connections; in Table 7-13 for partially restrained
can
be
calculated
using
Part
2
of
AISC
moment connections; and in Table 7-10 for braces
"Specifications for Structural Steel Buildings."
and link beams.
(h) Beam-to-column connections. For link
(c)
Modeling parameters and numerical
beams that are adjacent to a column, special
acceptance criteria for nonlinear procedures are
connection criteria are given in Section 15.4 of the
provided in Table 7-11 for deformation-controlled
AISC Seismic Provisions. Where the link beam is
components.
not adjacent to the column, a simpler criterion for
connection is given in Section 15.7 of the AISC
(d)
Expected strength of deformation-
Seismic Provisions. Where the simpler connections
controlled components and lower-bound strength of
are used, consideration must be given to transmission
force-controlled components shall be determined as
of collector forces into the EBF bay.
indicated in Paragraph 7-3b(9).
(i) Intermediate stiffeners. Section 15.3 of
the AISC Seismic Provisions provides requirements
7-4.
Concrete Moment-Resisting Frames.
for various types of stiffeners necessary for the
intended performance of the link beams. Stiffener
a.
General.
plates as described in those paragraphs are required at
the following locations (see Figure 7-25):
(1)
Function. Moment frames, like shear
walls, are vertical elements in a lateral-force-resisting
1. At the brace end(s) of the link beam.
system that transmit lateral forces to the ground;
2. At bf from each end where link beam
however, they differ from shear walls in that their
length is between 1.6 Ms/Vs and 2.6 Ms/Vs.
deflections
result
primarily
from
flexural
deformations of their elements.
3. At intermediate points along the link
(2) Frame behavior. The bending stiffness of
beam where shear stresses control or are high.
the moment-resisting frame provides the lateral
stability of the structure (Figure 7-26). It is important
(6) Acceptance criteria.
to remember that deformations resulting from the
(a) Response modification factors, R, for
dynamic response to a major earthquake are much
greater than those determined from the application of
Performance Objective 1A, are provided in Table 7-
the prescribed design forces. This
1.
(b) Modification factors, m, for enhanced
performance objectives, are provided in Table 7-12
for beams, columns, and fully restrained moment
7-64
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