LOAD TRANSFER MECHANISM
Column-to-column or column-to-foundation
connections are usually loaded by axial
normal forces and horizontal shear forces
in combination with bending moments. The
bending moments may be separated in pairs
of tension and compression forces. The shear
forces are transferred from one concrete
element to the other via the cross section of the
bolt. Additional friction forces may be generated
if compressive forces are present. The tension
forces in the baseplate are transferred by the
anchor bolts to the base structure. Due to axial
shift between the through-hole in the baseplate
(= axis of the anchor bolt) and the axis of the
anchor bars of the column shoe, an eccentricity
appears. This eccentricity is compensated
for by a pair of horizontal pair of forces
(see Figure 5 a). In case of tension loads in the
anchor, the moment due to eccentricity is taken
over by a tension force in horizontally arrange
stirrups and the compression force acting on the
side plate. By contrast, the compression forces
in the anchor bolts lead to the compression
forces on the upper part of the side plate, and
the tension forces in the horizontal part of the
rear bars.
With the older versions of column shoes TKM
and PKM, the eccentricity of the force within the
anchor bolt was compensated with a vertical
pair of forces consisting of the connecting
reinforcement of the column and the vertical
hanger reinforcement welded to the column
shoe (see Figure 5 b).
TECHNICAL
H
B
t
db
E
Ø1
Ø2
K
db
X
E
BOLDA® 30 BOLDA® 36 BOLDA® 39 BOLDA® 45 BOLDA® 52
H 1058 1365 1600 1852 2190
t 30 35 40 50 55
B 100 130 130 140 170
E 50 60 60 60 70
db 40 50 55 60 70
Ø1 25 28 28 32 40
Ø2 10 12 14 16 16
X 30 37 37 37 42
D 153 178 195 217 245
K 173 200 220 250 269
Weight 13.7 22.6 29.4 42.5 74.9
FIGURE 4: DIMENSIONS MM AND WEIGHTS KG OF BOLDA® COLUMN SHOES
bx
Pud
D
Mtd 20‰
d
Pud Pud
Mtd 20‰
d
Neutral
axis
Pud Pud
Nc Nc Nc
Nc Nc Nc
0,8x
0,8x
Mpd
Pud Pud Pud
Neutral
axis
c3,5‰
x
Nc = NRd Td1
FIGURE 5: LOAD TRANSFER MECHANISM OF DIFFERENT COLUMN SHOE SYSTEMS FOR TENSION FORCES WITHIN THE ANCHOR BOLTS
Nc
x
s2
s1 Te,tot
Td
d d1
a
Tension
force
Ns Ns Ns
ep
et
ep
et
z
z
ep
Tg
et
fcd
bx
Pud
0,8x
0,8x
Pud Pud Pud
c3,5‰
Mpd
Nc = NRd Td1
Nc
s2
c
s1 Te,tot
Td
d d1
a
Tension
force
Ns Ns Ns
ep
et
ep
et
z
z
ep
Tg
et
fcd
A) BOLDA® B) TKM/PKM
48 PEIKKO CONNECTIONS 1/2021