Page 139 - Handbook of Structural Steel Connection Design and Details

Design of Connections for Axial, Moment, and Shear Forces

124 Chapter Two

Since the block shear limit state fails, the bolts can be spaced out
to increase the capacity. Increase the bolt pitch from the 3 in
assumed above to 6 in. Then

A (7.75 1.5 1) 0.440 2 5.50 in 2
nv
A 0.88 in 2
nt
A 7.75 0.440 2 6.82 in 2
gv
A 1.32 in 2
gt
U 1.0
bs
F A 65 0.88 57.2 kips
u nt
0.6F A 0.6 65 5.50 214 kips
u nv
0.6F A 0.6 50 6.82 205 kips
y gv
R 0.75[57.2 min{214, 205}] 197 kips > 178 kips, ok
bs
The web bolt pattern shown in Fig. 2.32 is the final design. At this
point, there are four bolts in the web at 6-in pitch, but the six bolts
shown will be required.
1
2. Web plates: Try two plates, one each side of web, 6 in wide and /
2
in thick.
a. Gross area:
R 0.9 36 0.5 6 2 194 kips > 178 kips, ok
gt
b. Net area:
A (6 2 1) 0.5 2 4.0 in 2
nt
.85A 0.85 0.5 6 2 5.1 in 2
gt
R 0.75 58 4.0 174 kips 178 kips, no good
nt
5
Increase web plates to / in thick. Net area will be ok by inspection.
8
c. Block shear rupture: This is checked as shown in previous cal-
culations. It is not critical here.
3. Bearing/tearout: The bolt pattern and plates are now known, so
this combined limit state can be checked.
a. Bolt shear:
r 54.2 kips (double shear)
v
r 27.1 kips (single shear)
v
b. Bearing on W14 99 web:
r 0.75 2.4 0.875 0.440 65 45.0 kips
p

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