Civil Engineering Reference
In-Depth Information
9.3.4.3
Eccentrically Loaded Connections with Bolts in Shear and Tension
Small load eccentricities may often be ignored in slip-resistant bolted connections,
but large eccentricities should be considered in the design. Many bolted connections
are loaded eccentrically (e.g., the connections shown in
Figure 9.10b
and c). Eccentric
loads will result in combined shear and torsional moments or combined shear and
bending moments, depending on the direction of loading with respect to the bolts in
the connection.
9.3.4.3.1 Connections Subjected to Shear Forces and Bending Moments
A connection similar to that shown in Figure 9.10d is shown in Figure 9.19. The bolts
each side of the stiffener bracket resist both shear forces and bending moments.
9.3.4.3.1.1 Bolt Shear Stress
The shear stress on the bolts is
P
n
s
n
b
A
b
,
τ
b
=
(9.53)
where
n
b
is the number of bolts,
n
s
is the number of shear planes, and
A
b
is the nominal
cross sectional area of the bolt.
9.3.4.3.1.2 Bolt Tensile Stress
The tension,
σ
ti
, on bolt
i
from bending moment,
M
=
Pe
is
M
A
b
S
b
i
=
Pe
A
b
S
b
i
=
Peh
b
i
A
b
I
b
,
σ
t
i
=
(9.54)
where
A
b
is the nominal cross sectional area of bolt
i
,
S
b
i
is the “effective section
modulus” of bolt
i
I
b
/h
b
i
,
I
b
is the “effective moment of inertia” of the bolt group,
and
h
b
i
is the distance from bolt
i
to the neutral axis of the bolt group.
=
P
P
e
y
1
x
y
2
w
bi
x
y
2
x
y
1
x x
FIGURE 9.19
Bending and shear forces on a bolted connection.
