Title: Reinforced retaining wall construction element
Abstract: A precast concrete retaining wall construction element for retaining a soil mass in a railway installation or the like includes an upstanding solid face panel having the shape of a hexahedron where a rectangular front wall and an integral stem. The front wall defines an area of between about 18.75 and 75 square feet and wherein the ratio of the width of the face panel to its height is between about 0.75 to about 3.0. A reinforced element including an upward extension, an improved shear key and stacked arrangement are also disclosed.
Patent Number: 6,994,495 Issued on 02/07/2006 to Carey, et al.
| Inventors:
|
Carey; John M. (Ashburn, VA);
Neel; Thomas C. (Springfield, VA)
|
| Assignee:
|
The Neel Company (Springfield, VA)
|
| Appl. No.:
|
989414 |
| Filed:
|
November 17, 2004 |
| Current U.S. Class: |
405/286; 405/284 |
| Current Intern'l Class: |
E02D 29/02 (20060101) |
| Field of Search: |
405/284-286,262
|
References Cited [Referenced By]
U.S. Patent Documents
| 4067166 | Jan., 1978 | Sheahan.
| |
| 4655646 | Apr., 1987 | Babcock et al.
| |
| 4684294 | Aug., 1987 | O'Neill.
| |
| 4884921 | Dec., 1989 | Smith.
| |
| 4923339 | May., 1990 | Smith.
| |
| 4957395 | Sep., 1990 | Nelson.
| |
| 5131791 | Jul., 1992 | Kitziller.
| |
| 5163261 | Nov., 1992 | O'Neill.
| |
| 5528873 | Jun., 1996 | Correia et al.
| |
| 5697736 | Dec., 1997 | Veazey et al.
| |
| 5975810 | Nov., 1999 | Taylor et al.
| |
| 6539684 | Apr., 2003 | Graham.
| |
Primary Examiner: Lagman; Frederick L.
Attorney, Agent or Firm: Dennison, Schultz, Dougherty & MacDonald
Claims
What is claimed is:
1. A reinforced precast concrete retaining wall construction element for retaining
a soil mass comprising:
an upstanding solid face panel having the shape of a hexahedron with front and
rear walls, a top wall, two side walls and a bottom wall and wherein the area of
said front wall is between about 30 and about 40 square feet and the ratio of the
width of said face panel to the height of said face panel is between about 1.2
to about 1.6;
an integral stem extending rearwardly from said rear wall of said face panel
in a generally T-shaped arrangement for embedment in a soil mass;
said integral stem having an upper wall, a bottom wall, two side walls, a rear
wall and said upper and bottom wall each defining a notch therein and each of said
side walls including a plurality of horizontally aligned rows and vertically aligned
columns of pan inserts;
a shear key constructed and dimensioned to fit within one of said notches in
one of said upper and bottom walls and adapted to fit within a corresponding notch
in an abutting stem of a second element placed on top of or below said retaining
wall construction element; and
two steel reinforcing rods extending through and encased by said integral stem
and said face panel with one of said reinforcing bars extending into a first portion
of said face panel and the other of said reinforcing bars extending into an opposite
portion of said face panel
in which each of said rows of aligned pan inserts includes three pan inserts
and which include two sets of steel reinforcing rods with one set of two reinforcing
rods passing between the first and second pan insert in each of said columns and
in which a second set of two steel reinforcing rods pass between the second and
the third columns of pan inserts and in which one of said steel reinforcing rods
in each of said sets extends into said face panel in a first direction and the
other reinforcing rod in said sets extending in an opposite direction into said
face panel.
2. A reinforced precast concrete retaining wall construction element according
to claim 1, in which said face panel extends upwardly for a distance of about 3
feet above said upper wall of said integral stem.
3. A reinforced precast concrete retaining wall construction element according
to claim 1, in which each of said pan inserts defines an area of between about
0.56 square feet and about 1.56 square feet.
4. A reinforced precast concrete retaining wall construction element according
to claim 3 in which each of said faces of said pan insert defines an area of about
one square foot.
5. A reinforced precast concrete retaining wall construction element according
to claim 1 in which said face panel and said stem each have a thickness of between
about 7 inches and 8 inches.
6. A reinforced precast concrete retaining wall construction element according
to claim 5 in which each of said notches has a width of about one foot and a depth
of about 0.5 feet.
7. A reinforced precast concrete retaining wall construction element according
to claim 6 in which each of said shear keys extend outwardly from said integral
stem by a distance of about one-half inch on each side thereof.
Description
FIELD OF THE INVENTION
This invention relates to a precast concrete retaining wall construction element
and more particularly to a precast concrete retaining wall construction element
for retaining a soil mass.
BACKGROUND FOR THE INVENTION
Precast concrete retaining wall construction elements are known. For example,
a U.S. Pat. No. 4,684,294, of O'Neill, discloses a retaining wall construction
element having a forwardly disposed rectangular face panel and an integral embedment
beam which extends into and is anchored by the soil mass. The embedment beam includes
upper and lower walls, side walls and a sloping rear wall. In addition, the embedment
beam includes notches for engagement which transverse support beams which form
a soil interruption system to reduce internal pressure and which serve to lock
the embedment beams together. The embedment beams further include pan inserts and
a V-shaped groove disposed in the sloping rear wall to increase the frictional
engagement between the embedment beam and the soil mass. The construction elements
in accordance with the O'Neill patent have been widely used for many applications.
However, it is presently believed that there is a large commercial market
for an improved precast concrete retaining wall construction element in accordance
with the present invention. There should be a large commercial market for such
elements because they are particularly applicable for railroad embankments and
other large installations that may be repeatedly subjected to significant forces
and/or vibrations.
The improved precast concrete retaining wall construction elements in accordance
with the present invention fully meet the American Railway Engineering and Maintenance
Association (AREMA) requirements for railroad installations. Further, such elements
are economical to manufacture, ship and to install in a safe manner which reduces
the risk for employees working on such installations. Further, the precast concrete
retaining wall construction element in accordance with the present invention, are
sized for efficient shipment by truck and have a pleasing appearance.
BRIEF SUMMARY OF THE INVENTION
In essence, the present invention contemplates a precast concrete retaining wall
construction element for retaining a soil mass. The element includes an upstanding
solid face panel having the shape of a hexahedron with front and rear walls, a
top wall, two side walls and a bottom wall. An important feature of the present
invention resides in the area of the front wall which is between about 18.75 and
about 75 square feet and wherein the ratio of the width of the face panel to the
height of the face panel is between about 0.75 to about 3.0.
In a preferred embodiment of the invention, a "standard unit" includes a front
wall having an area of between about 30 square feet and about 40 square feet, preferably
about 37½ square feet and wherein the ratio of the width of the face panel
to the height of the face panel is between about 0.75 to about 3.0, and preferably
between about 1.2 to about 1.6.
The element also includes an integral stem or embedment member extending rearwardly
from the rear wall of the face panel in a generally T-shaped construction. The
integral stem has an upper wall, a bottom wall, two side walls, a rear wall and
with one or more notches defined in the upper and bottom wall. Further, each of
the side walls of the integral stem includes one or more pan inserts therein. A
shear key is constructed and dimensioned to fit within one of the notches in one
of the upper and bottom walls of the stem and is adapted to fit within a corresponding
notch in an abutting stem of a second element which is placed on top of or below
the retaining wall construction element.
In a second embodiment of the invention, the precast concrete retaining wall
construction
element wherein each of the elements set forth in the previous paragraph includes
steel reinforcing rods extending through and encased by the integral stem and the
face panel with one of the reinforcing bars extending outwardly in a first direction
of the face panel and the other of the reinforcing bars extending outwardly in
an opposite direction into the face panel.
In a third embodiment of the invention, the precast retaining wall construction
element for retaining a soil mass includes the elements of the first embodiment
of the invention and also includes one or more shear keys which fit within one
of the notches in one of the upper or bottom walls and is adapted to fit within
a corresponding notch in an abutting stem of a second element placed on top of
or below the retaining wall construction element. In this embodiment of the invention,
the shear key includes a face having a cross sectional area of about one square foot.
A fourth embodiment of the invention includes all of the elements of the first
embodiment. However, in this embodiment the face panel includes an extension extending
upwardly above the integral stem by distance of up to about 5 feet. A 5 foot extension
on top of a 5 foot height of a standard unit gives a total height of 10 feet which
is the limit due to shipping and results in a face panel having a cross sectional
area of about 75 square feet. In this example, the area of the upper extension
and the portion of the front wall below the extensions are each about 37½
square feet.
A fifth embodiment of the invention contemplates a plurality of stacked elements
wherein a first element as defined in the first embodiment of the invention is
stacked on top of an element in an aligned and abutting relationship. In this embodiment
of the invention, a retaining wall construction element in accordance with the
fourth embodiment of the invention may be used as an upper or top element in the
stacked array of such elements. Further, the shear key is constructed and dimensioned
to fit within one of the notches in an upper wall of one stem and within a corresponding
notch in a bottom wall of the stem of the second element.
The invention will now be described in connection with the accompanying drawings
wherein like reference numerals have been used to designate like parts.
DESCRIPTION OF THE FIGURES
FIG. 1 is a perspective view of a retaining wall construction element in accordance
with a first embodiment of the invention;
FIG. 2 is a side elevational view of the retaining wall construction element
shown in FIG. 1;
FIG. 2A is a sectional view of the element shown in FIG. 2 and taken along the
line A—A in FIG. 2;
FIG. 2B is a sectional view of the element shown in FIG. 2 and taken along the
line B—B in FIG. 2;
FIG. 3 is a top view of the element shown in FIG. 2;
FIG. 4 is a front view of a retaining wall construction element in accordance
with a second embodiment of the invention;
FIG. 5 is a side elevational view of the elements shown in FIG. 4;
FIG. 5A is a cross-sectional view taken along the line A—A in FIG. 5;
FIG. 5B is a cross-sectional view taken along the line B—B in FIG. 5;
FIG. 6 is a top view of the element shown in FIGS. 4 and 5;
FIG. 7 is a side view of a stem portion of an element in accordance with the
present invention and including two pair of corresponding notches and a shear key
in one pair of corresponding notches;
FIG. 8 is a side view of a shear-key in accordance with one embodiment of the invention;
FIG. 9 is a front view of the shear key shown in FIG. 8;
FIG. 10 is a plan view of the shear key shown in FIGS. 8 and 9;
FIG. 11 is a side view in accordance with another embodiment of the invention;
FIG. 12 is a side view of a retaining wall construction element in accordance
with another embodiment of the invention;
FIG. 13 is a top view of the elements shown in FIG. 12;
FIG. 13A is a sectional side view illustrating the steel bar reinforcement as
used in one embodiment of the invention;
FIG. 13B is a sectional front view illustrating the steel bar reinforcement
as used in the embodiment of the invention shown in FIG. 13A;
FIG. 14 is a side view of a retaining wall construction in accordance with another
embodiment of the invention;
FIG. 14A is a side sectional view which illustrates the steel reinforcing rods
in another embodiment of the invention;
FIG. 14B is a front sectional view which illustrates the steel reinforcing rods
in a face panel in accordance with the embodiment of the invention shown in FIG. 14A;
FIG. 15 is a side view of a retaining wall construction element according to
a further embodiment of the invention which shows the steel reinforcing elements;
FIG. 16 is a front view of the elements shown in FIG. 15 and which shows the
steel reinforcing rods disposed therein;
FIG. 17A is a side view of a shear key which includes a pair of U-shaped reinforcing bars;
FIG. 17B is a schematic illustration of the front view of a pair of U-shaped
reinforcing rods as used in the embodiment of the invention shown in FIG. 15;
FIG. 18 is a load diagram which illustrates typical lateral earth pressures
from two railroad tracks adjacent to a retaining wall construction in accordance
with the present invention;
FIG. 19 is a side view of a typical rail facility application; and
FIG. 20 is a perspective view of one embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
FIGS. 1,
2,
2A,
2B and
3 show a precast concrete
retaining wall construction element
2 in accordance with a first embodiment
of the invention. As shown, the element
2 includes a face panel
12
having a height of about 5 feet and a width of about 7½ feet. In a preferred
embodiment of the invention, the face panel defines a front face having an area
of between about 30 and 40 square feet and preferably about 37½ square feet.
The dimensions are based on various considerations including the requirements of
the American Railway Engineering and Maintenance Association (AREMA). For example,
the lateral pressure required for various installations must be met. In the present
case i.e., one that is used for rail facility applications such as grade separation
structures, bridge approaches and abutments, slope stabilization etc. each installation
must comply with the AREMA requirements and at the same time optimize the value
of the installation. For example, dimensions are also based on various considerations
including the safety of workers, transportation and manufacturing costs, raw material
costs, appearance and loading.
As illustrated, the element
2 includes an integral stem
14 or embedment
beam member which is formed in a generally T-shaped arrangement. The face panel
12 and integral stem
14 which are integrally cast from concrete at
a manufacturing site. The face panel
12 also includes a forward wall
16,
a rear wall
18, side walls
20, a top wall
21 and a bottom
wall
22. An integral cast concrete trapezoidal support member
23
extends rearwardly from the rear wall
18 with its base or widest portion
adjacent to the rear wall and its top portion extending into the integral stem
14. As illustrated, the top wall
21 defines a flat surface. Also
in this embodiment of the invention, the face panel
12 includes an upper
extension above the stem
14 which retains additional fill on the top of
an installation.
For railroad applications, a number of considerations call for an upward extension
of the face panel as for example, as required to allow an overburden of 2 to 3
feet of soil to provide an obstacle free layer of soil below the tracks and above
the integral stems. This 1 to 3 feet layer also accommodates for a 1 to 2 percent
grade and for electrical cable for signals.
As shown in the figures, the integral stem
14 is joined to the rear wall
18 of the face panel
12 by means of the trapezoidal support member
23 which reduces stress at the juncture. The integral stem
14 includes
an upper wall
25, a bottom wall
26 and side walls
27 and
28.
The upper wall
25 and lower wall
26 each define one or more notches
30 and
32 for engagement with a shear key (not shown in FIGS. 1 and
2). The side walls
27 and
28 each include a series of pan inserts
33 or indentations which become filled with compacted soil to help hold
the element
2 in place within a soil mass.
FIGS. 2,
2A,
2B and
3 illustrate a preferred embodiment
of the invention wherein a plurality of steel reinforcing bars, rods or rebars
are used to reinforce the front panel
12 and integral stem
14. As
illustrated, the integral stem
14 includes a plurality of pan inserts
33
which are disposed in a plurality of parallel rows and columns. As illustrated,
a plurality of completely encased reinforcing sets of rebars
35 extend parallel
along the integral stem
14 in an upper and lower portion thereof and in
between the horizontal rows of pan inserts
33. The rebars
35 also
extend into the front face panel
12. As illustrated, each of the rebar sets
include two rebars with one of the rebars extending into the face panel
12
in a first direction and a second of the rebars extending in an opposite direction
within the front panel
12. The front panel
12 also includes a plurality
of vertically and horizontally disposed rods
36 and
37 respectively.
As shown, the rebars
36 and
37 also extend into an upper extension
40 of the face panel
12. A plurality of vertically disposed rebar
pairs
38 are disposed in the integral stem
14 with one pair disposed
between each column of pan inserts
33 with one of said pair disposed on
one side of the rebar
35 and a second of the pairs on an opposite side as
shown in FIG. 2A. The arrangement of the horizontal rebars
35 is shown more
clearly in FIG. 2B wherein six rebars are shown two in each set of three in the
horizontally disposed reinforcing rods.
A further embodiment of the invention is illustrated in FIGS. 4,
5,
5A,
5B and
6. As shown therein the element
2 includes a face panel
12 having a forward wall
16, a rear wall
18, side walls
20,
a top wall
21 and a bottom wall
22. The element
2 also includes
an integral stem
14 which extends rearwardly from the rear wall
18
to define a T-shaped construction. As illustrated, the stem
14 has the same
height as the front panel
12 i.e., about 5 feet and as shown as a length
of 12 feet which maybe reduced in successive layers from the bottom of a stacked
array to the top thereof. Such lengths can go to 30 feet.
As illustrated in FIGS. 5,
5A,
5B and
6, the integral stem
14 includes a plurality of pan inserts
33 arranged in two parallel
rows and five parallel columns. In a preferred embodiment of the invention, the
pan inserts
33 have a height of about 1 foot, 5 inches and a width of about
1 foot but may vary from about 1 foot to 1.5 feet in height and from about 0.5
feet to 1.0 feet in width. In addition, there are corresponding and aligned pan
inserts
33 on each side of the integral stem
14 each of which constitutes
a recess of about two inches. In this embodiment of the invention, the integral
stem has a height of about 5 feet which is equal to the height of the face panel
12 and a width of about 7 inches which is slightly less than a thickness
of about 8 inches for the face panel.
A further embodiment of the present invention relates to a shear key as illustrated
in FIGS. 7-11,
17A and
17B. As illustrated, a shear key
37
is constructed and dimensioned to fit within the notches
30 or
32
and adapted to fit within a corresponding notch in an abutting stem
14 when
placed on top of or below another retaining wall element. As illustrated, the shear
key
37 is in the form of a polyhedron having eight sides with two opposite
sides (a cross section) defining a hexagon. The key
37 is preferably about
eight inches between opposite sides i.e., slightly larger than the seven inch width
of the integral stem
14 so that it extends outwardly by about ½ inch
on each side of the integral stem to facilitate handling of the shear key
37.
FIGS. 8,
9 and
10 illustrate a shear key
37 which has a height
of about 7½ inches and a width of about 11 inches from opposite sides of the
hexagonal face and about 9 inches along the top and bottom thereof.
In a further embodiment of the invention, a shear key
38 includes a circular
passage way
39 extending through the key from one hexagonal face side to
the other to lighten the key and further facilitate handling.
In another embodiment of the invention (see for example, FIGS. 17A and 17B) the
shear key
37 includes fully encased steel reinforcing rods
40 and
41. In this embodiment each of the reinforcing rods
40 and
41
are U-shaped with two legs and a connecting member. In this embodiment, the shear
key includes a first portion adjacent to one of the hexagonal sides and a second
portion adjacent to an opposite hexagonal side. A connecting member of a first
U-shaped reinforcing rod
40 is disposed in and fully encased by the first
portion of the shear key
37 with its leg portions extending into the shear
key. Further, the connecting member of the second U-shaped reinforcing rod
41
is disposed in and fully encased by the second portion of the shear key
37
with its legs extending inwardly into the key
37. As illustrated, the connecting
members of the reinforcing rods
40 and
41 are disposed in a crossed-relationship
as illustrated in FIG. 17B.
A still further embodiment of the invention is shown in FIGS. 12A,
12B
and
13 and is generally similar to the elements shown in FIGS. 1-3. For example,
the precast concrete retaining wall construction element in accordance with this
embodiment of the invention includes a face panel
12 having a width of 7½
feet and a height of about 5 to 10 feet. The additional height i.e., above 5 feet,
is used in an uppermost element to resist movement of a top layer of soil in a
railroad installation. The element also includes an integral stem
14, pan
inserts
33 and notches
30 but does not include notches
32
in an upper wall
25 of the integral stem
14. A key feature in this
embodiment of the invention resides in one or two integral reinforcing elements
45. This integral reinforcing element may take the form of a single wall
or pair of walls as shown in FIG. 12B and extends above the integral stem by about
⅔'s of the distance to the top of the front wall
12. The reinforcing
elements
45 may take the form of a pair of support walls
45 as shown
in FIG. 13.
Another embodiment of the invention is illustrated in FIGS. 14,
14A
and
14B. As shown in FIG. 14, a precast concrete retaining wall construction
element is generally similar to the element shown in FIGS. 12A,
12B and
13 and includes a face panel
12, an integral stem
14 and a
pair of integral reinforcing elements
45. However, as shown in FIG. 14,
the element
2 also includes one or two buttresses
47 between the
integral stem
14 and integral reinforcing element
45 to provide further
support for an extending front panel
12. The buttresses
47 and support
members are used to provide further support for a front panel that extends upwardly
from the upper wall of the integral stem
14 by between about 3 to 5 feet
so that the front panel may have a height of between 8 to 10 feet.
In the aforementioned embodiment, as shown in FIG. 14, it may also be desirable
to provide further reinforcement with rebars or other steel reinforcing rods as
shown in FIGS. 14A and 14B. As shown in FIG. 14A, a pair of rebars pass through
and are encased by the panel
12, reinforcing elements
45 and buttresses
47 and extend down into the integral stem
14. In addition, the integral
stem
14 includes a plurality of U-shaped reinforcing rods between columns
of pan inserts as well as a plurality of rebars above, between and below the rows
of pan inserts.
FIGS. 15 and 16 illustrate a modification of the embodiment shown in FIGS.
14,
14A and
14B. In FIGS. 15 and 16, the face panel
12 has
a height of between about 5 feet, 6 inches to about 7 feet, 6 inches and integral
stem
14 of about 2 feet, 6 inch height. The integral stem
14 includes
a single row of pan inserts
33 with a pair of rebars above the pan inserts
and a pair of rebars below the inserts. Reinforcing rods extend from an upper portion
of the face panel through the buttresses and into the integral stem
14.
The configuration of reinforcing rods of the face panel is shown in FIG. 16.
FIG. 18 is a load diagram that shows typical lateral earth pressures from two
railroad tracks adjacent to a retaining wall construction in accordance with the
present invention. The standard heavy rail (Cooper E-80) load applied for the present
invention is 1,882 pounds per square foot of track and is based on AREMA, Section
2.2.3C. The retaining wall construction is designed for the sum of the lateral
earth pressure plus the surcharge loads from the adjacent tracks. The lateral earth
pressure from the train surcharge was calculated as a strip load based on a Boussinesq
distribution as provided in AREMA, Section 20.3.2.2. Other consideration in developing
precast concrete retaining wall construction elements in accordance with the present
invention include manufacturing and raw material costs, shipping costs, safety
of the workers, labor costs, etc.
A typical railroad application is illustrated in FIG. 19. Such applications may
be applicable for grade separation structures, bridge approaches and abutments,
track widening, slope stabilization, railroad yard improvements, platforms, service
and access roads, loading and unloading facilities and wing walls.
FIG. 20 illustrates one form of the invention, which is particularly applicable
for railroad installation. As shown, a precast concrete retaining wall construction
element
2′ includes a face wall
16′ having an upper
extension
20′, a support member or haunch
23′ and a
buttress
47′ which connects the upper extension
20′
and integral stem
14′.
It should also be recognized that at times the upper extension may be added to
any of the standard units which presently include half units having a face panel
with a height of 2½ feet and width of 7½ feet, a ¾ unit wherein
the face panel is 3.75 feet by 7½ feet and a full unit which is 5 feet by
7½ feet and wherein the maximum height of a unit is 10 feet.
While the invention has been described in connection with its preferred embodiments,
changes and modifications may be made therein without departing from the scope
of the appended claims.
*
