Page 116 - 2018_IRC

FOUNDATIONS

R403.1.1 Minimum size. The minimum width, W, and R403.1.3.5.3 and extend not less than 14 inches (357
thickness, T, for concrete footings shall be in accordance mm) into the stem wall. Standard hooks shall comply
with Tables R403.1(1) through R403.1(3) and Figure with Section R608.5.4.5. Not fewer than one No. 4 hor-
R403.1(1) or R403.1.3, as applicable. The footing width izontal bar shall be installed within 12 inches (305 mm)
shall be based on the load-bearing value of the soil in accor- of the top of the stem wall and one No. 4 horizontal bar
dance with Table R401.4.1. Footing projections, P, shall be shall be located 3 to 4 inches (76 mm to 102 mm) from
not less than 2 inches (51 mm) and shall not exceed the the bottom of the footing.
thickness of the footing. Footing thickness and projection
for fireplaces shall be in accordance with Section R1001.2. R403.1.3.2 Masonry stem walls with concrete foot-
The size of footings supporting piers and columns shall be ings. In Seismic Design Categories D , D and D 2
1
0
based on the tributary load and allowable soil pressure in where a masonry stem wall is supported on a concrete
accordance with Table R401.4.1. Footings for wood foun- footing, not fewer than one No. 4 vertical bar shall be
dations shall be in accordance with the details set forth in installed at not more than 4 feet (1219 mm) on center.
Section R403.2, and Figures R403.1(2) and R403.1(3). The vertical bar shall have a standard hook and extend
Footings for precast foundations shall be in accordance to the bottom of the footing and shall have support and
with the details set forth in Section R403.4, Table R403.4, cover as specified in Section R403.1.3.5.3 and extend
and Figures R403.4(1) and R403.4(2). not less than 14 inches (357 mm) into the stem wall.
Standard hooks shall comply with Section R608.5.4.5.
R403.1.2 Continuous footing in Seismic Design Catego- Not fewer than one No. 4 horizontal bar shall be
ries D , D and D . Exterior walls of buildings located in installed within 12 inches (305 mm) of the top of the
0
1
2
Seismic Design Categories D , D and D shall be supported wall and one No. 4 horizontal bar shall be located 3 to 4
1
0
2
by continuous solid or fully grouted masonry or concrete inches (76 mm to 102 mm) from the bottom of the foot-
footings. Other footing materials or systems shall be ing. Masonry stem walls shall be solid grouted.
designed in accordance with accepted engineering practice.
Required interior braced wall panels in buildings located in R403.1.3.3 Slabs-on-ground with turned-down foot-
Seismic Design Categories D , D and D with plan dimen- ings. In Seismic Design Categories D , D and D ,
2
1
0
0
2
1
sions greater than 50 feet (15 240 mm) shall be supported by slabs-on-ground cast monolithically with turned-down
continuous solid or fully grouted masonry or concrete foot- footings shall have not fewer than one No. 4 bar at the
ings in accordance with Section R403.1.3.4, except for two- top and the bottom of the footing or one No. 5 bar or
story buildings in Seismic Design Category D , in which all two No. 4 bars in the middle third of the footing depth.
2
braced wall panels, interior and exterior, shall be supported
on continuous foundations. Where the slab is not cast monolithically with the
footing, No. 3 or larger vertical dowels with standard
Exception: Two-story buildings shall be permitted to hooks on each end shall be installed at not more than 4
have interior braced wall panels supported on continu- feet (1219 mm) on center in accordance with Figure
ous foundations at intervals not exceeding 50 feet (15 R403.1.3, Detail 2. Standard hooks shall comply with
240 mm) provided that: Section R608.5.4.5.
1. The height of cripple walls does not exceed 4 feet
(1219 mm). R403.1.3.4 Interior bearing and braced wall panel
footings in Seismic Design Categories D , D and D .
1
0
2
2. First-floor braced wall panels are supported on In Seismic Design Categories D , D and D , interior
1
0
2
doubled floor joists, continuous blocking or floor footings supporting bearing walls or braced wall pan-
beams. els, and cast monolithically with a slab on grade, shall
3. The distance between bracing lines does not extend to a depth of not less than 12 inches (305 mm)
exceed twice the building width measured paral- below the top of the slab.
lel to the braced wall line. R403.1.3.5 Reinforcement. Footing and stem wall
R403.1.3 Footing and stem wall reinforcing in Seismic reinforcement shall comply with Sections R403.1.3.5.1
Design Categories D , D , and D . Concrete footings through R403.1.3.5.4.
2
0
1
located in Seismic Design Categories D , D and D , as
2
1
0
established in Table R301.2(1), shall have minimum rein- R403.1.3.5.1 Steel reinforcement. Steel reinforce-
forcement in accordance with this section and Figure ment shall comply with the requirements of ASTM
R403.1.3. Reinforcement shall be installed with support A615, A706 or A996. ASTM A996 bars produced
and cover in accordance with Section R403.1.3.5. from rail steel shall be Type R. The minimum yield
strength of reinforcing steel shall be 40,000 psi
R403.1.3.1 Concrete stem walls with concrete foot- (Grade 40) (276 MPa).
ings. In Seismic Design Categories D , D and D where
1
2
0
a construction joint is created between a concrete foot- R403.1.3.5.2 Location of reinforcement in wall.
ing and a concrete stem wall, not fewer than one No. 4 The center of vertical reinforcement in stem walls
vertical bar shall be installed at not more than 4 feet shall be located at the centerline of the wall. Hori-
(1219 mm) on center. The vertical bar shall have a stan- zontal and vertical reinforcement shall be located in
dard hook and extend to the bottom of the footing and footings and stem walls to provide the minimum
shall have support and cover as specified in Section cover required by Section R403.1.3.5.3.
2018 INTERNATIONAL RESIDENTIAL CODE ® 91
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