Page 77 - Handbook of Structural Steel Connection Design and Details

Design of Connections for Axial, Moment, and Shear Forces

62 Chapter Two

Since the brace force can be tension or compression, compres-
sion will control. The slenderness ratio of the unsupported length
of gusset is

Kl 0.5 3 8.5 212
5 5 9.82
r 1.5

The use of K 0.5 comes from the work of Gross (1990).
Since Kl/r < 25

F 0.9F 0.9 36 32.4 ksi
a y
and the buckling strength of the gusset is
R 27.8 1.5 32.4 1350 > 855 kips, ok
wb
This completes the brace-to-gusset part of the design. Before pro-
ceeding, the distribution of forces to the gusset edges must be
determined. From Fig. 2.8,

24.10
e 5 5 12.05 e 5 8.37 b 5 12.5 5 15.0
B
C
2
10.6875
21

5 tan a b 5 41.68
12
V C 5 P cos
5 855 3 0.747 5 638 kips
V e 638 3 8.37
H 5 C C 5 5 218 kips
C
e 1 12.05 1 12.5
B
H 5 P sin
2 H 5 855 3 0.665 2 218 5 351 kips
C
B
M B 5 H B e B 5 351 3 12.05 5 4230 kips-in
Note that, in this special case 2, the calculations can be simpli-
fied as shown here. The same results can be obtained formally

with the UFM by setting 12.5 and proceeding as follows.
With tan
0.8906,

2 0.8906 5 12.05 3 0.8906 2 8.37 5 2.362

Setting 12.5, 13.5. Since is approximately 15.0,
there will be a couple, M , on the gusset-to-beam edge. Continuing
B
2
2
r 5 2s13.5 1 8.37d 1 s12.5 1 12.05d 5 32.9
P 855
5 5 26.0
r 32.9

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