Page 125 - Handbook of Structural Steel Connection Design and Details

Design of Connections for Axial, Moment, and Shear Forces

110 Chapter Two

Figure 2.26 Column base plate.

Example. The column of Fig. 2.26 is a W24 84 carrying 600 kips. The con-
crete has f 4.0 ksi. Try a base plate of A36 steel, 4 in bigger than the
c
1
1
1
column in both directions. Since d 24 / and b 9, N 24 / 4 28 / ,
8 f 8 8
b 9 4 13. Try a plate 28 13. Assume that 2 in of grout will be used,
2
so the minimum pier size is 32 17. Thus A 28 13 364 in , A 32
1 2
2
17 544 in , 2A 2 /A 1 5 1.22 , 2 (ok), and
F 0.6 0.85 4 1.22 2.49 ksi
c p
600
f p 5 5 1.65 ksi , 2.49 ksi, ok
364
28 2 0.95 3 24.125
m 5 5 2.54
2
13 2 0.8 3 9
n 5 5 2.90
2
224.125 3 9
n 5 5 3.68
4
4 3 24.125 3 9.0 1.65
x 5 2 5 0.52
s24.125 1 9.0d 2.49
220.52
l 5 5 0.85
1 1 21 2 0.52
l max {2.54, 2.90, 0.85 3.68} 3.13
2 3 1.65
t p 5 3.13 5 0.99 in
B0.9 3 36
Use a plate 1 13 28 of A36 steel. If the conservative assumption of
1
1 were used, t 1.17 in, which indicates a 1 / 4-in-thick base plate.
p
Erection considerations. In addition to designing a base plate for the
column compression load, loads on base plates and anchor rods during
erection should be considered. The latest OSHA requirements postulate
a 300 lb. load 18 in off the column flange in the strong axis direction,
and the same load 18 in off the flange tips in the weak axis direction.
Note these loads would be applied sequentially. A common design load

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