t counterweights.
The M900Ds are owned by the two Chinese companies that head the project’s construction: Shanghai Mechanised Construction Company (SMCC) and China State Construction and Engineering Company (CSCEC). Both companies purchased the cranes under contracts that allow for them to be bought back, but it is expected that SMCC will keep their unit for future projects.
Luffing cranes were required because of the unique design of the building. By the end of August there will only be space for one crane on the building core. This crane will be required to lift the steel for the final ten floors into place around and above the hole, which will begin at the 91st floor.
Wang Wu Ren, vice chief engineer of CSCEC, says it was the start lift power of the M900D that was the deciding factor for the cranes for this project. “The diesel engine is much more powerful than an electric one and has been a factor in the speed of construction,” he said. The project has averaged one floor every four days. The diesel-powered cranes also have not tapped into the site electricity grid, whose capacity is finite and in high demand.
Initially the cranes operated with a driver and two spotters—one on the ground and one at the top—but now that the building is over 80 floors high a third spotter positioned around the 50th floor has been added to each team. “Even so,” says Wang, “we sometimes have to stop on foggy days because we can’t see the loads between floors.” Weather permitting, four of these teams keep the cranes operating 24 hours a day.
A third crane, a Favelle Favco M440D, was recovered to another part of the site as the tapering building core does not leave enough space for all three cranes to operate. Steel brackets off the building core support the two remaining M900Ds.
These M900D cranes were modified for the site from the existing M760D that was used on the Burj Al Arab Hotel in Dubai. The engines and winches were enlarged to cope with the extra line length of over 700m and the tower was strengthened to cope with the higher wind speeds at the heights at which they must operate.
Final recovery of the M900D will be with a Favelle Favco R370 which will in turn be recovered with an SDD20/15 derrick crane.
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