Abstract:
A concentrically loaded foundation pier system which includes several concentrically stacked steel pipes filled with concrete. The entire pier is installed centrally beneath the footing of the structure. Shims are placed between the top-most pier element and a pier cap which prevents shifting when the soil expands and contracts. The final structure is end-loaded and pressed to the bedrock or other load-bearing strata.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority in U.S. Provisional Patent Application No. 62/170,090 filed Jun. 2, 2015, which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates generally to a foundation pier system, and more specifically to a concentrically loaded pier system with pier cap and lifting assembly subsystems and methods of use thereof. 
         [0004]    2. Description of the Related Art 
         [0005]    When constructing buildings or other large structures, movement of that structure due to soil movement and compression is a common concern. It is common to offset these issues with piers, piles, and other foundation elements constructed beneath the structure which penetrate deeper into the earth. Typically a borehole is drilled into the ground, and then concrete and reinforcing (e.g. steel rebar) are placed into the bore. These foundation elements help to compensate for poor surface soil conditions and large structural design loads. 
         [0006]    Typical existing pier and piles include several variations, each having its own issues. The helical pier suffers from uneven loading and requires that the footing of the structure be compromised. Concrete shoring pads do not penetrate the earth deep enough for many structures and therefore suffer from shifting soil. Concrete pilings suffer a similar fate. Drilled concrete piers are located at a fixed depth at all times, and this depth may be incorrect. Offset steel piers again require that the footing of the structure be compromised when installed, and suffers from uneven loading. 
         [0007]    The angle of the shaft on a prior-art drilled concrete pier is not completely vertical, which compromises durability. Drilled concrete piers are drilled to a fixed depth, which very often is not the correct depth. Drilled concrete piers are friction piers meaning they rely on the soil to create friction and press against them to hold them in place. Soil shrinks and expands depending on weather conditions, which will cause them to fail. Drilled concrete piers require a long project time. To start the holes will be drilled, and then the concrete is poured. Next the concrete needs to dry for a week or longer in order to cure and raise the structure. The drilled concrete piers typically require large excavating equipment which is invasive to the homeowner&#39;s property. 
         [0008]    The prior-art concrete piling pier is made of only concrete and susceptible to cracking and weathering over time. Concrete piling piers are friction piers which rely on the soil to hold them in place. There is a huge design flaw with this system. When the soil gets wet or dry it will expand and contract causing it to lose friction. This means it will eventually fail. This is a common problem with these piers because they rely on the soil which is always changing. The concrete piling pier&#39;s shims are not contained, which means that even slight movements in the soil can cause the shims to misalign and cause settlement. The shims on concrete piling piers are often intentionally broken on the job site with a hammer so that they fit correctly. This creates an uneven surface that allows for very little contact between the shim and concrete block, decreasing the strength of the pier. 
         [0009]    The prior-art offset steel piers have hollow steel tubing and only use steel in their construction. The offset steel pier is installed on the side of the footing rather than underneath, therefore structural loads do not transfer directly onto the pier. This makes the spot directly under the bracket vulnerable to breaking under pressure. The offset steel pier has a steel bracket with up to a four inch offset which makes them vulnerable to buckling directly beneath the bracket. The majority of foundation repair companies that use the offset steel pier need to use large excavating equipment to install their piers. This requires more money which translates to an increase in their pier pricing. It also increases the chance of damaging a property. 
         [0010]    Other prior art systems attempt to improve upon the basic structural pier or pile. These include staged piers having lifting assemblies including jacks mounted directly below the structure. The lifting platform using the jacks can be a problem when the jacks are not properly utilized, resulting in an unstable structure while the pier is being constructed beneath the lifting platform. 
         [0011]    What is needed is a foundation pier system including a pier cap subsystem for providing superior stability for the building structure. 
         [0012]    Heretofore there has not been available foundation pier system and method of use thereof with the advantages and features of the present invention. 
       SUMMARY OF THE INVENTION 
       [0013]    The present invention generally provides a concentrically loaded foundation pier system which includes several concentrically stacked steel pipes filled with concrete. The entire pier is installed centrally beneath the footing of the structure. Shims are placed between the top-most pier element and a pier cap which prevents shifting when the soil expands and contracts. The final structure is end-loaded and pressed to the bedrock or other load-bearing strata. 
         [0014]    It should be noted that the present invention is not limited to a single shape or size, and could be larger or smaller than indicated in the following example. A preferred embodiment of the present invention is installed by first digging a 3′×3′ hole to access the bottom of a footing or beam of a structure. This may be achieved from inside or outside of the structure. Approximately 28 inches of working room below the structure is required for this example. A hydraulic pump is used to install the various components. The concentrical pier segments are driven into the ground one at a time until bedrock, load-bearing strata, or an installed base is reached. The lifting platform is temporarily attached to the driven pier in order to start the lifting process. The jacks of the lifting platform are set against the structure and act to lift the structure. Once the structure has been lifted an appropriate amount, the pier cap and shims are installed onto the end of the pier. The lifting platform may then be removed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The drawings constitute a part of this specification and include exemplary embodiments of the present invention illustrating various objects and features thereof 
           [0016]      FIG. 1  is a front elevational view of a preferred embodiment of the present invention showing a lifting platform engaging a pier column and a structure. 
           [0017]      FIG. 2  is a front elevational view of a preferred embodiment of the present invention without the lifting platform. 
           [0018]      FIG. 3  is a side elevational view thereof. 
           [0019]      FIG. 4  is a three-dimensional isometric view of a pier cap element of a preferred embodiment of the present invention. 
           [0020]      FIG. 5  is a side elevational view thereof. 
           [0021]      FIG. 6  is a front elevational view thereof. 
           [0022]      FIG. 7  is a bottom plan view thereof. 
           [0023]      FIG. 8  is a three-dimensional isometric view thereof showing the pier cap from below, a portion of the pier cap being removed and demonstrating how the pier cap encapsulates the pier column. 
           [0024]      FIG. 9  is a three-dimensional isometric view of a steel and concrete segment adapter for connecting an embodiment of the present invention to an all-concrete segment. 
           [0025]      FIG. 10  is a sectional view thereof taken about the line of  FIG. 9 . 
           [0026]      FIG. 11  is a sectional view showing the element of  FIG. 9  encompassed in the preferred embodiment of  FIGS. 1-8 . 
           [0027]      FIG. 12  is an exploded three-dimensional isometric view of a lifting platform assembly element of a preferred embodiment of the present invention. 
           [0028]      FIG. 13  is a three-dimensional isometric view thereof, showing the lifting platform assembled. 
           [0029]      FIG. 14  is a side elevational view thereof, showing the lifting platform in a disassembled state. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0030]    I. Introduction and Environment 
         [0031]    As required, detailed aspects of the present invention are disclosed herein, however, it is to be understood that the disclosed aspects are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art how to variously employ the present invention in virtually any appropriately detailed structure. 
         [0032]    Certain terminology will be used in the following description for convenience in reference only and will not be limiting. For example, up, down, front, back, right and left refer to the invention as orientated in the view being referred to. The words, “inwardly” and “outwardly” refer to directions toward and away from, respectively, the geometric center of the aspect being described and designated parts thereof. Forwardly and rearwardly are generally in reference to the direction of travel, if appropriate. Said terminology will include the words specifically mentioned, derivatives thereof and words of similar meaning. 
         [0033]    II. Preferred Foundation Pier System  2   
         [0034]    Referring to the figures,  FIG. 1  shows a complete foundation pier system  2 , including generally a concentrically aligned pier column  4 , a pier cap  6 , and a lifting platform  8  mounting a pair of jacks  9  for lifting the structure  10  when the cap  6  is being installed. The lifting platform is configured to be removed after installation of the cap  6 . The pier column  4  reaches bedrock  12  or suitably solid earth far below the structure  10  in a preferred embodiment to provide structural stability. 
         [0035]      FIGS. 2 and 3  shows how the pier cap  6  is installed to the top-most pier  18 , which rests upon a number of concentrically stacked pier segments  14 , each pier including a tapered top portion  16  for engaging with the base of the next pier in the column. The pier cap  6  is constructed from a top plate  24 , a front plate  20 , back plate  22 , the front and back plates joined with bolts  26  secured by nuts  28 . The concentrically stacked pier segments  14  and the top-most pier  18  are formed from steel pipe filled with high-strength concrete. A preferred embodiment may use 0.217 steel pipe. The concentrically loaded structure allows loads to be transferred vertically along a single axis which alleviates any fail points. The front plate  20  is loose, and can be released from the back plate  22  by removing the nuts  28  from the carriage bolts  26 . 
         [0036]    The pier segments  14  generally include the top-most pier  18  which interfaces with the cap  6 , the primary segments  14  as identified in the figures, and a base pier segment which does not have a concave bottom portion, but is instead filled for maximum structural support. The base pier segment is the first of the primary segments  14  put into the ground. 
         [0037]      FIGS. 4-8  show the pier cap in more detail, including the receiver space  30  within the finished cap  6  which receives the top-most pier  18 . A shim  32  is installed over the top-most pier  18  which prevents shifting of the foundation system  2  when the earth and soil around the system settles or shifts. A second shim  33  may be placed if needed. Additional shims could also be used to fit the space. The shims  32 ,  33  are contained within the cap  6  and provide a relatively tight seal around the top-most pier  18 . 
         [0038]      FIGS. 9-10  show an adapter subsystem  34  which receives the concentrically stacked pier column  4  and interfaces it with an existing concrete friction pier  60  made of concrete pier segments  60  supported by a rebar alignment retention pin  41  as shown in  FIG. 11 . As shown in  FIG. 11 , the adapter base  36  is aligned with the other structure of concrete pier segments  60  for the concentrically stacked pier column  4  to remain substantially vertically oriented, thereby functioning at a designed level. 
         [0039]    The adapter base  36  includes a receiver  38  for receiving the base of the bottom-most pier in the pier column  4 , similar to the tapered top portions  16  of the pier segments  14 . 
         [0040]      FIGS. 12-14  show the lifting platform  8  which is primarily constructed from a front platform plate  42  and a rear platform plate  44  connected together via several mounting bolts  46  threaded into receivers  54  and washers  56  spaced between the front platform plate  42  and the rear platform plate  44  as shown in  FIG. 14 . The front  42  and rear  44  platform plates include corresponding alignment joint inserts  48  and alignment joint recesses  50  to ensure the two plates are aligned properly. A pier recess  52  is formed between the front  42  and rear  44  platform plates, such that the lifting platform  8  can be installed around one of the concentrically stacked pier segments  14 . As shown in  FIG. 1 , jacks  9  are placed atop the lifting platform  8  once the platform is installed, and the jacks can be used to raise the structure  10  such that the pier cap  6  can be installed as shown in  FIG. 8 . 
         [0041]    III. Method of Installation of Foundation Pier System  2   
         [0042]    In a preferred embodiment, the present invention is installed underneath of a structure  10  to provide structural support. The process is begun by digging approximately a 3′×3′ hole to access the bottom of the footing/beam. This may be achieved from inside or outside of the structure.  28  inches of working room below the footing/beam is required. These present invention is not limited to these dimensions, as larger or smaller scaled versions of the present invention may require more or less space. 
         [0043]    The pier  4  segments  14  are installed into the earth using a hydraulic pump. The pier segments  14  are interlocked via the top-portions  16  of each pier interlocking with the base of the next pier above it. This allows the concentric load to be transferred from concrete to concrete along the pier structure  4 . The pier segments  14  are driven into the ground one at a time. This process is repeated until bedrock, load-bearing strata, or the friction adapter subsystem  34  are reached. Because the segments are driven directly underneath the footing of the structure  10 , the foundation is not jeopardized or damaged due to bolting to or cutting into the footing. 
         [0044]    The lifting platform assembly  8  is temporarily attached to the pier structure  4  to lift the structure  10  via the jacks  9  or other methods. For example, a manifold lifting system may also be used. Once the structure  10  has been lifted, the pier cap  6  is placed over the top-most pier  18 , along with the shim(s)  32 ,  33 . The shims are contained within the pier cap to prevent future shifting of the foundation pier system  2 . The finished pier is then installed, the lifting platform assembly  8  and jacks  9  are removed, and the structure is suitably supported. 
         [0045]    It is to be understood that while certain embodiments and/or aspects of the invention have been shown and described, the invention is not limited thereto and encompasses various other embodiments and aspects.