Page 98 - Handbook of Structural Steel Connection Design and Details

Design of Connections for Axial, Moment, and Shear Forces

Design of Connections for Axial, Moment, and Shear Forces 83

Beam to column. The fourth connection interface (the first interface is
the brace-to-gusset connection, not considered here), the beam-to-
column, is the most heavily loaded of them all. The 80 kips horizontal
between the gusset and column must be brought back into the beam
through this connection to make up the beam (strut) load of 212 kips
axial. This connection also sees the 132 kips vertical load from the
gusset-to-beam connection.
Bolts. The shear per bolt is 132/8 16.5 kips 21.6 kips, ok. The
reduced tension design strength is

90 16.5
r 0.75 c1.3 3 90 2 a ba bd0.601
t 0.75 3 48 0.601
21.8 kips 40.6 kips,
so use r 21.8 kips. Since 21.8 kips > 80/8 10.0 kips, the bolts are
t
ok for tension and shear.
End Plate. As discussed for the gusset-to-column connection, there will
be no prying action and hence double curvature in the end plate, so the
required end plate thickness is

4.44 3 10.0 3 2.12
t req 5 B 3 3 58 5 0.736 in

3
A / -in end plate is required. This plate will be run up to form the gusset-
4
to-column connection, so the entire end plate is a 3/4-in plate (A36).
Column web. Using the yield-line analysis for the gusset-to-column
connection, T 11.25, g 5.5, l 9
2 3 11.25 9
P 0.9 8 2.42 c 1 d
u B 5.75 2 3 5.75
48 kips 80 kips, no good
Again, the column web must be stiffened as shown in Fig. 2.15, or a dou-
bler must be used.
Stiffener. If stiffeners are used, the most highly loaded one will carry
the equivalent tension load of three bolts or 30.0 kips to the column
1
flanges. The stiffener is treated as a simply supported beam 12 / in
2
long loaded at the gage lines. Figure 2.15 shows the arrangement. The
shear in the stiffener is 30.0/2 15.0 kips, and the moment is 15.0
(12.5 5.5)/2 52.5 kips-in. Try a stiffener of A36 steel 1/2 4:
15.0
f 5 7.50 ksi 21.6 ksi, ok
v 0.5 3 4
52.5 3 4
f 5 26.3 ksi 32.4 ksi, ok
b 0.5 3 4 2
The 1/2 4 stiffener is ok. Check buckling, b/t 4/0.5 8 15, ok.

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