component under the design loading condition. In
this document, QCE is defined as the nominal
(3) Design actions.
strength, QN, multiplied by 1.25, unless otherwise
(a) Deformation-controlled actions shall be
noted in Chapters 7 through 10.
calculated according to Equation 6-2:
(b)
Force-controlled actions.
Force-
QUD = QG " QE
(6-2)
controlled actions in structural or nonstructural
components
or
elements
are
those
responses
where:
generally characterized by the Type 3 curve and in
some cases by the Type 2 curve in Figure 6-1.
QUD = design action due to gravity loads
Acceptance criteria for the capacity of these
and earthquake loads.
components or elements are provided in Chapter 7,
and the components or elements shall be evaluated
QG = action due to design gravity loads as
in accordance with the provisions of this paragraph.
The value of force-controlled design action, QUF,
defined in ASCE 7.
need not exceed the maximum action that can be
QE = action due to design earthquake loads.
developed in a component considering the nonlinear
behavior of the structure. In lieu of more rational
Deformation-controlled
actions
in
structural
analysis, design actions may be calculated according
to Equation 6-4a or 6-4b. Note that QE has been
components shall satisfy Equation 6-3:
determined from the pseudo-lateral load, V, defined
mQCE $ QUD
(6-3)
in Paragraph (2) above as the basic spectral response
force, SaW, modified by C1, C2, and C3 to represent
where:
the expected deformation in the building.
In
Equation 6-4b, QE is divided by the modification
m =
factors to restore QE to a force-controlled action. The
component or element demand
force delivery factor, J, in Equation 6-4a, represents
modifier to account for expected ductility of the
deformation associated with this action at selected
an approximation of the additional reduction in the
Performance Level (see Chapters 7, 8, 9 and 10).
force delivered to a force-controlled component or
element by a yielding component of the seismic
QCE = expected strength of the component
framing system.
or
element
at
the
deformation
level
under
consideration for deformation-controlled actions.
QE
QUF = QG
(6-4a)
C1C2C3 J
For QCE, the expected strength shall be determined
considering all co-existing actions acting on the
6-8
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