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

Advanced Building Skins
deformation). A too fast hardening limits the possible dissipation energy before the cable strength is
reached.
Two significant effects are achieved by the new cable end connector:
Significant energy dissipation due to high plastic deformations.
Reduction and control of cable forces and thus reduction and control of the forces which are
forwarded to the frame construction.
In the development of appropriate cable end connectors the following aspects were considered:
a low increase of the trigger load under high strain rates as they occur under blast loads
a small scattering of the activation force FA,
a small scattering of crash force Fc, and
a choice of crash materials with different hardening behavior
The newly developed cable end connectors were tested quasi-static, as well as with realistic
deformation speeds as they occur under explosion loads (1 m/s up to 5 m/s).
5.6 Development of an Assessment Tool
The structural behavior of explosion-resistant cable net facades is extremely complex. This is
particularly true if the non-linear behavior of dissipative cable end connectors should be considered. In
a joint project of the Department of structural analysis of the University of Armed Forces Munich and
Gartner Steel and Glass GmbH in Würzburg, the dependencies of the different parameters were
examined among themselves with a standardized load of explosion [13]. The results were
implemented in a design tool, developed with Microsoft Excel, which is used for preliminary design
and parametric studies [14].
As the load scenario the GSA-D level (table 1) was chosen. In the United States this is a common level
for buildings with higher security requirements.The examined parameter combinations are
summarized in table 3. Five idealized force displacement curves for the cable-end-connectors (SEV
types) were defined (figure 13). The ratio of activation force to crash force is 60% for all cable-endconnectors
(FA/ F(c) = 0.6). This ensures that under consideration of the scatter of both forces the
activation force is always higher than the crash force.
The five SEV types differ in the plastic hardening area (Figure 13). For SEV 1 it is twice as large as
for SEV 2 and SEV 3 has an ideal plastic plateau without hardening. SEV 1, 2a, and 3a are unlimited
in their plastic deformation. For SEV 2b and 3b the plastic deformation is limited to 200 mm. After
this deformation they harden again to a linear elastic behavior with high rigidity. This behavior
considers that the length of the crash absorber and therefore the energy that could be absorbed by
plastic deformation is limited. The variations of SEV 1, 2a and 3a are suitable to determine the
required plastic deformation length and to design related crash absorbers. The assessment tool can be
used to design cable-end-connectors with "tailor-made" capacity of energy absorption.
Figure 13: Idealized force-deflection curves of five cable end connectors (SEV) [13]
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