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

5.4 Glass Clamp Connector
Advanced Building Skins
The glass clamp connector shown in the Figure 11 allows a significant larger residual strength of
broken laminated glass panes [9]. Much higher loads can be carried before whole laminated glass
panes break out, however, so even higher loads affect the cables. In this connection a perforated plate
of carbon is embedded into the layers of the laminated glass. The carbon plate is connected by Kevlar
twines with a cone on the outside of the pane. The cone is free of any forces under regular loads and
attaches the clamp only in the case of glass breakage and a larger deformation of the glass pane.
Figure 11: Patented glass clamp [11]
5.5 Cable End Connector
Cables with a straight direction require a high axial pre stress to limit the deformation under wind
loads to an acceptable level. There is therefore the risk that the cables exceed their breakage strength
and tear under explosion loads. A newly developed cable end connector is schematically represented
in figure 12. This connector is very stiff until a defined activation force FA to ensure a minimal
deformation of the cable under the regular load combinations with pre stress, self-weight, temperature,
and wind. Under a blast load a triggering device allows a controlled elongation of the cable end
connector with simultaneous energy dissipation. In the version shown in the figure 12 the activation
force is determined by a breaking point in the primary load path. After triggering the axial tensile force
is redirected to a secondary load path, in which one or more crash absorber, e.g. with aluminum foam,
are integrated.
before triggering
(Point P1)
connection to
frame construction
crash absorber
triggering device
cable force S
after triggering
(Point P2)
cone
plastic
compression
Figure 12: Patented cable-end-connector before and after fuse breakage [12]
In the crash absorber a yield force Fc ("crash force") is activated that is smaller than the activation
force FA. Crash materials show a hardening under increasing crash deformations. The challenge is to
find the best force displacement function for the explicit facade and to realize this function with the
belonging crash absorber (defined by the crash material, cross section and initial crash absorber
length). A too slow hardening of the crash material requires a too long deformation length until the
required amount of energy is dissipated (defined by the integral of the crash force over the crash
- 9 -
carbon plate
Kevlar twines
elastic
force-deformation-graph
plastic
energy dissipation
hardening
of crash-
material