Civil Engineering Reference
In-Depth Information
Thirty-two-foot-tall foundation walls for the MCI Mid-Continent Data Center in Omaha,
Nebraska. (Courtesy of Economy Forms Corporation.)
walls have nonrectangular cross sections (such as ribbed wall panels) and/or should
e
be
greater than one-sixth of wall thicknesses, the regular design procedure for columns sub-
ject to axial load and bending (Code 14.4) must be followed.
The practical use of the empirical wall formula, which is given at the end of this para-
graph, is for relatively short walls with small moments. When lateral loads are involved,
e
will quickly exceed one-sixth of wall thicknesses. The number 0.55 in the equation is an
eccentricity factor that causes the equation to yield a strength approximately equal to that
which would be obtained by the axial load and bending procedure of Chapter 10 of the
Code if the eccentricity is
h
/6.
c
32
h
k
2
c
A
g
P
nw
0.55
f
1
(ACI Equation 14-1)
where
0.70
gross area of the wall section (in.
2
)
A
g
c
vertical distance between supports (in.)
h
overall thickness of member (in.)
k
effective length factor determined in accordance with the values given in
Table 18.1.
