Civil Engineering Reference
In-Depth Information
1.0
F
bt
F
bU
F
bv
F
vU
1.0
FIGURE 9.15
Bolt shear and tension interaction.
(solid line) and Equation 9.39
F
bt
F
bU
2
F
bv
F
vU
2
+
=
1.0,
(9.39)
where
F
bt
is the ultimate tensile stress under combined shear and tension;
F
bU
is
the ultimate tensile stress under tension only;
F
bv
is the ultimate shear stress under
combined shear and tension;
F
vU
is the ultimate shear stress under shear only and is
equal to 0.62
F
bU
(see Equation 9.19).
Therefore, Equation 9.39 may be expressed as
F
bt
F
bU
2
2.60
F
bv
F
bU
2
+
=
1.0.
(9.40)
Equation 9.39, in terms of allowable stresses, is
σ
bt
f
bt
2
τ
bv
f
bv
2
+
=
1.0,
(9.41)
where
σ
bt
is the tensile stress in the bolt (including prying action effects).
f
bt
is the
allowable bolt tensile stress for bearing-type connections or the nominal tensile stress
from pretension for slip-resistant connections and is equal to
T
bP
/A
b
.
τ
bv
is the shear
stress in the bolt;
f
bv
is the allowable effective bolt shear stress and is equal to either
f
bv
for slip-resistant connections (Equation 9.22) or
f
bv
for bearing-type connections
the nominal area of the bolt (1.33
A
st
)
; and
A
st
is the effective bolt area through the
threaded portion of the bolt.