Civil Engineering Reference
In-Depth Information
Figure 5.2
Elevations of beam-to-column joints
consists of individual bars, rather than welded fabric, the tension in the
bars may be assumed to contribute to the bending resistance of the joint,
as shown in Fig. 5.2(d). Small-diameter bars may fracture before the
rotation of the hogging region of the beam becomes large enough for the
resistance of the joint to reach its design value, so these bars should be at
least 16 mm in diameter [8].
In the fin-plate joint of Fig. 5.2(a), the bolts are designed mainly for
vertical shear, and the flexural stiffness is low. The end-plate joint of
Fig. 5.2(c) is likely to be 'semi-rigid' (defined later). The bolts at A are
usually designed for tension only, and bolts in the compression zone (B
and C) are designed for vertical shear only.
To achieve a 'rigid' connection it may be necessary to use an extended
end plate and to stiffen the column web in regions D and E, as shown in
Fig. 5.2(b).
Resistance of an end-plate joint
Until tabulated data become available, design of a semi-rigid partial-strength
end-plate joint, as in Fig. 5.2(c), requires extensive calculations. These are
explained, with an example, in the
Designers' Guide to EN 1994-1-1
[17].
An outline of the method is now given, assuming beams of the same
depth on opposite sides of the column.
The rotation capacity of the joint is ensured by using a thin end plate,
so that yield lines form in it before the bolts at A fracture in tension.
Plastic bending of the column flange and yielding of the column web at D
