Joints - The Behaviour and Design of Steel Structures to EC3 - page 410

platesmaybeprovidedononeorbothsides.Thisjointmaybeusedincontinuous
construction.
Themoment,axialforce,andsheararetransferredfromonememberbybearing
and shear through the bolts to the plates, to the other bolts, and then to the other
member. The flange plates only transfer the flange axial force components of the
moment M Ed , axial force N Ed , while the web plates transfer all of the shear V Ed
together with the web components of M Ed and N Ed .
9.5.10 Beam seat
Abeamseat(Figure9.17a)transfersabeamreaction R Ed toitssupport.Aseating
plate may be fillet welded to the bottom flange to increase the support bearing
area, while holding-down bolts provide positive connections to the support. If a
load-bearing stiffener is provided to increase the web bearing capacity, then this
will effectively prevent lateral deflection of the top flange (see Figure 6.19).
Thebeamreaction R Ed istransferredbybearingthroughtheseatingplatetothe
support.
9.5.11 Base plate
A base plate (Figure 9.17b) transfers a column axial force N Ed and shear V Ed to
a support or a concrete foundation, and may also transfer a moment M Ed . The
base plate is fillet welded to the flanges and web of the column, while the anchor
or holding-down bolts provide connections to the support. Pinned bases used in
simpleconstructionoftenusefouranchorbolts,andtheflexibilityoftheseandthe
base plate limits the effective moment resistance.
An axial compression N Ed is transferred from the column by end bearing or
weld shear to the base plate, and then by plate bending, shear, and bearing to the
support.An axial tension force N Ed is transferred from the column by weld shear
to the base plate, by plate bending and shear to the holding-down anchor bolts,
and then by bolt tension to the support. The shear force V Ed is transferred from
thecolumnbyweldsheartothebaseplate,andthenbyshearandbearingthrough
the holding-down bolts to the support, or by friction. Specific guidance on the
design of holding-down bolts is given in Clause 6.2.6.12 of EC3-1-8 [1], while
moregeneralguidanceonthedesignofbaseplatesasidealisedT-stubassemblies
is given in Clause 6.2.
9.6 Design of bolts
9.6.1 Bearing bolts in shear
The resistance F v of a bolt in shear (Figure 9.1a) depends on the shear strength
of the bolt (of tensile strength f ub ) and the area A of the bolt in a particular shear
plane (either the gross area, or the tensile stress area through the threads A s ,as