anchor bolts (fig. 3-7). The holes should be slightly
larger than the bolts so that some lateral adjustment of
the bearing plate is possible. The angle connections,
by which the columns are attached to the bearing
plates, are bolted or welded in place according to the
size of the column, as shown in figure 3-8.
After the bearing plate has been placed into
position, shim packs are set under the four comers of
each bearing plate as each is installed over the anchor
bolts, as shown in figure 3-9. The shim packs are 3- to
4-inch metal squares of a thickness ranging from 1 1/6
to 3/4 inch, which are used to bring all the bearing
Figure 3-7.Column bearing plate.
Figure 3-8.Typical column to baseplate connections.
Figure 3-9.Leveled bearing plate.
plates to the correct level and to level each bearing
plate on its own base.
The bearing plates are first leveled individually by
adjusting the thickness of the shim packs. This
operation may be accomplished by using a 2-foot level
around the top of the bearing plate perimeter and
diagonally across the bearing plate.
Upon completion of the leveling operation, all
bearing plates must be brought either up to or down to
the grade level required by the structure being erected
All bearing plates must be lined up in all directions
with each other. This may be accomplished by using
a surveying instrument called a builders level. String
lines may be set up along the edges and tops of the
bearing plates by spanning the bearing plates around
the perimeter of the structure, making a grid network
of string lines connecting all the bearing plates.
After all the bearing plates have been set and
aligned, the space between the bearing plate and the
top of the concrete footing or slab must be filled with
a hard, nonshrinking, compact substance called
GROUT. (See fig. 3-9.) When the grout has hardened
the next step is the erection of the columns.
Wide flange members, as nearly square in cross
section as possible, are most often used for columns.
Large diameter pipe is also used frequentl y (fig. 3-10),
even though pipe columns often present connecting
difficulties when you are attaching other members.
Columns may also be fabricated by welding or bolting
a number of other rolled shapes, usually angles and
plates, as shown in figure 3-11.
If the structure is more than one story high, it may
be necessary to splice one column member on top of
another. If this is required, column lengths should be