Building Design and Construction Handbook - Merritt - Ventech!

STRUCTURAL STEEL CONSTRUCTION 7.77
where a � clear distance between transverse stiffeners, in
h � clear distance between flanges, in
t � web thickness, in
The load may be considered distributed over a web length equal to the panel
length (distance between vertical stiffeners) or girder depth, whichever is less.
Web Stiffeners on Columns. The web of a column may also be subject to crippling
by the thrust from the compression flange of a rigidly connected beam, as
shown at point a in Fig. 7.36. Likewise, to ensure full development of the beam
plastic moment, the column flange opposite the tensile thrust at point b may require
stiffening.
When stiffeners having a combined cross-sectional area A st, in 2 , are required on
the column whenever A st computed from Eq. (7.48) is positive
P � Fyct(tb� 5k)
A � (7.48)
st
where t � thickness of column web, in
t b � thickness, in, of beam flange delivering concentrated load
F yc � column steel yield stress, ksi
F ys � stiffener steel yield stress, ksi
P � computed force delivered by beam flange or connection plate multiplied
by 5 ⁄3 when force is a result of dead and live loads, or by 4 ⁄3 when it is
a result of wind or earthquake forces, kips
k � distance from face of column to edge of fillet on rolled sections (use
equivalent for welded sections)
Regardless of the preceding requirement, a single or double stiffener is needed
opposite the compression force delivered to the column at point a when
FIGURE 7.36 Web crippling in a column at a welded joint with a beam.
F ys