Civil Engineering Reference
In-Depth Information
The design bearing resistance of bolts can be calculated according to EC3
(BS EN 1993-1-8) [2.13] as follows:
k
1
a
b
f
u
dt
g
M2
F
b
,
Rd
¼
ð
3
:
103
Þ
f
ub
f
u
where
a
b
is the smallest of
a
d
;
or 1.0
e
1
3
d
o
in the direction of load transfer
:
a
d
¼
for end bolts
ð
3
:
104
Þ
p
1
3
d
o
1
4
a
d
¼
for inner bolts
perpendicular to the direction of load transfer
8
e
2
k
1
is the smallest of 2
:
d
o
1
:
:
7or2
5 for edge bolts
ð
3
:
105
Þ
4
p
2
k
1
is the smallest of 1
:
d
o
1
:
7or2
:
5 for inner bolts
that according to EC3 (BS EN 1993-1-8) [2.13], the bearing resistance
F
b,Rd
for bolts in oversized holes is 0.8 times that of bolts in normal holes and, in
slotted holes, where the longitudinal axis of the slotted hole is perpendicular
to the direction of the force transfer, and is 0.6 times that of bolts in round,
normal holes. For countersunk bolt, the bearing resistance
F
b,Rd
should be
based on a plate thickness
t
equal to the thickness of the connected plate
minus half the depth of the countersinking.
The design tension resistance of bolts specified in EC3 (BS EN 1993-
1-8) [2.13] can be calculated as follows:
k
2
f
ub
A
s
g
M2
F
t
,
Rd
¼
ð
3
:
106
Þ
where
k
2
¼
0.63 for countersunk bolt; otherwise,
k
2
¼
0.9. The punching
shear resistance can be calculated as follows:
0
:
6
pd
m
t
p
f
u
g
M2
B
p
,
Rd
¼
ð
3
:
107
Þ
where
d
m
is the mean of the across points and across flats dimensions of the
bolt head or the nut, whichever is smaller, and
t
p
is the thickness of the plate
under the bolt or the nut. For bolts in combined shear and tension, the fol-
lowing interaction equation should be satisfied:
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