Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF I~IE INVENTION
The present invention relates to the
construction of retaining walls and is more par-
ticularly concerned with a concrete block for use
in the strengthening of terraces, embankments and
banks, the protection of gardens, slopes, under-
passes and road embankments as well as in noise
protection mounds.
Concrete blocks specifically designed
for the construction o~ ret~;n;ng walls are already
known. For example, Canaaian Patent ~o. 1,116,422
discloses an earth retaining wall formed by stacked,
alternately staggered rows of spaced, nesting,
chevron-shaped concrete blocks. Each hlock is
formed on its upper side with a dihedral protru-
sion and on its underside with a complementar~
di~edral recess such that the blocks may lie one
upon the other without mortar connection and
interlock with one another due to their roof-
shaped angulax configuration. The underside ofeach block is also narrower than the upper side
so as to provide step-like shoulders in the wall
assembly for good anchorage with the earth. How-
ever, when it is desired to form a relatively
high retaining wall, the blocks of some of the
courses must be connected with one anothex using
connection tubes which pass into holes formed in
the blocks and extend continuously through the
blocks in the direction of the courses' the blocks
are then anchored to the bank with earth ties
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attached either directly or indirectly to the
connection tubes and extending into the bank.
It has been found in practice that when
stacking the blocks described above, it is difficult
to align the blocks with each other so as to pro-
vide complete contact engagement between the recess
of a given block and the protrusion of an underlying
block, and there is thus often a gap between two
blocks arranged one upon the other. Even if a
block is properly fitted upon another one, it may
still be displaced in a direction normal to the
course when a force of relatively small magnitude
is applied to the block in such direction. More-
over, due to the particular configuration of the
blocks, it is not possible to provide different
wall arrangements which would add to the aesthetic
look of the wall~
Sl)MMARY OF l'EIE INVENTI ON
It is therefore an object of this inven-
tion to overcome the aforementioned drawbacks andto provide a block for the construction of a
retaining wall, which i5 self-aligning.
It is a further object of the invention
to provide a block of the above tyoe which combines
stability, aesthetic value and versatility.
It is yet another object of the invention
to provide such a block which is easy to install
and adaptable to a variety of terrains~
In accordance with -the present invention,
~here is provided a block for the construction of a
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retaining wall, comprising a body of concrete mate-
rial having upper and lo~er faces of like contour,
each face being formed with a pair of dihedral
protrusions and a pair o dihedral recesses, the
protrusions and recesses alternating with each other
and extending in parallel relationship. The protru-
sions and recesses of the upper face are complemen-
tary to the recesses and protrusions respectively
of the lower face to define upper and lower bearing
surfaces. A retaining wall may thus be formed by
arrangin~ a plurality of these blocks in courses
one above the other with the protrusions and re-
cesses defining the lower bearing surface of a
block interfitting respectively with the recesses
and protrusions defining the upper bearing surface
of an underlying block, the protrusions and recesses
permitti.ng self-alignment of the blocks while pre-
venting displacement thereof in a direction normal
to the courses~
Owing to the provision of two dihedral
protrusions and two dihedral recesses on each of the
upper and lower faces of the concrete block accord-
ing to the invention, the block when laid upon an-
other one will slide in place as a result of its own
weight and thus complete contact engagement will be
ensured between the protrusions and recesses defin-
ing the lower bearing surface of the block and the
respective complementary recesses and protrusions
defining the upper bearing surface of the underlying
block. Moreover, slnce these protrusions and recesses
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provide a double interlocking engagement between two
superposed blocks, the blocks in the wall assembled
position are very stable and they can be displaced
relative to one another in a direction normal to the
courses only with great difficulty, usually requiring
a forc~ ofrelatively high magnitude.
BRIEF DESCRIPTION OF T~IE DRAWINGS
Further features and advantages of the
invention will ~ecome more readily apparent from the
following description of a preferred embodiment
thereof as illustrated by way of example in the
accompanying drawings, in which:
Figure 1 is a perspective view of a con-
crete block according to the invention'
Figure 2 is a sectional view of the block
shown in Fig~ 1,
Figure 3 which is on the same sheet of
drawings as Fig. 1 is a sectional view of an earth
re~;n;ng wall constructed with the blocks of
Fig. 1, and
Figure 4 is a sectional persF~ctive view
of another wall assembly which may be effected using
the blocks of Fig. 1~
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring first to Figs 1 and 2, there is
shown an elongated concrete block generally designated
by reference numeral 10 and haviny upper and lower
faces 12 and 14 as well as opposite end faces 16 and
18, the upper and lower faces having substantially
the same length. The block 10 is specifically de-
signed for the construction of retaining walls and
is made of concrete
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material ha~ing a minimum strength of 48 ~pa (7,000
lbs/sq. inch).
The upper face 12 of the block is formed
with a pair of dihedral protrusions 20,22 and a pair
of dihedral recesses 24,26. The lower face 14 is
similarly formed with a pair of dihedral protrusions
28,30 and a pair of dihedral recesses 32,34. As
shown, the protrusions and recesses of each of the
upper and lower ~aces alternate with each other and
extend in parallel relationship in a direction
normal to the longitudinal axis o~ the block~ More-
over, the protrusions 20,22 and recesses 24,26 of
the upper face 12 are complementary to the recesses
32,34 and protrusions 28,30 respectively of the
lower face 14 to define upper and lower bearing
surfaces, and are disposed in vertical alignment
therewith. Each of these protrusions and recesses
forms a dihedral angle of about 130. ~s best
shown in Fig. 2, one of the planar surfaces defined
by each protrusion for~s an angle ~ of about 15
to the horizontal, -the other planar surface forming
an angle ~ of about 30 to -the horizontal.
On the other hand, the end face 18 of the
block 10 is planar and is joined to the upper and
25 lower faces 12 and 14 by chamfered edges 36. The
other end face 16 is toothed and formed with an
angular shoulder 38.
Figure 3 shows how the blocks 10 may be
stacked vertically to form a retaining wall for an
earth bank 40~ Since the upper and lower faces
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12 and 14 of each bloc]~ have like contour, a block
can be inverted so that its surface 12 faces
downwardly and -thus be positioned over another
block with its surface 12 abutting the top surface
12 of the underlying block, It is therefore pos-
sible to arrange some of the blocks 10 in courses
so that their planar end surfaces 18 face outwardly
and their toothed end surfaces 16 face the earth
40, and to arrange other bloc]~s in courses so that
their planar end surfaces 18 face instead the earth
and their -toothed end surfaces 16 face outwardly,
whereby such courses can be alternated as shown in
Fig. 3. This of course renders the blocks 10
quite versatile and adds to the aesthetic loo~ of
the resulting wall.
The retaining wall may be constructed on
a concrete footing 4~ embedded in the earth. When
it is desired to construct a vertical wall of
relatively low height, for instance having a height
of up to about 4 feet, the first course of blocXs 10
can be laid directly on the horizontal top surface of
the footing 42. When the first course has been laid,
the wall may then be erected by arranging the blocks
in further courses one above the o-ther according to
the desired pattern. As ~hown in Fig. 3, the pro-
trusions and recesses of the blocks interfit with
each other to provide complete contact engagement
between the superposed blocks, and also provides a
double interlocking engagement therebetween which
prevents displacement of the blocks in a direction
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normal to the courses. The angular shoulders 38
further provide good anchorage with the earth 40.
In the case of relatively high retaining
walls, the wall must be angularly inclined as shown
in Fig. 4. To this end, ~he first course 44 of
blocks 10 is laid with butt joints in the still
unset soft concrete of the footing 46 and pressed
therein to provide the desired inclination of the
retaining wall~ me blocks o~ the upper courses 48
can be arranged with open joints to -form interspaces
50 which can receive decorative plantsO The blocks
10 can also be arranged with closed joints as in
the two uppermost courses 52 shown in Fig. 4. For
maximum safety, the last course is usually set in
place with mortar.
~ lthough the retaining wall is illustrated
in Fig. 4 with the planar end surfaces of the blocks
all facing outwardly, it is apparent that such a
wall can also be constructed with the toothed end
surfaces of the blocks all facing outwardly.
Finally, it should be noted that a retain-
ing wall constructed with the blocks 10 is held in
place solely by the equilibrium existing between
the weight of the wa~l and the pressure exerted
by the earth bank 40. Since the thickness and
unitary mass of the blocks making up the wall remain
unchanged as the height of the bank increases, it is
thus necessary to increase the angle of inclination
of the wall in order to maintain this equilibrium
and compensate for the pressure which increases with
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height. rrhis inclination generally varies from
about 90 to about 60,
