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

Advanced Building Skins
anchor points. For this reason minimizing the reaction forces always has to be the main aim. Whether
a tensile roof is anchored in an already existing structure or in the ground no matter the foundation
concept, high forces result in additional costs at all times.
Therefore the arrangement of struts and their guying cables is a very critical issue. The smaller the
angle between the compression and tension elements is, the higher the internal forces in these
construction components get. In case the available space is limited, maximization of the structure’s
covered area becomes a main goal. For the corners to be the closest possible to the boarders of the
construction site, the angle between struts and guying cables will end up being minimized. For
avoiding difficulties with high anchor forces, restraint columns could be a considerable alternative.
But one has to be aware, the lightweight characteristics of membrane structures will end at soil level.
Moment bearing foundations are by all means heavy-weight.
But to give an additional input on architectural design, restraint columns do not need to have structural
purpose only. They could as well be part of the overall design concept. Besides the engineering
requirements, it is up to the designer to transform a restraint column into (e.g.) a sculpture and make it
part of a story (about the architectural intent).
Figure 2: Different arrangements of struts and guying cables and the corresponding triangles of forces
To reduce anchor forces sometimes it may be an option to amend the design and add additional anchor
points while keeping the overall appearance similar and knowing more foundations are needed.
Figure 3: Implementation of an additional anchor point to reduce the anchor forces
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