Page 117 - Structural Steel Designers Handbook AISC, AASHTO, AISI, ASTM, and ASCE-07 Design Standards

Brockenbrough_Ch03.qxd 9/29/05 5:05 PM Page 3.49

CONNECTIONS

CONNECTIONS 3.49

First line of bolts
30°

Last line of bolts

Whitmore section

FIGURE 3.30 Whitmore section for distribution of stresses.

and
dF y
λ= (3.52)
t w 47 500 +112 000, ( d c 2/ ) 2
,
where t w is web thickness (in) and dimensions d and c (in) are defined in Fig. 3.31. This procedure can
also be used to check buckling for a beam web in bending with flanges coped both top and bottom.
The above analysis is based on plate buckling coefficient k, which is equal to
  bm  2 
.
+ .
 .
k = 0 608 07 164  (3.53)
  a  
where a = c = length of plate parallel to the compressive force (c)
b = d/2 = width of plate perpendicular to the compressive force
m = number of half sine waves in buckled plate at minimum compressive stress (m = 1 for a
plate simply supported along both loaded edges and one unloaded edge and free along
the other unloaded edge)
The assumption that the supported unloaded edge is pinned is conservative. If the supported
unloaded edge is assumed fixed, then
π
k = 083 093ν +134  a  2 + 010  mb  2 (3.54)
.
− .
.
.
 mb   a 
π

FIGURE 3.31 Bending may cause plate buckling.

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