Page 112 - 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 97

Each of the connection interfaces will now be designed.
1. Gusset to top chord.
a. Weld: Weld length is 70 in.
711
f 5 5 5.08 kips/in
v
2 3 70
86.6
f 5 5 0.61 kips/in
a
2 3 70
569 3 2
f 5 0.23 kips/in
b 70 2
2
2
f 2s5.08d 1 s0.61 1 0.23d 5 5.1 kips/in
R
5.1
D 5 3.7 16 ths
1.392
Check ductility
0.23 2
2
f 5.08 1 a0.61 1 b 5 5.1 kips/in
ave B 2
Since 1.25 f 6.4 > 5.1, size weld for ductility requirement
ave
6.4
D 5 4.60
1.392
5
Use / fillet weld.
16
b. Gusset stress:
711
f 5 13.5 ksi , 21.6 ksi, ok
v
0.75 3 70
86.6 569 3 4
f f 1 5 2.27 ksi , 32.4 ksi, ok
a b 2
0.75 3 70 0.75 3 70
c. Top chord web yield: The normal force between the gusset and
the top chord is T 86.6 kips and the couple is M 569 kips-in.
c c
The contact length N is 70 in. The couple M is statically equiva-
c
lent to equal and opposite normal forces V M /(N/2) 569/35
s c
16.2 kips. The normal force V acts over a contact length of N/2
s
35 in. For convenience, an equivalent normal force acting over
the contact length N can be defined as
N 2 V 86.6 2 16.2 119 kips
N Cequiv.
C s
Now, for web yielding
R 1.0 (5k N) F t 1.0 (5 1.625 70) 50 0.510
wy yw w
1992 kips 119 kips, ok

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