below and at top of openings or immediately above
lintels, at floor and roof levels, and at top of parapet
1.
Reinforced grouted masonry is that
walls. Intermediate bond beams will be provided as
type of construction made with two wythes of
required to conform to the maximum spacing of
masonry units in which the collar joint between is
horizontal bars. When, however, the height is not a
reinforced and filled solidly with concrete grout. The
multiple of this normal spacing, the spacing may be
grout may be placed as the work progresses or after
increased up to a maximum of 24 inches (610mm) ,
the masonry units are laid.
Collar joints will be
provided the bond beams are supplemented with joint
reinforced with deformed bars, both vertical and
reinforcement. One line of joint reinforcement will
horizontal. Reinforcement and embedded items such
be provided for each 8-inch (203mm) increase in the
as structural connections and electrical conduit shall
spacing. No additional bond beam will be required
be positioned so as to allow proper placement of
between window openings that do not exceed
grout. All units will be laid in running bond with full
6 feet (1.8m) in height, provided the prescribed
shoved head and bed mortar joints. Masonry headers
supplemental joint reinforcement is installed.
To
will not project into grout spaces.
Clipped-brick
facilitate the placement of steel or concrete core fill,
headers will be used where the appearance of
the top bond beam for filler walls or partitions may
masonry headers is required (see Figure 7-10).
be placed in the next-to-top course. The area of bond
beam reinforcement will be included as part of the
2. Reinforced hollow masonry is that type
minimum horizontal steel.
of construction made with a single wythe of hollow
masonry units (concrete or clay blocks), reinforced
(f) Design for crack control. Guidelines
vertically and horizontally with steel bars, and cores
provided in TM 5-809-3/NAVFAC DM-2.9/AFM
and voids containing reinforcing bars or embedded
88-3, Chapter 3, will be utilized to minimize cracking
items are filled with grout as the work progresses (see
of masonry walls due to drying shrinkage and
Figure 7-11).
thermal expansion and contraction. The placement of
control joints must be coordinated with the seismic
3. Reinforced filled-cell masonry is that
design.
Because the control joints provide a
type of construction made with a single wythe of
complete separation of the masonry, the location of
hollow masonry units, reinforced vertically and
control joints fixes the length of wall panels, and in
horizontally with deformed steel bars, and all cores
turn, the rigidity of the walls, the distribution of
and voids are filled solidly with grout after the wall is
seismic forces, and the resulting unit stresses.
laid (see Figure 7-12).
Therefore, adding, eliminating, or relocating control
joints will not be permitted once the structural design
(e)
Bond beams.
Bond beams will be
is complete. Control joints will never be assumed to
located as indicated in Figure 7-13. Reinforcement
bars in bond beams will be lapped as prescribed in
ACI 530 at splices, at intersections, and at corners.
Bar splices will be staggered. Bond beams will be
provided at top of masonry foundation wall stems,
7-30
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