Page 99 - Handbook of Structural Steel Connection Design and Details

Design of Connections for Axial, Moment, and Shear Forces

84 Chapter Two

Weld of stiffener to column web. Assume about 3 in of weld at each gage
line is effective, that is 1.5 1 2 3. Then

10.0 1 0.5 3 10.0 3
D 5 5 1.19 use fillet welds
2 3 3 3 1.5 3 1.392 16
Weld of stiffener to column flange.
15.0 3
D 5 5 1.66 use fillet welds
2 3 s4 2 0.75d 3 1.392 16

Weld of end plate to beam web and doubler plate. The doubler is 3/16 in thick
and the web is 0.305 in thick, so 0.1875/0.4925 0.38 or 38% of the load
2
goes to the doubler and 42% goes to the web. The load is 2132 1 80 2
154 kips. The length of the weld is 13.66 2 0.530 12.6 in. The weld
size to the doubler is D 0.38 154/(2 12.6 1.392) 1.67 and that
to the web is D 0.42 154/(2 12.6 1.392) 1.84, so 3/16 in min-
imum fillets are indicated.

Additional discussion. The 80-kip horizontal force between the gusset
and the column must be transferred to the beam-to-column connections.
Therefore, the column section must be capable of making this transfer.
The weak axis shear capacity (design strength) of the column is

R 1.0 0.6 50 0.710 14.5 2 618 kips > 80 kips, ok
v
It was noted earlier that the column and the beam require couples to
be in equilibrium. These couples could act on the gusset-to-column and
gusset-to-beam interfaces, since they are free vectors, but this would
totally change these connections. Figure 2.14b shows them acting in the
members instead, because this is consistent with the L weld method.
For the column, the moment is 80 17 1360 kips-in and is shown
with half above and half below the connection. The bending strength
of the column is M 0.9 50 133 5985 kips-in so the 1360/2
py
680 kips-in is 11% of the capacity, which probably does not seriously
reduce the column’s weak axis bending strength. For the beam, the
moment is 132 17 132 7 1320 kips-in (should be equal and
opposite to the column moment since the connection is concentric—the
slight difference is due to numerical roundoff). The bending strength
of the beam is M 0.9 50 69.6 3146 kips-in so the 1320 kips-
px
in couple uses up 42% of the beam’s bending strength. This will greatly
reduce its capacity to carry 212 kips in compression and is probably not
acceptable.
This completes the design of the connection by the L weld method. The
reader can clearly see how the loads filter through the connection, that

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