Page 177 - Handbook of Structural Steel Connection Design and Details

Design of Connections for Axial, Moment, and Shear Forces

162 Chapter Two

Figure 2.61 Prying action with reinforcing (washer)
plate.

2.5.2 Reinforcement of axial force
connections

It sometimes happens that a simple beam connection, designed for shear
only, must after fabrication and erection be strengthened to carry some
axial force as well as the shear. In this case, washer plates can sometimes
be used to provide a sufficient increase in the axial capacity. Figure 2.61
shows a double-angle connection with washer plates that extend from the
toe of the angle to the k distance of the angle. These can be made for each
bolt, so only one bolt at a time need be removed, or if the existing load
is small, they can be made to encompass two or more bolts on each side
of the connection. With the washer plate, the bending strength at the
“stem” line, section a-a of Fig. 2.61 is
1
M F pt 2
n u
4
while that at the bolt line, section b-b, is
1 1 tp 2
2
2
2
M F p (t t ) F pt a1 1 b M
n 4 u p 4 u t 2 n
t p 2
where 1 a b and the remaining quantities are in the notation
t
of the AISC 13th Edition Manual (2005). With the introduction of , the
prying action formulation of the AISC Manual can be generalized for
washer plates by replacing wherever it appears by the term d . Thus
1 t c 2
r 5 ca b 2 1d
s1 1 d t

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