FEMA 453 Design Guidance for Shelters and Safe Rooms

Blast-resistant detailing requires continuous top and bottom reinforcement
with tension lap splices staggered over the spans,
confinement of the plastic hinge regions by means of closely
spaced ties, and the prevention of shear failure prior to developing
the flexural capacity (see Figure 2-11). One- or two-way
slabs supported on beams provide the best resistance to near contact
satchel threats, which may produce localized breach, but allow
the structure to redistribute the gravity loads. Concrete columns
must be confined with closely spaced spiral ties, steel jackets, or
composite wraps. This confinement increases the shear resistance,
improves the ductility, and protects against the shattering effects
resulting from a near contact explosion. Cast-in-place exterior
walls or precast panels are best able to withstand a sizable stand-off
vehicular explosive threat and may be easily detailed to interact
with the reinforced concrete frame as part of the lateral load-resisting
system.
Figure 2- Multi-span slab splice locations
Structural deSign criteria
2-2