these components. The following paragraphs provide general
guidance on frame loads, anchorage design, and wall analysis.
Frame Loads. The window frame must develop the static
design strength of the glazing pane, ru. Otherwise, the design
is inconsistent with frame assumptions, and the peak blast
pressure capacity of the window assemblies predicted by Safevue
will produce a failure rate in excess of the prescribed failure
rate. This results because frame deflections induce higher
principal tensile stresses in a pane, thus reducing the capacity
available to safely resist the blast loading.
In addition to the load transferred to the frame by the
glazing, frame members must also resist the static load, ru,
applied to all exposed members. Maximum allowable limits for
frame design are:
a) Deflection. For glazings that rely on glass for
their resistance function, no frame member should
have a relative displacement exceeding 1/264th of
its span or 1/8 inch (3 mm), whichever is less. For
glazings that rely on polycarbonate for their
resistance function, no frame member should have a
relative displacement exceeding 1/100th of its span.
b) Stress. The maximum stress in any member should not
exceed fy/1.65, where fy is the static yield stress
of the frame material obtained from its catalogued
c) Fasteners. The maximum stress in any fastener
should not exceed fy/2.00, where fy is the static
yield stress of the fastener material obtained from
its catalogued specification.
d) Rotation. To ensure that early edge failure does
not occur and propagate, limit rotations for glazing
stops to a maximum of 0.5 degrees for monolithic
glass, one degree for laminated glass, and two
degrees for plastics.
Safevue automatically computes the line shears and rebound.
Refer to the Safevue User's Manual for displaying or printing
Rebound. Response to the dynamic blast load will cause
the window to rebound with a negative (outward) deflection. The
outward pane displacement and the stress produced by the negative
deflection must be safely resisted by both pane and frame. If