The present invention related to fencing and, more particularly, to the construction of footings for structures such as fence posts.
Segmental retaining walls are commonly used in both residential and commercial applications to create usable real estate. Fencing is often required behind such walls to reduce the potential for falls and other potential hazards. In addition, guardrails usually are required in applications where parking lots or roadways are located near top of the wall.
Fence posts typically are mounted using concrete footings. A concrete footing can be created by digging a cavity in the ground, placing a bottom portion of the fence post in the cavity, and pouring concrete into the cavity.
Segmental retaining walls often include a reinforcing tie back system. For example, multiple layers of geosynthetic soil reinforcing material (commonly referred to as “geogrid”) can be secured to the wall face so that the layers extend horizontally into the surrounding stone or soil. The interaction between the stone or soil and the reinforcing material can help to stabilize the wall face, i.e., the portion of the wall formed by stacked concrete blocks.
Digging a cavity for a fence-post footing near a segmental retaining wall, after the reinforcing material has been installed, can necessitate drilling through the reinforcing material. Drilling through the reinforcing material can adversely affect the integrity thereof, and therefore is undesirable. Hence, the cavities for fence posts located near segmental retaining walls are usually created as the wall is constructed.
Fence-post cavities can be created using cylindrical cardboard forms, such as the SONOTUBE form available from Sonoco Products Company. These forms usually are provided in relatively long lengths, and therefore must be cut to a desired length at the installation site. The form is placed on the backfill material (typically soil) used behind that wall, as backfill material reaches a predetermined height. The predetermined height is chosen so that the top of the form is exposed from above ground after the wall has been completed, and all backfill material has been introduced and compacted. The form defines an open cavity in the ground that can receive the fence post.
The soil used as backfill material is usually kept moist, to help to achieve maximum density during compacting. Cardboard forms can be adversely affected by such moisture. Moisture from precipitation also can affect the integrity of a cardboard form. Also, the loads on the cardboard form resulting from the compacted backfill material, if excessive, can cause the form to collapse.
Alternatively, the form used to create the cavity can be created by cutting a predetermined length of polyvinyl chloride (PVC) or high-density polyethylene (HDPE) pipe. These materials are usually delivered to the installation site in ten or twenty-foot lengths. The need to cut the pipe creates an additional step in the construction process for the wall. Moreover, installers often cut the pipe using concrete demolition saws, chain saws, and other tooling not made for this particular use, thereby creating a potential safety hazard.
The cavity defined by the form creates a potential for injuries resulting from tripping over or stepping into an open hole in the ground. Moreover, the open cavity can fill with dirt and other debris, particularly in installations where fence posts will not be installed immediately after completion of the segmental retaining wall.
Many design codes, and many design engineers require that fence posts used near segmental retaining walls be placed at lest three feet from the wall face. This requirement is intended to minimize the potential for the fence post to affect the structural integrity of the wall face. In particular, a linear force placed on the fence post, in a direction toward the wall face, has the potential to cause direct sliding of the fence post and footing toward the wall face. Such a force also introduces a moment on the fence post that can urge the fence post and footing toward the wall face. Movement of the fence post toward the wall face potentially can weaken, bulge, or overturn the wall face if the fence post is located too close to the wall face. Hence, fence posts often must be installed at least three feet from the face of a segmental retaining wall to avoid placing excessive loads on the wall face.
The real estate located between the wall face and the fence as a result of the three-foot setback requirement represents underutilized space. This area also creates a potential safety hazard. For example, individuals (and in particular, children) can fall from the setback area onto the surface in front of the wall.
The three-foot setback requirement usually places the sleeves at a location in the soil backfill behind the wall face (rather than in the crushed stone backfill used directly adjacent to the wall face.) This requirement can potentially interfere with the compacting operations performed on the backfill soil. For example, care must be exercise to avoid contacting the sleeves the equipment used to compact the soil. Moreover, the size of the compacting equipment may be limited by the need to maneuver around the sleeves.
The three-foot setback requirement also introduces the potential for the fence post to be installed too close to the wall face by mistake, in violation of design codes or site plans. In such cases, an entire fence may need to be removed and reinstalled at the proper location.
A preferred embodiment of a device for creating a footing for a structure comprises a reinforcing member having a base extending a first direction, and a leg extending in a second direction. The device also comprises a sleeve defining a cavity for receiving the leg, a portion of the fence post, and an anchoring material for securing the leg to the structure.
A preferred embodiment of a footing for a structure comprises an anchoring material having a portion of the structure embedded therein, and a reinforcing member.
The reinforcing member has a leg embedded in the anchoring material, and a base extending from the anchoring material so that the base can be exposed to backfill material around the footing.
A preferred embodiment of a sleeve for use in creating a footing for a structure comprises a main portion that defines a cavity for receiving the fence post and an anchoring material. The main portion is split into a first and a second half so that the first half can be stacked on the second half.
A preferred method for creating a footing for a structure proximate a wall face of a segmental retaining wall comprises providing a device comprising a sleeve and a reinforcing member. The reinforcing member has a leg positioned within the sleeve, and a base.
The preferred method also comprises placing the device on a layer of backfill material behind the wall face so that the sleeve is located adjacent the wall face and the base extends away from the wall face, covering the base with at least one other layer of the backfill, placing a bottom portion of the structure in the sleeve, and filling the sleeve with an anchoring material.
A preferred embodiment of a device for creating a footing for a fence post comprises a first sleeve for receiving a portion of the fence post and extending in a first direction, and a second sleeve coupled to the first sleeve and extending in a second direction. The first and second sleeves can receive an anchoring material, and the second sleeve can generate a force and a moment in response a weight of the anchoring material and a weight of backfill material acting on the second sleeve.
The foregoing summary, as well as the following detailed description of a preferred embodiment, are better understood when read in conjunction with the appended diagrammatic drawings. For the purpose of illustrating the invention, the drawings show an embodiment that is presently preferred. The invention is not limited, however, to the specific instrumentalities disclosed in the drawings. In the drawings:
The figures depict a preferred embodiment (or various components) of a device 10 for constructing a footing for fence post. The figures are each referenced to a common coordinate system 11. The device 10 comprises a sleeve 12 and a reinforcing member 14. The reinforcing member 14 includes a leg 16, and an adjoining base 18.
The device 10 is described herein in connection with a fence post. This particular application is described for exemplary purposes only. The device 10 can be used to construct footings for other types of structures and structural components, such as (but not limited to) light posts, sign posts, guard rail posts, etc. (The term “structure,” as used throughout the specification and claims, is intended to encompasses structures, and structural components.)
The sleeve 12 preferably attaches to the reinforcing member 14 so that the leg 16 is positioned within the sleeve 12, and the base 18 extends from the sleeve 12 (see
An anchoring material, such as 3,000 psi concrete 23, can be poured into the sleeve 12 after the lower portion 20a of the fence post 20 has been placed therein (see
The concrete 23, upon hardening, anchors the fence post 20 to the leg 16 of the reinforcing member 14. The base 18 of the reinforcing member 14 can interact with the surrounding backfill material, e.g., soil, crushed stone, etc., to generate forces that resist bending moments and linear forces on the fence post 20. Further details relating to these features are presented below.
The sleeve 12 has a main portion 22 (see
The main portion 22 of the sleeve 12 preferably has two diametrically opposed split lines 24 (see
The diameter of the main portion 22 should be sufficient to permit the main portion 22 to accommodate the lower portion 20a of the fence post 20, and the leg 16 of the reinforcing member 14. The optimal length of the main portion 22 is application dependent, and can vary with factors such as the amount of force the device 10 needs to produce to counteract bending moments and linear forces on the fence post 20.
The first half 22a has two slits 32 formed therein (see
(Direction terms such as upper, lower, above, below, etc., are used with reference to the component orientations depicted in
The sleeve 12 preferably includes a cover portion 26. The cover portion 26 is split into a first half 26a and a second half 26b. The first half 26a of the cover portion 26 adjoins the first half 22a of the main portion 22. The second half 26b of the cover portion 26 adjoins the second half 22b of the main portion 22.
Preferably, the first and second halves 26a, 26b each have an area 28 of reduced thickness extending along an outer perimeter thereof. In other words, the reduced-thickness areas 28 of the first and second halves 26a, 26b preferably adjoin the respective first and second halves 22a, 22b of the main portion 22.
The first and second halves 26a, 26b of the cover define a notch 27 located at the approximate center of the cover portion 26.
The sleeve 12 can be formed from a suitable material such as HDPE, using a suitable process such as injection molding (other materials and other manufacturing processes can be used in the alternative). The thickness of the main portion 22 should be sufficient to withstand the forces generated by the backfill material placed around the sleeve 12 and compacted during construction of the segmental retaining wall 40 behind which the device 10 is installed (discussed below) (the wall 40 is depicted in
The sleeve 12 also includes a bottom portion 36. The bottom portion 36 preferably includes a first half 36a that adjoins the first half 22a of the sleeve 22, and a second half 36b that adjoins the second half 22b of the sleeve 22 (see
The leg 16 of the reinforcing member 14 adjoins the base 18, as discussed above. Preferably, the leg 16 and the base 18 are substantially perpendicular, i.e., the first and second portions 16, 18 preferably are separated by an angle of approximately ninety degrees.
The reinforcing member 14 preferably is formed from wire mesh. For example, the reinforcing member 14 can be formed from a piece 15 of wire mesh having the shape depicted in
The width (“y” axis dimension”) and length (“z” axis dimension) of the leg 16 preferably are selected so that the leg 16 can fit within the main portion 22 of the sleeve 12. The optimal dimensions of the base 18 are application dependent, and can vary with factors such as the amount of force the device 10 needs to produce to counteract external forces on the fence post 20 (discussed below).
The device 10 preferably comprises two struts 30. Each strut 30 preferably has a hook portion 31 formed at each end thereof (see
The reinforcing member 14 and the struts 30 should be formed from a material (or materials) having suitable strength to withstand the forces exerted thereon by the fence post 20 and the backfill material placed around in device 10 during installation thereof (discussed below). The material from which the reinforcing member 14 and the struts 30 are formed should also possess sufficient corrosion resistance for potential use in moist soil. Moreover, the material from which the reinforcing member 14 is formed should be sufficiently malleable to permit the reinforcing member 14 to be formed from the piece 15 of wire mesh in the above-described manner.
The slits 32 formed in the main portion 22 and the slits 41 formed in the bottom portion 36 of the sleeve 12 can facilitate attachment of the sleeve 12 to the reinforcing member 14. In particular, the struts 30 can be inserted into respective ones of the slits 32 as the sleeve 12 is placed over the leg 16. (The slits 41 permit the struts 30 to enter the slits 32.) A portion of each strut 30 moves upward in the associated slit, and eventually enters the opening 34 formed above the slit 32 as the sleeve 12 is advanced over the reinforcing member 14.
The portions of the struts 30 that enter the openings 34, it is believed, will remain in the associated opening 34 until the sufficient downward force is exerted on the reinforcing member 14 to drive the struts 30 back into the associated slits 32. This feature can help retain the reinforcing member 14 in place on the sleeve 12 before and during installation of the device 10.
The base 18 preferably extends from the sleeve 12 in a direction substantially perpendicular to the longitudinal axis of the sleeve. (The longitudinal axis the sleeve 12 is denoted the line “A” in
The device 10 can be used to form a footing 47 for a fence post, such as the fence post 20, when the fence post 20 is installed behind the segmental retaining wall 40 (see
The segmental retaining wall 40 can initially be constructed in a conventional manner. For example, a trench for receiving a lowermost (base) row of blocks 46 can be excavated along the planned path of the wall 40 (the blocks 46 can be, for example, mortarless concrete blocks). The ground at the bottom of the trench can be stabilized and compacted using a vibrating mechanical plate. The base row of blocks 46 can be placed in the trench and leveled.
The voids in each block 46 can be filled with crushed stone or other suitable material. The area in back of the blocks 46 can be backfilled to the approximate height of the blocks 46 using crushed stone 52 or other suitable material. The area behind the crushed stone can be filled with on-site soil 54. (Filling material other than the crushed stone 52 and on-site soil 56 can be used as backfill, in the alternative). The soil 54 can be compacted, preferably to approximately ninety-five percent of maximum density. (The crushed stone and soil used as backfill hereinafter are referred to as “the backfill material.”)
Successive overlying rows of blocks 46 can be formed in a similar manner. A reinforcing tie back subsystem, such as sheets of geogrid 56, can be attached to each row of blocks 46. The sheets of geogrid 50 can extend outward from the blocks 46, onto the adjacent layer of backfill material, by a predetermined distance. Each sheet of geogrid 50 should be tensioned before being covered by the overlying layer of backfill material.
The device 10 should be installed so that the top of the sleeve 12 is accessible from above ground after the wall 40 has been completed and back-filled (see
Stakes (not shown) can be driven through the holes 38 formed in the first and second halves 36a, 36b of the bottom portion 36 of the sleeve 12. The stakes can help to stabilize and secure the device 10 in place before and during placement of the backfill material around the device 10. (The weight of the backfill material acting on the bottom portion 36 of the sleeve 12 also can help to stabilize the device 10 during installation.)
The device 10 optimally should be positioned so that the main portion 22 of the sleeve 12 contacts the adjacent row of blocks 46 (see
The spacing between adjacent ones of the devices 10 is dependent upon the desired distance (spacing) between adjacent ones of the fence posts 20. The notch 27 defined by the cover portion 26 can receive the tab (not shown) commonly located on the end of conventional tape measures. The notch 27 can act as a convenient means for holding the tab at the approximate center of the device 10 as the position of the adjacent device 10 is determined based on measurements obtained from the tape measure.
The remaining rows of blocks 46 and layers of backfill material can subsequently be completed, in substantially the same manner as the previous the rows and layers. Caps 58 can be installed on top of the uppermost row of blocks 46, if desired.
The sheets of geogrid 50 located at the same level (z-axis position) as the sleeve 12 can be slit, so that sheets of geogrid 50 can be wrapped around the main portion 22.
The sleeve 12 forms a cavity in the backfill material. The cavity can accommodate the bottom portion 20a of the fence post 20. The device 10 can remain in place, with the cover portion 26 installed, until the fence post 20 is about to be installed. The cover portion 26 can prevent substantial amounts of soil or other debris from falling into the cavity formed by the sleeve 12 before the fence post 20 is installed. Moreover, the cover portion 26 can reduce or eliminate the potential for injuries caused by tripping over or stepping into an open hole in the ground. (Hence, the cover portion 26 can be particularly beneficial in applications where the fence post 20 will not be installed immediately upon completion of the wall 40.)
The cover portion 26 can be removed by cutting the first and second halves 26a, 26b of the cover portion 26 along the areas 28 of reduced-thickness. The reduced-thickness areas 28, it is believed, make it possible to cut through the cover portion 26 with minimal difficulty, using simple tooling such as a manual saw, a utility knife, etc.
The lower portion 20a of the fence post can be placed in the main portion 22 after the cover portion 26 has been removed. A suitable anchoring material such as the concrete 23 can be poured into the main portion 22 of the sleeve 12 once the cover portion 26 has been removed.
The concrete 23 fills the main portion 22, and immerses the lower portion 20a of the fence post 20, the leg 16 of the reinforcing member 14, and a portion of the base 18 of the reinforcing member 14 (see
The footing 47 can reinforce the fence post 20. In particular, the fence post 10 can be subject to an external force that generates a counterclockwise moment thereon (from the perspective of
The weight of the backfill material above the base 18 of the reinforcing member 14 causes the backfill material to exert a downward force “F2” on the base 18. (Soil compacted to ninety-five percent of maximum density weighs approximately 125 pounds per cubic foot. Hence, the force F2 can potentially be substantial.)
The force F2 can generate a clockwise moment “M2” that acts on the fence post 20 by way of the footing 47 (see
The magnitude of the moment M2 can be varied by varying the total surface area of the base 18 on which the backfill material acts in a downward fashion. This can be achieved, for example, by varying the size of the mesh from which the reinforcing member 14 is formed, or by varying the overall size of the base 18.
The force F1, in addition to generating the moment M1, urges the fence post 20 toward the wall ace 39. The force F1, if excessive, can cause direct sliding of the fence post 20 toward the wall face 39. Such sliding can potentially weaken, bulge, or overturn the wall face 39 if the fence post 10 is located directly adjacent the wall face 39.
The device 10 can generate a force “F3” that counteracts the force the F1 (see
The magnitude of the force F3 can be varied by varying the total amount of surface area on the base 18 that faces the “−x” direction (so as to react the force F1 through contact with the backfill material). This can be achieved, for example, by varying the size of the mesh from which the reinforcing member 14 is formed, or by varying the overall size of the base 18.
Many design codes and site plans require a fence post installed directly adjacent a segmental retaining wall to withstand an applied load of approximately twenty pounds per linear foot of fence. The use of the device 10, it is believed, provides the fence post 20 with sufficiently reinforcement to meet this standard. In particular, the moment M2 and the force F3 exerted by the device 10 on the fence post 20 can counteract the moment M1 and the force F1, and thereby reduce the potential for the M1 and the force F1 to weaken, bulge, overturn, or otherwise affect the wall face 39 when the fence post 20 is installed immediately adjacent the wall face 39.
The use of the device 10, by permitting the fence post 20 (and the associated fence 60) to be installed directly adjacent the wall face 39, can obviate the need for a setback between the wall face 39 and the fence 60. Hence, the underutilization of real estate, and the potential safety hazard resulting from the use of such setbacks can be eliminated.
Eliminating the need for a setback also can eliminate the potential for mistakenly installing the fence 60 too close to the wall face 39 in violation of a design code or site plan. Hence, the potential need to remove and reinstall the fence 60 due to such mistakes can be reduced or eliminated through the use of the device 10. Moreover, the footing 47, it is believed, can be constructed without using substantially more concrete than a footing constructed in a conventional manner.
Placing the device 10 directly adjacent the wall face 39 also can reduce the potential for the sleeve 12 to interfere with the compacting operations performed on the backfill soil 54. In particular, placing the device 10 directly adjacent the wall face 39 can cause most, or all of the sleeve 12 to extend through the crushed stone 52. Hence, a substantial portion of the sleeve 12 does not extend through the soil 54. The sleeve 12 therefore does not interfere substantially with the compacting operation performed on the soil 54. Moreover, this arrangement can facilitate the use of larger compacting equipment than otherwise would be possible, because the compacting equipment does not need to be maneuvered around the sleeves 12.
The split configuration of the sleeve 12 permits the sleeve 12 to be shipped in a relatively compact, unassembled condition. In particular, the halves of each unassembled sleeve 12 can be stacked, and placed in a relatively small box or container for shipping. As the volume of each sleeve 12 in an unassembled condition is substantially less than its volume in an assembled condition, the ability to disassemble the sleeve 12 into two halves can make it relatively easy and inexpensive to ship the sleeves 12, particularly where a relatively large number of sleeves 12 are shipped together.
The sleeve 12 can be manufactured and shipped to the user in a predetermined height, thereby eliminating time, effort, and potential hazards associated with the need to cut the sleeve 12 to size at the installation site. Moreover, the sleeve 12 can be formed from a durable material, such as HDPE, that is substantially impervious to moisture in the soil in which it is buried, and that can withstand the loads generated by the backfill material on the sleeve 12 is buried.
The foregoing description is provided for the purpose of explanation and is not to be construed as limiting the invention. While the invention has been described with reference to preferred embodiments or preferred methods, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Furthermore, although the invention has been described herein with reference to particular structure, methods, and embodiments, the invention is not intended to be limited to the particulars disclosed herein, as the invention extends to all structures, methods and uses that are within the scope of the appended claims. Those skilled in the relevant art, having the benefit of the teachings of this specification, may effect numerous modifications to the invention as described herein, and changes may be made without departing from the scope and spirit of the invention as defined by the appended claims.
For example, device sleeve 12 and the reinforcing member 14 can be formed as a unitary structure, using techniques such as injection molding.
The sleeve 12 can be used by itself, without the reinforcing member 14 or the struts 30. (The footing produced using the sleeve 12 alone, however, will not be able to provide the same degree of reinforcement as the footing 47 produced using the device 10.)
The first sleeve 102 can receive the bottom portion 20a of the fence post 20. The first and second sleeves 102, 104 can be filled with a suitable anchoring material (not shown), such as the concrete 23, introduced by way of the open top of the first sleeve 102.
The device 100 can generate reactive forces in response to a linear force applied to the fence post 20 in the “−x” direction, in a manner substantially similar to device 10. The device 100 can be equipped with the various features of the device 10, e.g., a cover for the top of the first sleeve 102, a split configuration, etc.
This application claims priority under 35 U.S.C. § 119(e) to U.S. provisional application No. 60/508,713, filed Oct. 3, 2003, the contents of which is incorporated by reference herein in its entirety.
Number | Date | Country | |
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60508713 | Oct 2003 | US |