Multiple piece bracket assembly for lifting and supporting a structure

Abstract

An improvement for a bracket assembly of the type used in lifting and supporting a structure or shallow foundation element on a pile is provided. The bracket assembly rests on top of a deep foundation pile positioned adjacent to a structure. The bracket has inside and outside sections, the inside section is a weldment consisting of a bearing member which engages and attaches to the structure or foundation element. The inside section also functions as a guide for installing a pile. The outside section is further divided into upper and lower parts. The lower outside section has a pile guide and a spaced apart U-shaped adjustment bolt that together cradle the pile. The upper outside section caps the pile and attaches to the lower outside section using threadably adjustable rods. The outside section attaches to the inside section thereby fixing the bracket assembly against horizontal translation and rotation about a horizontal axis with respect to the pile.

Description

BACKGROUND OF THE INVENTION

A structure supported on a shallow foundation can become unstable and begin to settle as a result of unsatisfactory soil conditions or flaws in the original foundation design. Often foundation settlement results in the structure becoming out of level and structural damage can occur. Without a stable foundation to rest on, the structure will become unsafe and require additional foundation reinforcing to secure it. Prior art designs have been used to support a structure that rests upon a failing or unstable foundation utilizing a variety of methods. Typically piles which rest on load bearing strata have been placed directly under the structural foundation. However, placement of these piles beneath an existing structure or shallow foundation element can be difficult, often requiring deep excavations to provide the necessary overhead clearance. The current invention allows for placement of a deep pile adjacent to a structure eliminating the need for deep excavations. The current invention is a bracket assembly used to transfer the vertical structure loads to an adjacent deep foundation pile that bears on a load bearing strata.

The bracket assembly, which in conjunction with a deep foundation pile installed adjacent to an existing structure, is used for lifting and securing a structure attached to a failing foundation. Typically, piles are installed in sections that are coupled together using bolts, pins or the like. Prior art exists in the form of a bracket assembly that is fitted with a pile guide that cradles the pile and helps to keep the pile in the correct orientation with respect to the structure. The capability to install a bracket assembly onto the supported structure or shallow foundation element prior to installation of the associated deep foundation pile allows the installer to potentially utilize the bracket pile guide as an installation tool. However, the pile guide opening is often too small to allow free passage of the pile section coupling elements. Further, without a guide to assist during pile installation, misalignment of the pile shaft is likely. The pile must then be forced into proper position to engage the foundation bracket, which imparts a bending force or moment into the pile.

Prior art designs have previously supported failed or shallow footings. Piers made of concrete, reinforce concrete, timber, steel pipe, steel tubing, and solid steel bar bent into a helix have seen use at many sites to remedy failing foundations with varying success. The adequate transfer of the load from the foundation to the pier concerns contractors, engineers, and owners alike. Commonly, contractors place piers below a foundation by jack-hammering through a foundation, often through a basement floor. Piers directly below a foundation become impractical because of overhead height constraints and damage to an existing structure. To minimize risks, contractors excavate wider access holes lest, piers become to short. Short piers have proven cumbersome and time consuming for contractors and result in questionable flexural rigidity.

The difficulty in providing a bracket assembly is shown by prior art bracket designs that transferred a foundation load to a particular style of pier. In U.S. Pat. No. 5,120,163, Holdeman, et al, U.S. Pat. No. 5,171,107 Hamilton, et al, U.S. Pat. No. 5,246,311 West, et al, each described a bracket for a specific style or size of a pier. Some prior bracket designs state a feature to accommodate different sizes and style of piers, but, only provide a partial front to rear engagement between the installed pier and a bracket. Typically, an installed pier has a clearance between the lower portions of the bracket and the front edge of the bracket and the front edge of a pier towards the foundation.

In U.S. Pat. No. 6,079,905, Riuz, et al, for example, the adjustable brackets only engage the upper portions of the bracket and the back edge of an installed pier farthest from the foundation. These prior art bracket provide little means of contact between the lower portion of the bracket and the front edge of a pier towards a foundation. Under typical loads without contact at both the lower front and the upper rear edges of the pier, the prior art brackets rotate about an axis perpendicular to the length of the pier. Rotation causes the foundation support portion of a bracket to disengage from a foundation opening a gap, thus reducing the effect of load capacity of a bracket. Contractors and owners alike desire a bracket assembly adaptable for various shapes and sizes of piers and adjustable to prevent rotation and moment between a bracket and a pier. Thus, the present invention has the ability to fully support the foundation, fully embrace the pier, and to maintain such, and to prevent slippage between the bracket and the supported foundation.

SUMMARY OF THE INVENTION

A bracket assembly used to transfer gravity loads from a structure or a shallow foundation element to a deep foundation pile is presented. Although prior art does exist for a bracket assembly, which will accommodate piles of various shapes and sizes, this new invention provides two novel improvements. The current invention incorporates a three-piece bracket design. The inside section of the bracket is secured to the structure or shallow foundation element, using concrete wedge-type anchors, structural bolts or similar attachment means and methods, prior to installation of the deep foundation pile. A secondary component in the form of a U-shaped bracket, or similar configuration, is then attached to the inside section to act as a temporary pile installation guide. After the pile has been installed the temporary pile guide is removed and the permanent outside section of the bracket assembly is attached to the inside section. The outside section of the bracket is further divided into upper and lower parts. The lower outside section consists of a pile guide and a spaced apart threadably adjustable U-bolt that together cradle the pile and, help to secure the pile in its final position with respect to the supported structure. The upper outside section consists of a load plate with holes that align with matching holes in the lower outside section. When used in conjunction with a pipe shaft style pile, the upper outside section also includes a length of solid steel rod, which is attached to the lower side of the load plate and inserted into the hollow pipe shaft to act as a pile stiffener. Threaded rods are passed through the aligning holes and are secured with nuts above the upper outside section and below the lower outside section thus effectively locking the two parts of the outside section together. A secondary component, in the form of a temporary lifting frame, attaches to the lower outside section and extends above and over the top of the load plate. A jack is then placed between the load plate and the lifting frame. When the jack is engaged the upper and lower outside sections of the bracket are moved closer together. Since the pile is assumed immobile, with respect to the surrounding ground, the lower bracket assembly, and thus attached structure, is lifted and can be secured in position using the threaded rods and nuts that lock the two parts of the outside bracket section together.

As with prior art bracket assemblies, the current invention is used to transfer vertical gravity force or ground force uplift loads from a structure to a deep foundation pile that is horizontally offset from the foundation. In order to provide for the bracket assembly to furnish stabilization and location of the foundation, with respect to any uplifting loads or forces, it may be that the bracket may be welded or otherwise secured to the top of the pile in order to resist such tensile forces. The location of the pile relative to the foundation results in a rotational force (moment) being induced into the bracket under the action of these vertical loads. The induced moment has a tendency to rotate the bracket away from the support structure, about a horizontal axis, resulting in a reduction of the effective bearing contact area between the bracket and the structure. The current invention, when fully assembled, provides a pile guide and a spaced apart threadably adjustable U-bolt mechanism that actively engages and captures the pile shaft. When the U-bolt is secured in position the bracket can no longer rotate about a horizontal axis resulting in a fixed connection. Prior art that utilizes anti-rotation adjustments typically have one or two horizontal adjustment points, one near the top of the bracket and one near the bottom. The lower adjustment typically consists of a threaded bolt that is tightened against the pile shaft forcing the upper end of the shaft to bias against the upper support thereby securing the bracket against rotation relative to the pile shaft. The lower adjustment is positioned under the structure requiring the installer to reach under the supported structure to make the adjustments. However, unlike prior art designs of bracket anti-rotation adjustment systems, the current invention U-bolt adjustment mechanism is oriented with the threads facing away from the supported structure thus allowing for easier and safer access without the need to reach under the supported structure. The adjustability of the current invention provides for a safer, more accurate and easier system installation.

A unique feature of the current invention is the three-piece construction. The inside bracket section attaches to a structure or shallow foundation element and serves as a pile installation guide. The outside bracket section is further divided into upper and lower parts. The upper part caps the top of the installed pile and attaches to the lower part of the outside bracket section using threadably adjustable rods.

The lower part consists of a guide that cradles the pile and an adjustable U-bolt mechanism that together serve to secure the bracket against horizontal translation and rotation about a horizontal axis relative to the pile.

Since the weight (gravity force) of the supported structure is offset from the longitudinal axis of the pile, transfer of the structure load to the deep foundation pile results in a horizontal axis rotation force, or moment, being imparted into the bracket. The induced moment has a tendency to rotate the bracket away from the structure resulting in a reduction of the effective bearing area between the bracket and the structure. This new invention utilizes an anti-rotation U-bolt mechanism which, when properly adjusted, eliminates horizontal axis rotation of the bracket relative to the pile. An additional feature of the new invention is the orientation of the U-bolt mechanism threaded adjustments away from the structure allowing the installer to safely secure the bracket to the pile without reaching under the supported structure.

The concept of this idea is to provide a product for lifting a foundation and provide it with support, so a lifting bracket that could be used in conjunction with a 2½ inch extendable pipe anchor, or related types of anchors or piers. As such brackets currently exist, they are rated at a maximum working load of approximately 25 kips and 50 kips, which can accommodate the 2½ inch extendable pipe anchor. However, it would advantageous to be able to attach such a bracket, as of this current invention, to a foundation prior to the installation of the anchor. With the configuration of the current brackets, available upon the market, this sequence is not possible, due to interference with the coupling bolts as the anchor is being installed. Hence, the design for this multi-piece bracket assembly has been made, whereby one section is attached to the foundation and serves as an installation guide for the pipe anchor, and the second section is installed after the anchor has been driven to its supporting position. The second portion of the bracket then cradles and helps to secure the anchor in its final position.

Thus, there exists a need for a bracket assembly to lift and support a shallow foundation element or structure. A further need exists for a bracket pile guide design that facilitates the proper positioning of various size deep foundation pile shafts. A still further need exists for a pile guide design that will accommodate various pile shaft and coupling configurations without physical contact interference during the pile installation process. A still further need exists for a way to secure the foundation support bracket against rotation about a horizontal axis under load.

Therefore, it is an object of the present invention to provide a method for transferring the vertical gravity load, or weight force, of a structure or shallow foundation element to a deep foundation pile installed adjacent to the structure. It is also an object of the present invention to provide a method for transferring a ground surface generated force, acting vertically upward upon a structure or shallow foundation element, to a deep foundation pile installed adjacent to the structure.

It is further an object of the current invention to provide a temporary pile installation guide to help facilitate the accurate positioning of various sizes and configurations of deep foundation piles.

It is a further object of the present invention to prevent horizontal axis rotation of the bracket, relative to the installed deep foundation pile, under axial compressive or tensile loads thus maintaining bearing area engagement between the bracket and the supported structure.

Another object of the present invention is to provide pile-to-bracket horizontal alignment adjustability with an improved ease of use and improved safety of operation by permitting adjustment without requiring the installer, or the installer's tools, to reach under the supported structure to accomplish the adjustments.

Other objects and purposes may become more apparent to those skilled in the art upon reviewing the summary of the invention as provided herein, and upon undertaking a study of the description of its preferred embodiment, in view of the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an overall isometric view of the complete bracket mounted on a pile (2) and supporting a shallow foundation element or structure (1);

FIG. 2 is a view detailing the inside section (A) of the bracket assembly attached to the shallow foundation element or structure (1) with concrete wedge-type anchors or structural bolts (13);

FIG. 2B is a view showing the temporary pile guide (C) attached to the inside section (A) of the bracket assembly with the pile (2) being installed;

FIG. 3 is a detail view showing how the lower outside section (B2) of the bracket assembly is attached to the inside section (A);

FIG. 4 is a view showing the installation of bolts (14) and nuts (12) securing the lower outside bracket section (B2) to the inside section (A);

FIG. 5 is a view showing the installation of the anti-rotational U-bolt (3) and nuts (4);

FIG. 6 is a view showing how the upper outside section (B1) of the bracket assembly is placed on top of the lower outside section (B2), also detailing how the attached reinforcement rod (15) is inserted into a pipe shaft style pile (2);

FIG. 7 is a detail showing how the threaded rods (5) are inserted through the holes in the upper outside section (B1) of the bracket assembly and through aligning holes in the lower outside section (B2);

FIG. 8 details how nuts (6) are attached to the threaded rods (5) effectively locking the upper (B1) and lower (B2) parts of the outside bracket section together;

FIG. 9 shows how the lifting frame (D) in conjunction with the jack (17) is used to lift the structure (1).

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present art overcomes the prior art limitations by providing a bracket of the type used in lifting and supporting a structure or shallow foundation element (1) and that can be installed on a pile (2) positioned adjacent to the structure (1); said bracket utilizing a temporary pile guide (C) to help facilitate installation of the pile. Additionally, the bracket incorporates a system to help eliminate horizontal axis rotation of the bracket assembly under load, thereby maintaining adequate bearing surface contact area between the bracket and the structure. These along with other critical features of the current bracket assembly are here presented in detail utilizing the attached sketches FIG. 1 thru FIG. 9. In references to the bracket assembly, ‘back’ refers to the side of the assembly opposite the structure and, ‘front’ refers to the side adjacent to the structure. The call-outs for each component illustrated in the drawings are consistent throughout all ten figures.

Beginning with FIG. 1, the complete installed bracket assembly is shown secured to a pile (2) and supporting a structure or shallow foundation element (1). The pile (2) is installed adjacent to the structure (1) to a depth sufficient to bear on bedrock or other load bearing strata. In FIGS. 1-9 the pile (2) has a tubular cross-section, though the present invention will accommodate other pile shapes. Attached to the pile (2) and supporting a structure or shallow foundation element (1) is the current invention; a bracket assembly used to transfer vertical loads imparted by the structure to the deep foundation pile (2) installed adjacent to the structure (1). The inside bracket section (A) is an L-shaped bent steel plate, the horizontal leg of which extends under and supports the structure (1) with the vertical leg parallel and attaching to the vertical face of the structure (1). Also included on the inside bracket section (A) is a means for inserting bolts (14) to attach the lower outside bracket section (B2). The lower outside bracket section (B2) consists of two vertical spaced apart plates (20) that form the sides of a pile guide and, two horizontally oriented structural angles (7) which weld to the back of the plates (20) forming the back of the pile guide. When the lower outside bracket section (B2) is attached to the inside section (A) a completely enclosed pile guide is formed. Also included is a structural angle (9), attached to the lower back side of the vertical plates (20) that forms the attaching means for a U-bolt (3) that fits around and cradles the pile (2). Positioned parallel to and spaced apart from the vertical plates (20) are the lifting plates (8). The functionality of each of the bracket components will be explained in detail using FIGS. 2 through 9.

Turning to FIG. 2, the inside bracket section (A) is attached to the structure or shallow foundation element (1) using structural bolts, concrete wedge-type anchors, or similar attachment means? (13). The inside bracket section (A) is comprised of a steel plate (10) bent in an L-shape with one leg oriented horizontally and located under and bearing against the lower side of the structure or foundation element (1) and the other leg oriented vertically and attached to the vertical face of the structure or foundation element (1). Two plates (11) that function as an attachment means for the lower outside bracket (B2) are located on the back side of the vertical face of the bent plate (10). Bolts (14) and nuts (12) are used to secure the connection between the inside bracket section (A) and the lower outside bracket section (B2). The top two bolts (14) are placed in position as shown leaving a gap between the head of each bolt (14) and the inside face of plates (11). The loosely attached bolts (14) provide a means for hooking the upper end of either the temporary pile guide (C—not shown) or the lower outside bracket section (B2—not shown) onto the inside bracket section (A). The temporary pile guide (C) or the lower outside bracket section (B2) can then be rotated into position against the inside bracket section (A), capturing the pile (see FIG. 3).

Continuing with FIG. 2B, a temporary pile guide (C) has been rotated into position and is shown attached to the back side of the inside bracket section (A) using all six bolts (14) and nuts (12) to temporarily secure the connection. After attaching the temporary pile guide (C) the pile (2) is passed through the guide (C) and installed in the ground to a depth adequate to support the structural loads which will be imposed. The temporary pile guide (C) keeps the pile (2) in the proper orientation with respect to the foundation (1) during installation. After the pile (2) has been installed to the proper depth, the temporary pile guide (C) is removed from the inside bracket section (A).

Moving to FIG. 3, detailing how the lower outside bracket section (B2) is attached to the inside bracket section (A). The temporary pile guide (C—not shown) has been removed leaving the top bolts (14) in position in the flat plates (11). The top attachment holes in the lifting plates (8) on the lower outside bracket section (B2) are slotted (not shown) allowing the upper end of the bracket section (B2) to be hooked over the bolts (14). The lower outside bracket section (B2) is then rotated into position aligning the remaining four holes in flat plates (11) with matching holes in the lifting plates (8).

Turning to FIG. 4, the holes in flat plates (11) on the inside bracket section (A) are aligned with the holes in the lifting plates (8) on the lower outside bracket section (B2). Four additional bolts (14) are passed through the aligning holes and are secured in position with nuts (12). In the FIG., one of the structural angles (7) as well as the pile has been removed from the view for greater clarity. After the bolts (14) have been secured, an enclosed pile guide is formed helping to fix the pile (2—not shown) against lateral movement.

Continuing with FIG. 5, the U-bolt (3) is positioned with each of the legs on opposing sides of the pile (2). The legs of the U-bolt are then inserted into aligning holes in structural angle (9). Nuts (4) are then threadably attached to the legs of the U-bolt (3). The nuts (4) are adjusted until the upper end of the pile (2) biases against the top structural angle (7). The bracket assembly is now fixed against horizontal axis rotation with respect to the pile (2).

Rotating to FIG. 6, the positioning of the upper outside bracket section (B1), which consists of a load plate (21) and an attached vertically oriented steel shaft (15), is detailed. The pile (2), which in this application is a hollow section pile or pipe shaft style helical anchor, is installed adjacent to the structure (not shown). Under load a rotational force or moment is imparted into the bracket, therefore, the bracket assembly tries to rotate about a horizontal axis away from the supported structure or shallow foundation element (1—not shown). The rotational force is partially offset by the U-bolt (3) bearing against the pile (2). Under this type of loading, the pile (2) will try to buckle around the point where the U-bolt (3) makes contact with the pile (2). To offset its tendency to buckle, the pile (2) should be reinforced at the point of contact with the U-bolt (3). As the upper outside bracket section (B1) is brought into position on top of the pile (2) the steel shaft (15) slides into the pile (2) past the point where the U-bolt (3) contacts the pile. The steel shaft (15) provides the internal reinforcement needed to prevent the pile (2) from buckling under load.

Moving to FIG. 7, placement of the threaded rods (5) is detailed. The upper outside bracket section (B1) has been installed and the load plate (21) is resting on the upper end of the pile (2). The upper outside bracket section (B1) is positioned so that the holes in the load plate (21) are vertically aligned with matching holes (not shown) in the lower outside bracket section (B2). Threaded rods (5) are passed through holes in the load plate (21). The rods (5) are then passed through the aligning holes (not shown) in the lower outside bracket section (B2).

Continuing with FIG. 8, each of the threaded rods (5) must be held in position until nuts (6) are secured to the upper ends of the rods (5) above the load plate (21). After the nuts (6) are secured, the bolt is released. Nuts (6) may then be threadably attached to the lower end of the rods (5) below the lower outside bracket section (B2). The upper (B1) and lower (B2) outside bracket sections are now attached. If the nuts (6) are tightened, the two bracket sections will move closer together.

Finishing with FIG. 9, the bracket assembly is shown fully assembled and in operation. A secondary component in the form of a lifting frame (D) is attached to the bracket. The lifting frame (D) consists of two vertically oriented steel bars (19). At the lower end of each bar, (19) two steel plates are welded to opposing sides forming a clevis. The clevises have a horizontally oriented hole that aligns with slots in the lifting plates (8) on the lower outside bracket section (B2). The upper end of each bar (19) has a series of horizontally oriented holes designed to align with matching holes in the upper load frame (16). The lifting frame (D) is positioned above the installed bracket assembly with pins (18) placed in the aligning holes attaching the steel bars (19) to the lifting plates (8). Likewise, the upper load frame (16) is positioned between the two vertical bars (19) aligning the holes. Pins (18) are placed in the aligning holes attaching the vertical bars (19) to the upper load frame (16). A jack (17) is positioned between the load plate (21) and the upper load frame (D). As the jack (21) is engaged against the upper load frame (D), the lower outside (B2) and inside (A) bracket assemblies are raised with respect to the load plate (21). Since the load plate (21) bears on the top of the pile (2), and because the pile is assumed to be immobile with respect to the ground, as the jack (17) is engaged, the structure (1) is lifted. After the structure (1) is lifted into its final position, the nuts (6) are snug tightened on the threaded rods (5). The lifting frame (D) and jack (17) can now be removed leaving the bracket assembly securing the structure (1).

Variations or modifications to the subject matter of this invention may occur to those skilled in the art upon reviewing the description of the invention as provided herein. Such variations, if within the scope of this development, are intended to be encompassed within the parameters of the invention as defined. The description of the preferred embodiment, and their disclosure in the drawings, are set forth for illustrative purposes only.

Claims

1. A bracket assembly for lifting and supporting a structure, said bracket assembly being applied in cooperation with a pier adjacent to a foundation to initiate foundation support, an angled plate having a first plate for securement to the edge of a foundation, and an integral lower plate that locates beneath the edge of the foundation to provide support therefor, a temporary pile guide connecting to said first wall of the angled plate and provided for positioning said pile during its installation within the ground to a structure supporting depth, wherein pile guide is then removed, a bracket means securing to said angled plate, said bracket means having an upper portion that secures with the first wall of the angled plate, and said bracket having a lower portion that locates under the angled plate and supports the foundation, the lower portion of the bracket capable of being rigidly connected to the angled plate, an installation bracket temporarily securing to the upper portion of the bracket to accommodate a jack means therein for lifting the bracket means for supporting the foundation upwardly relative to its installed pier, and fastening means tightened to fix the angled plate and its bracket means for supporting the structure at its lifted position.

2. The bracket assembly of claim 1 wherein the installation bracket and the jacking means are removed once the bracket means and the angled plate has been affixed to the pier to maintain the lifted structure relative to said pier.

3. The bracket assembly of claim 2 wherein said installation bracket includes a load plate, secured to the upper end of an installed pier, and which is removable once the bracket means has lifted the structure relative to the installed pier, and the bracket means has been affixed to the installed pier.

4. The bracket assembly of claim 1 wherein upon removal of the temporary pile guide, the bracket means is connected to the outer upper surface of the first wall of the angled plate, and said bracket means is then pivoted into position downwardly wherein its supports underneath the lower wall of the angled plate in preparation for installation of the installation bracket and jacking means for lifting the structure relative to the installed pier.

5. The bracket assembly of claim 1 and including a pair of vertical plates, one of each vertical plate affixed to the outer edge of the first wall of the angled plate, and said plates capable of being fastened to initially the temporary pile guide, and then the bracket means for initially driving a pile into the ground, and for securement of the bracket means to the installed pile once the structure has been lifted by the bracket assembly during its operation.

6. The bracket assembly of claim 4 and including a U-bolt means applied to the lower portion of the bracket means and embracing the installed pier to reduce the horizontal axis of rotation of the bracket relative to the pier during lifting and support of the foundation through application of the bracket assembly.