Page 166 - 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 151

The design “bolt value” will be the minimum of the bolt shear, bearing, and tearout:
Bolt shear

r v 5 s2d15.9 5 31.8 kips/bolt
Since the W12 22 has the thinner web, it will be checked for bearing and tearout

Bearing at W12 22 web
r 5 0.75s2.4ds65ds0.75ds0.260d 5 22.8 kips/bolt

1
Tearout at W12 22 web (assuming a maximum optional cope depth of 1 / 2 in)
0.813
r 5 0.75s1.2ds65da1.75 2 bs0.260d 5 20.4 kips/bolt
2
Bearing and tearout at splice plates does not govern by inspection.
From Table 7-7, for ex 2.25 and n 3, C 2.11. Therefore,

2.11s20.4d 5 43.0 kips

Neglecting the tearout check as would have been done prior to the 3rd of the
AISC LRFD Manual of Steel Construction, the bolt group capacity would have been
2.11(22.8) 48.1 kips. The instantaneous center of rotation method assumes that
the bolt is the weakest element. However, when the capacity of the group is lim-
ited instead by the strength of the connected material, an alternative force dis-
tribution can produce an increased calculated capacity (Thornton and Muir, 2004).
If the capacity of the bolt group is optimized, the calculated capacity, considering
bolt tearout, becomes 46 kips, still a considerable decrease from the capacity
neglecting the tearout limit states, but a considerable increase from the 43 kips
capacity that results from the worst case.

2.4.6 Extended single plate shear
connections (shear tabs)
The 2005 AISC Manual includes specific information relating to the
design of extended single-plate connections. For decades the Manual has
provided information regarding the design of connections with extended
gages, but never included much detail regarding the required checks for
such connections. Single-plate shear connections can be very economi-
cal connections. In-fill beams can be drilled on the fabricator’s drill line
with no further handling, since the beams will require none of the coping
required for more traditional beam-to-beam connections. Beam-to-
column-web connections are also made easier. Since the beam can be con-
nected beyond the column flanges erection is greatly eased. Unlike
double angle, end plate and sometimes single angle connections, there
will be no common bolts at the support, so safety is also improved.

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