Page 298 - 2018_IRC

WALL CONSTRUCTION

ends of walls, and at a maximum spacing of 10 feet anchored around vertical reinforcing bars with a
(3048 mm). standard hook.
Horizontal joint reinforcement shall consist of R606.12.3.3 Minimum reinforcement for masonry
not less than two wires of W1.7 spaced not more columns. Lateral ties in masonry columns shall be
than 16 inches (406 mm); or bond beam reinforce- spaced not more than 8 inches (203 mm) on center and
3
ment of not less than one No. 4 bar spaced not more shall be not less than / -inch (9.5 mm) diameter. Lat-
8
than 10 feet (3048 mm) shall be provided. Horizon- eral ties shall be embedded in grout.
tal reinforcement shall be provided at the bottom R606.12.3.4 Material restrictions. Type N mortar or
and top of wall openings and shall extend not less masonry cement shall not be used as part of the lateral
than 24 inches (610 mm) nor less than 40 bar diame- force-resisting system.
ters past the opening; continuously at structurally
connected roof and floor levels; and within 16 R606.12.3.5 Lateral tie anchorage. Standard hooks for
inches (406 mm) of the top of walls. lateral tie anchorage shall be either a 135-degree (2.4 rad)
R606.12.3 Seismic Design Category D or D . Structures standard hook or a 180-degree (3.2 rad) standard hook.
1
0
in Seismic Design Category D or D shall comply with R606.12.4 Seismic Design Category D . Structures in
2
0
1
the requirements of Seismic Design Category C and the Seismic Design Category D shall comply with the
2
additional requirements of this section. AAC masonry requirements of Seismic Design Category D and to the
1
shall not be used for the design of masonry elements that additional requirements of this section.
are part of the lateral force-resisting system. R606.12.4.1 Design of elements not part of the lateral
R606.12.3.1 Design requirements. Masonry elements force-resisting system. Stack bond masonry that is not
other than those covered by Section R606.12.2.2.2 shall part of the lateral force-resisting system shall have a hor-
be designed in accordance with the requirements of izontal cross-sectional area of reinforcement of not less
Chapters 1 through 7 and Sections 8.1 and 8.3 of TMS than 0.0015 times the gross cross-sectional area of
402, ACI 530/ASCE 5 and shall meet the minimum masonry. Table R606.12.4.1 shows minimum reinforc-
reinforcement requirements contained in Sections ing bar sizes for masonry walls. The maximum spacing
R606.12.3.2 and R606.12.3.2.1. Otherwise, masonry of horizontal reinforcement shall be 24 inches (610 mm).
shall be designed in accordance with TMS 403. These elements shall be solidly grouted and shall be con-
structed of hollow open-end units or two wythes of solid
Exception: Masonry walls limited to one story in units.
height and 9 feet (2743 mm) between lateral sup-
TABLE R606.12.4.1
ports need not be designed provided they comply MINIMUM REINFORCING FOR STACKED BONDED
with the minimum reinforcement requirements of MASONRY WALLS IN SEISMIC DESIGN CATEGORY D 2
Sections R606.12.3.2 and R606.12.3.2.1. NOMINAL WALL THICKNESS MINIMUM BAR SIZE
R606.12.3.2 Minimum reinforcement requirements (inches) SPACED AT 24 INCHES
for masonry walls. Masonry walls other than those 6 #4
covered by Section R606.12.2.2.3 shall be reinforced in 8 #5
both the vertical and horizontal direction. The sum of 10 #5
the cross-sectional area of horizontal and vertical rein- 12 #6
forcement shall be not less than 0.002 times the gross For SI: 1 inch = 25.4 mm.
cross-sectional area of the wall, and the minimum R606.12.4.2 Design of elements part of the lateral
cross-sectional area in each direction shall be not less force-resisting system. Stack bond masonry that is part
than 0.0007 times the gross cross-sectional area of the of the lateral force-resisting system shall have a horizon-
wall. Reinforcement shall be uniformly distributed. tal cross-sectional area of reinforcement of not less than
Table R606.12.3.2 shows the minimum reinforcing bar 0.0025 times the gross cross-sectional area of masonry.
sizes required for varying thicknesses of masonry Table R606.12.4.2 shows minimum reinforcing bar sizes
walls. The maximum spacing of reinforcement shall be for masonry walls. The maximum spacing of horizontal
48 inches (1219 mm) provided that the walls are solid reinforcement shall be 16 inches (406 mm). These ele-
grouted and constructed of hollow open-end units, hol- ments shall be solidly grouted and shall be constructed of
low units laid with full head joints or two wythes of hollow open-end units or two wythes of solid units.
solid units. The maximum spacing of reinforcement
TABLE R606.12.4.2
shall be 24 inches (610 mm) for all other masonry. MINIMUM REINFORCING FOR STACKED BONDED
R606.12.3.2.1 Shear wall reinforcement require- MASONRY WALLS IN SEISMIC DESIGN CATEGORY D 2
ments. The maximum spacing of vertical and hori- NOMINAL WALL THICKNESS MINIMUM BAR SIZE
zontal reinforcement shall be the smaller of one- (inches) SPACED AT 16 INCHES
third the length of the shear wall, one-third the 6 #4
height of the shear wall, or 48 inches (1219 mm). 8 #5
The minimum cross-sectional area of vertical rein- 10 #5
12
#6
forcement shall be one-third of the required shear
reinforcement. Shear reinforcement shall be For SI: 1 inch = 25.4 mm.

2018 INTERNATIONAL RESIDENTIAL CODE ® 273
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