Civil Engineering Reference
In-Depth Information
Table 3.25 Slip Factor m for Preloaded Bolts Specified in EC3
(BS EN 1993-1-8) [2.13]
Class of Friction Surfaces
Slip Factor m
A
0.5
B
0.4
C
0.3
D
0.2
If a slip-resistant connection is subjected to an applied tensile force,
F
t,Ed
or
F
t,Ed,ser
, in addition to the shear force,
F
v,Ed
or
F
v,Ed,ser
, tending to pro-
duce slip, the design slip resistance per bolt should be taken as follows:
k
s
nm F
p
,
C
0
:
8
F
t
,
Ed
,
ser
for a category B connection
:
F
s
,
Rd
,
ser
¼
ð
3
:
114
Þ
g
M3
,
ser
k
s
nm F
p
,
C
0
:
8
F
t
,
Ed
for a category B connection
:
F
s
,
Rd
¼
ð
3
:
115
Þ
g
M3
If, in a moment connection, a contact force on the compression side
counterbalances the applied tensile force, no reduction in slip resistance is
required.
3.10.2.2 Connections Made with Pins
Connectionsmadewithpins are also coveredbyEC3 (BSEN1993-1-8) [2.13].
The code provides rules for designing connections with pins. According to the
code, wherever there is a risk of pins becoming loose, they should be secured.
Pin connections in which no rotation is required may be designed as single-
bolted connections, provided that the length of the pin is less than three times
the diameter of the pin. In pin-connectedmembers, the geometry of the unstif-
fened element that contains a hole for the pin should satisfy the dimensional
requirements given in
Table 3.26
.
Pin-connected members should be arranged
to avoid eccentricity and should be of sufficient size to distribute the load from
the area of the member with the pin hole into the member away from the pin.
The design of solid circular pins specified in EC3 (BS EN 1993-1-8)
[2.13] is dependent on the failure mode expected. The shear resistance of
the pin can be calculated as follows:
F
v
,
Rd
¼
0
116
Þ
The bearing resistance of the plate and the pin specified in EC3 (BS EN
1993-1-8) [2.13] can be calculated as follows:
:
6
Af
up
=
g
M2
F
v
,
Ed
ð
3
:
Search WWH ::
Custom Search