STRUCTURAL GLASS FACADES - USC School of Architecture

deflections. As will be seen, the technique developed for open structures is well within these
parameters. The simple truss analysis is complicated by the bending moments caused by
the distributed loads along the face of the outer truss chords. Further testing of the program
and/or fine tuning of the calculation method may make it possible to tighten these
parameters for approximation.
Analytical Method for Closed Structures
The following is a simplified method for the analysis of a defined simple truss system. The
system is schematically represented in Figure 7.14. Primary input parameters are provided
by definition of the glass grid and uniform wind force. Definition of the glass grid includes the
vertical and horizontal module as well as the total vertical and horizontal span of the façade.
The horizontal grid module defines truss spacing. Steel system options are predefined, and
include front and back chord section properties. The user need only define the glass grid,
wind speed, and select a system type. The calculation method is to solve for a minimum
truss depth.
Compute truss depth;
The minimum depth will be defined by the maximum of one of the following parameters.
minimum depth (d) the largest value resulting from d , d , or d
f
b
d
where;
d f = depth computed based on the capacity of front chord.
d b = depth computed based on the capacity of back chord.
d d = depth computed based on deflection criteria.
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