(d)
Energy-dissipation devices shall be
Concrete shear wall or steel braced frame
capable of sustaining larger displacements (and
velocities for velocity-dependant devices) than the
building; T = 0.3 seconds;
maximum calculated in the MCE. The increase in
displacement (and velocity) capacity is dependent on
Concrete frame building; T = 0.7 seconds;
the level of redundancy in the supplemental damping
system as follows:
Steel frame building; T = 1.2 seconds;
1.
If four or more energy dissipation
Tall steel frame; T = 2.5 seconds.
devices are provided in a given story of a building, in
one principal direction of the building, with a
d.
Design Criteria.
minimum of two devices located on each side of the
center of stiffness of the story in the direction under
(1) General.
consideration, all energy dissipation devices shall be
capable of sustaining displacements equal to 130
(a) The energy-dissipation devices should
percent of the maximum calculated displacement in
be designed with consideration given to other
the device in the MCE. A velocity-dependant device
environmental conditions, including wind, aging
shall also be capable of sustaining the force
effects,
fatigue,
ambient
temperature,
associated with a velocity equal to 130 percent of the
operating temperature, and exposure to moisture or
maximum calculated velocity for that device in the
damaging substances.
MCE.
(b) The building height limitations should
2. If fewer than four energy dissipation
not exceed the limitations for the structural system
devices are provided in a given story of a building, in
into which the energy-dissipation devices are
one principal direction of the building, or fewer than
implemented.
two devices are located on each side of the center of
stiffness of the story in the direction under
(c) The mathematical model of a building
consideration, all energy-dissipation devices shall be
should include the plan and vertical distribution of
capable of sustaining displacements equal to 200
the energy-dissipation devices.
Analysis of the
percent of the maximum calculated displacement in
mathematical
model
should
account
for
the
the device in the MCE. A velocity-dependant device
dependence of the devices on excitation frequency,
shall also be capable of sustaining the force
ambient
and
operating
temperature,
velocity,
associated with a velocity equal to 200 percent of the
sustained loads, and bilateral loads.
Multiple
maximum calculated velocity for that device in the
analyses of the building may be necessary to capture
MCE.
the effects of varying mechanical characteristics of
the devices.
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