Page 135 - Handbook of Structural Steel Connection Design and Details

Design of Connections for Axial, Moment, and Shear Forces

120 Chapter Two

and the web load is

P 800 2 311 178 kips
w
The load path is such that the flange load P passes from the W14 90
f
(say) through the bolts into the flange plates and into the W14 120
flanges through a second set of bolts. The web load path is similar.
A. Flange connection.
1. Member limit states:
a. Bolts: Although not a member limit state, a bolt pattern is
required to check the chords. The number of bolts in double
shear is 311/(2 27.1) 5.74. Try 6 bolts in 2 rows of 3 as
shown in Fig. 2.34. This may need to be adjusted because of
bearing/tearout.
b. Chord net section: Check to see if the holes in the W14 90
reduce its capacity below 800 kips. Assume that there will be two
web holes in alignment with the flange holes.

A 26.5 4 1 0.710 2 1 .440 22.8 in 2
net
R 22.8 0.75 65 1111 kips > 800 kips, ok
net
c. Bearing/tearout: This will be checked after the splice plates are
designed.
d. Block shear fracture:

A (7.75 2.5 1.0)0.710 2 7.46 in 2
nv
s14.520 2 7.5d
A a 2 0.5 3 1b0.710 3 2 5 4.27 in 2
nt 2
A 7.75 0.710 2 11.0 in 2
gv
A 3.51 0.710 2 4.98 in 2
gt
F A 65 4.27 278 kips
u nt
0.6F A 0.6 50 11.00 330 kips
y gv
0.6F A 0.6 65 7.46 291 kips
u nv
U 1.0
bs
R 0.75[278 min{330, 291}] 427 kips > 311 kips, ok
bs

2. Flange plates:
Since the bolts are assumed to be in double shear, the load path is
such that one half of the flange load goes into the outer plate, and
one half goes into the inner plates.

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