WAC 51-51-0404
Section R404 -- Foundation and retaining
walls.
Table R404.1.1(3). Note corrected title:
10-INCH MASONRY FOUNDATION WALLS WITH REINFORCING WHERE d > 6.75 INCHESa,c
R404.1.2.2 Reinforcement for foundation walls. Concrete
foundation walls shall be laterally supported at the top
except where permitted in R404.1.2.2.1 and R404.1.2.2.2, and
at the bottom where required elsewhere in this code.
Horizontal reinforcement shall be provided in accordance with
Table R404.1.2(1). Vertical reinforcement shall be provided
in accordance with Table R404.1.2(2), R404.1.2(3),
R404.1.2(4), R404.1.2(5), R404.1.2(6), R404.1.2(7) or
R404.1.2(8). Vertical reinforcement for flat basement walls
retaining 4 feet (1,219 mm) or more of unbalanced backfill is
permitted to be determined in accordance with Table
R404.1.2(9).
For basement walls supporting above-grade concrete walls,
vertical reinforcement shall be the greater of that required
by Tables R404.1.2(2) through R404.1.2(8) or by Section 611.6
for the above-grade wall. In buildings assigned to Seismic
Design Category D0, D1 or D2, concrete foundation walls shall
also comply with Section R404.1.4.2.
R404.4 Retaining Walls. Retaining walls not supporting a
structure that are not laterally supported at the top and that
retain in excess of 24 inches (610 mm) of unbalanced fill
shall be designed to ensure stability against overturning,
sliding, excessive foundation pressure and water uplift.
Retaining walls shall be designed for a safety factor of 1.5
against lateral sliding and overturning.
[Statutory Authority: Chapter 19.27 RCW. 10-24-061, §
51-51-0404, filed 11/29/10, effective 7/1/11. Statutory
Authority: RCW 19.27.031 and 19.27.074. 10-03-098, §
51-51-0404, filed 1/20/10, effective 7/1/10. Statutory
Authority: RCW 19.27.190, 19.27.020, and chapters 19.27 and 34.05 RCW. 08-01-102, § 51-51-0404, filed 12/18/07, effective
4/1/08. Statutory Authority: RCW 19.27.074, 19.27.020, and
chapters 19.27 and 34.05 RCW. 07-01-090, § 51-51-0404, filed
12/19/06, effective 7/1/07.]