permit selection of a shallower, and more
moment-connected beam or beams in the plane
economical, beam section. However, the beam
of the frame at the column. Vu is not required to
depth and the length and depth of the haunch
must be carefully selected to assure that the
exceed the shear force determined from 0.8G Mp
plastic hinge will occur at the end of the haunch,
of the beams framing into the column flanges at
and not at the column face, for the combined
seismic and factored gravity load moments. If
(5) Width-thickness ratios. Beams shall
the beam size is based on stiffness to control
drift, the haunches may not contribute adequate
Specifications Table B5-1. When the ratio in
stiffness to permit reduction in the size of the
Equation 7-3 is less than or equal to 1.25,
columns shall comply with 8 in Table I-9-1 of
accommodate the required rotations within the
columns shall comply with Table B5-1 of the
connection itself and maintain the minimum
AISC Design Specifications.
required strength of Paragraph 7-5b(2)(a) are
permitted to be used provided that the additional
drift due to the connection deformation can be
connections. When tested connections do not
accommodated by the structure as demonstrated
by rational analysis. Such rational analysis shall
thinner flanges nor beams with thicker or wider
include consideration of overall frame stability,
flanges shall be considered to be qualified by the
including the P-delta effect.
Connection shear strength.
(7) Column/beam moment ratio. At any
required shear strength, Vu, of a beam-to-column
shall be determined using the load combination
strong column/weak beam relationship shall be
1.2D + 0.5L + 0.2S plus the shear resulting from
applying 1.1RyFyZ in the opposite sense on each
Alternately, Vu shall be
end of the beam.
justified by rational analysis. The required shear
strength is not required to exceed the shear
by Equations 4-6 and 4-7.
Panel zone shear strength.
required shear strength, Vu, of the panel zone
intersection of the beam and column center-line
shall be the shear force determined by applying
determined by projecting the sum of the nominal