NCCI: Tying resistance of a simple end plate connection
SN015a-EN-EU
NCCI: Tying resistance of a simple end plate connection
This NCCI provides rules for the determination of tying resistance of a Simple Joint
using an end plate connection for beam-to-column and beam-to-beam connections. It
covers the rules for the end plate, the supported beam and the supporting column web. The
rules may be used to evaluate the overall tying resistance of the connection, for all the
possible modes of failure, based on the rules in EN 1993-1-8 for determining the
resistances of individual components of the connection. The design procedure given in this
NCCI applies to an accidental limit state. The rules given in this NCCI can be applied to
both partial depth and full depth end plate connections, using non-preloaded bolts (i.e.
Category A: Bearing type bolted connections).
Contents
1. Design model 2
2. Parameters 3
3. Bolts in tension 4
4. End plate in bending 4
5. Supporting member in bending 5
6. Beam web in tension 6
7. Weld design 6
8. Limits of application 6
9. Background 6
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NCCI: Tying resistance of a simple end plate connection
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NCCI: Tying resistance of a simple end plate connection
SN015a-EN-EU
1. Design model
The design model is shown in Figure 1.1. The design procedure refers to an accidental limit
state.
1
1 1
3 3
4
2 2 2
Key: 1. End plate
2. Supported
beam
3. Column
4. Supporting
beam
Figure 1.1 End plate connection subject to tying force
The tying resistance and mode of failure of the connection is the value and mode that has the
lowest resistance of all the possible modes of failure. For rules for each of the modes of
failure, refer to Table 1.1 given below.
Table 1.1 Tying resistance of end plate connection
Mode of failure Section number
Bolts in tension N
Rd,u,1
3
End plate in bending N
Rd,u,2
4
Supporting member in bending N
Rd,u,3
5
Beam web in tension N
Rd,u,4
6
Note: There is no calculation of the tying resistance of a supporting beam, because it is
assumed that such a connection would not be designed for tying. Any requirements for tying
resistance would be satisfied by providing continuity of slab reinforcement and by
transferring tying forces through adjacent secondary beams framing directly into a column.
EN1993-1-8 does not give any guidance on tying resistance of connections. However,
because large strains and large deformations are associated with the failure modes given in
Table 1.1, it is recommended that ultimate tensile strengths (f
u
) can be used for calculating the
tying resistance and the partial factor for tying
M,u
can be taken as 1,1.
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NCCI: Tying resistance of a simple end plate connection
SN015a-EN-EU
2. Parameters
1
1
1
1
p
p
3
2
2
p
a
a
n = 2
p
p
e
e
h
p e
t
m
1
e
2,c
2
Key: 1. End plate
2. Supported beam
Figure 2.1 Fillet weld, throat and leg length.
d
c
Depth of straight portion of the column web
d
o
Diameter of hole
d
w
Diameter of washer or width across points of bolt head or nut
e
1
Longitudinal end distance (end plate)
e
2
Transverse edge distance (end plate)
e
2,c
Transverse edge distance (column flange)
f
u,b
Ultimate tensile strength of the bolt
f
u,b1
Ultimate tensile strength of supported beam
f
u,b2
Ultimate tensile strength of supporting beam
f
u,c
Ultimate tensile strength of column
f
u,p
Ultimate tensile strength of the end plate
h
p
Height of the end plate
m
p
Distance between the bolt line and the toe of the weld connecting the end plate to the
beam web (same as m for the end plate as in Figure 6.8 of EN1993-1-8)
n Total number of bolts (i.e. n
1
n
2
)
n
1
Number of horizontal rows of bolts
n
2
Number of vertical lines of bolts. This NCCI is for n
2
=2
p
1
Longitudinal bolt pitch
p
3
Gauge or distance between cross centres
t
f.c
Thickness of column flange
t
p
Thickness of the end plate
t
w,b1
Thickness of supported beam web
t
w,b2
Thickness of supporting beam web
t
w,c
Thickness of column web
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NCCI: Tying resistance of a simple end plate connection
SN015a-EN-EU
M,u
Partial factor for tying resistance equal to 1,1 (not given in EN1993-1-8)
3. Bolts in tension
u Rd, t, u,1 Rd,
F n N =
From Table 3.4 of EN1993-1-8:
u M,
s ub 2
u Rd, t,
A f k
F =
n is the total number of bolts
Where for tying resistance:
9 , 0
2
= k
1 , 1
u M,
=
4. End plate in bending
( )
ep2 u, Rd, ep1 u, Rd, u,2 Rd,
; min F F N =
From 6.2 of EN 1993-1-8
For mode 1:
( )
( )
p p w p p
u Rd, pl,1, w p
Rd T,1, ep1 u, Rd,
2
2 8
n m e n m
M e n
F F
+
= =
For mode 2:
p p
u Rd, t, p u Rd, pl,2,
Rd T,2, ep2 u, Rd,
2
n m
F n M
F F
+
+
= =
where:
( )
p c , 2 2 p
25 , 1 ; ; min m e e n =
( )
2
2 8 , 0 2
b1 w, 3
p
a t p
m
=
4
w
w
d
e =
d
w
is diameter of washer or width across points of bolt head or nut
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NCCI: Tying resistance of a simple end plate connection
SN015a-EN-EU
u M,
p u,
2
p p
u Rd, pl,2, u Rd, pl,1,
4
1
f t h
M M = =
u Rd, t, u,1 Rd, u Rd, t,
nF N F = =
(From section 3)
5. Supporting member in bending
5.1 Supporting column flange in bending
This check is not shown, because generally the supporting column flange will be thicker than
the end plate. If it is thinner, the column flange should be checked in bending in the same way
as the end plate in bending (see section 4).
5.2 Supporting column web in bending
If the supporting element is column web, then the tying resistance is:
( )
( ) ( ) (
5 , 0
1
5 , 0
1 1
1
u Rd, pl,
u,3 Rd,
1 1 5 , 1
1
8
=
m
N ) (See reference 2, check 14, p.100)
where:
u M,
2
c w, c u,
u Rd, pl,
4
1
t f
m =
f
u,c
is the ultimate tensile strength of the column
t
w,c
is the thickness of column web
c
3
1
d
p
=
( )
c
0
1
1 1
1
d
2
1 d
n
p n
=
c
0
1
d
d
=
d
c
is the depth of straight portion of the column web
d
0
diameter of hole
M,u
=1,1 for tying resistance
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NCCI: Tying resistance of a simple end plate connection
SN015a-EN-EU
6. Beam web in tension
u M,
b1 u, p b1 w,
u,4 Rd,
f h t
N =
1 , 1
u M,
= for tying resistance.
7. Weld design
The weld size specified for shear (SN014) will be adequate for tying resistance.
8. Limits of application
This NCCI applies to two vertical lines of bolts (i.e. n
2
=2) using non-preloaded bolts for
Category A: Bearing type bolted connection in accordance with EN1993-1-8 3.4.1.
9. Background
The rules in this NCCI are based on:
(1) European recommendations for the design of simple joints in steel structures -
Document prepared under the supervision of ECCS TC10 by: J.P. Jaspart, S. Renkin
and M.L. Guillaume - First draft, September 2003.
(2) Joints in Steel Construction Simple Connections (P212). The Steel Construction
Institute and The British Constructional Association Ltd., 2002.
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NCCI: Tying resistance of a simple end plate connection
SN015a-EN-EU
Quality Record
RESOURCE TITLE NCCI: Tying resistance of a simple end plate connection
Reference(s)
ORIGINAL DOCUMENT
Name Company Date
Created by Edurne Nunez SCI March 2005
Technical content checked by Abdul Malik SCI J uly 2005
Editorial content checked by D C Iles SCI 16/9/05
Technical content endorsed by the
following STEEL Partners:
1. UK G W Owens SCI 16/9/05
2. France A Bureau CTICM 16/9/05
3. Sweden A Olsson SBI 15/9/05
4. Germany C Mller RWTH 14/9/05
5. Spain J Chica Labein 16/9/05
Resource approved by Technical
Coordinator
G W Owens SCI 1/7/06
TRANSLATED DOCUMENT
This Translation made and checked by:
Translated resource approved by:
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