i. Case I. Case I applies to all openings
the maximum column dimension. Tie spacing for the
in nonstructural partitions over 100 square inches
remaining column height will be not more than 16
(64.5 x 103 mm2), and any opening in structural
bar diameters, 48 tie diameters, or the least column
partitions or exterior walls that is 2 feet (0.6m) or less
dimension, but not more than 18 inches (457mm).
both ways, but over 100 square inches. Jamb bars
Hooks in column ties will have a minimum turn of
will be provided on each side of the opening, and at
135 degrees plus an extension of at least six bar
least one bar, #4 (10M) or larger, will be provided at
diameters, but not less than 4 inches (102mm) at the
top and bottom of the opening. The lintel bars above
free end of the bar, except that where the ties are
the opening may serve as the top horizontal bar, and a
placed in the horizontal bed joints, the hook will
bond beam bar at the bottom of the opening may
consist of a 90-degree bend having a radius of not
serve as the bottom horizontal bar.
less than four bar diameters, plus an extension of 32
bar diameters.
ii. Case II. Case II applies to exterior
walls and structural partitions for any opening that
5.
Reinforcing in stacked bond. For
exceeds 2 feet (0.6m), but is not over 4 feet (1.2m) in
buildings in Seismic Design Categories A, B, and C,
any direction. The perimeter reinforcement will be
the minimum horizontal reinforcement ratio shall be
the same as in Case I, plus additional reinforcement
.0007 bt. This ratio shall be satisfied by uniformly
as follows: #4 (10M) or larger will be provided on all
distributed joint reinforcement fully embedded in
four sides of the opening, in addition to the bars
mortar or by horizontal reinforcement spaced not
required in Case I, and shall extend not less than 40
over 4 feet (1.2m), and fully embedded in grout. For
bar diameters or 24 inches (0.6m), whichever is
buildings in Seismic Design Categories D, E, and F,
larger, beyond the corners of the opening.
the minimum horizontal reinforcement ratio shall be
0.015 bt. If open end units are used and grouted
iii. Case III. Case III applies to any
solid, then the minimum horizontal reinforcement
opening that exceeds 4 feet (1.2m) in either direction
ratio shall be .0007 bt.
The above reinforcement
in exterior walls or structural partitions.
The
ratios may be satisfied by combinations of joint and
perimeter reinforcement will be the same as in Case
horizontal reinforcement.
II, except that vertical jamb bars will be provided in
lieu of the shorter vertical bars.
6. Reinforcing at wall openings. Since
the area around wall openings is vulnerable to failure,
(i) Additional details (see Figure 7-16).
supplemental reinforcement is prescribed herein. For
purposes of this paragraph, the term "jamb bars" will
mean bars of the same size, number, extent, and
anchorages as the typical vertical stud reinforcement
in that wall, and in no case less than one bar, #4
(10M) or larger (refer to Figure 7-15).
7-37
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