FEMA 453 Design Guidance for Shelters and Safe Rooms

Steel moment frame structures provide excellent ductility and
redundancy in response to blast loading. Steel braced frames may
similarly be designed to resist high intensity blast loads; however,
they are less effective in resisting the progression of collapse following
the loss of a primary load-bearing element. As a result,
first floor steel columns of existing buildings may be concrete
encased and first floor splices may be reinforced to increase their
resistance to local failure that could precipitate a progression of
collapse. The exterior façade represents the most fragile element
and is likely to be severely damaged in response to an exterior
detonation. Debris may be minimized by means of reinforced
masonry, sufficiently detailed precast panels, or laminated glass
façade. Nevertheless, a shelter within steel frame buildings would
best be located within interior space or a building core. Hardened
interior partitions may easily be constructed and anchored to existing
floor slabs, and lightweight metal gauge walls may be used
to retrofit existing buildings. Metal deck roofs with rigid insulation
supported by bar joist structural elements possess minimal
Structural deSign criteria
Figure 2-2
S steel light frames
2-