U.S. patent application number 13/946500 was filed with the patent office on 2013-11-14 for concrete bridge system and related methods.
The applicant listed for this patent is Scott D. Aston, Michael G. Carfagno, Philip A. Creamer. Invention is credited to Scott D. Aston, Michael G. Carfagno, Philip A. Creamer.
Application Number | 20130302093 13/946500 |
Document ID | / |
Family ID | 48903020 |
Filed Date | 2013-11-14 |
United States Patent
Application |
20130302093 |
Kind Code |
A1 |
Aston; Scott D. ; et
al. |
November 14, 2013 |
CONCRETE BRIDGE SYSTEM AND RELATED METHODS
Abstract
A concrete culvert assembly includes a set of spaced apart
elongated footers, a plurality of precast concrete culvert sections
supported by the footers. Each concrete culvert section has an open
bottom, an arch-shaped top wall and spaced apart side walls to
define a passage thereunder, each of the side walls extending
downward and outward from the top wall. Each of the side walls has
a substantially planar inner surface and a substantially planar
outer surface. First and second haunch sections each join one of
the side walls to the top wall. Each side wall is tapered from top
to bottom such that a thickness of each side wall decreases when
moving from the top of each side wall to the bottom of each side
wall. A bottom portion of each side wall has an exterior vertical
flat extending upward from a horizontal bottom surface thereof.
Inventors: |
Aston; Scott D.; (Liberty
Township, OH) ; Carfagno; Michael G.; (Dayton,
OH) ; Creamer; Philip A.; (Springboro, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Aston; Scott D.
Carfagno; Michael G.
Creamer; Philip A. |
Liberty Township
Dayton
Springboro |
OH
OH
OH |
US
US
US |
|
|
Family ID: |
48903020 |
Appl. No.: |
13/946500 |
Filed: |
July 19, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13756910 |
Feb 1, 2013 |
8523486 |
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13946500 |
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61714323 |
Oct 16, 2012 |
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61598672 |
Feb 14, 2012 |
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61595404 |
Feb 6, 2012 |
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Current U.S.
Class: |
405/126 ;
264/299 |
Current CPC
Class: |
B28B 7/02 20130101; E01F
5/005 20130101; B28B 1/14 20130101 |
Class at
Publication: |
405/126 ;
264/299 |
International
Class: |
E01F 5/00 20060101
E01F005/00 |
Claims
1-14. (canceled)
15. A method of manufacturing a concrete culvert section having an
open bottom, a top wall and spaced apart side walls to define a
passage thereunder, each of said side walls having a substantially
planar inner surface and a substantially planar outer surface, the
top wall having an arch-shaped inner surface and an arch-shaped
outer surface and a substantially uniform thickness, each side wall
having varying thickness that decreases when moving from the top of
each side wall to the bottom of each side wall, first and second
haunch sections, each haunch section joining one of the side walls
to the top wall, each haunch section defining a corner thickness
greater than the thickness of the top wall, the method comprising:
providing a form system in which, for each side wall, an interior
form structure portion defines the position of the inner surface of
the side wall and an exterior form structure portion defines the
position and orientation of the outer surface of the side wall, the
exterior form structure portion arranged to pivot or to move along
a surface of a top wall form structure portion; based upon an
established bottom span or rise for the culvert section, pivoting
the exterior form structure portion or moving the exterior form
structure portion to a position that sets a relative angle between
interior form structure portion and the exterior form structure
portion; and filling the form structure with concrete to produce
the culvert section.
16. The method of claim 15 wherein the exterior form structure
portion for each side wall includes a downward facing side arranged
to slide over a corresponding side wall form seat structure.
17. The method of claim 15 wherein a bottom form structure is
positioned between the interior form structure and the exterior
form structure to define the intended width for the bottom surface
of the resulting side wall.
18-24. (canceled)
25. A concrete culvert assembly for installation in the ground,
comprising a set of spaced apart elongated footers, a plurality of
precast concrete culvert sections supported by said footers in side
by side alignment, each of said concrete culvert sections having:
an open bottom, an arch-shaped top wall and spaced apart side walls
to define a passage thereunder, each of said side walls extending
downward and outward from the top wall, each of said side walls
having a substantially planar inner surface and a substantially
planar outer surface, first and second haunch sections, each haunch
section joining one of the side walls to the top wall, each haunch
section defining a corner thickness greater than a thickness of the
top wall, each side wall being tapered from top to bottom such that
a thickness of each side wall decreases when moving from the top of
each side wall to the bottom of each side wall, a bottom portion of
each side wall having an exterior vertical flat extending upward
from a horizontal bottom surface thereof, wherein the exterior
vertical flat is between about 3 inches and 7 inches high.
26. The concrete culvert assembly of claim 25 wherein each concrete
culvert section is formed in two halves, each half formed by one
side wall and a portion of the top wall, the two top portions
secured together along a joint at a central portion of the top wall
of the culvert section.
27. The concrete culvert assembly of claim 25 wherein each culvert
section is seated atop a foundation system and the exterior
vertical flat of each culvert section abuts lateral supporting
structure of the foundation system.
28. The concrete culvert assembly of claim 27 wherein the
foundation system includes precast concrete units and cast-in-place
concrete, the lateral supporting structure is cast-in-place
concrete.
Description
CROSS-REFERENCES
[0001] This application claims the benefit of U.S. Provisional
Application Ser. Nos. 61/595,404, filed Feb. 6, 2012; 61/598,672,
filed Feb. 14, 2012; and 61/714,323 filed Oct. 16, 2012, each of
which is incorporated herein by reference.
TECHNICAL FIELD
[0002] The present application relates to the general art of
structural, bridge and geotechnical engineering, and to the
particular field of concrete bridge and culvert structures.
BACKGROUND
[0003] Overfilled bridge structures are frequently formed of
precast or cast-in-place reinforced concrete and are used in the
case of bridges to support a first pathway over a second pathway,
which can be a waterway, a traffic route, or in the case of other
structures, a buried storage space or the like (e.g., for
stormwater detention). The term "overfilled bridge" will be
understood from the teaching of the present disclosure, and in
general as used herein, an overfilled bridge is a bridge formed of
bridge elements or units that rest on a foundation with soil or the
like resting thereon and thereabout to support and stabilize the
structure and in the case of a bridge to provide the surface of (or
support surface for) the first pathway.
[0004] In any system used for bridges, particularly stream
crossings, engineers are in pursuit of a superior blend of
hydraulic opening and material efficiency. In the past, precast
concrete bridge units of various configurations have been used,
including four side units, three-sided units and true arches (e.g.,
continuously curving units). Historical systems of rectangular or
box-type four-sided and three-sided units have proven inefficient
in their structural shape requiring large side wall and top-slab
thicknesses to achieve desired spans. Historical arch shapes have
proven to be very efficient in carrying structural loads but are
limited by their reduced hydraulic opening area. An improvement, as
shown and described in U.S. Pat. No. 4,993,872, was introduced that
combined vertical side walls and an arched top that provided a
benefit with regard to this balance of hydraulic open area to
structural efficiency. One of the largest drivers to structural
efficiency of any culvert/bridge shape is the angle of the corners.
The closer to 90 degrees at the corner, the higher the bending
moment and therefore the thicker the cross-section of the haunch
needs to be. Thus, the current vertical side and arch top shape is
still limited by the corner angle, which while improved is still at
one-hundred fifteen degrees.
[0005] A variation of the historic flat-top shape has also been
introduced, as shown in U.S. Pat. No. 7,770,250, that combines a
flat, horizontal top with an outwardly flared leg of uniform
thickness. The resulting shape provides some improvements to
hydraulic efficiency versus the flat-top by adding open area and
also provides some improvement structurally by flattening the angle
between the top and legs to about one-hundred ten degrees. However,
flat-tops are severely limited in the ability to reach longer spans
needed for many applications (e.g., the effective limit for flat
top spans is in the range of thirty to forty feet).
[0006] An improved bridge system would therefore be advantageous to
the industry.
SUMMARY
[0007] In one aspect, a concrete culvert assembly for installation
in the ground, includes a set of spaced apart elongated footers and
a plurality of precast concrete culvert sections supported by the
footers in side by side alignment. Each of the concrete culvert
sections has an open bottom, a top wall and spaced apart side walls
to define a passage thereunder. Each of the side walls extends
downward and outward from the top wall and has a substantially
planar inner surface and a substantially planar outer surface. The
top wall has an arch-shaped inner surface and an arch-shaped outer
surface and a substantially uniform thickness. First and second
haunch sections each join one of the side walls to top wall, each
haunch section defining a corner thickness greater than the
thickness of the top wall. For each side wall bot an interior angle
and an exterior angle is defined. The interior side wall angle is
defined by intersection of a first plane in which the inner surface
of the side wall lies and a second plane that is perpendicular to a
radius that defines at least part of the arch-shaped inner surface
of the top wall at a first point along the arch-shaped inner
surface of the top wall. The exterior side wall angle defined by
intersection of a third plane in which the outer surface of the
side wall lies and a fourth plane that is perpendicular to a radius
that defines at least part of the arch-shaped outer surface of the
top wall at a second point along the arch-shaped outer surface. The
third plane is non-parallel to the first plane. The interior side
wall angle is at least one-hundred and thirty degrees and the
exterior side wall angle is at least one-hundred and thirty-five
degrees, with the exterior side wall angle being different than the
interior side wall angle. Each side wall is tapered from top to
bottom such that a thickness of each side wall decreases when
moving from the top of each side wall to the bottom of each side
wall.
[0008] In one implementation of the foregoing aspect, for each side
wall of each concrete culvert section, an angle of intersection
between the first plane and the third plane is at least 1
degree.
[0009] In one implementation of the concrete culvert assembly of
the two preceding paragraphs, for each culvert section, a ratio of
haunch thickness to top wall thickness is no more than about
2.30.
[0010] In one implementation of the concrete culvert assembly of
any of the three preceding paragraphs, for each concrete culvert
section, the inner surface of each side wall intersects with an
inner surface of its adjacent haunch section at an interior haunch
intersect line, a vertical distance between the defined interior
haunch intersect line and top dead center of the arch-shaped inner
surface of the top wall being between no more than eighteen percent
(18%) of a radius of curvature of the arch-shaped inner surface of
the top wall at top dead center.
[0011] In one implementation of the concrete culvert assembly of
any of the four preceding paragraphs, for each concrete culvert
section, the inner surface of each side wall intersects with an
inner surface of its adjacent haunch section at an interior haunch
intersect line, the haunch section includes an exterior corner that
is spaced laterally outward of the interior haunch intersect line,
and a horizontal distance between each interior haunch intersect
line and the corresponding exterior corner is no more than about
91% of the horizontal width of the bottom surface of the side
wall.
[0012] In one implementation of the concrete culvert assembly of
any of the five preceding paragraphs, for each concrete culvert
assembly, a distance between the inner surface at the bottom of one
side wall and the inner surface at the bottom of the other side
wall defines a bottom span of the unit, the bottom span is greater
than a radius of curvature of the arch-shaped inner surface of the
top wall at top dead center.
[0013] In one implementation of the concrete culvert assembly of
any of the six preceding paragraphs, for each concrete culvert
section, the thickness at the bottom of each side wall is no more
than 90% of the thickness of the top wall at top dead center of the
top wall.
[0014] In one implementation of the concrete culvert assembly of
any of the seven preceding paragraphs, for each concrete culvert
section, a bottom portion of each side wall of each culvert section
includes a vertical flat segment on the outer surface.
[0015] In one implementation of the concrete culvert assembly of
any of the eight preceding paragraphs, each end unit of the
plurality of concrete culvert sections includes a corresponding
headwall assembly positioned on the top wall and the side
walls.
[0016] In one implementation of the concrete culvert assembly of
any of the nine preceding paragraphs, each headwall assembly
includes a top headwall portion and side headwall portions that are
formed unitary with each other and connected to the top wall and
side walls by at least one counterfort structure on the top wall
and at least one counterfort structure on each side wall. In
another implementation of the concrete culvert assembly of any of
the nine preceding paragraphs, each headwall assembly includes a
top headwall portion and side headwall portions that are formed by
at least two distinct pieces, the headwall assembly connected to
the top wall and side walls by at least one counterfort structure
on the top wall and at least one counterfort structure on each side
wall.
[0017] In one implementation of the concrete culvert assembly of
any of the ten preceding paragraphs, each haunch section includes
an inner surface defined by a haunch radius, for each side wall the
first point is the location where the radius that defines the
arch-shaped inner surface of the top wall meets the haunch radius
associated with the side wall.
[0018] In one implementation of the concrete culvert assembly of
any of the eleven preceding paragraphs, each concrete culvert
section is formed in two halves, each half formed by one side wall
and a portion of the top wall, the two top portions secured
together along a joint at a central portion of the top wall of the
culvert section.
[0019] In one implementation of the concrete culvert assembly of
any of the twelve preceding paragraphs, for each side wall the
first point is a location at which the arch-shaped inner surface
meets an inner surface of the haunch section adjacent the side
wall, and the second point is either a location where the
arch-shaped outer surface intersects the third plane or a location
where the arch-shaped outer surface meets a planar end outer
surface portion of the top wall at the haunch section.
[0020] In another aspect, a method is provided for manufacturing a
concrete culvert section having an open bottom, a top wall and
spaced apart side walls to define a passage thereunder, each of the
side walls having a substantially planar inner surface and a
substantially planar outer surface, the top wall having an
arch-shaped inner surface and an arch-shaped outer surface and a
substantially uniform thickness, each side wall having varying
thickness that decreases when moving from the top of each side wall
to the bottom of each side wall, first and second haunch sections,
each haunch section joining one of the side walls to the top wall,
and each haunch section defining a corner thickness greater than
the thickness of the top wall. The method involves: providing a
form system in which, for each side wall, an interior form
structure portion defines the position of the inner surface of the
side wall and an exterior form structure portion defines the
position and orientation of the outer surface of the side wall, the
exterior form structure portion arranged to pivot or to move along
a surface of top wall form structure portion; based upon an
established bottom span or rise for the culvert section, pivoting
the exterior form structure portion or moving the exterior form
structure portion to a position that sets a relative angle between
interior form structure portion and the exterior form structure
portion; and filling the form structure with concrete to produce
the culvert section.
[0021] In one implementation of the method of the preceding
paragraph, the form structure lays on one face and the exterior
form structure portion for each side wall includes a bottom side
arranged to slide over a corresponding side wall form seat
structure.
[0022] In one implementation of the method of any of the two
preceding paragraphs, a bottom form structure is positioned between
the interior form structure and the exterior form structure to
define the intended width for the bottom surface of the resulting
side wall.
[0023] In another aspect, a concrete culvert assembly for
installation in the ground includes a set of spaced apart elongated
footers, and a plurality of precast concrete culvert sections
supported by the footers in side by side alignment. Each of
concrete culvert sections has an open bottom, a top wall and spaced
apart side walls to define a passage thereunder. Each of the side
walls extends downward and outward from the top wall and has a
substantially planar inner surface and a substantially planar outer
surface. The top wall has an arch-shaped inner surface and an
arch-shaped outer surface, first and second haunch sections, each
haunch section joining one of the side walls to the top wall, each
haunch section defining a corner thickness greater than the
thickness of the top wall. Each side wall is tapered from top to
bottom such that a thickness of each side wall decreases when
moving from the top of each side wall to the bottom of each side
wall. A ratio of haunch thickness to top wall thickness at top dead
center is no more than about 2.30. The inner surface of each side
wall intersects with an inner surface of its adjacent haunch
section at an interior haunch intersect line, and each haunch
section includes an exterior corner that is spaced laterally
outward of the interior haunch intersect line. A horizontal
distance between each interior haunch intersect line and the
corresponding exterior corner is no more than about 91% of a
horizontal width of the bottom surface of the side wall, the
thickness at the bottom of each side wall is no more than 90% of
the thickness of the top wall at top dead center of the top wall,
and a ratio of a first vertical distance over a second vertical
distance is at least about 55%, where the first vertical distance
is the vertical distance between the height of the exterior corner
of the haunch and the height of top dead center of the arch-shaped
outer surface of the top wall, and the second vertical distance is
the vertical distance between the height of a defined interior
haunch intersect line and the height of top dead center of the
arch-shaped inner surface of the top wall.
[0024] In one implementation of the concrete culvert assembly of
the preceding paragraph, each concrete culvert section is formed in
two halves, each half formed by one side wall and a portion of the
top wall, the two top portions secured together along a joint at a
central portion of the top wall of the culvert section.
[0025] In another aspect, a concrete culvert section includes an
open bottom, a top wall and spaced apart side walls to define a
passage thereunder, each of the side walls extending downward and
outward from the top wall. Each of the side walls has a
substantially planar inner surface and a substantially planar outer
surface, and the top wall has an arch-shaped inner surface and an
arch-shaped outer surface and a substantially uniform thickness.
First and second haunch sections each join one of the side walls to
the top wall, each haunch section defining a corner thickness
greater than the thickness of the top wall. For each side wall an
interior side wall angle is defined by intersection of a first
plane in which the inner surface of the side wall lies and a second
plane that is perpendicular to a radius that defines at least part
of the arch-shaped inner surface of the top wall at a first point
along the arch-shaped inner surface of the top wall. An exterior
side wall angle is defined by intersection of a third plane in
which the outer surface of the side wall lies and a fourth plane
that is perpendicular to a radius that defines at least part of the
arch-shaped outer surface of the top wall at a point along the
arch-shaped outer surface, the third plane being non-parallel to
the first plane. The interior side wall angle is at least
one-hundred and thirty degrees, the exterior side wall angle is at
least one-hundred and thirty-five degrees, the exterior side wall
angle is different than the interior side wall angle. Each side
wall is tapered from top to bottom such that a thickness of each
side wall decreases when moving from the top of each side wall to
the bottom of each side wall.
[0026] In one implementation of the culvert section of the
preceding paragraph, a ratio of a first vertical distance over a
second vertical distance is at least about 55%, where the first
vertical distance is the vertical distance between the height of
exterior corner of the haunch and the height of top dead center of
the arch-shaped outer surface of the top wall, and the second
vertical distance is the vertical distance between the height of a
defined interior haunch intersect line and the height of top dead
center of the arch-shaped inner surface of the top wall.
[0027] In one implementation of the culvert section of either of
the two preceding paragraphs, each haunch section includes an inner
surface defined by a haunch radius, the first point is the location
where the radius that defines the arch-shaped inner surface of the
top wall meets the haunch radius.
[0028] In one implementation of the culvert section of any of the
three preceding paragraphs, the concrete culvert section is formed
by two halves, each half formed by one side wall and a portion of
the top wall, the two top portions secured together along a joint
at a central portion of the top wall of the culvert section.
[0029] In one implementation of the culvert section of any of the
four preceding paragraphs, each side wall has an exterior vertical
flat extending upward from a horizontal bottom surface thereof.
[0030] In another aspect, a concrete culvert assembly for
installation in the ground includes a set of spaced apart elongated
footers, a plurality of precast concrete culvert sections supported
by the footers in side by side alignment. Each of the concrete
culvert sections has an open bottom, an arch-shaped top wall and
spaced apart side walls to define a passage thereunder, each of the
side walls extending downward and outward from the top wall. Each
of the side walls has a substantially planar inner surface and a
substantially planar outer surface. First and second haunch
sections each join one of the side walls to the top wall, each
haunch section defining a corner thickness greater than a thickness
of the top wall. Each side wall is tapered from top to bottom such
that a thickness of each side wall decreases when moving from the
top of each side wall to the bottom of each side wall. A bottom
portion of each side wall has an exterior vertical flat extending
upward from a horizontal bottom surface thereof, wherein the
exterior vertical flat is between about 3 inches and 7 inches
high.
[0031] In one implementation of the culvert assembly of the
preceding paragraph, each concrete culvert section is formed in two
halves, each half formed by one side wall and a portion of the top
wall, the two top portions secured together along a joint at a
central portion of the top wall of the culvert section.
[0032] In one implementation of the culvert assembly of either of
the two preceding paragraphs, each culvert section is seated atop a
foundation system and the exterior vertical flat of each culvert
section abuts lateral supporting structure of the foundation
system.
[0033] In one implementation of the culvert assembly of any of the
three preceding paragraphs, the foundation system includes precast
concrete units and cast-in-place concrete, the lateral supporting
structure is cast-in-place concrete.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] FIG. 1 is a perspective view of one embodiment of a culvert
section;
[0035] FIG. 2 is a side elevation of the culvert section of FIG.
1;
[0036] FIG. 3 is an end elevation of the culvert section of FIG.
1;
[0037] FIG. 4 is a partial side elevation showing the haunch of the
culvert section of FIG. 1;
[0038] FIG. 4A is a partial side elevation showing an alternative
configuration of the outer surface in the region of the top wall
and haunch;
[0039] FIG. 5 is a side elevation showing configurations
corresponding various rises;
[0040] FIGS. 6 and 6A show a partial schematic view of a form
system used to produce the culvert section of FIG. 1;
[0041] FIG. 7 is a partial side elevation showing the haunch of the
culvert section of FIG. 1;
[0042] FIG. 8 is a perspective view of another embodiment of a
culvert section;
[0043] FIG. 9 is a side elevation of the culvert section of FIG.
8;
[0044] FIG. 10 is a partial side elevation of the culvert section
of FIG. 8 atop a footer;
[0045] FIGS. 11-14 show one embodiment of a plurality of culvert
sections according to FIG. 1 arranged side by side on spaced apart
footers, with each end unit including a headwall assembly;
[0046] FIG. 15 shows a side elevation depicting representative
reinforcement within the concrete culvert section and generally
running in proximity to and along the inner and outer surfaces of
the top wall and side walls; and
[0047] FIGS. 16-18 show an alternative embodiment of a form system
for constructing the units;
[0048] FIGS. 19-21 show a culvert assembly atop one embodiment of a
foundation system.
DETAILED DESCRIPTION
[0049] Referring to FIGS. 1-3, perspective, side elevation and end
elevation views of an advantageous precast concrete culvert
unit/section 10 are shown. The culvert unit 10 includes an open
bottom 12, a top wall 14 and spaced apart side walls 16 to define a
passage 18 thereunder. Each of the side walls has a substantially
planar inner surface 20 and a substantially planar outer surface
22. The top wall has an arch-shaped inner surface 24 and an
arch-shaped outer surface 26 and a substantially uniform thickness
T.sub.TW. In various implementations, the arch-shaped inner surface
and arch-shaped outer surface can each be made up of or defined by
(i) a respective single radius, (ii) a respective set of joined
radiuses (e.g., the surface is curved along its entire length) or
(iii) in some cases planar sections may be included either the most
center region of each arch-shaped surface or at the end portion of
each arch-shaped surface. As used herein the term "arch-shaped"
when referring to such surfaces encompasses all such variations.
Haunch sections 28 join each side wall 16 to the top wall 14.
[0050] Each haunch section has a corner thickness T.sub.HS greater
than the thickness T.sub.TW of the top wall. In this regard, the
corner thickness T.sub.HS is measured perpendicular to the curved
inner surface 30 of the haunch section along a line that passes
through the exterior corner 32 of the haunch section. While the
larger corner thickness of a unit as compared to the side wall and
top wall thickness of the same unit is critical to the structural
performance of the unit, the present culvert unit is configured to
more effectively distribute load from the top wall to the side
walls of the present culvert unit so that the corner thickness of
the present culvert unit can be reduced in comparison to prior art
culvert units.
[0051] In this regard, and with reference to the partial view of
FIG. 4, an interior side wall angle .theta..sub.ISWA between the
side wall 16 and the top wall 14 is defined by intersection of a
plane 34 in which the inner surface of the side wall lies and a
line or plane 36 that is tangent to the inner surface 24 of the top
wall at the point or line 38 where the top wall inner surface 24
meets the haunch inner surface 30 (e.g., where the inner surface of
the unit transitions from the radius R.sub.TW to the radius R.sub.H
defining the inner surface haunch). Thus, the plane 36 is
perpendicular to the radius R.sub.TW that defines the arch-shaped
inner surface of the top wall at a point 38 where the radius
R.sub.TW stops and the radius R.sub.H starts. In some
implementations R.sub.TW will define the entire span of inner
surface 24 from haunch to haunch. In other implementations the
center portion of the top wall inner surface 24 may be defined by
one radius and the side portions of the inner surface 24 may be
defined by a smaller radius R.sub.TW. The illustrated unit 10 is
constructed such that the interior side wall angle .theta..sub.ISWA
is at least one-hundred and thirty degrees, and more preferably at
least one-hundred thirty-three degrees. This relative angle between
the top wall and side wall reduces bending moment in the haunch
section as compared to prior art units, enabling the thickness of
the haunch sections 28 to be reduced and the amount of steel used
in the haunch sections to be reduced, resulting in a reduction in
material needed, along with a corresponding reduction in unit
weight and material cost per unit. Moreover, the center of gravity
of the overall unit is moved downward by reducing concrete in the
haunch sections, thereby placing the center of gravity closer to
the midway point along the overall height or rise of the unit. As
units will be generally shipped laying down as opposed to upright,
and it is desirable to place the center of gravity in alignment
with the center line of the vehicle bed used to ship the units,
this lowering of the center of gravity can facilitate proper
placement of units with an overall greater height on the vehicle
bed without requiring as much overhang as prior art units.
[0052] This reduction in concrete usage can further be enhanced by
appropriate configuration of the side walls 16 of the unit.
Specifically, an exterior side wall angle .theta..sub.ESWA between
the top wall 14 and the side wall 16 is defined by intersection of
a plane 42 in which the outer surface 22 of the side wall lies and
a line or plane 44 that is tangent to the top wall outer surface 26
at the point or line 46 where the outer surface 26 intersects the
plane 42. It is noted that for the purpose of evaluating the
exterior side wall angle the outer surface of the top wall is
considered to extend along the full span at the top of the unit
(e.g., from corner 32 to corner 32). The radius that defines the
outer surface 26 of the top wall near the corners 32 may typically
be R.sub.TW+T.sub.TW, but in some cases the radius of the outer
surface 26 in the corner or end region may vary. In other cases,
particularly for larger spans, as shown in FIG. 4A, the corner or
end regions of outer surface 26 may include planar end portions 27,
in which case the plane 44' would in fact be perpendicular to the
radius (e.g., R.sub.TW+T.sub.TW) that defines the outer surface 26
at the point or line 29 where that radius (e.g., R.sub.TW+T.sub.TW)
meets the planar end portion 27 of the surface 26.
[0053] As shown, the exterior side wall plane 42 is non-parallel to
the interior side wall plane 34, such that each side wall 16 is
tapered from top to bottom, with thickness along the height of the
side wall decreasing when moving from the top of each side wall
down toward the bottom of each side wall. In this regard, the
thickness of the side wall T.sub.SW at any point along it height is
taken along a line that runs perpendicular to the interior side
wall plane 34 (e.g., such as line 48 in FIG. 4). By utilizing side
walls with tapered thickness, the thickness of the bottom portion
of the side wall (e.g., where loads are smaller) can be reduced.
Preferably, the thickness at the bottom of each side wall may be no
more than about 90% of the thickness of the top wall, resulting in
further concrete savings as compared to units in which all walls
are of uniform and common thickness. Generally, in the preferred
configuration for concrete reduction, the exterior side wall angle
is different than the interior side wall angle, and is
significantly greater than angles used in the past, such that the
exterior side wall angle .theta..sub.ESWA is at least one-hundred
and thirty-five degrees and, in many cases, at least one-hundred
and thirty-eight degrees. An angle of intersection .theta..sub.PI
between the plane 34 in which the inner surface lies and the plane
42 in which the outer surface lies may be between about 1 and 20
degrees (e.g., between 1 and 4 degrees), depending upon the extent
of taper, which can vary as described in further detail below. In
certain implementations, the angle .theta..sub.PI is preferably at
least about 2-4 degrees.
[0054] Overall, the configuration of the culvert section 10 allows
for both hydraulic and structural efficiencies superior to
previously known culverts. The hydraulic efficiency is achieved by
a larger bottom span that is better capable of handling the more
common low flow storm events. The structural efficiency is achieved
by the larger side wall to top wall angle that enables the
thickness of the haunch to be reduced, and enabling more effective
longer span units (e.g., spans of 48 feet and larger). The reduced
corner thickness and tapered legs reduce the overall material cost
for concrete, and enables the use of smaller crane sizes (or longer
pieces for the same crane size) during on-site installation due to
the weight advantage.
[0055] The tapered side wall feature described above can be most
effectively utilized by actually varying the degree of taper
according to the rise to be achieved by the precast concrete unit.
Specifically, and referring to the side elevation of FIG. 5, the
rise of a given unit is defined by the vertical distance from the
bottom edges 50 of the side walls 16 to top dead center 52 of the
arch-shaped inner surface 24 of the top wall 14. Three different
rises are illustrated in FIG. 5, with rise R1 being the rise for
the unit shown in FIGS. 1-3, rise R2 being a smaller rise and rise
R3 being a larger rise. As shown, the side wall taper varies as
between the three different rises, utilizing a constant top span
S.sub.TW defined as the horizontal distance between the haunch
corners 32. Notably, in one embodiment, the side wall taper is more
aggressive in the case of the smaller rise R2 as demonstrated by
the exterior side wall surface 22' shown in dashed line form, and
the side wall taper is less aggressive in the case of the larger
rise R3 as demonstrated by the exterior side wall surface 22''
shown in dashed line form. This variation in taper is achieved by
varying the exterior side wall angle .theta..sub.ESWA (FIG. 4)
according to the rise or bottom span for the unit that is to be
produced. Each bottom span (S.sub.BR1, S.sub.BR2, S.sub.BR3) is
defined as the horizontal distance between the bottom edges of the
side wall inner surfaces 20. The bottom span is preferably greater
than the radius of curvature R.sub.TW of the arch-shaped inner
surface of the top wall at top dead center in order to provide more
effective waterway area for lower flow storm events (e.g., in the
case of creek or stream crossings). As shown FIG. 5, the inner
surface 20 of the side walls varies in length over the different
rises, but the interior side wall angle does not vary.
[0056] In order to achieve the variable side wall taper feature, a
form system is used in which, for each side wall, an interior form
structure portion for defining the interior side wall angle is
fixed and an exterior form structure portion defining the exterior
side wall angle can be varied by pivoting. The pivot point for each
exterior form structure portion is the exterior corner 32 of the
haunch section. Based upon a desired bottom span or rise for the
culvert section to be produced using the particular form, the
exterior form structure portion is pivoted to a position that sets
the appropriate exterior side wall angle and the exterior form
structure portion is locked in position. The form structure is then
filled with concrete to produce the culvert section. With respect
to the pivoting operation, as shown schematically in FIG. 6, the
form 60 is placed on its side for the purpose of concrete fill and
casting. A form seat 62 is provided for each side wall, with the
interior form structure portion 64 seating alongside the edge of
the form seat 62 as is typical in precasting of bridge units.
However, the exterior form structure portion 66, which pivots about
a hinge axis 68, has its bottom edge raised (relative to the bottom
edge of portion 64) so that portion 66 can move across the top
surface of the form seat 62 during pivot. The exterior side wall
angle may, in each case, be achieved by establishing a consistent
horizontal width W.sub.SB (FIG. 2) for the bottom surface of the
side wall for a given top span S.sub.TW, regardless of the rise
being produced. The form system includes a bottom form panel member
63 that is movable along the height of the form portion 64 and can
be bolted in place using bolt holes 69 provided in the form
structure 64. Similar bolt holes would be provided in the edge 67
of panel 63, and the edge 67 would be angled to match the surface
of form portion 64 so that surface 65 of the panel will be
horizontal when installed. Any unused bolt holes would be filled
with plug members. Once the bottom panel 63 is at the proper
location to produce the desired rise, portion 66 of the structure
can be pivoted into contact with the free edge of the panel 63 and
locked in position.
[0057] Referring now to FIG. 7, in the illustrated embodiment each
haunch section 28 is defined by an inner surface 30 with a radius
of curvature R.sub.H, and the inner surface 20 of each side wall
intersects with the inner surface of its adjacent haunch section 28
at an interior haunch intersect line or point 70, which is the
point of transition from the planar surface 20 to the radiused
surface 30. A vertical distance D.sub.IT between the height of the
defined interior haunch intersect line 70 and the height of top
dead center of the arch-shaped inner surface of the top wall should
be no more than about eighteen percent (18%) of the radius of
curvature R.sub.TW of the arch-shaped inner surface 24 of the top
wall at top dead center in order to more effectively reduce the
haunch corner thickness. Also, a ratio of the vertical distances
D.sub.OT/D.sub.IT, where D.sub.OT is the vertical distance between
the height of exterior corner 32 of the haunch and the height of
top dead center of the arch-shaped outer surface of the top wall,
should preferably be no less than about 55% and, more preferably,
no less than about 58%. Moreover, the exterior corner 32 of the
haunch section 28 is spaced laterally outward of the interior
haunch intersect line 70 by a relatively small distance, and
particularly a horizontal distance that is less than the horizontal
width W.sub.SB of the side wall bottom surface. For example, in
certain implementations the horizontal distance D.sub.IO between
each interior haunch intersect line 70 and the corresponding
exterior corner 32 is preferably no more than about 95% of the
horizontal width W.sub.SB of the side wall bottom surface, and more
preferably no more than about 91%.
[0058] Referring now to the embodiment shown in FIGS. 8-10, in some
cases it is desirable to provide a vertical flat segment 80 at the
bottom portion of each side wall 16. The vertical flat 80
facilitates the use of blocking structure (e.g., wooden blocks 82
with corresponding vertical surfaces) in combination with the
keyway/channel 84 in concrete footing 85 to hold the culvert
sections in place, preventing the bottom ends of the side walls
from moving outward under the weight of the culvert section, until
the bottom ends are grouted/cemented in place.
[0059] As shown in FIGS. 11-14, each end unit of the plurality of
concrete culvert sections includes a corresponding headwall
assembly 90 positioned on the top wall and the side walls of the
unit. As shown, in one implementation, each headwall assembly 90
includes a top headwall portion 92 and side headwall portions 94
that are formed unitary with each other and connected to the top
wall and side walls by at least one counterfort structure 96 on the
top wall and at least one counterfort structure 98 on each side
wall. The counterfort structures may be consistent with those shown
and described in U.S. Pat. No. 7,556,451 (copy attached). In
another implementation, as suggested by dashed lines 100, headwall
portions 94 and 96 may be formed as three distinct pieces.
Alternatively, as suggested by dashed line 102 the headwall
assembly may be formed in two mirrored halves. Wingwalls 104 may
also be provided in abutment with the side headwall portions and
extending outward therefrom as shown.
[0060] Although FIGS. 11-14 shows a fairly standard footing system
for use in connection with the inventive culvert sections of the
present application, alternative systems could be used. For
example, the culvert sections could be used in connection with the
foundation structures shown and described in U.S. Provisional
Application Ser. No. 61/505,564, filed Jul. 11, 2011 (copy
attached).
[0061] As shown in FIG. 15, the concrete culvert section typically
includes embedded reinforcement 110 and 112 generally running in
proximity to and along the inner and outer surfaces of the top wall
14 and side walls 16.
[0062] As reflected in FIGS. 5 and 6 above, in one embodiment
concrete culverts of varying rises can be achieved by maintaining
the outside corners of the top wall in the same position, but
pivoting the outside surface of each side wall outward for larger
rises, or inward for smaller rises. In an alternative embodiment
per FIGS. 16-18, different rises may be achieved by shifting the
outside corners of the top wall outward for larger rises and inward
for smaller rises. In particular, as shown in FIGS. 16 and 17, for
the rise shown in solid line form the outside corner is located at
position 32 and the outer surface 22 of the side extends downward
slightly toward the inner surface 20 producing a certain degree of
side wall taper. When a lower rise is desired the outside corner is
shifted inward to location 32a and when a higher rise is desired
the outside corner is shifted outward to a location 32b. Thus, the
width of the upper portion of the side wall is greater for higher
rises and lower for smaller rises. The horizontal bottom part 50 of
each side wall may be the same as between the different rises, and
likewise the vertical part or flat 80 of the bottom of each side
wall may have the same height dimension as between the different
rises.
[0063] FIG. 18 reflects a form system for achieving the above
embodiment, where the form system includes a top wall outer surface
form unit 150, a top wall inner surface form unit 152, a haunch
interior surface form unit 154, a side wall inner surface form unit
156, a side wall outer surface form unit 158 and a side wall bottom
surface unit 160. To achieve different rises using this form
system, the form unit 158 is moved along the surface of the form
unit 150 (per arrow 162) to the needed location and bolted thereto,
and the form unit 160 is moved to the appropriate location along
the space between form units 156 and 158 (per arrow 164) to the
appropriate location and bolted thereto. During this movement the
form unit 158 slides across the top of the form seat or base
structures 166a and 166b on which the form units are supported. The
interior side face 170 of the form unit 158 maintains its relative
angular orientation with respect to the opposed side face 172 of
the form unit 156 regardless of where the form unit 158 is
positioned, thus maintaining a similar degree of leg taper as
between different rises. The form units 158 and 160 may
additionally be bolted to the form base structure(s) 166a and/or
166b when moved to the needed locations for a given rise to assure
desired positioning. A system of alignable openings in the form
units 150, 158, 160 and/or the base structures 166a and 166b may be
provided for such purpose.
[0064] Referring now to FIGS. 19-21, in one embodiment the culvert
sections are supported atop a foundation system having precast
foundation units 200 with a ladder configuration as shown. The
units have spaced apart and elongated upright walls 202 and 204
forming a channel 205 between the walls and cross-member supports
206 extending transversely across the channel to connect the walls
202 and 204. The foundation units 200 lacks any bottom wall, such
that open areas or cells 208 extend vertically from the top to
bottom of the units in the locations between the cross-members 206.
Each cross-member support 206 includes an upper surface with a
recess 210 for receiving the bottom portion of one side of the
bridge/culvert sections 214. The side wall portions of the bridge
units 214 extend from their respective bottom portions upwardly
away from the combination precast and cast-in-place concrete
foundation structure and inward toward the other combination
precast and cast-in-place concrete foundation structure at the
opposite side of the bridge unit. The recesses 210 extend from
within the channel 205 toward the inner upright wall member 204,
that is the upright wall member positioned closest to central axis
212 of the bridge system. Thus, as best seen in FIG. 35, the
upright wall member 202 has a greater height than the upright wall
member 204.
[0065] The spacing of the cross-members 208 preferably matches the
depth of the bridge/culvert sections 214, such that adjacent end
faces of the side-by-side bridge units abut each other in the
vicinity of the recesses 210. Each cross-member support 206 also
includes one or more larger through openings 216 for the purpose of
weight reduction and allowing concrete to flow from one open area
or cell 208 to the next. Each cross-member support also includes
multiple axially extending reinforcement openings 218. An upper row
220 and lower row 222 of horizontally spaced apart openings 218 is
shown, but variations are possible. Axially extending reinforcement
may be extended through such openings prior to delivery of the
foundation units 200 to the installation site, but could also be
installed on-site if desired. These openings 218 are also used to
tie foundation units 200 end to end for longer foundation
structures. In this regard, the ends of the foundation units 200
that are meant to abut an adjacent foundation unit may be
substantially open between the upright wall members 202 and 204
such that the abutting ends create a continuous cell 224 in which
cast-in-place concrete will be poured. However, the far ends of the
end foundation units 200 in a string of abutting units may
typically include an end-located cross-member 206 as shown.
[0066] The walls 202 and 204 include reinforcement 226 that
includes a portion 228 extending vertically and a portion 230
extending laterally into the open cell areas 208 in the lower part
of the foundation unit 200. At the installation site, or in some
cases prior to delivery to the site, opposing portions 230 of the
two side walls can then be tied together by a lateral reinforcement
section 232.
[0067] The precast foundation units 200 are delivered to the job
site and installed on ground that has been prepared to receive the
units (e.g., compacted earth or stone). The bridge/culvert sections
214 are placed after the precast foundation units are set. The
cells 208 remain open and unfilled during placement of the bridge
units 214 (with the exception of any reinforcement that may have
been placed either prior to delivery of the units 200 to the job
site or after delivery). Shims may be used for leveling and proper
alignment of bridge/culvert sections 214. Once the bridge units 214
are placed, the cells 208 may then be filled with an on-site
concrete pour. The pour will typically be made to the upper surface
level of the foundation units 200. In this regard, and referring to
FIG. 35, due to the difference in height of the respective sides of
the foundation unit 200, the bottom portion 240 of the bridge unit
will be captured and embedded within the cast-in-place concrete 242
at the outer side of bottom portion 240. After the on-site pour,
the cast-in-place concrete at the outer side of the bottom portion
240 of the bridge unit is higher than a bottom surface of the
bottom portion 240 to embed the bottom portion at its outer side,
and the cast-in-place concrete at the inner side of the bottom
portion of the bridge unit is substantially flush with the bottom
surface of the bottom portion 240. In this manner, the flow area
beneath the bridge units is not adversely impacted by embedment of
the bottom portions 240 of the bridge units.
[0068] It is to be clearly understood that the above description is
intended by way of illustration and example only and is not
intended to be taken by way of limitation, and that changes and
modifications are possible. For example, while haunch sections with
curved inner surfaces and exterior corners are shown, variations
are possible, such as flat inner surfaces and/or a chamfered or
flat at the exterior corner. Also, embodiments in which the side
walls are not tapered are possible. Moreover, twin leaf embodiments
are contemplated, in which the each concrete culvert section is
formed by two halves having a joint (e.g., per dashed line 180 in
FIG. 16) at a central portion of the top wall of the culvert
section. Various joint types could be used, such as that disclosed
in U.S. Pat. No. 6,243,994. While one embodiment of a foundation
system is shown, the culvert assembly could be placed atop any
suitable foundation, including foundation systems with pedestal
structures. Accordingly, other embodiments are contemplated and
modifications and changes could be made without departing from the
scope of this application.
* * * * *