1. The size and spacing of
vertical reinforcement shown in Table
1805.5(5) is based on the use of reinforcement with
a minimum yield strength of 60,000 psi (414 MPa). Vertical
reinforcement with a minimum yield strength of 40,000 psi
(276 MPa) or 50,000 psi (345 MPa) is permitted, provided
the same size bar is used and the spacing shown in the table
is reduced by multiplying the spacing by 0.67 or 0.83, respectively.
2. Vertical reinforcement,
when required, shall be placed nearest the inside face of
the wall a distance, d, from the outside face (soil side)
of the wall. The distance, d, is equal to the wall thickness,
t, minus 1.25 inches (32 mm) plus one-half the bar diameter,
db [d = t – (1.25 + db/2)]. The
reinforcement shall be placed within a tolerance of ± 3/8
inch (9.5 mm) where d is less than or equal to 8 inches
(203 mm) or ±1/2 inch (2.7 mm) where
d is greater than 8 inches (203 mm).
3. In lieu of the reinforcement
shown in Table 1805.5(5),
smaller reinforcing bar sizes with closer spacings that
provide an equivalent cross-sectional area of reinforcement
per unit length of wall are permitted.
4. Concrete cover for reinforcement
measured from the inside face of the wall shall not be less
than 3/4 inch (19.1 mm). Concrete
cover for reinforcement measured from the outside face of
the wall shall not be less than 1.5 inches (38 mm) for No.
5 bars and smaller and not less than 2 inches (51 mm) for
larger bars.
5. Concrete shall have a specified
compressive strength, fc , of not less than 2,500
psi (17.2 MPa) at 28 days.
6. The unfactored axial load
per linear foot of wall shall not exceed 1.2 tfc ,
where t is the specified wall thickness in inches.
