Page 116 - 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 101

a. Bolts: Since the normal force is always compression, the bolts see
only the tangential or shear force; thus, the number of bolts
required is
64
5 2.2 use 4 bolts
28.8
b. Weld: Use a profile fillet weld of the cap plate to the truss verti-
cal, but only the weld to the web of the vertical is effective because
there are no stiffeners between the flanges of the top chord. Thus,
the effective length of weld is
(13.89 2 0.645)/cos 13.23 in
64
f 5 2.42 kips/in
v 2 3 13.23
86
f 5 3.25 kips/in
a 2 3 13.23
2
2
f 22.42 1 3.25 5 4.05 kips/in
R
4.05
The weld size required is 5 2.91
1.392
1
Use / 4 (AISC minmum size)
Check the W14 61 web to support required 2.91 16ths FW. For
welds of size W on both sides of a web of thickness t
w
1.0 0.6 F t 0.75 0.60 70 0.7071 W 2
y w
or
t 1.48 W for grade 50 steel
w
Thus for W 2.91/16 0.182
t 1.48 0.182 0.269 in
w min
Since the web thickness of a W14 61 is 0.375, the web can sup-
port the welds.
c. Cap plate:
The cap plate thickness will be governed by bearing. The bearing
design strength per bolt is
r 0.75 2.4 58 t 1
p p
The load per bolt is 64/4 16.0 kips. The required cap plate thick-
ness is thus

16.0
t 5 0.153
p 0.75 3 2.4 3 58 3 1

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