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Layher Scaffolding for Earthquake-Resistant Power Station
The order called for scaffolding to enclose the cooling towers, over 80 metres high, of the power station in Cavriglia, near Arezzo in Italy. This was necessary for compliance with new regulations relating to earthquake resistance in power stations. The scaffolding provided the specialists with access to perform the unavoidable concrete repair work.
The special shape of these cooling towers and their gigantic dimensions made this a very ambitious order: cooling towers have a round cross-section with a diameter that continually changes at various heights. The experts call this a rotational hyperboloid. The experienced scaffolding erectors from Sparer used a very ingenious combination of Layher SpeedyScaf and Layher Allround equipment for this geometry.
The erectors used SpeedyScaf for the circular scaffolding around the cooling tower. This job was completed particularly fast as a result. In the lower part, where the cooling tower tapers sharply inwards in the upward direction, every new scaffolding level was erected by fitting its outer standard onto the inner standard of the level underneath it, so that the frames were assembled in inward steps. The concentric scaffolding levels of decreasing size hugged the contour of the cooling tower up to the height at which the curvature lessened. Up to that level, both the diameter and the number of the scaffolding bays became smaller at each level.
The inward-stepped configuration also led to an unusually high load on the scaffolding, so that appropriate counter-measures had to be taken using Allround equipment in order to stabilize this part of the scaffolding sufficiently: more details are provided below.
From about 50 metres upwards, the point after which the diameter of the cooling tower changes only slightly, the erectors assembled all the remaining levels, right up to the top rim, in the conventional way, exactly one above the other, while compensating for the different distances from the cooling tower using bracket levels on the inside of the scaffolding. For stabilization, they used 16 kilometres of steel cable stretched over the entire structure, so that anchoring bolts could be dispensed with.
As already indicated, additional measures were needed to ensure stability in the lower area of the scaffolding subjected to heavy loads. Evenly distributed and radially arranged supporting towers made of Allround equipment provided the crucial bracing needed by the circular scaffolding.
These supporting structures are, thanks to Allround equipment, ideally matched to the circular scaffolding requiring the bracing effect, and thus absorb a substantial proportion of the horizontal load components from the SpeedyScaf structure. The top level of some of these supporting towers was decked and provided with a hoist to allow its use for interim storage of the material needed further up.
With this ingenious solution, the scaffolding erectors easily kept to their schedule: within just 45 days, the first cooling tower was surrounded with scaffolding and repair work could begin.
Data, facts and figures
- 18,000 m2 of SpeedyScaf
- 88 m high
- 45 days assembly time
- 16 km of steel cable for stabilization
- Circumference 220 m at the bottom, 110 m at 60 m up and 145 m at 82 m up
Caption:
This masterly accomplishment by the experts of Sparer Ponteggi S.A.S. is particularly intricate yet astoundingly strong.
In charge of PR enquiries or contacts with the press:
Ms. Andrea Beisswenger
E-Mail Andrea.Beisswenger@layher.com
Telephone +49 71 35 / 70-0
Fax +49 71 35 / 7070-422
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