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Design of
Cantilever
Retaining Wall
Revision of previous concepts
A retaining wall is a structure built for the purpose of holding
back or retaining or providing one-sided lateral confinement
of soil or other loose material.
The loose material being retained pushes against the wall,
tending to overturn and slide.
Retaining walls are used in many design situations where
there are abrupt changes in the ground slope.
Perhaps the most obvious examples to the reader occur along
highway or railroad cuts and fills. Often, retaining walls are
used in these locations to reduce the quantities of cut and fill
as well as to reduce the right-of-way width required if the
soils were allowed to assume their natural slopes. Retaining
walls are used in many other locations as well, such as for
basement walls, bridge abutments, and culverts.
Summary of Estimation
Height of Wall:
Overall height can be determined by adding frost penetration
height of 3’ to 6’, preferably 4’
Stem thickness:
7% to 12% of the overall height (i.e. 0.07h to 0.12h)
Stem Top thickness
12 in. preferable and
Minimum 8 in.
Stem bottom thickness
can be determined by adding a taper length of ¼ in.
per foot of height. (i.e. ¼ h)
Stem
Base Thickness:
7% to 10% of the overall height (i.e. 0.07h to 0.1h)
Min. thickness of 10in. to 12in. are used
Base Length:
40% to 60% of the overall height
(i.e. b = 0.4h to 0.6h)
Toe Length:
1/3 of base length
Problem
Design a cantilever retaining wall to support a bank of earth of 16 ft
height above the final level of earth at the toe of the wall. The backfill is
to b level, but a building is to be built on the fill.
Assume that surcharge load = x (x = Your Group No.) will approximate the
lateral earth pressure effect.
Weight of retained material = 130 lb/ft3
Angle of internal friction = 35o
Coefficient of friction b/w concrete and soil = 0.4
fc’=3000 psi
fy=40,000 psi
Maximum soil pressure = 5 k/ft2
CANTILEVER RETAINING WALL DESIGN
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