This invention relates in general to forming an adjustable foundation, and in particular, to a concrete slab foundation capable of being raised above the ground.
Many structures have been built on foundations or slabs made of concrete poured on top of soil. Constant changes in the weather and moisture levels in the soil frequently cause damage to such a foundation. In many instances, the foundation may buckle or even crack. This phenomenon occurs for a variety of reasons, including uneven changes in the water content of supporting soils, uneven compacting of soils, and uneven loads being placed on soils. Over time, uneven movement in the soils under a foundation can cause a foundation to bend or crack.
Therefore, it would be desirable to provide a method and apparatus that would allow a foundation to be poured on top of soil and subsequently raised to a desired height to eliminate potential problems caused by soil movement and/or problematic soils.
An embodiment of the system for forming a movable slab foundation as comprised by the present invention has a slab foundation and at least one support surface. At least one substantially vertical lifting member has first and second ends, the first end abuttingly contacts the at least one support surface. At least one support sleeve surrounds the at least one lifting member. The at least one support sleeve is encased within the slab foundation and is capable of movement axially along the length of the at least one lifting member. An engagement device is carried by the at least one support sleeve and is adapted to be engaged with the at least one lifting member when the slab is raised to a desired height, thereby preventing the at least one support sleeve from moving axially downward along the length of the at least one lifting member.
An embodiment of the system for forming a movable slab foundation as comprised by the present invention has a slab foundation and at least one support surface. At least one substantially vertical lifting member has a substantially cylindrical body with first and second ends, the first end abuttingly contacts the at least one support surface. At least one support sleeve surrounds the at least one support member. The at least one support sleeve has a hollow body with inner and outer surfaces. The inner surface of the body has a plurality of apertures located in and extending therethrough. The outer surface of the body has at least one reinforcing bar connected to and extending outwardly therefrom. The outer surface of the body and the at least one reinforcing bar are encased within the slab foundation. The at least one support sleeve and the slab foundation are capable of movement axially along the length of the at least one lifting member. A chuck body surrounds the at least one lifting member and is connected to the at least one support sleeve. The chuck body has a tapered inner surface that extends downwardly and outwardly from the at least one lifting member. The lower end of the tapered inner surface extends inward thereby forming a substantially upward facing shoulder. A shim surrounds the at least one lifting member. The shim is surrounded by the chuck body and has a tapered outer surface that is substantially geometrically complimentary to the inner surface of the chuck body. The tapered outer surface extends downwardly and outwardly from the at least one lifting member. The lower end of the tapered outer surface extends inward thereby forming a substantially downward facing shoulder. The shim has an inner surface that is substantially parallel to the at least one lifting member. The upward facing shoulder of the chuck body initially engages the downward facing shoulder of the shim such that the chuck body and the shim travel upward simultaneously. The chuck body is capable of limited downward movement independent of the shim. The limited downward movement of the chuck body causes the shim to engage the at least one lifting member, thereby restricting the movement of the chuck body downward relative to the lifting member and securing the sleeve and slab foundation at the desired height.
An embodiment of the present invention is directed to a method for forming a movable slab foundation. The method comprises placing a plurality of support surfaces below an intended slab foundation area. A plurality of support sleeves are placed in abutting contact with the plurality of support surfaces. A plurality of lifting members are placed within the plurality of support sleeves and moved downward within the plurality of support sleeves and into abutting contact with the plurality of support surfaces. A slab foundation is formed such that it encases the plurality of support sleeves. The plurality of support sleeves are simultaneously lifted to move the slab foundation along the length of the plurality of support members to a desired height. An engagement device carried by each of the plurality of support sleeves is engaged with each of the plurality of lifting members, thereby restricting the movement of the plurality of support sleeves downward relative to the plurality of lifting members and maintaining the desired height of the slab foundation.
So that the manner in which the features and benefits of the invention, as well as others which will become apparent, may be understood in more detail, a more particular description of the invention briefly summarized above may be had by reference to the embodiments thereof which are illustrated in the appended drawings, which form a part of this specification. It is also to be noted, however, that the drawings illustrate only various embodiments of the invention and are therefore not to be considered limiting of the invention's scope as it may include other effective embodiments as well.
The present invention now will be described more fully hereinafter with reference to the accompanying drawings in which a preferred embodiment of the invention is shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiment set forth herein; rather, this embodiment is provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.
Referring to
In this embodiment, the hole for the pier 13 is dug with a diameter such that the base plate 15 is fully encased within the concrete. Once the hole is dug, the pier 13 is formed by pouring concrete into the hole. The base plate 15 is then embedded in the concrete of the pier 13 such that the top or upper surface of the base plate 15 is substantially parallel with the ground surface 17. As previously discussed, in this embodiment, the anchor bolts 16 are connected to the base plate 15 and extend into the concrete of the pier 13 a distance below the base plate 15.
In this embodiment, a cylindrical exterior pipe or support sleeve 19 has an outer diameter that is less than the diameter of the base plate 15. The support sleeve 19 and the base plate 15 are sized such that the bottom surface of the support sleeve 19 is in supporting contact with the base plate 15. The length of support sleeve 19 is less than or equal to the desired thickness of the concrete slab 11. Reinforcing bars (rebar) 25 are connected to the outer surface of the sleeve 19. In this embodiment, a first leg 27 of the rebar 25 is connected to and extends outwardly and downwardly at an angle from the sleeve 19. A second leg 29 of the rebar 25 is substantially perpendicular to the support sleeve 19 and extends between the first leg 27 and the sleeve 19. The rebar 25 may be welded around the outer peripheries of the sleeve 19 at desired intervals. In an alternate embodiment, various reinforcing members may be connected to and extend outwardly from the outer peripheries of the sleeve 19 in various shapes and configurations.
A plurality of lift holes or apertures 33 are located in and extend radially outward through the inner surface 34 of the support sleeve 19. In this particular embodiment, two lift holes 33 are positioned opposite from one another. The lift holes 33 are designed to accept a lifting device or a lifting link.
A plate 35 is connected to the inner surface 34 of the sleeve 19. The plate 35 extends radially inward from the inner surface of the sleeve 19 before connecting to a chuck body 37. The chuck body 37 has a generally wedge-shaped cross section with a tapered inner surface 39. A small flange extends radially inward from the bottom of the tapered surface 39, thereby forming an upward facing shoulder 41. A shim 43 has a generally wedge-shaped cross section with a tapered outer surface 45 that is geometrically complimentary to the tapered inner surface 39 of the chuck body 37. The shim 43 rides within the chuck body 37. A small recess is located in and extends radially inward from the bottom of the tapered surface 45, thereby forming a downward facing shoulder 47. The inner surface 49 of the shim 43 has a plurality of downward angled teeth (not shown) extending along its length. An aperture or passage 51 extends axially through the center of the shim 43. The downward facing shoulder 47 of the shim 43 initially abuts against the upward facing shoulder 41 of the chuck body 37.
The sleeve assembly 19 is positioned atop the base plate 15. In an alternate embodiment, the lower end of the support sleeve 19 may be lightly tack welded to the base plate 15. The concrete slab 11 is then poured, which embeds the rebar 25 and the sleeve 19 within the slab 11. The concrete may be kept from bonding to the concrete pier 13 and the base plate 15 by an optional bond breaker layer (not shown).
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Attachment members or attachment rods 65 are connected to the lift holes 33 in the sleeve 19 in order to lift the slab 11 to its desired height. In this embodiment, the attachment rods 65 contain threads in at least an upper portion thereof. The attachment rods 65 pass through the apertures 57 in the support plate 55 and the apertures 63 in the lift plate 61. Nuts 67 are threaded onto upper portions of the attachment rods 65 located between the support plate 55 and the lift plate 61. The nuts 67 may be adjusted once the slab 11 has been lifted to permit removal of the hydraulic jack 59. The nuts 69 are threaded onto upper portions of the attachment rods 65, above the lift plate 61. The nuts 69 prevent the lift plate 61 from moving upward independently from the attachment rods 65 when the hydraulic jack 59 is activated.
Hydraulic fluid pressure is then applied to the jack 59, causing the jack 59 to lift the lift plate 61 and the attachment rods 65 upwards. As the lift plate 61 and the attachment rods 65 move upwards, the slab 11 and the sleeve assembly 19 encased therein also moves upwards. As the sleeve assembly 19 moves upwards, the chuck body 37 simultaneously moves upwards relative to the base plate 15. The upward facing shoulder 41 of the chuck body 37 abuts against the downward facing shoulder 47 of the shim 43, ensuring that the shim 43 simultaneously moves upward with the chuck body 37. The jack 59 moves the lift plate 61 and the attachment rods 65 upwards until the foundation slab 11 has been lifted above the ground surface 17 to a height slightly above the desired height. In the event that the hydraulic jack 59 needs to be removed during the lifting process, the nuts 67 can be tightened against the support plate 61, allowing the lifting device 59 and the lift plate 61 to be removed if necessary.
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The invention has significant advantages. The invention provides a method and apparatus that allows a foundation to be poured on top of soil and subsequently raised to a desired height to eliminate potential problems caused by soil movement and/or problematic soils.
In the drawings and specification, there have been disclosed a typical preferred embodiment of the invention, and although specific teams are employed, the terms are used in a descriptive sense only and not for purposes of limitation. The invention has been described in considerable detail with specific reference to these illustrated embodiments. It will be apparent, however, that various modifications and changes can be made within the spirit and scope of the invention as described in the foregoing specification and as set forth in the following claims
This application claims the benefit of and priority to U.S. Provisional Patent Application No. 61/239,823, filed on Sep. 4, 2009, herein incorporated by reference in its entirety.
Number | Date | Country | |
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61239823 | Sep 2009 | US |