US20130318896A1

US20130318896A1 - Pre-Tensioned Discrete Element Support System

Info

Publication number: US20130318896A1
Application number: US13/908,805
Authority: US
Inventors: Donald Scott Rogers
Original assignee: Individual
Current assignee: Newpark Mats and Integrated Services LLC
Priority date: 2012-06-04
Filing date: 2013-06-03
Publication date: 2013-12-05

Abstract

A matting system comprised of an assembly of discrete, individual small mat segments connected by pre-tensioned cable elements. The mat segments are configured to displace at the connecting surfaces of the mat segments at a predetermined load. The pre-tensioned cable elements holding the mat segments together are elastic through a reasonable displacement range so that the mat segments of the matting system will reassemble after the applied load is removed.

Description

PRIORITY

This application claims priority to U.S. provisional application Ser. No. 61/655,017 tiled Jun. 4, 2012, the entire content of which is hereby incorporated by reference.

FIELD OF THE INVENTION

This invention relates generally to the field of construction and crane matting, and more particularly to a pre-tensioned matting assembly comprised of a plurality of is discrete mat segments.

BACKGROUND OF THE INVENTION

Matting systems are utilized to provide temporary support surfaces or structures for construction sites and for temporary roadways. Such matting systems are typically utilized in areas having poor soil conditions that would not otherwise be accessible to heavy trucks, cranes, and construction equipment. Typical matting systems are comprised of a plurality of boards or panel elements that are fastened together to create a mat surface. Such designs rely on the properties of the beam strength (strength is in direction of beam) of the boards or panel elements that are fastened together to form a matting system.
The failure of such matting systems is primarily is due to excessive moment loads on the mat components (mat bending). Increasing the size of the boards or panel elements of the matting system increases the moment load potential for the matting system. Thus, a very small mat is difficult to break when compared to a large mat. In practice, mats that are very small are not practical to use because of high installation costs and the number of connections required.
Consequently, a need exists for a matting system that will have the load bearing characteristics of a very small mat with the construction efficiency associated with large matting systems.

SUMMARY OF THE INVENTION

The presented design provides a matting system having a support structure configured for a desired maximum design load for placement on a comparatively compliant underlayment or sub-base (soil in the case of a construction mat). When design load (rated load) for the matting system is exceeded, the support structure undergoes a geometrical change in configuration that allows additional support for the applied load from the underlying elements.
The presented design provides a matting system comprised of an assembly of a plurality of discrete, individual small parts or mat segments that are held together by a pre-tensioned wire or rod connector. The mat segments are designed to “give”, i.e. separate, at their adjoining connecting surfaces when the matting system is overloaded. The pre-tensioned connector holding the mat segments together is elastic through a reasonable displacement range so that the matting system will reassemble itself after the applied load is removed. Energy stored in the pre-tensioned connector assembly facilitates the positive return of the overstressed support structure back to its initial configuration.
In the presented design, the primary strength (for the matting system having a one dimensional tension system) is in the direction of assembly. The prefabricated “beam” of mat segments may be relatively weak when initially fitted together but the beam strength of the mat segments greatly enhanced when the mat segments are linked together by the pre-tensioned connector. Further, the construction geometry of the linked mat segments need not be limited to the shape of a beam or any other particular shapes. The mat segments would be made from a variety of skeletonized elements framed by a matrix of suitable material such as one made from plastic composites.
The construction described above can stand on its own or could be part of a more complicated composite structure that satisfies additional functional needs. As an example, an assembly of rigid structural elements could be covered by a softer outer material. This outer material could act to protect the rigid structural elements from impact loads and could also serve the activity for which the mat is employed (e.g., non-skid surface). In this way, multiple support structures could be housed in matting system comprised, of a matrix of differing material.
The matting system may also be provided with pre-tensioned connectors in multiple dimensions.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-section view of a matting system in accordance with the description set forth herein.

FIG. 2 is a partial top view of the matting system shown in FIG. 1

FIG. 3 is a schematic cross-section view of the matting system of FIG. 1 showing the interaction of the mat segment elements in response to an applied load that is less than the system design load.

FIG. 4 is a cross-section view of the matting system of FIG. 1 showing the interaction of the mat segment elements in response to an applied load, that is greater than the system design load.

FIG. 5 is a cross-section view of a matting system in accordance with the description set forth herein, the matting system being placed over an uneven support surface.

FIG. 6 is an alternate embodiment of the matting system of FIG. 1.

FIG. 7 is an alternate embodiment of the matting system of FIG. 1 having a shear force resistant mat segment interface.

FIG. 8 is an alternate embodiment of the mat segments of the matting system of FIG. 1, showing a mat segment having a skeletonized frame configured for a matrix filling of a desired material.

FIG. 9 shows an internal support frame or rib element for a mat segment.

FIG. 10 is a cross-sectional view of an alternate embodiment of the mat segments of the matting system of FIG. 1, showing a mat segment having the internal ribs shown in FIG. 9.

FIG. 11 is schematic top view of an alternate embodiment of the mat segments of the matting system of FIG. 1 with the connectors configured to intersect at a desired direction.

DESCRIPTION OF THE EMBODIMENT

Referring now to FIG. 1 and FIG. 2, there is shown the matting system (10) of Applicant's invention. The matting system (10) is comprised of a plurality of discrete, individual mat segments (12), preferably in strips or splines, each having at least one retainer bore (15). The mat segments (12) are held together by a pre-tensioned wire or rod connector (14) positioned through the retainer bore (15) of the adjoining mat segments and secured in tension by a fastener such as a nut (16). Placing the connector (14) in tension in the manner similar to that used in post-tensioned concrete slabs is thought to be suitable. The wire or rod connector (14) may be of any suitable material thought it is thought that steel rods or steel wire cables will be utilized.
The mat segments (12) are designed to “give” or separate at their adjoining connecting surfaces (11) at a predetermined load as the pre-tensioned connector rod deforms when the matting system is overloaded. As shown multiple mat segments are utilized to create the matting system (10). These mat segments (12) have an adjoining connecting surface (11) that is designed to facilitate deflection of the mat segments 12) during periods when the matting system is overloaded. It is thought that a matting system (to) comprised of mat segments (12) having connecting surfaces (11) comprised of concave surfaces (18) interfacing with adjoining convex surfaces (20) will serve to provide the desired deflection of the mat segments.
The pre-tensioned connector (14) holding the mat segments (12) together is designed to be elastic through a desired range of load conditions and displacements of adjoining mat segments (12) so that the matting system (10) will reassemble itself after the applied load is removed. Energy stored in the pre-tensioned connector (14) in the elastic range of the pre-tensioned connector will facilitate the positive return of the displaced mat segments (12) back to the initial mat configuration when the load displacing the mat segments and overstressing the matting system (to) is removed.
As further shown in FIG. 1 and FIG. 2, the interconnected mat segments (12) of the matting system (10) may include a surfacing overlay (21) to provide a non-skid surface to enhance surface traction, to protect the components of the mat segments from impact loads to prevent wear and tear, or to enhance weather resistance. The surfacing overlay (21) may be a discontinuous us overlay shown as (22) which would cover each individual mat segment (12) or a continuous overlay shown as (24) that would cover the upper surface of multiple mat segments (12) or the surface of the entire matting system (10). The overlay (21) may also cover the entire matting system (10), top and bottom, or the matting system (10) may be completely encased or encapsulated by the overlay (21).
Placement of the desired surfacing overlay (21) may be varied over the upper surface of the matting system (10) so that the overlay (21) may be tailored as desired to provide a surfacing (21) specific to a desired use. The surfacing overlay (21) may be any suitable surfacing material such as resilient asphalt or other pliable surfacing material such as a replaceable composite or wooden surfacing. Resilient asphalt may be particularly suitable for a mat system (10) having a continuous overlay (24).
FIG. 3 shows a schematic cross-section view of the matting system (10) of FIG. 1 positioned on an under-laying surface (30) to depict the interaction between adjoining mat segments (12) in response to an applied load (P) that is less than the design load of the matting system. A desired tension load (T) is applied by the pre-tensioned connector (14) Which compresses the mat segments (12) together. In such a position the mat segments (12) are held together by the tensioned connector (14) with the concave surfaces (20) positioned within the convex surfaces (18) of adjoining mat segments 12).
FIG. 4 shows a schematic cross-section view of the matting system (10) of FIG. 1 positioned on an under-laying surface (30) to depict the interaction between adjoining mat segments (12) in response to an applied load (P) greater than the design load of the matting system. As shown the pre-tensioned connector (14) is held at a desired design tension load (T) which compresses the mat segments (12) together. The connector (14) holds the mat segments (12) together and provides a predetermined reasonable elastic range of displacement of adjoining mat segments (12). This elastic range allows the adjoining mat segments (12) to be temporarily displaced from each other under overload as shown, with the concave surfaces (20) moved from within the convex surfaces (18) of adjoining mat segments (12). The mat segments (12) return to the configuration shown in FIG. 3 when the applied load (P) is decreased to the design load or less or removed, all together. When the design load (P) (rated load) for the matting system (10) is exceeded, the matting system (10) undergoes a geometrical change in configuration of the mat segments (12) that allows additional support for the applied load from the underlying subgrade elements.
FIG. 5 shows a cross-section schematic view of a matting system (10) in accordance with the description set forth herein, The matting system (10) is shown being placed over an uneven subgrade support surface (30). For installation over varying, uneven, or imperfect subgrade (30), such as one have a curb (32) or a surface depression, mat segments (12) the matting system (10) may be placed as desired to conform to and cover any surface curb (32) or surface depression. Then matting system (10) maybe post-tensioned by applying tension forces to the connector (14) to restrain the mat segments together to enhance the structural integrity of the matting system. Because the mat segments (12) are held together by a desired tension (T) in the connector (14) at a predetermined elastic range, the matting system (10) provides for displacement of the segments so that it may be used over uneven support surfaces (30).
Release of tension from the connector (14) will allow the mat to be reformed for another use in another configuration increasing the versatility and applications for the matting system.
Other configurations may also be utilized for the connection surfaces of adjoining mat segments (12) of a matting, system (10), For example, the matting system (10) may be configured simply as an enlarged two or three segment matt with adjoining segments (12) having a single concave surface adjoining a single convex surface as the connecting surface (11) as shown in FIG. 6. The matting system (10) could be comprised of mat segments (12) having adjoining connecting surfaces (11) for resisting shear forces. One such configuration may be adjoining mat segments (12) having a shear key or tongue (11 a) and a keyway or groove (11 b) for the connecting surfaces (11) as shown in FIG. 7.
A schematic top view of another embodiment of a mat segment (12) is shown in FIG. 8. Referring to FIG. 8, the matting system (10) may be comprised of a plurality of mat segments (12) having an external skeleton or frame (13) comprised of external frame walls (13 a). The walls (13 a) provide an open area (17) for containing a filling of a suitable matrix material (17 a), such as a polymer matrix. The walls (13 a) of the skeletonized frame (13) of the mat segments (12) may be made of any suitable material such as aluminum, aluminum alloys, steel, or plastic or polymer composites. The matrix (17 a) may be a polymer compound, an asphalt mix, concrete, or another suitable fill material. Desired adjoining connecting surfaces (11) may be incorporated into the frame (13) such as surfaces for facilitating deflection or for resisting shear loads.
Each mat segment (12) could also be provided with an internal support frame or rib element (19) such as that shown in FIG. 9. The rib element (19) may include a retainer bore (15) for receiving a connector (14). A polymer matrix molded around the internal frame (19) would complete a mat segment (12). The rib element (19) may be fabricated as a metal casting or from a molded polymer. As shown, the rib element (19) may be provided with the mat connecting surfaces (11) comprised of concave surfaces (18) interfacing with adjoining convex surfaces (20) or any other suitable connecting surfaces. FIG. 10 presents a schematic side view of an alternate embodiment of the mat segments (12) of the matting system of FIG. 1, showing a mat segment having the internal ribs (19) with concave surfaces (18) interfacing with adjoining convex surfaces (20) as shown in FIG. 9.
The construction described above for the matting system (10) can stand alone as a single mat or could be incorporated into a more complicated matting structure that satisfies additional functional needs. The matting system (10) may be configured with mat segments (12) having pre-tensioned or post-tensioned connectors (14) extending in multiple directions through the mat segments (12) as desired to provide additional mat flexibility and to distribute bending loads on the matting system (10) in multiple directions. For example, as shown in FIG. 11, connectors (14) may be configured to intersect or cross each at a desired angle such as diagonally or at ninety degree angles to retain the mat segments (12) in a matting system (10) in a desired position.
It will be evident that various other changes may be made in the form, construction and arrangement of the parts of the matting system described herein without departing from the spirit and scope of the invention or sacrificing its material advantages. It is thought that the proposed matting system presented herein will be understood from the foregoing description. The form described herein is intended to be merely an example embodiment of the invention.

Claims

I claim:

1. A matting system comprising:

(a) a plurality of discrete mat segments, each said mat segment configured with corresponding adjoining connecting surfaces, whereby when said adjoining connecting surfaces are fitted together, said adjoining connecting surfaces facilitate displacement of said mat segments at a predetermined mat load;

(b) an elongated connector extending through each said mat segment, said connector being placed in tension to hold said mat segments together in a desired configuration.

2. The matting system recited in claim 1 wherein said elongated connector is elastic through a desired displacement range.

3. The matting system as recited in claim 2 wherein energy stored said connector facilitates the return of displaced mat segments to their initial configuration upon removal of said predetermined mat load.

4. The matting system as recited in claim 3 wherein said mat segments are comprised of:

(a) an outer frame, comprised of a plurality of frame segments, said frame segments haying said corresponding adjoining connecting surfaces; and

(b) a matrix retained within said outer frame.

5. The matting system as recited in claim 4 wherein said matrix fill retained within said outer frame is a polymer composite.

6. The matting system as recited in claim 3 wherein said corresponding adjoining connecting surfaces comprise concave surfaces interfacing with adjoining convex surfaces.

7. The matting system as recited in claim 3 wherein said corresponding adjoining connecting surfaces have shear resistant surfaces.

8. The matting system as recited in claim 3 wherein said mat segments are comprised of a polymer composite.

9. The matting system as recited in claim 3 wherein said elongated connector is pre tensioned.

10. The mating system as recited in claim 3 wherein said elongated connector is post-tensioned.

11. The matting system as recited in claim 8 wherein said polymer composite segments have an internal rib structure.

12. The matting system as recited in claim 11 wherein said internal rib structure of polymer composite mat segments have said corresponding adjoining connecting surfaces.

13. The matting system as recited in claim 3 wherein said mat segments are provided with a plurality of elongated connectors, said elongated connectors intersecting at a desired angle.

14. A matting system comprising:

(a) a plurality of discrete mat segments, each said mat segment configured with corresponding adjoining connecting surfaces, whereby when said adjoining connecting surfaces are fitted together, said adjoining connecting surfaces facilitate displacement of said mat segments through a range of predetermined mat loads;

(b) an elongated connector extending through each said mat segment, said connector being placed in tension to hold said mat segments together in a desired configuration, said elongated connector being elastic through said range of predetermined mat loads to allow displacement of said discrete mat segments with respect to each other; and

(c) wherein said connector facilitates the return of said mat segments to their initial configuration after displacement upon removal of said predetermined mat loads.

15. The matting system as recited in claim 14 wherein said corresponding adjoining connecting surfaces comprise concave surfaces interfacing with adjoining convex surfaces.

16. The matting system as recited in claim 15 wherein said mat segments are comprised of;

(a) a frame comprised, of a plurality of frame members forming a framed opening, said frame members having corresponding adjoining connecting surfaces; and

(b) a fill material retained in said framed opening.

17. The matting system as recited in claim 14 wherein said polymer composite mat. segments have an internal rib structure.

18. The matting system as recited in claim 17 wherein said mat segments are comprised of a polymer composite.

19. The matting system as recited in claim 14 wherein said elongated connector is pre-tensioned.

20. The matting system as recited in claim 14 wherein said elongated connector is post-tensioned.

21. matting system as recited in claim 14 wherein said mat segments are covered by an overlay material.