(2) Damage caused by seismic displacements.
area, major equipment malfunction at a regional
Seismic displacements may also damage building
emergency response center, or the destruction of an
components. Nonstructural components attached to
irreplaceable historic structure.
Such events are
adjacent
floors
in
multistory
buildings
are
unacceptable, particularly when techniques are
particularly vulnerable to displacement damage.
available to prevent them.
Seismic isolation or
Light items that are unlikely to generate large inertial
energy dissipation systems can be incorporated into
forces may still be damaged by large imposed
the design of critical facilities to prevent these types
deformations.
Nonstructural components such as
of disasters from occurring.
glazing, precast cladding, rigid full-height partitions,
c.
Earthquake Effects - Acceleration vs.
sprinkler piping, hazardous material piping, and
Displacement.
exterior veneer or ornamentation may be damaged by
Building components may be
large interstory drifts caused by the seismic
damaged by both seismic accelerations and seismic
displacements of the building frame. Items that cross
displacements.
A particular type of component,
seismic joints between adjacent buildings are also
either structural or nonstructural, may be more
vulnerable to displacement damage.
sensitive to one or other type of damage. In order to
reduce earthquake damage, it is important to consider
(3) Damage identification. It is important to
whether critical building components are vulnerable
identity what critical building components are
to acceleration damage, displacement damage, or
vulnerable to damage, what type of damage they are
both.
vulnerable to, and what level of damage protection is
desired for critical components of a given facility in
(1) Damage caused by seismic accelerations.
order
to
identity
effective
damage
reduction
Seismic accelerations cause intense shaking that may
techniques. In some cases, acceleration control may
damage
structural
components,
nonstructural
be required in order to reduce potential acceleration
components, and piping or sensitive equipment. A
damage. In other cases, displacement control may be
building component may be damaged when the
most important. In still other cases, both acceleration
seismic
inertial
forces
generated
within
the
and displacement control may he required to provide
component exceed the elastic capacity of the
effective damage reduction.
component to resist those forces. Some examples of
damage due to excessive inertial forces caused by
d.
System Selection - conventional design,
seismic accelerations include the following: shear
seismic isolation, or energy dissipation.
The
cracking in a masonry shear wall; out-of-plane failure
selection of a structural system for a critical facility is
of a freestanding wall or heavy partition; shear failure
a complex process that must take many factors into
of anchor bolts at the base of a piece of heavy
consideration.
These factors include the dynamic
equipment; and pipe rupture at an anchor point for a
characteristics of the building, the surrounding soil,
long, unbraced section of heavy pipe.
and the critical nonstructural components.
Both
present construction costs and future damage costs
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