U.S. patent application number 12/658896 was filed with the patent office on 2011-08-18 for stormwater containment assembly and associated end section.
This patent application is currently assigned to Advanced Drainage Systems, Inc.. Invention is credited to John M. Kurdziel, David J. Mailhot.
Application Number | 20110200391 12/658896 |
Document ID | / |
Family ID | 44369759 |
Filed Date | 2011-08-18 |
United States Patent
Application |
20110200391 |
Kind Code |
A1 |
Mailhot; David J. ; et
al. |
August 18, 2011 |
Stormwater containment assembly and associated end section
Abstract
An end section or cap for a stormwater containment assembly
includes a substantially half-dome-shaped body member and a
connector disposed on the body member along a periphery or
perimeter thereof, for coupling the body member to a stormwater
chamber wall. The body member has a smooth convex outer surface
with an absence of reinforcement ribs and also has a smooth concave
inner surface with an absence of reinforcement ribs.
Inventors: |
Mailhot; David J.;
(Coventry, CT) ; Kurdziel; John M.; (Fort Wayne,
IN) |
Assignee: |
Advanced Drainage Systems,
Inc.
Hilliard
OH
|
Family ID: |
44369759 |
Appl. No.: |
12/658896 |
Filed: |
February 16, 2010 |
Current U.S.
Class: |
405/42 |
Current CPC
Class: |
E03F 1/003 20130101 |
Class at
Publication: |
405/42 |
International
Class: |
E02B 13/02 20060101
E02B013/02; E02B 11/00 20060101 E02B011/00 |
Claims
1. An end section for a stormwater containment assembly,
comprising: a substantially half-dome-shaped body member having a
smooth convex outer surface with an absence of reinforcement
structures thereon and further having a smooth concave inner
surface with an absence of reinforcement structures thereon; and a
connector disposed on said body member along a periphery or
perimeter thereof, for coupling said body member to a stormwater
chamber wall.
2. The end section defined in claim 1 wherein said connector is an
elongate corrugation integral with said body member along said
periphery or perimeter thereof.
3. The end section defined in claim 2 wherein said corrugation is
dimensioned to fit over a terminal lip or rib of said chamber
wall.
4. The end section defined in claim 3 wherein said corrugation
cooperates with said lip or rib to loosely couple said body member
to said chamber wall so as to allow for slippage between said
corrugation and said lip or rib in a direction radial with respect
to said chamber wall and said body member and transverse to said
corrugation and said lip or rib.
5. The end section defined in claim 4 wherein said corrugation
defines a longitudinally arcuate cross-sectionally tapered channel
receiving said lip or rib.
6. The end section defined in claim 1 wherein said body member has
a substantially half-dome shape with a pair of arcuate edges, said
connector being disposed along one of said edges.
7. An end section for a stormwater containment assembly,
comprising: a substantially half-dome-shaped body member having a
smooth convex outer surface with an absence of outwardly projecting
reinforcement ribs thereon and further having a smooth concave
inner surface with an absence of inwardly projecting reinforcement
ribs thereon; and an elongate longitudinally arcuate corrugation
integral with said body member along an edge or perimeter
thereof.
8. The end section defined in claim 7 wherein said corrugation is
integral with said body member along said edge or perimeter.
9. The end section defined in claim 8 wherein said corrugation is
dimensioned to fit over a terminal lip or rib of a main chamber
wall.
10. The end section defined in claim 9 wherein said corrugation
cooperates with said lip or rib to loosely couple said body member
to said chamber wall so as to allow for slippage between said
corrugation and said lip or rib in a direction radial with respect
to said chamber wall and said body member and transverse to said
corrugation and said lip or rib.
11. The end section defined in claim 10 wherein said corrugation
defines a longitudinally arcuate cross-sectionally tapered channel
receiving said lip or rib.
12. The end section defined in claim 7 wherein said body member has
a pair of arcuate edges, said corrugation being disposed along one
of said edges.
13. A stormwater containment assembly, comprising: a chamber member
having an arched or vaulted wall; and an end section including a
substantially half-dome-shaped body member having a smooth convex
outer surface with an absence of reinforcement structures thereon
and further having a smooth concave inner surface with an absence
of reinforcement structures thereon; and a connector disposed on
said body member along a periphery or perimeter thereof, for
coupling said body member to said arched or vaulted wall.
14. The stormwater containment assembly defined in claim 13 wherein
said connector is an elongate corrugation integral with said body
member along said periphery or perimeter thereof.
15. The stormwater containment assembly defined in claim 14 wherein
said corrugation is dimensioned to fit over a terminal lip or rib
of said arched or vaulted wall.
16. The stormwater containment assembly defined in claim 15 wherein
said corrugation cooperates with said lip or rib to loosely couple
said body member to said arched or vaulted wall so as to allow for
slippage between said corrugation and said lip or rib in a
direction radial with respect to said arched or vaulted wall and
said body member and transverse to said corrugation and said lip or
rib.
17. The stormwater containment assembly defined in claim 16 wherein
said corrugation defines a longitudinally arcuate cross-sectionally
tapered channel receiving said lip or rib.
18. The stormwater containment assembly defined in claim 13 wherein
said body member has a half dome shape with a pair of arcuate
edges, said connector being disposed along one of said edges.
Description
BACKGROUND OF THE INVENTION
[0001] The present disclosure relates to a fluid management system.
More particularly, the present disclosure relates to a stormwater
containment system, exemplarily utilizable beneath a parking lot.
This disclosure also relates to an end cap or end section that is a
component part of the stormwater containment system.
[0002] Stormwater containment systems are used to facilitate the
disposal of water run-off which occurs during rain storms. Such
systems may be used anywhere that the land use is enhanced by such
application. In large cities where land values are high developers
are motivated to go to underground containment. In some areas,
mosquito control or aesthetics may motivate a developer to go
underground even outside large cities.
[0003] Such containment systems include arched or vaulted chambers,
pipe systems or other crate type modular structures that are built
into the base of parking lots and streets for receiving and
temporarily housing stormwater run-off. Such a system is disclosed
in U.S. Pat. No. 7,118,306 to Kruger et al., U.S. Pat. No.
7,237,981 to Vitarelli, and U.S. Patent Application Publication No.
2007/0081860 by Goddard et al.
[0004] A problem with existing stormwater containment systems of
the above-referenced kind is that the end sections are sometimes
prone to failure. End sections constitute the end walls of the
arched or vaulted containment chambers. End sections are typically
reinforced along an inside surface with inwardly projecting ribs.
Reinforcement structures may also be provided along the outer
surfaces of the end sections. Reinforcement ribs typically extend
to the edges of the end sections and serve to transmit tensile and
compression forces. Reinforcement ribs and other reinforcement
structures concentrate tensile and/or compressive stresses and
channel the stresses along paths defined by the ribs. The ribs and
other reinforcement structures are viewed as necessary to
accommodate and support the immense weight of overlying soil and
asphalt layers that creates both vertical and horizontal forces on
the end section.
SUMMARY OF THE INVENTION
[0005] The present invention contemplates an improvement in
stormwater containment systems wherein the end caps or end sections
are smooth domed members with inner and outer surfaces that are
free of reinforcement ribs and preferably free of other structures
that extend over such a distance as to prevent a substantially
uniform stress distribution.
[0006] An end section for a stormwater containment assembly
comprises, in accordance with the present invention, a
substantially half-dome-shaped body member having a smooth convex
outer surface with an absence of reinforcement structures and
further having a smooth concave inner surface also with an absence
of reinforcement structures. The end section further comprises a
connector disposed on the body member along a periphery or
perimeter thereof, for coupling the body member to a stormwater
chamber wall.
[0007] More particularly, an end section body member in accordance
with the present invention is free of projecting reinforcement ribs
on both the inner concave surface and the outer convex surface. In
a preferred embodiment of the invention, the end section body
member is free of any projecting structures that extend over such a
distance as to prevent a substantially uniform stress distribution.
When the end cap is manufactured from polyethylene material, the
elimination or reduction of tensile stresses is most important
since polyethylene fails from a phenomenon known as environmental
stress cracking where in the presence of tensile stresses, cracks
may initiate at any scratch, flaw or sharp angle point such as at
the intersection of reinforcements, then propagate under the
tensile stress driving force until the structure fails.
[0008] Recesses may be provided in the outer surfaces of the end
section body members to function as handgrips for handling of the
end sections. The handgrip formations do not give rise to a
build-up of internal stresses. The handgrips are not so large as to
interfere with a substantially uniform tensile stress distribution.
Coupling corrugations extend along the periphery or edge of the end
section, parallel to an edge of the end section. The corrugations
function to couple the end section to vaulted main bodies or
chamber walls of stormwater containment systems.
[0009] Accordingly, a stormwater-chamber end section in accordance
with the present invention distributes loads throughout the body of
the end section and substantially reduces tensile stresses.
Localized tensile stresses do not build up at any point within the
end section but instead are directed uniformly to the periphery or
perimeter of the end section and transmitted therethrough to the
stormwater chamber wall.
[0010] In an end section in accordance with the present invention,
soil loads on the outside surface of the end section are carried
more uniformly by the end section without the stress concentrations
that otherwise occur at the reinforcement structures. Moreover,
without reinforcing ribs, loads carried by the end section are more
evenly distributed around the periphery or perimeter of the end
section and ultimately through the abutting chamber to the
surrounding soils.
[0011] In an end section in accordance with the present invention,
the end section has more freedom to deform slightly under the soil
load. As the end section or cap deforms, the surrounding soils
coalesce in an arched formation and carry loads that would
otherwise be carried by the end section. Although reinforced shells
in their entireties may be flexible, the present end section is
uniformly more flexible than the reinforced shell so that any
particular area of the present end section is more flexible and
there are no stress risers as there are no reinforced areas.
[0012] In accordance with further features of the present
invention, the connector is an elongate corrugation integral with
the body member along the periphery or perimeter thereof and
dimensioned to fit over a terminal lip or rib of the chamber wall.
The corrugation cooperates with the lip or rib to loosely couple
the body member to the chamber wall to allow for slippage between
the corrugation and the lip or rib in a direction radial with
respect to the chamber wall and the body member and transverse to
the corrugation and the lip or rib.
[0013] In an end section pursuant to the present invention, soil
arching also arises around the perimeter of the shell. Loads from
the end section are transferred to the abutting chamber at the web
of the corrugation. Since the end section is a separate component,
not integral to the chamber or bonded in any way to the chamber,
the end section is allowed to slip at the bearing surface against
the abutting chamber. The perimeter of the end section is
accordingly allowed to move radially outwardly and upwardly,
relieving load in the end section. Additional movement in the
direction of the load, away from the load, occurs as the web of the
chamber lip, rib or corrugation bends slightly. Solids around the
corrugation ultimately resist loads carried in compression by the
crest of the corrugation of the chamber. Similarly, solids around
the perimeter of the end section limit the outward radial movement.
Infinite slippage with no radial support would eventually lead to a
loss of compressive strength and failure by bending. Like
surrounding soils limiting the movement of the chamber, the
perimeter soil support limits the outward movement of the
perimeter.
[0014] In the design of thermoplastic structures, the reduction of
stresses in the plastic is a key objective since plastics creep
under continuous load. In the end section of the present invention,
long-term creep is managed and used to advantage to develop soil
arching and ultimately relaxation of stresses in the end section.
The key advantage of avoiding stress concentrations by elimination
of reinforcement ribs is especially beneficial when the end section
is made of polyethylene. Polyethylene exhibits a behavior of
cracking under sustained tensile stress. The end section of the
present invention minimizes tensile stresses and carries loads by
acting primarily in compression.
[0015] Pursuant to a further feature of the present invention, the
corrugation defines a longitudinally arcuate cross-sectionally
tapered channel receiving the lip or rib on the chamber wall, which
itself may take the form of a corrugation.
[0016] The body member of an end section in accordance with the
present invention has a half dome shape with a pair of arcuate
edges, the connector or corrugation being disposed along an upper
one of the edges.
[0017] An end section for a stormwater containment assembly
comprises, in accordance with a particular embodiment of the
present invention, a substantially half-dome-shaped body member
having a smooth convex outer surface with an absence of outwardly
projecting reinforcement ribs thereon and further having a smooth
concave inner surface with an absence of inwardly projecting
reinforcement ribs thereon. The end section further comprises an
elongate longitudinally arcuate corrugation integral with the body
member along an edge or perimeter thereof.
[0018] Reinforcement structures, particularly ribs, typically
extend to the edges of the end sections and serve to transmit
tensile and compression forces. Reinforcement ribs and other
reinforcement structures concentrate tensile and/or compressive
stresses and channel the stresses along paths defined by the ribs.
The ribs and other reinforcement structures are viewed as necessary
to accommodate and support the immense weight of overlying soil and
asphalt layers that creates both vertical and horizontal forces on
the end section.
[0019] A stormwater containment assembly in accordance with the
present invention comprises a chamber member having an arched or
vaulted wall and an end section including a substantially
half-dome-shaped body member and a connector disposed on the body
member along a periphery or perimeter thereof, for coupling the
body member to the arched or vaulted wall. The dome shaped body
member has a smooth convex outer surface with an absence of
reinforcement structures thereon and further has a smooth concave
inner surface with an absence of reinforcement structures thereon.
More specifically, the smooth convex outer and inner surfaces of
the body member are devoid of structures that span the body member,
i.e., that extend from one edge to an opposing edge of the body
member so as to carry or channel stresses across the body member
from an upper side to a lower side thereof.
[0020] In one embodiment of the present invention, the inner and
outer surfaces of the end section body member are completely smooth
and respectively free of inwardly and outwardly projecting ribs of
whatever kind.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a perspective disassembled view of a stormwater
containment system in accordance with the present invention.
[0022] FIG. 2 is a side elevational view of a vaulted or arched
main body section of the stormwater containment system of FIG.
1.
[0023] FIG. 3 is a side elevational view of an end cap or end
section of the stormwater containment system of FIG. 1.
[0024] FIG. 4 is a partial vertical longitudinal cross-sectional
view of the stormwater containment system of FIG. 1.
[0025] FIG. 5 is a schematic vertical cross-sectional sectional
view of an earthworks structure incorporating the stormwater
containment system of FIGS. 1-4.
DETAILED DESCRIPTION
[0026] FIG. 1 shows a stormwater containment system 10 including a
vaulted or arched main chamber section 12 and a domed end cap or
end section 14, both made of plastic materials. Generally,
acceptable thermoplastic materials include virgin impact-modified
polypropylene copolymers, virgin high molecular weight or medium
molecular weight polyethylene or impact-modified polypropylene
copolymers with recycled content or high density or medium density
polyethylene with recycled content. In a preferred embodiment, main
chamber section 12 is made from virgin impact-modified
polypropylene copolymers and end cap 14 is made from virgin high
molecular weight polyethylene. The main chamber 12 and domed end
cap 14 could alternatively be made from thermoset materials.
Containment system 10 is typically installed underground below a
pavement layer 16, as depicted in FIG. 5. End caps or sections 14
may be provided at one or both ends of a line of interconnected
chamber sections 12.
[0027] Chamber section 12 has an elliptical cross-section in a
plane perpendicular to a longitudinal axis 18, along line A-A in
FIG. 2. Chamber section 12 has a wall 20 provided with a plurality
of longitudinally spaced, outwardly projecting corrugations 22 and
a plurality of longitudinally spaced, outwardly projecting ribs 24.
Corrugations 22 have flat crests or landed bights 26 with
elliptical surfaces extending parallel to axis 18. Corrugations 22
further include side panels or webs 28 that are partially
transverse to axis 18. At their bases along opposite sides of wall
20, corrugations 22 flare in opposing longitudinal directions and
are formed with outwardly extending crest-stiffening ribs 30.
[0028] Ribs 24 alternate, or are interleaved, with corrugations 22.
Ribs 24 are of smaller outside diameter than corrugations 22 and
have smooth convex outer surfaces. Ribs 20 are located midway in
flat valleys 32 between adjacent or successive corrugations 18.
[0029] Opposite ends of chamber section 12 are formed with a lower
joint corrugation or rib 34 and an upper joint corrugation or rib
36 that enable a coupling of the chamber section 12 on a lower side
to end section 14 and to another chamber section 12 on an upper
side. Chamber wall 20 is further provided at opposite ends with
handling ports 64 (four in number).
[0030] End section 14 comprises a substantially half-dome-shaped
body member 38 having a smooth concave inner surface 40 and a
smooth convex outer surface 42 that are free of reinforcement ribs
or other projecting structures. Outer surface 42 is provided with
recessed handgrips 44 and 46 for enabling a single individual to
carry and set the end section 14 in place during installation. End
section 14 further comprises an elongate longitudinally arcuate
connector corrugation 48 disposed on body member 38 for coupling
the body member to stormwater chamber wall 20. Body member 38 of
end section 14 has a substantially half dome shape (with an
elliptical form, long axis oriented vertically, short axis
horizontally) with a pair of arcuate edges 50 and 60, connector
corrugation 48 being disposed along upper edge 50, which extends in
a vertical plane.
[0031] Connector corrugation 48 includes a pair of leg webs 52 and
54 connected to one another by a crest or bight web 56. In coupling
end section 14 to chamber section 12, end-cap corrugation 48 is
placed over lower joint corrugation or rib 34. As explained more
fully hereinafter, this partially loose coupling (along an upper
side of the end section) accommodates a limited deformation in end
section 14 and facilitates a reduction in load owing to soil
overarching. End section 14 is provided with three screw holes 62
(only one shown in FIG. 3) for fixing the periphery or edge 50 to
chamber wall 20 to maintain a positive connection during
backfilling. It is to be noted that too many screws could mitigate
the slip feature. Screws are preferred through the crest and
generally do not provide enough fixation to prevent the slip.
Consequently, no more than 3 screws should be provided to secure
the end section 14 for installation without effectively limiting
slip.
[0032] Connector corrugation 48 defines an elongate channel 58 that
receives the coupling rib or corrugation 34 on chamber wall 20.
Through its length, channel 58 extends along a generally elliptical
path and has a tapered transverse cross-section.
[0033] The domed shape of end section 14 serves to distribute
compressive loads throughout the body 38 of the end section and
substantially reduces, if not eliminates, internal tensile
stresses. Internal stresses do not build up at any point within end
section 14 but instead are directed uniformly to the periphery or
perimeter 50 of the end section and transmitted therethrough to
stormwater chamber wall 20.
[0034] In end section 14, soil loads on the outside surface 42 of
the end section are carried more uniformly by the end section
without the stress concentrations that otherwise occur at the
reinforcement structures. Moreover, without reinforcing ribs, loads
carried by end section 14 are more evenly distributed around upper
edge or perimeter 50 of the end section and ultimately through the
abutting chamber 12 to the surrounding soils.
[0035] In comparison with conventional reinforced end sections, end
section 14 has more freedom to deform slightly under a soil load.
As end section 14 deforms, the surrounding soils coalesce in an
arched formation and carry loads that would otherwise be carried by
the end section. Although reinforced shells in their entireties may
be flexible, end section 14 is uniformly more flexible than the
reinforced shell so that any particular area of the present end
section is more flexible and there are no stress risers as there
are no reinforced areas.
[0036] As discussed above, connector corrugation 48 is an elongate
corrugation integral with body member 38 along edge or perimeter 50
thereof and dimensioned to fit over terminal corrugation or rib 34
of chamber wall 20. Coupling corrugation 48 cooperates with
terminal corrugation or rib 34 (or 36) to loosely couple body
member 38 of end section 14 to chamber wall 20 of chamber section
12 to allow for slippage between the corrugation and the
corrugation or rib in a direction radial with respect to the
chamber wall and the body member and transverse to the corrugation
and the lip or rib.
[0037] In end section 14, soil arching also arises around the
perimeter of the shell. Loads from end section 14 are transferred
to the abutting chamber at the webs 52, 54, 56 of coupling
corrugation 48. Since end section 14 is a separate component, not
integral to chamber section 12 or bonded in any way to the chamber,
the end section is allowed to slip at the bearing surface--web
segments of terminal corrugation 34--against the abutting chamber
section 12. The perimeter 50 of end section 14 is accordingly
allowed to move radially outwardly and upwardly, relieving load in
the end section. Additional movement in the direction of the load,
away from the load, occurs as the web of the chamber lip, rib or
corrugation 34 bends slightly. Solids around the corrugation
ultimately resist loads carried in compression by the crest of the
corrugation of the chamber.
[0038] As depicted in FIG. 5, a plurality of separate underground
stormwater storage compartments with respective end sections 14 may
be installed in parallel to one another (respective longitudinal
axes 18 parallel) below pavement layer 16. Spacers (not shown) may
be provided to connect laterally adjacent chamber sections 12 to
one another. In one embodiment, chamber sections 12 each have a
length of 90'' (2286 mm), a height of 45'' (1143 mm), and an
outermost base width of 77'' (1905 mm), while end sections 14 each
have a base width (perpendicular to axis 18) of 71'' (1803 mm), a
base length (parallel to axis 18) of 25.5'' (673 mm) and a height
of 45.1'' (1145 mm).
[0039] Per FIG. 5, the stormwater containment compartments are
installed with foundation and embedment stone layers 66, 68, 70,
and 70. Lowermost layer 66 is a foundation stone layer 68 below the
stormwater storage chamber sections 12 and end sections 14.
Lowermost layer 66 consists of clean crushed angular stone with a
nominal size distribution of 3/4'' to 2'' (19 mm-51 mm). Layer 66
is subjected to plate compaction or rolling to achieve a flat
surface on which to set chambers and end caps. Embedment stone
layer 68 surrounds the chambers 12 and end sections 14 above the
foundation layer 66 and also consists of clean crushed angular
stone with a nominal size distribution of 1/4'' to 2'' (19 mm-51
mm). No compaction of layer 68 is required. Layer 70 consists of
granular well graded soil/aggregate mixtures, less than 35% fines.
Fill material for layer 70 starts from the top of embedment stone
layer 68 to 18'' above the tops of chamber sections 12 and the
peaks of end sections 14. Layer 70 is subjected to compaction after
12'' of material over the chambers is laid down. Compact additional
layers up to 6'' (152 mm) maximum lift to a minimum 95% Standard
Proctor Density. Roller gross weight should not exceed 12,000 lb
(53 kN). The dynamic force applied should not exceed 20,000 lb. (89
kN). Alternatively, most pavement subbase materials can be used in
lieu of layer 70. Fill material for layer 72 starts from the top of
layer 70 and extends to the bottom of pavement layer 16. Layer 72
consists of any rock or soil materials, native soils or material
specified by engineering plans. In general, layer 72 is prepared
according to engineering plans. Paved installation may have
stringent material and preparation requirements. It is recommended
that there be at least 24'' of fill material from the tops or peaks
of the stormwater chamber sections 12 to the bottom of a flexible
pavement layer 16. For non-paved installations where rutting from
vehicles may occur, a 30'' fill from the tops or peaks of the
stormwater chamber sections 12 to the finished grade is
recommended.
[0040] A non-woven geotextile meeting AASHTO M288 Class 2
separation requirements is to be installed to completely envelop
each stormwater each containment system 10, comprising one or more
chamber sections 12 and at least one end section 14, and to prevent
soil intrusion into the crushed angular stone. Adjacent geotextile
rolls should overlap per AASHTO M288 guidelines.
[0041] Although the invention has been described in terms of
particular embodiments and applications, one of ordinary skill in
the art, in light of this teaching, can generate additional
embodiments and modifications without departing from the spirit of
or exceeding the scope of the claimed invention. Accordingly, it is
to be understood that the drawings and descriptions herein are
proffered by way of example to facilitate comprehension of the
invention and should not be construed to limit the scope
thereof.
* * * * *