Figure 8-28.-Masonry wall horizontal joint reinforcement.
Both piers and pilasters are used to support heavy,
concentrated vertical roof or floor loads. They also
provide lateral support to the walls. Piers and
pilasters offer an economic advantage by permitting
construction of higher and thinner walls. They may
be constructed of special concrete masonry units
(figure 8-27) or standard units.
Block walls may be reinforced vertically or
horizontally. To reinforce verdically, place reinforcing
rods (called rebar) into the cores at the specified
spacing and till the cores with a relatively high-slump
concrete. Rebar should be placed at each corner and
at troth sides of each opening. Vertical rebar should
be spaced a maximum of 32 inches on center in walls.
Where splices are required, the bars should be lapped
40 times the bar diameter. The concrete should be
placed in one continuous pour from foundation to
plate line. A cleanout block maybe placed in the first
course at every rebar stud for cleaning out excess
mortar and to ensure proper alignment and laps of
Practical experience indicates that control of
cracking and wall flexibility can be achieved with the
use of horizontal joint reinforcing. The amount of
joint reinforcement depends largely upon the type of
Horizontal joint reinforcing, where
required, should consist of not less than two deformed
longitudinal No. 9 or heavier cold-drawn steel wires.
Truss-type cross wires should be 1/8-inch diameter (or
heavier) of the same quality. Figure 8-28 shows joint
reinforcement on 16-inch vertical spacing. The
location and details of bond beams, control joints, and
joint reinforcing should all be shown on the drawings.
PATCHING AND CLEANING BLOCK
Always fill holes made by nails or line pins with
fresh mortar and patch mortar joints. When laying
concrete masonry walls, be careful not to smear
mortar on the block surfaces. Once they harden,
these smears cannot be removed, even with an acid