advanced building skins 14 | 15 June 2012 - lamp.tugraz.at - Graz ...

Advanced Building Skins
In order to trace the roof curvature, 2.500 laser-cut steel plates were bended into L-shaped profiles to
generate a unidirectional substructure. Around 62.500 boreholes were positioned using parametric
modelling tools to match the node points. This way more than 95% of the roof surface could be quite
easily engineered. The Pareto principle (also known as the 80–20 rule) states that, for many events,
roughly 80% of the effects come from 20% of the causes; hence the utilized time follows the same
principle. The required time to detail the remaining last 5% of the roof (edges and skylights) was definitively
more than 80% of the detailing time. The comparatively small surface area of the ten skylights
was constructed by laser-cutting 400 individually metal sheets with 25.200 individually positioned
bolts. Furthermore edge lines were extracted from the 3D model to laser-cut rubber foils, which
could be utilized as cutting gauges for the aluminum profiles along the skylight edges.
Figure 8: Individual laser-cut metal sheets of one skylight (Werner Sobek Stuttgart)
One of the main challenges in detailing the cladding metal sheets, was the definition of non-standard
fixation points to be compatible with the roofs movement. Thanks to parametric design tools, the skylight
cladding surfaces and the relative fixings were automatically generated. Especially the positioning
of the bolts played a major role in the detail design of the skylights. Since the local curvature in the
skylights is higher than elsewhere in the roof, bolts welded on the rear side of the metal sheets forces
the sheets in position along the edges without any material preforming process. A Gaussian curvature
analysis was performed to identify the areas with small curvature radii in both directions.
Figure 9: Metal cladding at the skylights. The red arrows indicate zones of strong double curvature.
(Teleya)
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