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

Advanced Building Skins
The main problem in the design of glass fins is the development of the connection between the glass
part and the supporting (steel) structure. Usually bolted connections in combination with grout, resin
or thermoplastic blocks (POM, PA 6) are used [1]. Disadvantages of this type of connection are the
boreholes in the glass, which have to be realised before the heat strengthening process and which bring
extra costs and imperfections (for example an offset of the glass edges in the case of laminated glass).
2 Analysed Types of Glass Fins
The aim of the research was the optimisation of suspended glass fins, focusing on the load application
from the fin into the steel supporting structure [2]. This interesting research topic was proposed by
Waagner-Biro Stahlbau AG. Two different geometries were analysed, a rectangular one and a
trapezoidal one. As contact materials the grout Hilti HIT-HY70 and the thermoplastic material
polyoxymethylene (POM) were used and compared for both geometries. This resulted in four different
types of glass fins, which were analysed in this research. In all cases laminated glass formed of three
sheets of fully tempered glass and polyvinylbutyral (PVB) as an interlayer was used. The fins had a
length of 2,8 m and the support area was 0,5 m long. Other dimensions are shown in Figure 2. In the
numerical model the glass was simulated as one sheet with shell elements with a thickness of 24 mm.
The effect of the lamination was not important, since the fins were loaded in the plane of the glass
sheets and stability problems were not analysed in this research project. For the experimental tests a
stability failure was also excluded.
2.1 Geometries
First, the more common rectangular geometry (Figure 2 left) has been analysed. In this case the dead
load is transferred by a bolted connection with one bolt. Horizontal loads (e.g. wind load) are
transferred by contact at the glass edges. In the case of the second analysed geometry (Figure 2 right),
due to the inclined edge, all the loads can be transferred by contact at the glass edges. The big
advantage is that no boreholes and no bolts are needed anymore.
Figure 2: Rectangular (left) and trapezoidal (right) geometry of the analysed glass fins
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