Title: Re-enforced composite sheet piling segments
Abstract: A re-enforced composite sheet piling segment is disclosed. The segment of sheet piling includes multiple panels. The panels of the segment come together at an angle to form a corner. A re-enforcement is placed in the corner of the segment. The re-enforcement has a cross-sectional area that is convex shaped.
Patent Number: 7,008,142 Issued on 03/07/2006 to Moreau
| Inventors:
|
Moreau; Jeff (225 Town Park Dr., Suite 300, Kennesaw, GA 30144)
|
| Appl. No.:
|
695234 |
| Filed:
|
October 28, 2003 |
| Current U.S. Class: |
405/281; 405/274 |
| Current Intern'l Class: |
E02D 5/02 (20060101) |
| Field of Search: |
405/274-281
|
References Cited [Referenced By]
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| 2128740 | Aug., 1938 | Dougherty.
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| 2332812 | Oct., 1943 | Rieger.
| |
| 4690588 | Sep., 1987 | Berger.
| |
| 4863315 | Sep., 1989 | Wickberg.
| |
| 5145287 | Sep., 1992 | Hooper et al.
| |
| 5292208 | Mar., 1994 | Berger.
| |
| 5333971 | Aug., 1994 | Lewis.
| |
| 6000883 | Dec., 1999 | Irvine et al.
| |
| 6033155 | Mar., 2000 | Irvine et al.
| |
| 6053666 | Apr., 2000 | Irvine et al.
| |
| 6092346 | Jul., 2000 | Even et al.
| |
| 6106201 | Aug., 2000 | Bourdouxhe.
| |
| 6190093 | Feb., 2001 | Bastian et al.
| |
| Foreign Patent Documents |
| 0545838 | Sep., 1993 | EP.
| |
Primary Examiner: Lagman; Frederick L.
Attorney, Agent or Firm: Mixon; David E., Bradley Arant Rose and White, LLP
Parent Case Text
This is a Divisional Application of U.S. patent application Ser. No. 10/286,564
entitled "Re-Enforced Composite Sheet Piling Segments" that was filed on Nov. 1, 2002.
Claims
What is claimed is:
1. A segment of sheet piling, comprising:
a plurality of panels, where each panel is joined to at least one other panel
to form a corner with an interior angle and an exterior angle, where the interior
angle is smaller than exterior angle; and
a re-enforcement with a convex cross-sectional area that is located in the interior
angle between the panels.
2. The segment of sheet piling of claim 1, where the panels are made of an anisotropic material.
3. The segment of sheet piling of claim 1, further comprising:
a first connector that is formed on a panel at a first edge of the segment of
sheet piling, where the first connector is configured to connect two segments of
sheet piling together; and
a second connector that is formed on a panel at a second edge of the segment
of sheet piling, where the second connector is configured to connect two segments
of sheet piling together.
4. The segment of sheet piling of claim 3, where the first connector is a male connector.
5. The segment of sheet piling of claim 4, further comprising a re-enforcement
with a triangular cross-sectional area that is located between the male connector
and the panel.
6. The segment of sheet piling of claim 3, where the second connector is a female connector.
7. A segment of sheet piling, comprising:
a plurality of panels, where each panel is joined to at least one other panel
to form a corner with an interior angle and an exterior angle, where the interior
angle is smaller than the exterior angle; and
means for re-enforcing the interior angle of the corner with a re-enforcement
with a convex cross-sectional area.
8. The segment of sheet piling of claim 7, further comprising:
a male connector on at least one end of the segment; and
means for re-enforcing the male connector.
Description
BACKGROUND OF INVENTION
1. Field of the Invention
The invention relates generally to the composition and structure of building
materials. More specifically, the invention relates to re-enforced sheet piling segments.
2. Background Art
Sheet piling is a construction material that is commonly used to build walls
such as retaining sea-walls. The sheet piling is typically manufactured in individual
segments that are attached to other segments to form a continuous wall. Since the
segments are usually driven into the ground for stability, the segments may be
several meters tall.
Sheet piling was once commonly made with steel or other metals. However, such
piling may now be made with fiber re-enforced polymers (FRP). FRPs are formed out
of a cured resin that has been re-enforced with fibers made of materials such as
glass. The resin typically may be polyester or vinylester. While not as strong
as steel, these materials offer better performance due to resistance to corrosion
and other effects of chemical environments. Steel is an example of an "isotropic"
material in that loads are distributed equally through out the material. In contrast,
FRPs are generally considered "anisotropic" in that loads are not distributed equally
in the material. For example, a composite material such as fiberglass is stronger
along the orientation of the glass fibers than in other areas of the material.
While the FRP materials are resistant to corrosion, they will absorb water
when exposed to that environment for long periods of time. This is a particular
problem when sheet piling made from FRPs is used to build a seawall. If the sheet
piling is exposed long enough and absorbs enough water, the structure may become
weakened to the point of failure. Additionally, when FRP sheet piling is used to
build a seawall, it also is exposed to active pressure from soil on one side of
the wall while being exposed to a passive pressure from the water on the other
side. Over time, the panels of material can weaken and the panels may deform or
fail catastrophically under this type of pressure alone or combined with any weakening
of the material from water absorption.
The potential for such failures are particularly acute at the joints that join
the panels together and at any corner or edge of a panel. According to modeling,
maximum tension occurs at the corner angles of the panels. Typical solutions involved
re-enforcing points of potential failure on a panel of sheet piling with a concave
shaped re-enforcement. However, these re-enforcements have proven insufficient
to provide the additional strength to a panel made of anisotropic materials (such
as FRPs).
SUMMARY OF INVENTION
In some aspects, the invention relates to a segment of sheet piling, comprising:
a plurality of panels, where each panel is joined to at least one other panel at
an angle; and a re-enforcement with a convex cross-sectional area that is located
in the angle between the panels.
In other aspects, the invention relates to a segment of sheet piling, comprising:
a plurality of panels, where each panel is joined to at least one other panel to
form a corner; and means for re-enforcing the corner.
Other aspects and advantages of the invention will be apparent from the following
description and the appended claims.
BRIEF DESCRIPTION OF DRAWINGS
It should be noted that identical features in different drawings are shown with
the same reference numeral.
FIG. 1 shows an overhead view of two joined sheet piling segments in accordance
with one embodiment of the present invention.
FIG. 2 shows an overhead view of a re-enforced corner of a sheet piling segment
in accordance with one embodiment of the present invention.
FIG. 3 shows and overhead view of a joint of two joined sheet piling segments
in accordance with one embodiment of the present invention.
DETAILED DESCRIPTION
FIG. 1 shows an overhead view of two joined sheet piling segments
10a
and
10b in accordance with one embodiment of the present invention.
The two sheet piling segments or "sheets" shown are typically used in construction
of seawalls in either freshwater or saltwater environments. In the present embodiment,
each sheet
10a and
10b is made of three distinct panels
12 that are roughly configured in a "Z" shaped arrangement. Each panel fits
with adjacent panels to form a corner
14 of the segment. The panels
12
form an angle of approximately 120° at each corner
14. In alternative
embodiments, the number of panels in a segment of sheet piling may vary along with
their relative angles to each other.
The two segments
10a and
10b are connected at a joint.
One panel
10a has a male joint attachment
16, while the other
panel
10b has a female joint attachment
18. These two attachments
16 and
18 fit together to form the joint that interlocks the segments
10a and
10b. Multiple segments are fitted together
to form a length of wall. In this embodiment, each segment has a male joint attachment
16 and a female joint attachment
18 on alternative ends of the segment.
In alternative embodiments, segments may have two male attachments or two female attachments.
If the segments are used to construct a seawall, forces are exerted on the panels
12 and the joint on one side by soil and on the other side by water. In
the present embodiment, the segments
10a and
10b are
re-enforced along the panels
20 and the corners
22 in order to prevent
the segments from bulging at these points and potentially failing catastrophically.
The panel re-enforcement
20 has a circular cross-section and is centered
on the panel
12. An overhead view of the corner re-enforcement
22
is shown in FIG. 2 in accordance with one embodiment of the present invention.
The re-enforcement
22 is centered on the corner
14 of the two panels
12 of the sheet piling segment. Re-enforcing this area of the corner
14
helps prevent the panels
12 from bulging outward and compromising the integrity
of the corner
14. The re-enforcement
22 has a convex cross-sectional
shape that maximizes the re-enforcement strength for the corner while optimizing
the use of materials to manufacture the sheet. A re-enforcement with a convex cross-sectional
shape is particularly suited for used with anisotropic materials such as FRPs.
A convex re-enforcement helps prevent rupturing of a matrix of fibers in the material.
In order to prevent separation of the sheet piling segments
10a and
10b at the joint, the male joint attachment
16 is re-enforced
between the attachment
16 and its panel
12. An overhead view of the
male joint attachment re-enforcement
24 is shown in FIG. 3 in accordance
with one embodiment of the present invention. The re-enforcement
24 is centered
between the panel
12 and the male attachment
16. Re-enforcing this
area of the attachment
16 helps prevent twisting and buckling of the male
attachment
16 that would result in its separation from the female attachment
18. The re-enforcement
24 has a triangular cross-sectional area that
maximizes the re-enforcement strength of the attachment
16 while optimizing
the use of materials. A triangular shaped re-enforcement
24 is used due
to the 90° angle between the panel
12 and the bottom of the male attachment
16.
In some embodiments, the dimensions of the sheet may be 18 inches long (i.e.,
the linear length from the male attachment to the female attachment of a segment)
and 8 inches wide (i.e., the linear distance between the two end panels of the
segment). The segment may have a height of several feet or longer. The thickness
of a panel of the segment may be 0.25 inches. In alternative embodiments, these
dimensions may vary accordingly.
The segment of sheet piling may be made of polyurethane material. Polyurethane
is a material with hydrophobic properties of low water absorption, even when the
outer skin has been breached (e.g., by drill holes). The material is also highly
impact resistant and stable under prolonged exposed to ultra-violet (UV) radiation
and saltwater. In typical applications, polyurethane may be "heat cured". Curing
is a chemical process where a liquid material (e.g., a resin) cross-links to form
a solid. The curing process may be initiated or accelerated by the application
of heat. It is commonly done during the molding process and may take a few seconds
to a few hours for completion depending on the materials involved.
Polyurethane elastomers are one member of a large family of elastic
polymers called rubber. Polyurethane may be a liquid that can be molded into any
shape or size. It is formed by reacting a polyol (an alcohol with more than two
reactive hydroxyl groups per molecule) with a diisocyanate or a polymeric isocyanate
in the presence of suitable catalysts and additives. The chemical formula for polyurethane
is: C
3H
8N
2O. A wide variety of diisocyanates and
polyols can be used to produce polyurethane in alternative embodiments. It should
be understood that the term "polyurethane" includes a wide variety of thermoplastic
polyurethane elastomers that are manufactured differently and may have different
performance characteristics.
In an alternative embodiment, polyurethane may be used as a base component of
a multi-component mixture. Such a multi-component material includes: a hardening
catalyst such as isocyanate and a resin such as polyurethane. The advantage of
a multi-component mixture is that it does not require heat during the curing process.
In alternative embodiments, alternative materials could be used that are suitable
as a hardening catalyst and a resin.
In an alternative embodiment, a polyurethane based material (either alone as a
single component material of polyurethane or in a multi-component material) is
used with re-enforcing fibers to form the sheet piling segments. The segments are
manufactured by a process called "pultrusion". With the pultrusion process, the
fibers are pulled through a wet bath of polyurethane resin. The fibers are wetted
with polyurethane by the bath. The wet fibers are then cast into a matrix to increase
the structural strength of the segment. The matrix may be a woven pattern whose
design may vary to increase the strength of the finished product. The material
is then pulled through a die where the segment of sheet piling is formed. The segment
is then heat cured to solidify the polyurethane and complete the manufacture of
the segment. The fibers used in the process may be made of glass, carbon, or other
suitable material that provides strength to the material.
In an alternative embodiment, sheet piling segments may be made of standard FRP
materials with a water-resistant gel coating applied to the surface of the piling.
The gel-coating will prevent absorption of water by the underlying FRP material
and consequently prevent weakening of the integrity of the sheet piling segment.
An example of a suitable material for use as a gel coating is a "neopental isothalic
acid resin" system. This material protects FRPs from water absorption while it
also resists barnacles and other parasites. In other embodiments, other suitable
water-resistant materials could be applied to the surface of the FRP to prevent
water absorption.
While the invention has been described with respect to a limited number of
embodiments, those skilled in the art, having benefit of this disclosure, will
appreciate that other embodiments can be devised which do not depart from the scope
of the invention as disclosed here. Accordingly, the scope of the invention should
be limited only by the attached claims.
*
