PRECAST CONCRETE CULVERT SYSTEM

PONCEAU PREFABRIQUE EN BETON

English Abstract

ABSTRACT

A precast concrete culvert system includes a series of
open bottom culvert sections each having parallel spaced
vertical side walls integrally connected to an arcuate top wall
having a curved inner surface with a radius of curvature at
least twice the rise defined between the top center of the
curved inner surface and the bottom surfaces of the side walls.
The side walls rest on footers and have outer surfaces which
form sharp corners with the top surface of the top wall and have
a vertical height at least sixty percent and preferably between
eighty and ninety percent of the rise. The vertical height is
also less than fifty percent of the radius of curvature which is
between twenty and fifty feet and preferably either about
twenty-five or forty feet. The end sections have vertical head
walls, and the vertical side walls are adapted to connect with
angularly disposed vertical concrete wing walls to provide for a
smooth hydraulic flow into and through the series of the culvert
sections. Culvert sections may also be precast with a taper to
form a curved conduit or be precast with end walls to form an
underground tank or be precast with parallel spaced and
outwardly projecting end ribs.

Claims

- 14 -
THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE ARE CLAIMED ARE DEFINED AS FOLLOWS:
1. A concrete culvert assembly comprising a set of
parallel spaced elongated footers, a plurality of precast
concrete culvert sections supported by said footers in
predetermined alignment, each of said culvert sections having an
open bottom and including parallel spaced vertical side walls
having bottom surfaces supported by said footers, an arcuate
concrete top wall integrally connected to each of said side
walls of each said section, said side walls of each said section
having opposing inner surfaces defining a span substantially
greater than the length of said side and top walls, said arcuate
top wall of each section having a generally uniform thickness
with a curved inner surface having a radius of curvature at
least twice the rise defined between the top center of said
curved inner surface and said bottom surfaces of said side
walls, each of said side walls of each said section having a
generally uniform thickness and a substantially flat vertical
outer surface with a vertical height between fifty-five and
ninety percent of said rise and less than fifty percent of said
radius of curvature, said concrete top wall of each said section
having a curved outer surface forming a relatively sharp corner
with said outer surface of each said side wall, reinforcing
members embedded in said concrete of each said section and
extending generally parallel to said outer surfaces of said top
and side walls, and said inner surface of each said side wall
and said inner surface of said top wall of each said section
being connected by a surface cooperating with said relatively

sharp corner to define a corner thickness substantially greater
than the uniform thickness of said side and top wall.


- 15 -
2. A culvert assembly as defined in claim 1 wherein said
span is within a range from about sixteen and twenty-four feet,
and said radius of curvature is about twenty-five feet.
3. A culvert assembly as defined in claim 1 wherein said
span is within a range of about thirty to thirty-six feet, and
said radius of curvature is about forty feet.
4. A concrete culvert assembly comprising a set of
elongated footers, a plurality of precast tapered concrete
culvert sections mounted on said footers in longitudinal
alignment, each of said culvert sections having an open bottom
and including parallel spaced vertical side walls having bottom
surfaces resting on said footers, an arcuate top wall integrally
connected to each of said side walls of each said section, said
side walls of each said section having opposing inner surfaces
defining a span greater than the length of said side and top
walls, said arcuate top wall of each section having a generally
uniform thickness with a curved inner surface having a radius of
curvature at least twice the rise defined between the top center
of said curved inner surface and said bottom surfaces of said
side walls, one of said side walls of each said culvert section
having a length less than the length of the other said side
walls to provide for curving said culvert assembly, each of said
side walls of each said section having a generally uniform
thickness and a generally flat vertical outer surface with a
vertical height at least fifty-five percent of said rise and
less than fifty percent of said radius of curvature, said
concrete top wall of each said section having a curved outer

surface forming a relatively sharp corner with said outer


- 16 -
surface of each said side wall, reinforcing members embedded in
said concrete of each said section and extending generally
parallel to said outer surfaces of said top and side walls, and
said inner surface of each said side wall and said inner surface
of said top wall of each said section being connected by a
surface cooperating with said relatively sharp corner to define
a corner thickness substantially greater than the thickness of
said side and top walls.

5. A culvert assembly as defined in claim 4 wherein each
of said tapered culvert sections has one end surface normal to
said side walls and the opposite end surface inclined relative
to said side walls.
6. A precast concrete assembly adapted to be used as a
culvert, comprising a plurality of precast concrete culvert
sections mounted on said footers in longitudinal alignment, each
of said culvert sections having an open bottom and including
parallel spaced vertical side walls having bottom surfaces, an
arcuate top wall integrally connected to each of said side walls
of each said section, said side walls of each said section
having opposing inner surfaces defining a span greater than the
length of said side and top walls, said arcuate top wall of each
section having a generally uniform thickness in lateral cross-
section and a curved inner surface with a radius of curvature at
least twice the rise defined between the top center of said
curved inner surface and said bottom surfaces of said side
walls, each of said side walls of each said section having a
generally uniform thickness in lateral cross-section and a

generally flat vertical outer surface with a vertical height at
least fifty-five percent of said rise and less than fifty



- 17 -
percent of said radius of curvature, said concrete top wall of
each said section having a curved outer surface forming a
relatively sharp corner with said outer surface of each said
side wall, said top wall of each section having laterally
extending end portions forming ribs with a thickness greater
than the thickness of an intermediate portion connecting said
end portions to define a recess within said outer surface of
said top wall, reinforcing members embedded in said concrete of
each said section and extending generally parallel to said outer
surfaces of said top and side walls, and said inner surface of
each said side wall and said inner surface of said top wall of
each said section being connected by a surface cooperating with
said relatively sharp corner to define a corner thickness
substantially greater than the thickness of said side and top
walls.
7. An assembly as defined in claim 6 wherein each of said
side walls has vertically extending end portions forming ribs
with a thickness greater than the thickness of an intermediate
portion connecting said end portions to define a recess within
said outer surface of said side wall.
8. An assembly as defined in claim 7 and including
conduits extending within said end portions of said top and side
walls for receiving and confining prestressed tendons.
9. A concrete assembly adapted to be buried within the

ground, comprising a concrete base, a series of precast concrete
sections mounted on said base in longitudinal alignment, each of
said sections having an open bottom and including parallel
spaced vertical side walls having bottom surfaces resting on


- 18 -
said base, an arcuate concrete top wall integrally connected to
each of said side walls of each said section, said side walls of
each said section having opposing inner surfaces defining a span
greater than the length of said side and top walls, said arcuate
top wall of each section having a generally uniform thickness
with a curved inner surface having a radius of curvature at
least twice the rise defined between the top center of said
curved inner surface and said bottom surfaces of said side
walls, each of said side walls of each said section having a
generally uniform thickness and a substantially vertical outer
surface with a vertical height at least fifty-five percent of
said rise and less than fifty percent of said radius of
curvature, said concrete top wall of each said section having a
curved outer surface forming a relatively sharp corner with said
outer surface of each said side wall, reinforcing members
embedded in said concrete of said section, said inner surface of
each said side wall and said inner surface of said top wall of
each said section being connected by a surface cooperating with
said relatively sharp corner to define a corner thickness
substantially greater than the thickness of said side and top
walls, and two of said sections forming end sections and having
integrally cast end walls, whereby said sections cooperate with
said base to define an enclosed chamber adapted to receive a
fluid.
10. An assembly as defined in claim 9 and including a
flexible rubber-like hollow fluid container within said chamber.
11. A concrete culvert assembly comprising a set of
parallel spaced elongated footers, a plurality of precast
concrete culvert sections mounted on said footers in


- 19 -
longitudinal alignment, each of said culvert sections having an
open bottom and including parallel spaced vertical side walls
having bottom surface resting on said footers, an arcuate top
wall integrally connected to each of said side walls of each
said section, said side walls of each said section having
opposing inner surfaces defining a span greater than the length
of said side and top walls, said arcuate top wall of each
section having a generally uniform thickness with a curved inner
surface having a radius of curvature at least twice the rise
defined between the top center of said curved inner surface and
said bottom surfaces of said side walls, each of said side walls
of each said section having a generally uniform thickness and a
generally flat vertical outer surface with a vertical height at
least fifty-five percent of said rise and less than fifty
percent of said radius of curvature, said concrete top wall of
each said section having a curved outer surface forming a
relatively sharp corner with said outer surface of each side
wall, said arcuate top wall of each culvert section including
connector means located at substantially the top center of said
top wall and providing for precasting and transporting each said
culvert section in two half-sections, reinforcing members
embedded in said concrete of each said section and extending
generally parallel to said outer surfaces of said top and side
walls, and said inner surface of each said side wall and said
inner surface of said top wall of each said section being
connected by a surface cooperating with said relatively sharp
corner to define a corner thickness substantially greater than
the uniform thickness of said side and top walls.

12. A culvert assembly as defined in claim 11 wherein said
connector means in said top wall comprise a connector member


- 20 -
having an H-shaped cross-sectional configuration, and filler
means associated with said connector member for receiving
opposing edge surfaces of said top wall.
13. A concrete culvert assembly comprising a set of
elongated footers, a plurality of precast tapered concrete
culvert sections mounted on said footers in longitudinal
alignment, each of said culvert sections having an open bottom
and including parallel spaced vertical side walls having bottom
surfaces resting on said footers, a top wall integrally
connected to each of said side walls of each said section, said
side walls of each said section having opposing inner surfaces
defining a span greater than the length of said side and top
walls, one of said side walls of each said culvert section
having a length less than the length of the other said side wall
to provide for curving said culvert assembly, each of said side
walls of each said section having a generally uniform thickness
and a generally flat vertical outer surface, said concrete top
wall of each said section having an outer surface forming a
relatively sharp corner with said outer surface of each said
side wall, reinforcing members embedded in said concrete of each
said section and extending generally parallel to said outer
surfaces of said top and side walls, and said inner surface of
each said side wall and an inner surface of said top wall of
each said section being connected by a surface cooperating with
said relatively sharp corner to define a corner thickness
substantially greater than the thickness of said side walls.

14. A culvert assembly as defined in claim 13 wherein each

of said tapered culvert sections has one end surface normal to


- 21 -
said side walls and the opposite end surface inclined relative
to said side walls.
15. A concrete assembly for installation within the
ground, comprising a concrete base, a series of precast concrete
sections mounted on said base in longitudinal alignment, each of
said sections having an open bottom and including parallel
spaced vertical side walls having bottom surfaces resting on
said base, a concrete top wall integrally connected to each of
said side walls of each said section, said side walls of each
said section having opposing inner surfaces defining a span
greater than the length of said side and top walls, each of said
side walls of each said section having a generally uniform
thickness and a substantially vertical outer surface, said
concrete top wall of each said section having an outer surface
forming a relatively sharp corner with said outer surface of
each said side wall, reinforcing members embedded in said
concrete of said section, said inner surface of each said side
wall and an inner surface of said top wall of each said section
being connected by a surface cooperating with said relatively
sharp corner to define a corner thickness substantially greater
than the thickness of said side and top walls, a set of end
walls on two of said sections to form end sections, all of said
sections cooperating with said base to define an enclosed
chamber, and means forming at least one fluid receiving tank
within said chamber.

16. An assembly as defined in claim 15 wherein said tank
comprises a rigid cylindrical tank, and means supporting said

tank within said chamber in spaced relation to said base and
said side walls of each said section.


- 22 -
17. An assembly as defined in claim 15 and including two
of said cylindrical tanks disposed within said chamber with
generally parallel axes.
18. An assembly as defined in claim 15 wherein one of said
section includes means defining a manhole within said top wall
of said section to provide for convenient inspection of said
tank.

19. A concrete culvert assembly comprising a set of
parallel spaced elongated footers, a plurality of precast
concrete culvert sections mounted on said footers in
longitudinal alignment, each of said culvert sections having an
open bottom and including parallel spaced vertical side walls
having bottom surfaces resting on said footers, an arcuate top
wall integrally connected to each of said side walls of each
said section, said side walls of each said section having
opposing inner surfaces defining a span greater than the length
of said side and top walls, said arcuate top wall of each
section having a generally uniform thickness with a curved inner
surface having a radius of curvature at least twice the rise
defined between the top center of said curved inner surface and
said bottom surfaces of said side walls, said radius of
curvature being at least twenty feet and said rise being at
least five feet, each of said side walls of each said section
having a generally uniform thickness and a generally flat
vertical outer surface with a vertical height at least sixty
percent of said rise and less than fifty percent of said radius
of curvature, said concrete top wall of each said section having

a curved outer surface forming a relatively sharp corner with


- 23 -
said outer surface of each said side wall, reinforcing members
embedded in said concrete of each said section and extending
generally parallel to said outer surfaces of said top and side
walls, and said inner surface of each said side wall and said
inner surface of said top wall of each said section being
connected by a surface cooperating with said relatively sharp
corner to define a corner thickness substantially greater than
the uniform thickness of said side and top walls.

20. A culvert assembly as defined in claim 19 wherein said
radius of curvature of said inner surface of said arcuate top
wall of each said section is about twenty-five feet and said
outer surface of said top wall of each said section forms an
angle between 105 degrees and 120 degrees with said outer
surface of each said side wall to define said relatively sharp
corner.
21. A culvert assembly as defined in claim 19 wherein said
radius of curvature of said inner surface of said arcuate top
wall is about forty feet.
22. A culvert assembly as defined in claim 19 and
including two rows of said culvert sections arranged in parallel
spaced relation, means forming longitudinally extending recesses
defining seats on the upper portions of the opposing said side
walls of said culvert sections in said rows, and separate
arcuate concrete panels each having opposite longitudinal edge

portions supported by said seats.
23. A culvert assembly as defined in claim 22 wherein each
of said concrete panels has a curved inner surface with a radius


- 24 -
of curvature generally equal to said radius of curvature of said
inner surface of said top wall of each said culvert section.
24. A culvert assembly as defined in claim 19 wherein said
surface connecting said inner surfaces of said top wall and each
side wall of each said section has a radius of curvature of
several feet.
25. A concrete culvert assembly comprising a set of
parallel spaced elongated footers, a plurality of precast
concrete culvert sections mounted on said footers in
longitudinal alignment, each of said culvert sections having an
open bottom and including parallel spaced vertical side walls
having bottom surfaces resting on said footers, an arcuate top
wall integrally connected to each of said side walls of each
said section, said side walls of each said section having
opposing inner surfaces defining a span greater than the length
of said side and top walls, said arcuate top wall of each
section having a generally uniform thickness with a curved inner
surface having a radius of curvature at least twice the rise
defined between the top center of said curved inner surface and
said bottom surfaces of said side walls, said radius of
curvature being at least twenty feet and said rise being at
least five feet, each of said side walls of each said section
having a generally uniform thickness and a generally flat
vertical outer surface with a vertical height at least sixty
percent of said rise and less than fifty percent of said radius
of curvature, said concrete top wall of each said section having
a curved outer surface forming a relatively sharp corner with

said outer surface of each said side wall, reinforcing members
embedded in said concrete of each said section and extending


- 25 -
generally parallel to said outer surface of said top and side
walls, said inner surface of each said side wall and said inner
surface of said top wall of each said section being connected by
a surface cooperating with said relatively sharp corner to
define a corner thickness substantially greater than the
thickness of said side and top walls, a pair of substantially
vertical wing walls extending outwardly at an angle from the end
said culvert section, and said wing walls having vertical inner
surfaces extending from said vertical inner surfaces of said
side walls of said end culvert section.

26. A concrete culvert assembly comprising a set of
parallel spaced elongated footers, a plurality of precast
concrete culvert sections mounted on said footers in
longitudinal alignment, each of said culvert sections having an
open bottom and including parallel spaced vertical side walls
having bottom surfaces resting on said footers, an arcuate top
wall integrally connected to each of said side walls of each
said section, said side walls of each said section having
opposing inner surfaces defining a span greater than the length
of said side and top walls, said arcuate top wall of each
section having a generally uniform thickness with a curved inner
surface having a radius of curvature at least twice the rise
defined between the top center of said curved inner surface and
said bottom surfaces of said side walls, said radius of
curvature being at least twenty feet and said rise being at
least five feet, each of said side walls of each said section
having a generally uniform thickness and a generally flat
vertical outer surface with a vertical height at least sixty
percent of said rise and less than fifty percent of said radius
of curvature, said concrete top wall of each said section having


- 26 -
a curved outer surface forming a relatively sharp corner with
said outer surface of each said side wall, reinforcing members
embedded in said concrete of each said section and extending
generally parallel to said outer surfaces of said top and side
walls, said inner surface of each said side wall and said inner
surface of said top wall of each said section being connected by
a surface cooperating with said relatively sharp corner to
define a corner thickness substantially greater than the
thickness of said side and top walls, and an end said culvert
section includes a vertical head wall projecting upwardly from
the end of said top wall.


- 27 -
CLAIMS OF THE SUPPLEMENTARY DISCLOSURE OF THE INVENTION
27. A concrete culvert assembly for installation within
the ground, comprising a set of elongated footers, a plurality
of precast concrete culvert sections supported by said footers
in predetermined alignment, each of said culvert sections having
an open bottom and including parallel spaced vertical side walls
having bottom surfaces supported by said footers, a concrete top
wall integrally connected to each of said side walls of each
said section, said side walls of each said section having
opposing inner surfaces defining a span substantially greater
than the length of said side and top walls, each of said side
walls of each said section having a generally uniform thickness
and a substantially flat vertical outer surface, said concrete
top wall of each said section having an outer surface forming a
relatively sharp corner with said outer surface of each said
side wall, reinforcing members embedded in said concrete of each
said section and extending generally parallel to said outer
surfaces of said top and side walls, each said side wall and
said top wall of each said section having inner surfaces
connected by a surface cooperating with said relatively sharp
corner to define a corner thickness substantially greater than
the uniform thickness of said side wall, a precast concrete wing
wall projecting outwardly from each said side wall of the end
said culvert section and supported by an extension of the
corresponding said footer, and each said precast wing wall
including a rigidly connected precast wall anchor projecting
laterally from said wing wall into the ground.

28. A culvert assembly as defined in claim 27 wherein each
said wall anchor includes an inclined outer flange wall



- 28 -
connected to the corresponding said wing wall by a web wall
disposed generally perpendicular to said wing wall.
29. A culvert assembly as defined in claim 28 wherein said
web wall includes embedded reinforcing elements projecting into
said wing wall.
30. A culvert assembly as defined in claim 28 wherein said
flange wall of each said anchor has a lower end portion
projecting downwardly below the corresponding said web wall and
the top of the corresponding said footer, and a body of concrete
between said lower end portion and the adjacent said footer for
securing said wall anchor relative to said footer.
31. A concrete culvert assembly for installation within
the ground, comprising a set of elongated footers, a plurality
of precast concrete culvert sections supported by said footers
in predetermined alignment, each of said culvert sections having
an open bottom and including parallel spaced vertical side walls
having bottom surfaces supported by said footers, an arcuate
concrete top wall integrally connected to each of said side
walls of each said section, said side walls of each said section
having opposing inner surfaces defining a span substantially
greater than the length of said side and top walls, said
concrete top wall of each section having a generally uniform
thickness with a curved inner surface having a radius of
curvature at least twice the rise defined between the top center
of said curved inner surface and said bottom surface of said
side walls, each of said side walls of each said section having
a generally uniform thickness and a substantially flat vertical
outer surface, said concrete top wall of each said section


- 29 -
having an outer surface forming a relatively sharp corner with
said outer surface of each said side wall, reinforcing members
embedded in said concrete of each said section and extending
generally parallel to said outer surfaces of said top and side
walls, said inner surface of each said side wall and said inner
surface of said top wall of each said section being connected by
a surface cooperating with said relatively sharp corner to
define a corner thickness substantially greater than the uniform
thickness of said side and top wall, a precast concrete wing
wall projecting outwardly from each said side wall of the end
said culvert section, and each said wing wall including a
rigidly connected precast wall anchor projecting laterally from
said wing wall into the ground.
32. A culvert assembly as defined in claim 31 wherein each
said wall anchor includes an inclined outer flange wall
connected to the corresponding said wing wall by a web wall
disposed generally perpendicular to said wing wall.

33. A culvert assembly as defined in claim 32 wherein said
web wall includes embedded reinforcing elements projecting into
said wing wall.
34. A culvert assembly as defined in claim 32 wherein said
flange wall of each anchor has a lower end portion projecting
downwardly below the corresponding said web wall and the top of
the corresponding said footer, and a body of concrete between

said lower end portion and the adjacent said footer for securing
said wall anchor relative to said footer.


- 30 -
35. A concrete culvert assembly for installation within
the ground, comprising a set of elongated footers, a plurality
of precast concrete culvert sections supported by said footers
in predetermined alignment, each of said culvert sections having
an open bottom and including parallel spaced vertical side walls
having bottom surfaces supported by said footers, a concrete top
wall integrally connected to each of said side walls of each
said section, a precast concrete wing wall projecting outwardly
from each said side wall of the end said culvert section and
supported by an extension of the corresponding said footer, and
each said precast wing wall including a rigidly connected
precast wall anchor projecting laterally from said wing wall
into the ground.
36. A culvert assembly as defined in claim 35 wherein each
said wall anchor includes an inclined outer flange wall
connected to the corresponding said wing wall by a web wall
disposed generally perpendicular to said wing wall.
37. A culvert assembly as defined in claim 36 wherein said
web wall includes embedded reinforcing elements projecting into
said wing wall.
38. A culvert assembly as defined in claim 36 wherein said
flange wall of each said anchor has a lower end portion
projecting downwardly below the corresponding said web wall and
the top of the corresponding said footer, and a body of concrete

between said lower end portion and the adjacent said footer for
securing said wall anchor relative to said footer.


- 31 -
39. The culvert assembly of claims 35, 36 or 37 wherein
reinforcing members are embedded in the concrete.
40. A concrete culvert assembly for installation within
the ground, comprising a set of elongated footers, a plurality
of precast concrete culvert sections supported by said footers
in predetermined alignment, each of said culvert sections having
an open bottom and including parallel spaced vertical side walls
having bottom surfaces supported by said footers, an arcuate
concrete top wall integrally connected to each of said side
walls of each said section, reinforcing members embedded in said
concrete of each said section and extending generally parallel
to said outer surfaces of said top and side walls, a precast
concrete wing wall projecting outwardly from each said side wall
of the end said culvert section, and each said wing wall
including a rigidly connected precast wall anchor projecting
laterally from said wing wall into the ground.
41. A culvert assembly as defined in claim 40 wherein each
said wall anchor includes an inclined outer flange wall
connected to the corresponding said wing wall by a web wall
disposed generally perpendicular to said wing wall.
42. A culvert assembly as defined in claim 41 wherein said
web wall includes embedded reinforcing elements projecting into
said wing wall.
43. A culvert assembly as defined in claim 41 wherein said
flange wall of each said anchor has a lower end portion
projecting downwardly below the corresponding said web wall and
the top of the corresponding said footer, and a body of concrete


- 32 -
between said lower end portion and the adjacent said footer for
securing said wall anchor relative to said footer.

Description

13319~
BACKGROUND OF THE INVENTION
This invention relates to the production of precast
concrete culvert sections which are usually installed in end-to-
end alignment in the ground for directing a stream under a
roadway and in place of using a bridge for spanning the stream.
In the construction of such precast concrete culvert sections,
it is desirable for the sections to have a configuration which
effectively and efficiently utilizes the lateral forces acting
on the side walls of the culvert section by the surrounding
earth or soil to provide the culvert section with high strength
for supporting substantial vertical loads on the top wall of the
section. It is also desirable for the culvert section to have a
minimum wall thickness, provide for a smooth flow of water into
and through the culvert section and permit the maximum flow of
water with a minimum overall height or rise of the culvert
section. In addition, it is desirable for the culvert section
to be constructed so that culvert sections with different spans
and different heights or rises may be economically produced in
order to accommodate water streams of various sizes.
Different forms of concrete culvert sections have been
either proposed or made, for example, as disclosed in U.S.
Patent No. 1,412,616 and as produced by Zurn Industries, Inc. of
Erie, Pennsylvania and marketed under the trademark "BEBO".
However, the culvert sections which have been previously
proposed or constructed fail to provide all of the above
desirable features, as apparent after studying and analyzing the
culvert sections.
SUM~ARY OF TH~_INVENTION.
The present invention is directed to an improved ~
precast concrete culvert system which provides all of the
~`,`';' ""


- 2 - ~ 33 ~ ~2 1

desirable features mentioned above, including an efficient
structure which effectively utilizes the forces exerted by the
surrounding soil to provide high strength for supporting
substantial vertical loads. The culvert system of the invention
may also be efficiently produced in different spans and rises
with a simple and ec~nomically constructed forming system and
provides for attaching vertical concrete wing walls to produce a
hydraulically smooth flow through the culvert sections~ The
above mentioned features and advantages of the invention and
other features and advantages will be apparent from the
following description, the accompanying d.rawing and the appended
claims.

BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a perspective view of an underground
lS installation of a concrete culvert system including several
culvert sections constructed in accordance with the invention to
provide for a flowing stream under a roadway, and with a center
portion broken away;
Figure 2 is a vertical cross-section through one of
the culvert sections shown in Figure 1;
Figure 3 is a perspective view of a culvert section
shown in Figures 1 and 2;
Figure 4 is an elevational end view of a series of
culvert sections assembled and connected in accordance with the
invention to provide an underground water retention tank.
Figure 5 is a perspective view of a ribbed culvert
section constructed in accordance with a modification of the
invention;
Figure 6 is a section taken generally on the line 6-6
of Figure 5;

~' ~

~ 3 - 1 3 3 1 9 ~
Figure 7 is a plan view of a series of tapered culvert
sections constructed in accordance with the invention to form a
curved conduit;
Figure 8 is a perspective view of an underground tank
formed with culvert sections constructed in accordance with the
invention;
Figure 9 is a section of the tank taken generally on
the line 9-9 of Figure 8;
Figure 10 is a fragmentary section of the culvert
section shown in Figure 3 and mounted on pedestal walls
projecting upwardly from footers connected by a base slab; and
Figuré 11 is a fragmentary section of a split culvert
section formed in two half sections, also constructed in
accordance with the invention.
DETAILED PESCRIP~ION OF THE PREFERRE~ E~BODIMENTS OF THE
INVENTION
Figure 1 illustrates a precast concrete culvert system
including a series of precast concrete culvert sections 10 which
are placed in alignment or end-to-end on parallel spaced
continuous concrete footers 12 formed within trenches in the
ground. The footers 12 may be connected by a poured concrete
slab, and the assembled culverts 10 are covered by compacted
soil G after the culvert sections are placed on the footers 12.
The compacted soil supports a roadbed for a roadway or pavement
P which extends across the assembled culvert sections. The
opposite precast end sections of the assembled culvert sections
10 connect with integral corresponding vertical head walls 14
and vertical wing walls 16 which may be precast and extend
outwardly at an angle to define an entrance and exit for water
flowing in the channel C formed within the soil. Preferably,
~.


133~21

adjacent culvert sections 10 are secured together by welding or
bolting abuttlng metal plates 18 having portions embedded with
the concrete.
Referring to Figures 2 and 3, each of the culvert
sections 10 includes parallel spaced vertical side walls 22
which are integrally connected to an arcuate top wall 24. The
inner surface of the top wall 24 has a radius of curvature R1
which is between twenty feet and fifty feet and preferably about
twenty-five feet or forty feet depending on the span S defined
between the parallel inner surfaces of the side walls. The
thickness T of the side walls and the top wall is within a range
of eight inches to fourteen inches, and a thickness T of ten
inches has been found suitable for spans S between fourteen feet
and thirty-six feet.
15 The outer surfaces of the side walls 22 have a height
H which is at least fifty-five to sixty percent of the rise R
defined between the bottom surfaces of the side walls and the
top inner surface of the top wall 24. The vertical height H of
the slde walls 22 is also less tha,n fifty percent of the radius
of curvature R1 which is at least twice the rise R. In the
optimum construction of each culvert section 10 having a radius
of curvature R1 of about twenty-five feet, the height H of the
side walls 22 is between seventy and ninety percent of the rise
R. In culvert sections having a radius of curvature R1 of about
forty feet, the height H of the side walls is preferably between
fifty-five and eighty percent of the rise R. The outer surface
of each side wall 22 joins with the top surface of the top wall
24 to form a relatively sharp corner with an angle A of between
105 degrees and 120 degrees and preferably about 112 degrees.
The length L of each culvert section 10 may range between four
A : -~

. . ,~ , . . , . : . . . . . . , . . . . , , . , . . , .. , . , , . . , , , , . . ~ . , .

r 1331921

feet and ten feet, depending upon the span S, and is preferably
about eight feet for most spans. The inner surfaces of the side
walls 22 and the top wall 24 are joined together by a curved
surface having a radius R2 of about three feet for spans S
generally between sixteen and twenty-four feet and a radius of
about four feet for greater spans such as thirty and thirty-six
feet. This provides the corner portions with a substantially
greater thickness. In the longer spans, it is also sometimes
desirable to connect or blend the curved surface having a four
1~ feet radius with the inner surface of the top wall 24 by means
of a curved surface having a ten foot radius.
As shown in Figure 2, a grid 26 of crossing steel
reinforcing rods or members are embedded within the vertical
side walls 22 relatively close to the outer surfaces of the side
walls, and an arcuate grid 28 of crossing steel reinforcing rods
or members is embedded within the top wall 24 relatively close
to the upper surface of the top wall. A similar arcuate grid 29
of crossing reinforcing rods or members is also embedded within
the top wall 24 relatively close to the inner surface of the top
wall. The rein~orcing rods forming the grids 26, 28 and 29
substantially increase the load carrying strength of the culvert
sections 10 as may be required to handle heavy loads or traffic
on the crossing pavement P. In place of the reinforcing bars
forming the grids 26, 28 and 29, embedded prestressed tendons,
which may be pretensioned or post-tensioned, may be used, or
crimped steel fibers or ribbons may be dispersed throughout the
concrete when it is being mixed. It has been determined that
such reinforcing fibers or ribbons are sufficient reinforcement
for many uses of the precast culvert sections.

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~ 13~1921

Referring to Figure 4, a series of precast culvert
sections 10' are arranged in paraliel spaced relation on
corresponding continuous concrete footers 12', and each of the
culvert sections 10' is provided with a longitudinally extending
recess 32 within the upper portion of one side wall 22'. The
recesses 32 support precast arcuate concrete panels 35 which
have a radius of curvature substantially the same as the radius
of curvature R1 of the top walls 24' of the culvert sections
10'. The assembly of the culvert section 10' and arcuate panels
35 illustrated in Figure 4 is ideally suited for forming an
underground water retention or storage tank. For example, the
tank may be used to retain temporarily water collecting from the
storm sewers for a large parking lot or other large area which
collects a substantial volume of water in a rain storm. The
bottom of the tank may be paved with concrete or asphalt.
It has been found that the construction and assembly
of culvert sections as described above in accordance with the
invention, provides desirable advantages. Specifically, the
above described values and relationships between the radius R1,
the wall height H and the rise R provide the optimum
configuration for utilizing the lateral or horizontal forces
acting against the side walls 22 to support the earth or ground
G and other loads on the top wall 24. The vertical side walls
22 also provide for connecting the vertical wing walls 16 in a
manner which produces a smooth flow of water into and from the
culvert formed by the sections 10. The forces of the earth
acting horizontally against the upper corners of the side walls
22 are also effective in helping to counteract the outward
forces on the side walls 22 by the downward forces or loads on
the arcuate top wall 24.

3~921

In concrete culvert sections 10 may be efficiently
precast on end or in a normal position and in metal forms which
provide for conveniently changing the span S and the height H of
the side walls 22. That is, the height of the side walls 22 may
be varied by repositioning bulkheads within the forms of the
side walls, and the span may be conveniently varied by adding or
removing curved form sections for the top wall 24 and having the
radius R1. Thus the radius R1 remains constant or the same for
culvert sections with different spans S, and the corner portions
where the side walls 22 join with the top wall 24 also remain
substantially constant with culvert sections of different spans
S .
It is also within the scope of the invention to
precast each culvert section with the outer surfaces of the side
walls 22 and the top wall 24 with a cavity or recess which
reduces the wall thickness within the center portions of the
walls and thereby reduces the volume and weight of concrete
required to make each section. As shown in Figures 5 and 6, a
culvert section 10' has walls 22' and 24' with thicker edge or
end portions 42 which are connected by a thinner intermediate
portion 43 and are provided with additional reinforcing steel
44. For example, the end portions 42 may have a thickness of 12
inches and the intermediate portion 43 a thickness of 5 inches.
The end portions 42 may also be provided with tubes or conduits
46 for receiving post-tensioning members or cables.
The culvert sections may also be conveniently made in
a tapered configuration with one side wall being narrower than
the other side wall so that a series of the tapered culvert
sections may be arranged on curved footers to form a curved
conduit. As shown in Figure 7, a series of tapered culvert

- 8 - 1 3 ~1 9 2



sections 52 and 54 are arranged to provide a radius R2 of
centerline curvature. Preferably, the outer side wall of each
section 52 and 54 has a width W1 which is no greater than 8
feet, and the width W2 of the inner side wall is selected
according to the desired radius R2, but is preferably not less
than 2 feet. The tapered sections 52 and 54 are produced simply
by filling or blocking in the lower portion of the forms which
produce the culvert sections on end. Thus each of the tapered
culvert sections 52 and 54 has one end surface which is normal
to the side walls and an opposite end surface which is inclined
or tapered with respect to the side walls. The tapered sections
52 and 54 are arranged on the footers with the normal end
surfaces of two adjacent sections 52 and 54 abutting each other
and with the tapered end surfaces of two adjacent sections 52
and 54 abutting each other.
As mentioned above, the precast concrete culvert
sections of -the invention may also be used to form an
underground tank 60. In the arrangement shown in Figures 8 and
9, the opposite end sections 62 and 64 are pre-cast with the
same cross-sectional configuration as the culvert sections 10
but with integral vertical end walls 66 and with an access
manhole 68 in the top wall of the section 64 near the end wall
66. The sections 10, 62 and 64 are placed on a poured concrete
base slab 72 which may be of any length. The assembled sections
on the base slab may be provided with an inner coating or liner
and/or enclose a rubber-like bladder 74 or "pillow" tank if it
is desired to provide a secondary confinement for a specific
hazardous material or fluid.
As shown in Figure 10, it is also within the scope of

the invention to install the culvert sections 10 or 10' on

,. . 1 3 3 ~

reinforced concrete pedestal walls 78 which are cast on footers
82 and project upwardly by several feet to provide for a larger
passage under the sections. The footers 82 may be integrally
connected by a reinforced base slab 83 having a predetermined
slope towards a lower surface within the center portion of the
slab.
Referring to Figure 11, it is also within the scope of
the invention to precast each culvert section 10 or 10' in two
half sections or portions 10" which are coupled or joined
together at the top center by means of a longitudinally
...., " "~, ... ..
extending "H" beam 86 or a set of longitudinally space shore H-
shaped brackets. Strips 88 of rubber or resilient bearing pads
are placed within the channels defined by the beam 86 to
compensate for roughness or irregularities in the abutting edge
surfaces of the half culvert sections 10".
While the precast concrete culvert systems herein
described constitute preferred embodiments of the invention, it
is to be understood that the invention is not limited to these
precise culvert systems, and that changes may be made therein
without departing from the scope and spirit of the invention as
defined in the appended claims.

:: ,
~, "
: ,




~9 ,.

1331921
,

BRIEF PESCRIPTION OF THE DRAWINGS QF THE SUPPLEMENTARY
DISCLQSURE
Figure 12 is a perspective view of an end culvert
section supported by footers which also support precast wing
walls having integral anchor walls;
Figure 13 is a fragmentary section taken generally on
the line 13-13 of Figure 12;
Figure 14 is a fragmentary plan view of the culvert : :
section and wing walls shown in Figure 12;
Figure 15 is a vertical section taken generally on the
line 15-15 of Figure 12; and
Figure 16 is a section similar to Figure 9 and showing
another form of underground tank system. ~ :
DETAILED DESCRIPTION OF THE SUPPLEMENTARY DIS~LOSURE QF THE
. ,
15 INVENTION :~
Referring to Figure 12, the precast end culvert ~ :
section 10 includes an integrally cast head wall 14 and is
supported by poured concrete footers 12 in the same manner as
dlsclosed above in connection with Figures 1-3. Figure 12 also
shows a pair of precast wing walls 95 which are also supported
by the footers 12 and are connected to the footers by a layer of
grout 97 (Figure 15). Each of the wing walls 95 includes
parallel spaced mats of steel reinforcing bars 99 and is rigidly
connected to the adjacent side wall 22 of the end culvert
section 10 by a pair of vertically spaced angular tie plates
102. As shown in Figure 13, each of the tie plates 102 has ~ ; .
opposite end portions connected by bolts 104 to corresponding
anchor blocks 106 embedded within the side walls 22 of the .~
culvert section 10 and within the wing walls 95. ~::

''','' ~',;~,',''''.
''


~33192~

Each of the precast wing walls 95 includes an
integrally connected precast wall anchor 110 having a generally
T-shape configuration in horizontal cross-section. Each wall
anchor 110 includes a vertical web or center wall 112 which
connects the wing wall 95 to an inclined head wail or flange
portion 114. A mat 116 of reinforcing steel is embedded within
each flange portion 114 and is connected to vertically spaced
steel reinforcing rods 118 which are embedded within the center
wall 112 and have angular end portions 121 embedded within the
corresponding wing wall 95. Preferably, the wall anchors 110
are precast with the projecting end portions 121 of the
reinforcing rods 118. The wall anchors 110 are then positioned
above the forms for precasting the wing walls 95 so that the end
portions 121 of the rods depend downwardly into the forms
defining the wing walls. Each wing wall 95 is then precast so
that the end portions 121 are embedded within the concrete
forming the wing wall, thereby forming a rigid and positive
connection between each wall anchor 110 and its corresponding
wing wall 9S.
As shown in Figure 15, preferably the excavation grade
126 for each wing wall is formed at an incline less than the
incline of the outer head or flange portion 114 of the wall
anchor 110 and extends downwardly below the top of the footer
12. This permits the assembly of each wing wall 95 and the
integrally connected wall anchor 110 to be easily set in place
on the supporting footer 12, as shown in Figure 15. The lower
portion of the flange wall 116 of each wall anchor 110 projects
downwardly below the connecting wall 112 and below the top
surface of the footer 12. Concrete 128 is then poured onto each
footer 12 so that the concrete fills the angular space between

~a
3 ~ g2 1
the wall anchor 110 and the footer 12. After the concrete 128
sets, the back fill or earth G is filled into the space behind
each wing wall 95 so that the earth fills the space on opposite
sides of the center wall 112 and between the flange portions 114
and the wing wall 95. The earth also fills the space between
the grade 126 and the inclined outer surface of each wall anchor
110. The precast wing walls 95, including the integrally

, , ,:, ~,
connected wall anchors 110, provide for significantly reducing
the time required to form the wing walls and thereby
significantly reduce the installation cost for a culvert system
in accordance with the invention. The wall anchors 110 and
concrete 12~ retain each wing wall in its installed position.
Referring to Figure 16, a series of culvert sections
10, 62 ~nd 64 as described above in connection with Figure 8,
may also be used for enclosing one or more tanks 135 for
containing a liquid. Each of the cylindrical tanks 135 is
preferably formed of metal and is supported by a pair of axially
spaced saddles 137. The saddles rest on a poured concrete floor
138 having an inner center portion defining a cavity or well 139
as also shown in Figure 9. As described above, the end culvert
section 64 is provided w.lth a manhole 68 which provides access
for a person to inspect the tanks 135 periodically, especially

. .:: .:.
when the tanks are used for storing a toxic liquid. In the
event a tank 135 develops a leak, the liquid would be confined
within the well or cavity 139. The culvert sections are also
sealed to each other and to the floor 138 to provide a secondary
enclosure for confining any liquid which might leak from a tank
135. Since the tanks 135 are exposed within the culvert system,

any leak may be easily detected and repaired. The underground
tank and enclosure system shown in Figure 16 also provides for
;


3 :
13~g2~ ~

rapid and economical installation of underground tanks. This
is, after the floor 138 is poured and the tanks 135 are located
on the floor, the culvert sections are installed on the floor
138 over the tanks and then covered by the earth. As mentioned
above in connection with Figure 8, the manhole 68 provides
access from the ground surface to the space within the sections.
While the precast concrete culvert systems herein
described constitute preferred embodiments of the invention, it
is to be understood that the invention is not limited to these
precise culvert systems, and that changes may be made therein
without departing from the scope and spirit of the invention as
defined in the appended claims.

Representative Drawing