Note: Descriptions are shown in the official language in which they were submitted.
CON CRE TE WALL PANE L S YS TEM
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~IELD O~ INVENTION
This invention relates generally to the field
of wall construction and more particularly to precast
concrete walls.
DESCRIPTION OF PRIOR ART
Fence and wall construction, being approximately
as old as civilization, is a well developed art, infrequently
the subject of major technological improvement. HoweveT,
more recent developments in civilization, and particularly
the modern superhighways, have created the need for a new
type of wall, sometimes referred to as highway barrier wall.
The fundamental purpose of highway barrier wall is
to effectively separate the highway from adjacent areas, but
the specific purpose varies. It can be to protect the high-
way form falling rocks OT erosion; or to maintain the scenic
nature of a highway by screening off eyesore areas such as
junkyards. Inversely, the specific purpose can be to protect
adjacent populated areas from the highway. The appearance,
the dangers and the sound of traffic on a highway can be
eliminated or substantially reduced by effective use of high-
way barrier walls.
Conventional fencing, such as wooden board or metal
chain link are commonly used and may effectively function to
screen off eyesores and keep people and animals away from
a highway. However, such fencing is limited in function
(e.g., little or no sound barrier) and deteriorates rapidly
without constant maintenance.
Conventional masonry walls, such as brick, stone
or cast in situ concrete can be effective for most purposes,
but they are not only prohibitively costly to erect but
time consuming and, once in place, equally difficult to
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remove.
Developing prefabricated panels that can be quickly
and easily assembled to form an effective highway barrier
wall has been a promising solution to the aforementioned
disadvantages of conventional fencing and masonry walls.
However, it is not an easily achieved solution primarily
because prefabrication requires standarization whereas no
two highway barrier walls are the same. Each must conform
to the terrain upon which it is erected as well as the
curvature of the highway. It must also be strong enough
to resist the forces working against it, the most common
of which is the wind, which at 80 m.p.h. exerts a force
of 25 pounds per square foot.
Among the earliest and still most common pre-
fabricated highway barrier walls are those formed of sheet
metal panels. Such panels, generally corrugated, are ex-
tended between and attached to anchored posts. The posts
are anchored by being pile driven into the terrain or sunk
in concrete piers. The depth to which the post is anchored
is constant, so the height of the post reflects the height
of the terrain in which it i5 anchored and the panels between
are stepped up or down, accordingly. This makes the system
adaptable to the terrain. The fact that the corrugated
metal panels are to some degree horizontally flexible allows
for accomodation to the curvature of the highway. Highway
barrier walls of corTugated metal panels meet the require-
ments of being adaptable and relatively easy to install.
However, if they are of sufficiently heavy guage to with-
stand the wind forces they are correspondingly costly.
They also have to be maintained to protect from oxidization
and are relatively ineffective as a sound barrier.
Precast concrete panels overcome the aforementioned
disadvantages of corrugated metal panels. They are
maintenance-free, relati~ely inexpensive and effective
sound barriers. However, past attempts to use precast concrete
panels in forming highway barrier walls have been unsuccess-
ful because they are less adaptable than corrugated metal
panels. They are totally inflexible and difficult to attach
to the anchored posts between which they extend. WheTeas
the metal panels can be bolted to gussets on the posts or
welded to the posts at any angle, concrete panels cannot
be so easily secured. To date, the most successful use of
precast concrete panels to form highway barrieT walls has
envolved the use of supporting posts OT columns having an
"I" shaped configuration in cross section. The supporting
posts OT columns of metal or concrete are anchored in the
terrain and the precast concrete panels extend between them,
with their opposite sides engaged within the channels formed
on each side of the "I" shaped column. To accomodate vari-
ations in the terrain, it is necessary to ~ig out the area
adjacent an elevated support column and partially bury
one end of the panel before stepping up to the next level.
The channels formed on each side of the "I" shaped sup-
pOTting column allow for vertical mobility of the panel,
that is the panels' elevational relation to the column may
vary according to the elevation of the terrain. This
provides adequate vertical flexibility to accomodate the
terTain. HoweveT, horizontal flexibility, to accomodate curva-
ture in the highway, is difficult OT impossible with this system.
The reason is that the joint between panel and supporting
post must be so tight as to allow minimal horizontal move-
ment. Otherwise, wind forces knocking the panel back and
forth within the channel of the supporting column would
WeaT away at the engaged pOTtion of the channel making
the joint increasingly looser and eventually the panel
would crack and become disengaged. The only way of achieving
a necessary CUrVatuTe of the wall is to use two support
co~umns, immediately adjacent to but angled a--ay from one
another to the degree required to effect the necessary
angular relationship bet-~een the adjacent panels.
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Generally the present invention seeks to overcome the
aforementioned disadvantages of the prior art by providing a
strong, maintenance-free, inexpensive wall suitable for use as
highway barrier wall, a wall that can be easily and quickly
assembled from standardized precast concrete elements and a wall,
the elements of which are adaptable to such horizontal and vertical
curvature as the situation may require while maintaining a totally
rigid relationship after installation.
SUMMARY OF THE INVENTION
The invention in one aspect comprehends an integral
precast concrete unit for use in erecting a prefabricated wall
structure comprising a rectangular panel member and at least one
column member integrally positioned on one vertical end of the
panel member, the column member having a greater width than the
panel member and defining a channel on one side. The channel
has a trapezoid cross-section with a longest side of the trapezoid
opening onto the one side. The panel member having a width less
than the width of the column channel whereby when a panel member
of a like second unit is positioned within the column channel
of the first unit, the second unit may be selectively positioned
with respect to the first unit.
The invention in another aspect pertains to a
prefabricated wall structure comprising in combination a plurality
of wall units, each wall unit being constructed as an integral
precast concrete structure comprising a rectangular panel member
and at least one column member positioned on one vertical end
of the panel member. The column member has a greater width than
the panel member and defines a channel on one side, the channel
having a trapezoid cross-section with a longest side of the
trapezoid opening onto the one side. The panel member has a width
less than the width of the column channel allowing the panel member
to be positioned within the column channel of an adjacent unit
to allow selective positioning of second unit with respect to
the first unit.
The invention also pertains to a method of erecting
a precast concrete wall structure comprising a plurality of
members, each of which is formed with a wall unit having a panel
section and a column section integral to the panel section, the
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column section defining a channel having a width which is greater
than the width of the panel section. The erecting method
comprising the steps of forming a pier provided with a weld plate
on its upper end in the ground, positioning a column section of
the wall unit so that a weld plate on the bottom of the column
section is flush against the pier weld plate, securing the pier
weld plate and column weld plate together, positioning another
unit adjacent the first unit so that the end of the panel section
extends into the channel of the column section of the mounted
unit, securing the second unit in the same manner as previously
described, and securing the panel section within the channel of
the column section.
More specifically, each wall unit preferably includes
a panel portion of uniform thickness and along one side, a support
column that is approximately three times thicker than the panel
portion. In each column, on the side opposite the panel portion,
is formed a channel three to four inches in depth and somewhat
wider than the thickness of the panel portion. On the bottom
of each column, there is a metal weld plate.
It should be emphasized that the panel portion and column
form an integral wall unit. The unit is precast with metal
reinforcement bars throughout.
For reasons that will be explained, some wall units
are precast with support columns on each of its opposite sides.
Holes are dug in the terrain along which the wall is
to run. The size of the hole is proportionate to the height of
the wall to be erected. The hole is filled with concrete to form
a support pier, and a metal weld plate appropriately attached
to metal reinforcement bar on its underside is sunk into the pier
so that its upper surface is approximately at terrain level.
The support piers, thus formed, are placed at intervals roughly
equivalent to the length of the wall unit.
When erecting a wall, each column in sequence is
positioned on a support pier, so the weld plate on the underside
of the support column is in registry with the weld plate on the
upper surface of the support pier. When correctly positioned,
the two weld plates are welded together.
The unsupported edge of the panel portion of the next
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unit in sequence, is placed in the channel of the support column
forming a tongue and groove joint. It is important that there
be sufficient play in this joint to allow the panel to be angled
within the channel rather than necessarily in strict alignment
with the support column. Each wall unit may thus be positioned
at a slight angle to the next so as to form a curved wall. Because
highways, by their nature, avoid sharp turns, a relatively gentle
curvature is normally all that is required of highway barrier
walls. However, to provide for more extreme curves, the support
columns on some units are formed with channel along its side
adjacent to and at a right angle with the panel portion.
Just as the play in the tongue and groove allows for
horizontal curvature of the wall, it is appreciated that vertical
displacement of the panel within the channel allows for a panel
to be on a lower elevation than the adjacent channel bearing
support column in which it is engaged. As mentioned earlier,
some wall units are formed with a support column on each of its
opposite sides. This is because in installation over uneven
terrain, the topmost panel unit (that is, the one on the highest
relative elevation) is installed first. It has a support column
on each side. The next wall unit in sequence (from either side)
is cut-away on its tongue side, and its support column side is
at a lower elevation than the first wall unit. The cut-away
portion is easily effected at the time the unit is precast, by
blocking off one corner of the mold. The required angle and extent
of the cut-away depends on the steepness of the hill, but for
purposes of standardization, a two foot diagonal cut-away has
proved to be adaptable to most inclines.
Once the horizontal displacement and vertical angle
of the tongue and groove relationship between panel and adjacent
support column channel has been established, it is then secured
by forcing grout into the channel to fill the voids between the
tongue portion of the panel and the channel. When this cures,
the joint becomes stable and secure.
One other advantage to the use of precast concrete wall
units, is that the surface can be readily textured so as to
increase its acoustical insulating qualities.
It will be appreciated that the wall formed according
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to this invention is very strong and stable. However, should
circumstances require its removal, the joint between support column
and pier can be unwelded and the grouted joint between panel units
broken away. Thus the wall can be disassembled and removed with
relatively little time and effort; and most of the panels remain
intact and reusable.
While the invention has thus far been described in terms
of highway barrier walls, it will be appreciated that it would
be appropriate to any situation, in which it was desired to quickly
and easily assemble prefabricated concrete panels to form a wall,
particularly where adaptability to elevational inclines and
horizontal curvatures are desirable. Other objects and advantages
of the present invention will be more readily apparent in the
following discussion of the accompanying drawings, in which:
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a front view of a wall unit of the present
invention;
Figure 2 is a partial cut-away view of the panel and
column taken along line A - A' of Figure l;
Figure 3 is a partial cut-away view of a wall unit
secured to an anchoring pier of the present invention;
Figure 4 is a partial cut-away view of a column and
panel showing one manner in which a wall unit may be secured to
an adjacent wall unit to form a wall;
Figure 5 is a partial cut-away view of a column and
panel showing another manner in which a wall unit may be secured
to an adjacent wall unit to form a wall;
Figure 6 illustrates a manner in which a series of wall
units may be secured to form a wall along a vertica~lly varying
path; and
Figure 7 is a top plan view of Figure 6.
DETAILED DESCRIPTION OF THE DRAWINGS
The best mode and preferred embodiment of the present
invention is illustrated in Figures 1 through 7.
Turning to Figure 1, a wall unit, generally indicated
at 10, comprises a panel 12 of generally rectangular form with
a column 14 integrally cast along one side of panel 12. The
length, height and thickness of panel 12 may vary according to
the specific intended use of the wall unit 10, although a certain
minimum thickness of panel 12 is necessary in order for wall unit
10 to support itself against the forces of gravity and wind.
A partial cut-away section of panel 10 is shown in
Figure 2, and illustrates various construction details of the
panel 10. A plurality of reinforcement rods 16 are cast within
wall unit 10 to form a rectangular reinforcement network. In
Figure 2, several vertical rods 16 are illustrated end-on and
several horizontal rods 16 are illustrated in profile. The
horizontal rods 16 which traverse the length of panel 12 extend
beyond the length of panel 12 into the center of column 14, thereby
reinforcing the unitary structure of wall unit 10.
A trapezoidal channel 18 is formed in one side of column
14. The channel 18 comprises back wall 15 parallel to the surface
13 of column 14 in which channel 18 is set, and two side walls
17 at an angle of up to 11~ from a line perpendicular to surface
13. A weld plate 26, shown in phantom in Figure 2, is attached
to the bottom of column 14, preferably by being welded to a
plurality of vertical reinforcement rods 16 prior to the casting
of wall unit 10.
Turning now to Figure 3, a pier 20 is placed in the
ground to be attached to the bottom of column 14. Pier 20 has
a ground Ievel horizontal top surface 21 on which is placed pier
weld plate 24. Pier weld plate 24 is secured to pier 20 by
vertical pier rods 22. Pier weld plate 24 and pier rods 22 may
be welded to one another and then placed in pier 20 immediately
after the concrete of pier 20 has been poured. The concrete of
pier 20 is poured in the ground at the precise site desired for
placement of a column 14. The depth and diameter of the pier
increase in proportion to the height of the wall unit to be
attached. For instance, a wall unit that is ten (10) feet high
requires a pier two and a half (2-~) feet in diameter and seven
(7) feet deep, whereas a unit twenty (20) feet high requires a
pier three and a half (3-~) feet in diameter and twelve (12) feet
deep. These dimensions are calculated to withstand wind forces
up to eighty (80) miles per hour.
Column 14 may be placed atop pier 20 so that column
weld plate 26 is flush against pier weld plate 24. The lower
edges of column 14 form a chamfer 19 to allow access to the weld
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plate during placement. The pier 20 and column 14 are structurally
joined together by bead welding the exposed side edges of the
weld plates 24 and 26. Because all piers 20 must be cast at least
several hours prior to the installation of wall units 10 in order
to allow concrete to cure, it is frequently impossible to achieve
a precise placement of piers 20 so that exact alignment of the
weld plates is extremely difficult. However, this problem is
overcome in the present invention by scaling the pier 20 and pier
weld plate 24 to be significantly wider and longer than the column
weld plate 26. Therefore, a placement error of less than several
inches in the location of pier 20, which is readily achievable
in the current state of construction arts, can be easily
accommodated without construction delays.
Figure 4 illustrates the manner in which adjacent wall
units 10 may be joined to one another to form a continuous wall.
The trapezoidal channel 18 of a column 14 surrounds the end of
an adjacent panel 12', and the spaces formed between the end of
panel 12' and channel 18 may be filled with grout in order to
secure the connection between adjacent units. It can be seen
in Figure 4 that the trapezoidal cross-sectional shape of channel
18 advantageously allows a certain degree of freedom in the angle
formed between the panel 12 and panel 12'. Thus, minor wall path
curvature over short distances, and a cumulative substantial wall
path curvature over longer distances, may be easily accommodated
during construction of a wall.
A more severe angle between adjacent wall units may
be accommodated as illustrated in Figure 5. The channel 18 may
be formed in the side of column 14, rather than in the end of
column 14 as illustrated in Figure 4. Thus, a wall panel 12'
is shown attached to column 14 in Figure S at an angle which may
be adjusted to a certain extent on either side of a right angle.
When the wall unit 10 is cast with the channel 18 in the side
of column 14, an alternative weld plate 27 is placed on the bottom
of column 14 so as to avoid interference with channel 18 and panel
12'.
The manner of securing adjacent wall units to form a
continuous wall as disclosed in Figures 4 and 5 is sufficient
to accommodate minor vertical variations in the wall path.
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However, it is quite common in construction of walls to encounter
significant vertical variations which cannot be accommodated by
minor adjustments allowable within the system heretofore described.
Such height variations might typically be on the order of two
feet of vertical drop across a panel length of twelve feet.
Figures 6 and 7 illustrate a wall unit system adapted
to accommodate vertical path variation. At local peak 38 of a
vertically varying path, a pair of piers 20 are placed in the
ground and a dual column wall unit 30 is installed. The dual
column wall unit 30 is similar to the wall unit 10 except that
the panel 12 has a column 14 on each end. Other piers 20 are
then placed on the sides of the hill leading away from local peak
38 so that cut-away wall units 32 may be installed leading downward
from the dual columns 14 of units 30.
Each cut-away wall unit 32 had one corner adjacent to
the ground opposite column 14 cut-away, preferably by being cast
with a block structure in the mold. The cut-away shape is
preferably diagonal as is illustrated in Figure 6, although a
rectangular cut-away and other shapes may also advantageously
be used. The cut-away 34 is of sufficient size to allow the panel
of unit 32 to meet the column of an adjacent unit without
interference with the pier 20 attached to the column of the
adjacent unit, which is elevated relative to the bottom edge of
the panel.
When such a construction system is used on adjacent
local peaks 38, the wall systems extending toward one another
between the adjacent peaks will meet in an incongruent fashion.
That is, the column 14 of one panel will face the column 14 of
another panel. In this situation, a columnless wall unit may
be cast so as to fit precisely between the columns 14. The
columnless wall unit 36 may then be inserted in channels 18 of
the adjacent columns 14 and secured with grout as described above
to complete a continuous wall system.
The surfaces of the wall units described above may be
cast in a variety of textures and patterns to meet requirements
of decoration planning as well as acoustic preferences while
maintaining the advantageous construction and installation
characteristics described above. Thus, an inventive concrete
wall panel system has been described which combines economy and
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ease of manufacture, ready adaptability to various terrain
features, simplicity of installation and removal, sturdiness,
and acoustic and appearance advantages.
In the foregoing description, the invention has been
described with reference to a particular preferred embodiment
although it is to be understood that the specific details shown
are merely illustrative and that the invention may be carried
out in other ways without departing from the true spirit and scope
of the following claims.
