CRAWLER CRANES Ӏ SECTOR REPORT
Tadano high on a wind farm
The St Gotthard wind farm is at an altitude of over 2,000 metres. A team from Swiss crane and transport specialist Toggenburger was charged with erecting it. They faced a whole series of adversities. As well as being at high altitude the work area was extremely tight; and it was also about 20 metres lower than the foundation for the Enercon E 92 wind turbine. And since this was accompanied by the absence of a suffi ciently large fl at area, the 132-metre boom had to be installed ‘downhill’ with a gradient of four degrees. The company brought in Tadano specialist Willi Friesen to get assistance from the manufacturer in planning the work. Toggenburger used a giant Tadano CC 3800-1 – which was actually somewhat oversized for the 100-metre-tall Enercon E 92 wind turbine but the site conditions left no other choice. On one hand, there was the relatively large distance of 32 metres between the crane setup area and the wind turbine foundation, which would require working with a correspondingly large radius; on the other, the setup area was located 18 metres below the tower foundation, meaning that this difference had to be added to the wind turbine’s actual height. Ultimately, however, using the large 650-tonne crane came with an advantage: “Thanks to the CC 3800 1’s extraordinary lifting capacity in an LH+LF3 confi guration, even without Superlift we were able to cost-effectively offer Enercon an additional crane for erecting towers at the wind farm,” reports Toggenburger’s Manuel Widmer. Other obstacles appeared. At the measuring-up and planning
process it emerged that putting together the boom as usual would not be possible due to the unavoidable downhill slope of 4°. Here Friesen gave assistance: “The downhill slope on rough and uneven terrain, combined with the tight space conditions, meant that the boom and LF had to be put together while suspended in the air,” he says. He obtained an analysis which indicated the main boom points that had to be undergirded so that the structure would not be overloaded. “Willi Friesen was an absolute godsend, and this type of fl exible and expert support is something we truly appreciate,” said Widmer.
Once at the site, there was yet another potential hindrance: the assist crane was only able to work at a large distance from the CC 3800 1, and the components had to be brought one by one from the temporary staging area; and each time the truck drove to the setup area it had to go through an extremely tight, steep, and winding access road - which was a challenge in itself. “We had to reduce the corresponding weights signifi cantly, and that meant, for example, removing the winches and A-frame from the base crane and bringing them to the mountain separately,” said Widmer. And since the setup area itself had very little space for temporarily setting down the crane components, everything had to be delivered just-in-time from the temporary staging area: “Getting the crane parts to the mountain really was a logistical challenge.” After the diffi cult preparation, the lifts themselves were business
as usual. “With an LSL + LF_6; 120-m + 12-m boom confi guration, the CC 3800 1 was able to safely lift all components with a 20° LF offset at a radius of 32 meters with very little Superlift counterweight (on the decoupled Split Tray),” explained Widmer. The heaviest load was the nacelle, at 65 tonnes: “And yet the crane could have easily handled more than that,” added crane operator Stefan Graf. “Its lifting capacity is remarkably large for a 650-tonne crane.”
62 CRANES TODAY
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