IMPROVED STRIP SOIL REINFORCING AND METHOD OF MANUFACTURING

Abstract

A soil reinforcing element and method of manufacturing for use in a mechanically stabilized earth (MSE) structure. A smooth metal strip is fabricated into a soil reinforcing element that is manufactured from stock pulled from a coil, the surface of the strip surface is manipulated using the technique of cold forming. Where the manipulated surface is optimized to consist of a peak and a valley to increase the pullout resistance when embedded in an earthen formation involving a mechanically stabilized earth (MSE) structure.

Claims

1. A strip soil reinforcing element, for use in a mechanically stabilized earth (MSE) structure, comprising: a stock member consisting of a strip wherein all surfaces on said strip are smooth, where the surface of the strip is manipulated using a cold forming process by passing said strip through opposing surfaces of two profile dies imparting a resistance profile on said strip; said resistance profile includes at least one first peak member on a first side of said strip having said first side and an opposite second side, and extending between respective at least a first flat section and a second flat section of said strip; each of said first and said second flat sections extending along a common plane; a first flat side and a second flat side on opposing sides of said at least one peak member having equal lengths and defining an obtuse medial angle therebetween; a first obtuse angle defined from said first flat side of said at least one first peak relative to said first flat section and a second obtuse angle defined from said second flat side of said at least one first peak relative to said second flat section; and said first obtuse angle and said second obtuse angle being between 160-140 degrees and said obtuse medial angle between said first and said second flat sides is between 120-100 degrees; whereby said resistance profile optimizes a pullout resistance of said strip soil reinforcing member from said mechanically stabilized earth (MSE) structure during a use thereof.

2. The strip soil reinforcing element, according to claim 1, further comprising: at least a second peak member on said strip; and said first peak member and said second peak member spaced on said strip by at least one of said first and said second flat sections therebetween.

3. The strip soil reinforcing element, according to claim 2, wherein: said at least first and second peak members being either both on said first side of said strip or on opposite sides of said strip relative to said common plane.

4. The strip soil reinforcing element, according to claim 3, wherein: a length of said first and said second flat sections is one of uniform and nonuniform between respective said first and said second peak members.

5. The strip soil reinforcing element, according to claim 4, wherein: said stock member being manipulated using said cold forming process is at least one of carbon steel, stainless steel, an iron alloy, an aluminum alloy, a copper alloy, and a bronze alloy.

6. The strip soil reinforcing element, according to claim 5, wherein: a proximal end of the strip has a through bore.

7. A system, for constructing a mechanically stabilized earth (MSE) structure, comprising: a strip soil reinforcing element consisting of a metal strip fabricated with cold formed profiled resistance profile having at least a plurality of peaks along a flat surface and a through bore at a proximal end; a facing panel element having a facing panel anker with a coupling device extending from a back face of a facing panel element and adjustably accepting said proximal end of said strip soil reinforcing element and said strip soil reinforcing element; a coupling device extending through said proximal end and said facing panel anker to secure said strip soil reinforcing member to said facing panel anker wherein the combined coupling device and said strip soil reinforcing element capable of swiveling along a common plane.

8. The system, according to claim 7, further comprising: a plurality of said strip soil reinforcing elements each containing a plurality of said cold formed profiles along respective flat surfaces; each of said strip soil reinforcing elements consisting of a strip wherein all surfaces on said strip are smooth, where the surface of the strip is manipulated forming said cold formed profile using a cold forming process by passing said strip through opposing surfaces of two profile dies imparting said resistance profile on said strip; said resistance profile includes said plurality of peaks on a first side of said strip and each said peak having said first flat side and an opposite second flat side, and extending between respective at least a first flat section and a second flat section of said strip; each of said first and said second flat sections extending along said common plane; a first flat side and a second flat side on opposing sides of said at least one peak member having equal lengths and defining an obtuse medial angle therebetween; a first obtuse angle defined from said first flat side of each said peak relative to said first flat section and a second obtuse angle defined from said corresponding second flat side of each said peak relative to said second flat section; and said first obtuse angle and said second obtuse angle being between 160-140 degrees and said obtuse medial angle between said first and said second flat sides is between 120-100 degrees; whereby said resistance profile optimizes a pullout resistance of said strip soil reinforcing member from said mechanically stabilized earth (MSE) structure during a use thereof.

9. The system, according to claim 8, further comprising: a plurality of facing panel elements each having a plurality of facing panel ankers each with a corresponding coupling device extending from a respective back face of each said facing panel element and adjustably accepting respective said proximal ends of said plurality of strip soil reinforcing elements and securing respective said strip soil reinforcing element; and a plurality of soil lifts along said plurality of facing panel elements relative to a base level and a finished grade; and each said plurality of soil lifts is secured in said mechanically stabilized earth (MSE) structure with a corresponding series of said strip soil reinforcing elements.

10. The system, according to claim 9, wherein: each said strip soil reinforcing elements includes, in said plurality of peaks at least a first peak ember and a second peak member; and said at least first and said second peak members being either both on said first side of said strip or on opposed sides of said strip relative to said common plane.

11. The system, according to claim 10, wherein: a length of said first and said second flat sections of each said strip of said plurality of strips is one of uniform and nonuniform between respective said first and said second peak members.

12. The system, according to claim 11, wherein: said strip soil reinforcing elements are each selected from one of a carbon steel, stainless steel, an iron alloy, an aluminum alloy, a copper alloy, and a bronze alloy.

13. A method manufacturing a strip soil reinforcing element using coiled metal comprising the steps of: a. placing the coiled metal on an unwinding pedestal and unwinding the coiled metal as a strip; b. passing the strip through a first straightening station forming an initially straightened strip; c. passing the initially straightened strip through a cold pressing profiling station and imparting a resistance profile consisting of at least a plurality of cold formed peaks along a surface of said strip; wherein said cold pressing profiling station contains a fixed dye and a movable dye each having complementary profiles so that during said step of imparting said resistance profile a final straightened portion is formed between respective said peaks and valleys along said surface of said strip; d. passing the strip through a punch station; e. passing the strip through a guillotine and cutting said strip to a predetermined length; f. placing the finished strip in a stack; and g. banding the finished stack of strips.

14. The method, according to claim 13, wherein: said resistance profile includes said plurality of said cold formed peaks on said strip and each said peak having said first flat side and an opposite second flat side, and extending between respective at least a first flat section and a second flat section of said strip; each of said first and said second flat sections extending along a common plane on said final straightened portions; a first flat side and a second flat side on opposing sides of said peak members having equal lengths and defining an obtuse medial angle therebetween; a first obtuse angle defined from said first flat side of each said peak relative to said first flat section and a second obtuse angle defined from said corresponding second flat side of each said peak relative to said second flat section; and said first obtuse angle and said second obtuse angle being between 160-140 degrees and said obtuse medial angle between said first and said second flat sides is between 120-100 degrees; whereby said resistance profile optimizes a pullout resistance of said strip soil reinforcing member from said mechanically stabilized earth (MSE) structure during a use thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] FIGS. 1 and 2A provide an illustrative punching shear model calculation of an improved strip soil reinforcing embodiment that is a flat metal strip containing smooth surface on a top and a bottom and along edges following defined passive profiles shown here on a peak and a valley on a top surface thereof (with FIG. 1 noting an analysis element thereof for calculation.)

[0044] FIG. 2B is an illustrative mirrored profile of FIG. 2A wherein an illustrative passive profile containing a peak and a valley are mirror imaged on a single element relative to a direction of force.

[0045] FIGS. 3A, 3B, and 3C provide alternative isometric images of cold formed metal strips according to the present invention.

[0046] FIG. 4A provides a method of manufacturing that is adaptive to cold forming using either strip coil or straightened feed bar stock.

[0047] FIG. 4B provides an illustrative cold press forming step of bending to a desired passive profile and a final straightening of a previously provided bar strip having an initial straightening upon removal from a strip coil.

[0048] FIG. 5 is an illustrative isometric assembly of an improved strip soil reinforcing element having a panel anker assembled thereto.

[0049] FIG. 6 is an isometric illustrative view of a mechanically stabilized earth (MSE) structure containing one or more improved strip soil reinforcing elements affixed in a facing element or panel element, as shown, in an alternative embodiment on a first lift or first drift level.

[0050] FIG. 7 is a further isometric illustrative view of a mechanically stabilized earth (MSE) structure containing one or more improved strip soil reinforcing elements with a plurality of facing panel elements on a base level relative to a retained fill portion forming an earth retaining structure.

[0051] FIG. 8 is a sectional illustrative view showing an assembly of a facing panel element and a plurality of improved strip soil reinforcing elements in a mechanically stabilized earth (MSE) structure with a plurality of lifts or drift levels for enhanced tension resistance.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0052] Reference will now be made in detail to embodiments of the invention. Wherever possible, same or similar reference numerals are used in the drawings and the description to refer to the same or like parts or steps. The drawings are in simplified form and are not to precise scale. The word ‘couple’ and similar terms do not necessarily denote direct and immediate connections, but also include connections through intermediate elements or devices. For purposes of convenience and clarity only, directional (up/down, etc.) or motional (forward/back, etc.) terms may be used with respect to the drawings. These and similar directional terms should not be construed to limit the scope in any manner. It will also be understood that other embodiments may be utilized without departing from the scope of the present invention, and that the detailed description is not to be taken in a limiting sense, and that elements may be differently positioned, or otherwise noted as in the appended claims without requirements of the written description being required thereto.

[0053] Various operations may be described as multiple discrete operations in turn, in a manner that may be helpful in understanding embodiments of the present invention; however, the order of description should not be construed to imply that these operations are order dependent.

[0054] Referring now to FIGS. 1 through 8 collectively, FIGS. 1 to 3 provide an improved strip soil reinforcing embodiment for a mechanically stabilized earth (SME) structure that is a flat metal strip containing smooth surface on a top and a bottom and along edges following defined passive profiles shown here on a peak and a valley on a top surface thereof (with FIG. 1 noting an illustrative analysis element thereof for calculation.).

[0055] As noted in FIGS. 1-8, and FIGS. 1 to 3 more directly, the passive profile includes a peak and valley separated by a generally flat surface and are essentially mirror images of one another when viewing the side surface and are formed from cold material using die forming. The spacing and shape of the peak and valley profile is optimized and may be verified by using the below geometric requirements and physically tested using a method of pullout testing. The surface profile is fabricated by the method of cold forming using profiled dies as will be discussed. This provides the further economic advantage of fabricating improved strip soil reinforcement using stock material that is contained on a coil.

[0056] FIG. 1 is an analysis of pullout resistance of improved strip soil reinforcing elements as invented herein and is a function of frictional resistance that develops along the interface of the soil reinforcing element and the soil in tension by passive resistance that develops at the location of a profile that is generally perpendicular to the direction of the applied force. The configuration and orientation of the passive profile invented herein is therefore important to optimize pullout resistance without adding cost to the element.

[0057] When an element contained in soil is loaded so it is pushed into the soil the soil will fail along a surface. The surface, also known as a failure surface, is a function of the friction angle of the soil. The failure surface propagates at an angel of 45+ϕ2. Where ϕ (phi) is the internal friction angle of the soil. An element that is placed in soil and loaded can only move when force exceeds the strength of the soil. When soil failure occurs the passive element punches into the soil in the direction of failure as shown in FIG. 1.

[0058] The wedge of soil in front of the element defined by Zone-I (ABC) (I) must move the surrounding soil defined by Zone-II (II) out of the way. The angle alpha (α) is a function of the internal friction angle of the soil. The angle beta (β) is a function of the applied force and the compacted density of the surrounding soil as well as the dilatancy characteristics of the soil. The angles alpha (α) and beta (β) are correlated to the angle of 45 degrees plus one-half the internal friction angle of the soil. Zone-II (II) is above zone AD (as shown). During tension, the more that Zones-II and Zones-III (III) are allowed to propagate unobstructed the higher the pullout resistance of the soil reinforcing element. The failure surface follows the outer profile of Zones II, III, and provides substantial resistance to movement when suitably positioned and assembled in a mechanically stabilized earth (MSE) structure.

[0059] The preferred embodiment passive profile is shown in FIGS. 2A, 2B, and 3A-3C is of a triangular profile where the acute profile angle theta (θ) is preferably between 20-44 degrees and more preferably between 30-40 degrees (relative to the complementary obtuse angle between (opposite acute profile angle theta (θ)) (as shown). The complementary obtuse angle is therefore between 160 degrees (180−20 degrees) 136 degrees (180−44 degrees) and more preferably between 140 degrees (180 degrees−40 degrees) and 150 degrees (180 degrees−30 degrees). The range of these angles is the range of internal friction angle for soils that are typically used as backfill in Mechanically Stabilized Earth (MSE) structures. When the profile is limited to this angle Zone-II can fully develop and the pullout resistance is of the soil reinforcing element is optimized. It should be understood that other angles are possible and can be determined for a particular soil using pullout testing.

[0060] Referring further specifically to FIGS. 2B, and 3A-3C, to increase the pullout resistance the passive resistance triangular element in FIG. 2A is repeated and alternatively mirrored to the bottom surface and spaced at a distance that limits the interference or overlap of the failure surfaces. This arrangement allows for the flat portions therebetween to fall within the same plane so that the acute and obtuse angles may be readily calculated as is noted herein with certainty that in either direction of force (e.g., FIG. 2A, 2B show direction of force leftward to the image, but the retention force is directly in the opposite direction rightward). As a result, it is conceived that in an imaginary isosceles triangle calculated between the two opposing isosceles peak-sides having a base angle at A (e.g., in FIG. 2A) there are two opposite acute profile angles theta (θ) and the remaining obtuse medial angle ACA (FIG. 2A) may be calculated (e.g., 180 internal degrees−(2× the acute profile angles theta (θ)) such that the obtuse medial angle may be preferably between 100 to 120 degrees).

[0061] Referring additionally further to FIGS. 3A-3C wherein a plurality of respective improved strip soil reinforcing elements 80, 80B, and 80C are provided. Profile element 80 includes the profile as noted in FIG. 2B with passive profiles inverted and regularly spaced so that there are regular flat portions 81, 81 spacing passive profiles forming obtuse angles 82, 82 off the flat portions 81, 81 separated by medial obtuse angles 83, 83 etc. defined between the obtuse angles 82, 82, as shown. Alternatively, profile element 80B is shown with passive profiles that are inverted and spaced by two different flat portions 81 (longer) and 81A (shorter), each with respective obtuse angles (relative to flat portions 81) 82A, 82A and a medial obtuse angle 83A (defined between obtuse angles 82A), as shown. Further alternatively, a profile element 80C is provided with regular uniform flat portions 81, 81, and spaced passive profile elements on only one side with respective obtuse angles 82C, 82C spaced by a medial obtuse angle 83C, as shown.

[0062] It will be recognized that the noted peaks and valleys are optimized and are intermittently spaced along the metal strips by the method of cold forming and are essentially mirror images of each other when viewing the surface. As a result, it will be recognized that the present concept may be adapted to the present alternative embodiments without departing from the scope and spirit of the Applicant's invention.

[0063] Referring now additionally to FIGS. 4A and 4B wherein, in FIG. 4A a method of manufacturing using alternative a cold strip coil (initially), or a provided cold bar stock (initially) is provided. The process includes the steps noted, and includes using coiled metal that is; 1. Placed on an unwinding pedestal; 2. Passed through a unwinding, slitting, and strip feeding and straightening station; 3. Passed through a punch station; 4. Passed through a profiling station or alternatively a twisting and profiling station 5 to an optional induction heating station; 6. Cut to length in a guillotine; 7 and optionally punched with a through hole 8 and then placed in a stack; 9. Banded and transported. The process therein is provided without further general heating and is noted as cold forming.

[0064] Additionally, referring to FIG. 4B where the surface profiling and further straightening is provided, the initially straightened stock flattened bar 50 (cold) is provided to a set of dies, with top die 40A complementing bottom die 40B with a desired profile spaced between flat sections (as shown). In a next step, the dies are compressed and the profile is cold formed in the bar and then fed along a fixed bed 40 to a punch and shear station 42 to have a through hole provided at an end and the bar cut to a desired production length providing a formed improved strip soil reinforcing element 80 (or 80B or 80C, etc.) as may be determined, then a stack and band and bundle step is noted (combining FIGS. 4A, 4B), as is noted the relative stations and steps can be operated moved in different orders and still obtain the same desired outcome.

[0065] Referring additionally now to FIGS. 5 to 8, wherein, an assembled improved strip soil reinforcing element 1 is provided with the reinforcing soil strip element 80 and a panel anker 90 shaped to be retained within a panel facing element 108. A through hole 91 in panel anker 90 and in element 80 provides for the assembly and fixing with a threaded 72, washers 73, 73 and a nut 71 during a use to form an assembly with combined mechanically stabilized earth (MSE) structure.

[0066] As noted in FIGS. 6, 7, and 8 a mechanically stabilized earth (MSE) structure 10 includes reinforced panel facing elements 108 of differing heights and shapes, typically supported on a footer or leveling pad 101 relative to a base level 109, and improved strip soil reinforcing assemblies 1 are secured to panel facing elements 108 at respective lifts or drifts 106 having thicknesses of soil based upon desired parameters, and capped with a moment slap 104 and a roadway 110 with a traffic barrier 105 relative to a desired finish grade 102. In one alternative embodiment (FIG. 7) there is retained fill 111 based on the respective site requirements.

[0067] Although only a few embodiments have been disclosed in detail above, other embodiments are possible, and the inventors intend these to be encompassed within this specification. The specification describes certain technological solutions to solve the technical problems that are described expressly and inherently in this application. This disclosure describes embodiments, and the claims are intended to cover any modification or alternative or generalization of these embodiments which might be predictable to a person having ordinary skill in the art.

[0068] Also, the inventor intends that only those claims which may use the word ‘means’ or use the words ‘means for’ to be interpreted under 35 USC 112. Moreover, no limitations from the specification are intended to be read into any claims, unless those limitations are expressly included in the claims.

[0069] Where a specific numerical value is mentioned herein, it should be considered that the value may be increased or decreased by 20% (e.g., an angle of X degrees+/−20% is understood as within the disclosure and still staying within the teachings of the present application, unless some different range is specifically mentioned. Where a specified logical sense is used, the opposite logical sense is also intended to be encompassed.

[0070] Having described at least one of the preferred embodiments of the present invention with reference to the accompanying drawings, it will be apparent to those skills that the invention is not limited to those precise embodiments, and that various modifications and variations can be made in the presently disclosed system without departing from the scope or spirit of the invention. Thus, it is intended that the present disclosure cover modifications and variations of this disclosure provided they come within the scope of the appended claims and their equivalents.