U.S. patent application number 12/571067 was filed with the patent office on 2010-04-01 for system for supporting slab with concrete pier.
Invention is credited to Frederick S. Marshall.
Application Number | 20100080658 12/571067 |
Document ID | / |
Family ID | 42057681 |
Filed Date | 2010-04-01 |
United States Patent
Application |
20100080658 |
Kind Code |
A1 |
Marshall; Frederick S. |
April 1, 2010 |
SYSTEM FOR SUPPORTING SLAB WITH CONCRETE PIER
Abstract
A foundation slab for a structure is repaired by driving piers
into the ground and then lifting the slab against the piers. A
bracket assembly is attached between the slab and a jack. One or
more jacks are used to drive piers into the ground and to raise the
slab. One or more brackets remain installed to support the slab on
the piers.
Inventors: |
Marshall; Frederick S.;
(Arlington, TX) |
Correspondence
Address: |
BRACEWELL & GIULIANI LLP
P.O. BOX 61389
HOUSTON
TX
77208-1389
US
|
Family ID: |
42057681 |
Appl. No.: |
12/571067 |
Filed: |
September 30, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61101940 |
Oct 1, 2008 |
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Current U.S.
Class: |
405/232 ;
405/230 |
Current CPC
Class: |
E02D 35/00 20130101 |
Class at
Publication: |
405/232 ;
405/230 |
International
Class: |
E02D 5/00 20060101
E02D005/00 |
Claims
1. A method for lifting a building slab, the method comprising: (a)
attaching a bracket assembly to the slab; (b) placing a pier
segment in engagement with the bracket assembly; (c) attaching a
jack between the bracket assembly and the pier segment; (d)
extending a member of the jack to drive the pier segment into the
ground; and (e) adding additional pier segments and repeating step
(d) until lifting the slab a predetermined distance.
2. The method according to claim 1, wherein step (a) comprises
cantilever mounting the bracket to the slab.
3. The method according to claim 1, wherein step (e) further
comprises: providing the bracket assembly with a pair of support
legs, each having an aperture; passing a rod through the apertures
in the support legs; and retracting the member of the jack until
one of the pier segments transfers force to the rod.
4. The method according to claim 3, wherein step (e) further
comprises having a U-shaped member between the ram and an uppermost
pier segment to enable the rod to pass between the ram and the
uppermost pier segment.
5. The method according to claim 1, wherein step (a) comprises
securing the bracket to a vertical side wall of the slab; and step
(c) positions the jack alongside the vertical sidewall.
6. The method according to claim 1, wherein step (a) comprises
attaching the brackets to the slab by passing a plurality of
fasteners through a plurality of holes located on the brackets and
into a vertical sidewall of the slab.
7. The method according to claim 1, further comprising, after step
(e), placing a retaining member between a top of an uppermost one
of the pier segments and the bracket assembly, then removing the
jack such that a weight from the slab transfers through the bracket
assembly to the pier segment.
8. The method according to claim 1, wherein the bracket assembly
has 2 support legs that are spaced apart and a base plate; step (a)
comprises attaching the base plate to the slab with the support
legs normal to a vertical side wall of the slab; and step (b)
comprises placing the pier segment between the support legs.
9. A method for lifting a building slab, the method comprising: (a)
providing a bracket assembly having a base plate and two support
legs, the support legs being spaced part, and each support leg
having an aperture; (b) attaching the bracket assembly to a
vertical sidewall of the slab, with the support legs of the bracket
assembly normal to the vertical sidewall of the slab, by passing a
plurality of fasteners through a plurality of holes located on the
bracket assembly and into the vertical sidewall of the slab; (c)
placing a pier segment between the support legs and in engagement
with the bracket assembly; (d) attaching a jack alongside the
vertical sidewall and between the bracket assembly and the pier
segment; (e) extending a member of the jack to drive the pier
segment into the ground; (f) adding additional pier segments and
repeating step (e) until lifting the slab a predetermined distance;
(g) passing a rod through the apertures in the support legs; and
(h) retracting the member of the jack until one of the pier
segments transfers force to the rod.
10. The method according to claim 9, wherein step (g) comprises
placing shims between one of the pier segments and the rod.
11. The method according to claim 9, wherein step (d) comprises
providing a plurality of hooks connected to the jack and engaging a
lower edge of the support legs with the plurality of hooks.
12. The method according to claim 9, wherein step (g) comprises
having a U-shaped member between the ram and an uppermost pier
segment to enable the rod to pass between the ram and the uppermost
pier segment.
13. The method according to claim 9, wherein step (a) comprises
providing a circular guide member mounted between the support
members, and step (e) comprises driving the pier segment downward
through the guide member.
14. An apparatus for lifting a portion of a slab, the apparatus
comprising: a plurality of pier segments, each having a horizontal
width; a first bracket assembly comprising first and second support
members, wherein the first bracket assembly is adapted to be
attached to a substantially vertical portion of the slab, the first
and second support members are adapted to protrude away from the
substantially vertical portion of the slab, and a distance between
the first support member and the second support member is greater
than the horizontal width of the pier segments; a jack adapted to
releasably engage the first bracket assembly and drive the pier
segments into the ground; and a retaining device adapted to
transfer a weight of a portion of the slab from the first bracket
assembly to the pier segments, enabling the jack to be removed.
15. The apparatus according to claim 14, wherein the retaining
device comprises a rod that inserts through aligned apertures in
the support member.
16. The apparatus according to claim 15, further comprising a
U-shaped member, the U-shaped member being adapted to transfer
force from a ram of the jack to the at least one pier segment, and
a slot located in the U-shaped member allows the rod to be inserted
into the aperture.
17. The apparatus according to claim 15, further comprising shims
between a top of the pier segment and the retaining device.
18. The apparatus according to claim 14, wherein a pair of hooks on
the jack extend down and engage a lower edge of the support
members.
19. The apparatus according to claim 14, further comprising a
circular guide member mounted between the support members, the pier
segments extending downward through the guide member.
20. The apparatus according to claim 14, wherein the bracket
assembly comprises two separate brackets, each having a mounting
plate and one of the support members extending at a 90 degree angle
therefrom.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional
Patent Application No. 61/101,940, filed on Oct. 1, 2008, which
hereby is incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates in general to supporting a
foundation, and in particular, to a pier and the bracket used to
attach the slab to the pier and the method used to adjust the slab
using the pier and bracket.
[0004] 2. Brief Description of Related Art
[0005] Concrete slabs are frequently used as foundations for
structures such as houses or commercial buildings. There are a
variety of ways to build a slab. One way involves clearing topsoil
from the ground at the location where the slab will be poured,
placing form boards on the ground to define the slab, and then
pouring concrete within the form boards. Trenches may be dug into
the ground prior to pouring the concrete, thus creating thicker
sections of concrete when the concrete fills the trench. Over time,
the ground supporting the slab may shift, resulting in cracks in
the slab and sagging portions of the slab. In severe cases,
portions of the slab may be four inches or more below the desired
original slab height.
[0006] One technique for slab repair is to drive piers into the
ground with a hydraulic ram, such as a truck-mounted hydraulic ram.
The piers are distributed about the perimeter of the slab, or at
least about the portion of the slab that needs to be raised. Each
pier is driven to a desired depth, such as down to rock or down to
more stable soil. Hydraulic jacks are then attached to the piers
and to the slab and the slab is raised to the desired elevation.
Finally, the piers are affixed to the side of the slab via wall
brackets to maintain the slab at the new elevation. It is necessary
to use counterweight to support the jack while driving the piers.
The weight of the truck of a truck-mounted jack may be used, but it
is desirable to drive the piers without requiring a truck or other
heavy piece of equipment to move to each pier location.
SUMMARY OF THE INVENTION
[0007] In an exemplary embodiment, a foundation slab on a
structure, such as a house or a commercial building, may be
repaired by first attaching a bracket assembly to the side of the
slab. Each bracket assembly may have two or more angle brackets,
wherein each angle bracket has a slab leg and a support leg. The
slab leg may attach to the side of the slab by bolts or any other
technique. The support leg protrudes from the slab leg, and thus
from the slab. A pier segment is placed between the protruding
support legs and a jack frame is used to attach a jack to the
protruding support legs.
[0008] Pier segments are sections of piling, such as 12'' long
cylinders, that are stacked together as they are driven into the
ground to form a pier assembly. Pier segments may be made of any of
a variety of materials. The pier segments could be, for example,
steel pipe, concrete cylinders, or concrete filled steel pipe. In
some embodiments, steel pipe may be driven into the ground and
later filled with concrete. In any of the embodiments, the pier
assembly may be tensioned with one or more cables after the pier
segments are driven into the ground.
[0009] The first pier segment driven into the ground is an anchor
segment wherein the end of the anchor segment is enclosed so as to
not fill with soil as it is pressed into the ground. The end of the
first pier segment may have a point or rounded tip to make it
easier for the pier segment to displace soil as it is driven into
the ground.
[0010] Pier segments are driven into the ground, one at a time, by
a jack attached to the bracket assembly. As the jack presses the
pier segments into the ground, the jack is held stationary by the
weight of the slab, which is transferred to the jack via the
bracket assembly and jack frame. One pier assembly is driven at a
time, and thus the entire weight of the slab may be applied to the
jack.
[0011] After all the pier segments are pressed into the ground,
jacks may be placed on one or more of the pier segments and used to
raise the slab. A plurality of jacks are simultaneously used to
raise the slab and are thus able to overcome the weight of the
slab, with each jack lifting, for example, 5-6 tons of slab weight.
A U-shaped bracket may be located between the ram of the jack and
the top of the pier assembly. The U-shaped bracket allows a rod to
slide through side-holes on the bracket assembly and across the
center of the pier assembly. Shims are placed between the top of
the pier assembly and the rod and then the jack is lowered to
transfer the weight of the slab, via the bracket assembly, rod, and
shims, to the pier assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a front view of an embodiment of a bracket
assembly, jack, and pier.
[0013] FIG. 2 is a sectional top view of the bracket assembly and
pier of FIG. 1, taken along the 2-2 line.
[0014] FIG. 3 is a sectional top view of an alternative embodiment
of the bracket assembly and pier of FIG. 1, taken along the 3-3
line of FIG. 4.
[0015] FIG. 4 is a front view of the alternative embodiment of FIG.
3.
[0016] FIG. 5 is a sectional view of the pier segments and the
cable anchor segment of the pier assembly.
[0017] FIG. 6 is a side view of the bracket assembly, pier, and
jack of FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
[0018] The present invention will now be described more fully
hereinafter with reference to the accompanying drawings which
illustrate embodiments of the invention. This invention may,
however, be embodied in many different forms and should not be
construed as limited to the illustrated embodiments set forth
herein. Rather, these embodiments are 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, and the prime notation, if used,
indicates similar elements in alternative embodiments.
[0019] Referring to FIG. 1, foundation slab 100 may be used to
support a house or other building. In this embodiment, slab 100 is
made of concrete. As will be described in detail, below, a
plurality of brackets 102 may be used to drive a plurality of piers
104 into the ground and then raise and support slab 104 on the
plurality of piers 104. In an exemplary embodiment, a plurality of
bracket assemblies 102 are spaced apart on slab 100. A plurality of
pier assemblies 104 are driven into the ground, one for each
bracket assembly 102. Finally, portions of slab 100 are raised to a
desired position and supported on pier assemblies 104.
[0020] In the preferred embodiment, bracket assembly 102 includes
two angle brackets 106. Each bracket 106 has slab leg or mounting
plate 107 and support plate or leg 112 that are generally
perpendicular to each other. Slab mounting plate 107 may be a
generally flat piece of metal that is generally parallel to and
adapted to be in abutting contact with a vertical side surface
portion or sidewall 113 of slab 100. Alternatively, slab mounting
plate 107 may be other shapes, such as an I-beam or a length of
tubular steel having a generally square, rectangular, or D-shaped
cross section. Slab mounting plate 107 is connected to slab 100 by,
for example, passing bolts 108 (FIG. 2) through apertures 110 and
into slab 100. Alternatively, in additional embodiments, angle
bracket 106 may be connected to slab 100 by a variety of means,
including, for example, bolts, adhesives, or by attaching a beam or
rod to the bracket. A depression, or pit, may be dug alongside slab
100 at the location of each bracket assembly 102 to facilitate
connecting bracket assemblies 102 to slab 100. The lower edge of
bracket 106 may be flush with the lower the edge of sidewall 113 of
slab 100, as shown in FIG. 1, or may be positioned some distance
above the lower edge 113 of the sidewall of slab 100.
[0021] Referring to FIG. 2, support leg 112 is substantially
perpendicular to slab mounting plate 107 and protrudes away from
slab 100 when angle bracket 106 is connected to slab 100. The
mounting of bracket 106 to slab sidewall 113 is thus a cantilever
mounting. Like slab mounting plate 107, support leg 112 may be
generally flat or may have other cross-sectional shapes. Support
leg 112 may have one or more retainer apertures 114. Each retainer
aperture 114 is an aperture located in and extending through
support leg 112 of angle bracket 106. The retainer aperture or
apertures 114 on a single angle bracket 106 may be aligned with
corresponding retainer aperture or apertures 114 on the opposite
angle bracket 106.
[0022] In some embodiments, slab mounting plate 107 and support leg
112 may be integrally formed of a single piece of material. In an
alternative embodiment, angle bracket 106 may be created by
connecting slab mounting plate 107 to support leg 112, such as by
welding or by threaded fasteners. Furthermore, in another
additional embodiment, bracket assembly 102 may be a single piece
of material (not shown) such as a plate having two or more support
legs protruding from and substantially perpendicular to the
plate.
[0023] Referring to FIGS. 3 and 4, in an alternative embodiment, a
circular guide member such as, for example, cylinder 122 may be
supported between angle brackets 106 and used to guide or support
pier assembly 104. Cylinder 122 may be a steel pipe or tube,
supported by the ends of spacer bracket 116. Cylinder 122 may have
other shapes to accommodate various cross-sectional shapes of pier
assembly 104. A spacer bracket 116 may be located between cylinder
122 and each angle bracket 106. Preferably, each spacer bracket 116
is a C-channel bracket with three generally flat sides.
Alternatively, spacer bracket 116 may have any other shape suitable
for supporting cylinder 122 between angle brackets 106.
[0024] The two end pieces 118 of each spacer bracket 116 are
generally flat and parallel to each other, and each end piece 118
is at a right angle to the back piece 120, thus giving the spacer
bracket 116 a general "C" shape when viewed from above, as shown in
FIG. 3. End pieces 118 may be welded, bolted, or otherwise
connected to cylinder 122. Similarly, the back piece 120 of spacer
bracket 116 may attach to the support leg 110 of angle bracket 106
by welding, bolting, or any other technique. In other embodiments,
spacer brackets 116 could have different points of contact with
cylinder 122. For example, each spacer bracket 116 could contact
cylinder 122 in just one place at the midpoint of a line parallel
to the diameter of cylinder 122 and perpendicular to the slab 100,
or the spacer bracket 116 could attach at the top edge of the
cylinder 122 rather than on the surface of the cylinder 122.
Cylinder 122 could be made out of materials other than steel.
Preferably, the spacer brackets 116 distribute the load relatively
evenly about the axis of the cylinder and thus reduce the bending
moment exerted on the cylinder 122.
[0025] Referring back to FIG. 1, pier assembly 104 is comprised of
pier segment 128. Pier segment 128 may be a length of steel pipe or
may be a concrete cylinder. In some embodiments wherein pier
segment 128 includes a concrete cylinder, a steel sleeve may be
located around the outer edge of the concrete cylinder. Pier
segment 128 may be any length. For example, in one embodiment, pier
segment 128 may be approximately 12-18 inches long. Pier segment
128 may be any diameter. For example, in one embodiment, pier
segment 128 may be approximately 4-12 inches. Multiple segments of
pier segment 128 may be preformed and stacked on top of each other
during installation to achieve the desired overall length of pier
assembly 104.
[0026] One or more sections of pier assembly 104 may be different
from other sections of pier assembly 104. The first segment to be
driven into the ground, for example, may be anchor segment 134.
Anchor segment 134 may have an enclosed end 136, which may, for
example, prevent soil from filling anchor segment 134 as anchor
segment 134 is driven into the ground. Enclosed end 136 may have a
rounded or pointed shape to facilitate penetration into the earth.
The last pier segment to be driven into the ground before raising
slab 100 is identified as pier segment 138. Uppermost pier segment
138 may be the same as or different than the other pier segments
128 used in pier assembly 104.
[0027] Each pier segment 128 may have a cable passage or bore 140
extending through the pier segment 128. Bracket assembly 102 may be
used with any type of pier including, for example, a hollow steel
tube, a concrete-filled steel tube, or a non-segmented pier.
[0028] Jack 142 may be used to drive pier segments 128 into the
ground. Jack 142 may be a hydraulic jack, or any other type of
jack. Ram 144 extends from jack 142 to exert a downward force on
pier segment 128. In an exemplary embodiment, jack frame 146 is
used to attach jack 142 to angle brackets 106. Jack frame 146 may
include hooks 150 depending from an upper frame 148. Hooks 150 may
be hooked or otherwise connected to angle brackets 106. Upper frame
148 may connect to the upper end of jack 142. In this embodiment,
hooks 150 engage lower edges of support legs 112 of brackets
106.
[0029] In some embodiments, plate 152 may be used to distribute
force across the top of pier segment 128. In this embodiment, plate
152 is a circular steel plate. In alternative embodiments, plate
152 may be a square plate or another geometric shape.
Alternatively, plate 152 may comprise brackets, I-beams, or any
other shape suitable for distributing force across the top edge of
pier segment 152. The horizontal width of plate 152 is generally at
least as wide as the horizontal width of pier segment 128, but is
smaller than the distance between angle brackets 106.
[0030] Plate 152 may be used on anchor segment 134, pier segment
128, and uppermost pier segment 138 when each of the pier segments
is driven into the ground. Plate 152 may also be used to distribute
weight across the top of uppermost pier segment 138 when slab 100
is lifted and supported by pier assembly 104. Bracket assembly 102
and jack frame 146 tend to center the force exerted by jack 142 on
pier assembly 104 and thus reduce the bending moment exerted on
pier assembly 104.
[0031] Still referring to FIG. 1, in the preferred embodiment, slab
100 of the structure is lifted by first attaching bracket assembly
102 to slab 100. Then jack 142 is attached to the bracket assembly
102 and used to drive piers segments 134, 128, 138 into the ground.
Anchor segment 134 is driven into the ground by ram 144, and then
ram 144 is retracted, pier segment 128 is placed on top of anchor
segment 134 and then ram 144 is again extended, thus urging pier
segment 128 towards anchor segment 134, and urging anchor segment
134 deeper into the ground. Additional pier segments 128 may be
driven into the ground until pier assembly 104 reaches its desired
depth. Uppermost pier segment 138 is the last pier segment driven.
Pier assembly 104 is not directly under slab 100, but rather,
offset.
[0032] Additional bracket assemblies 102 are attached to slab 100
and additional pier assemblies 104 are driven into the ground.
Thus, even though multiple pier assemblies 104 are used for a
single slab 100, only one pier assembly 104 is driven at a time.
Thus, only one column of pier segments 128, 134, or 138 is forced
into the ground at a time.
[0033] As pier assemblies 104 are driven into the ground,
displacing solid soil as they are driven, they may encounter
greater and greater resistance. In some applications, slab 100 is
lifted to its desired position as pier segments 128 are driven into
the ground, in which case it may not be necessary to drive
additional pier segments 128. In other applications, pier
assemblies 104 are driven to a particular depth such as, for
example, until reaching bedrock, until reaching a predetermined
depth, or upon encountering a predetermined amount of
resistance.
[0034] In some embodiments, no hole is drilled or dug in the ground
at the location where the pier segments are driven into the ground.
As they are pressed into the ground, subsequent pier segments 128
transfer force to anchor segment 134, thus causing anchor segment
134 to continue to displace solid soil until pier assembly 104 is
driven to its desired depth. In some embodiments, only a shallow
hole or indentation is created in the ground at the location where
the pier segments are driven into the ground.
[0035] As ram 144 of jack 142 pushes against pier segment 128, it
exerts upward force on jack 142. Hooks 150 transfer vertical force
from jack 142 to angle brackets 106, and ultimately to slab 100.
Jack 142 is unable to move away from the earth because of the
weight of slab 100. Jack 142 may exert a great deal of force, such
as, for example, 50,000 ft. lbs of force. The force causes anchor
segment 134 to displace soil and penetrate the ground. At least
initially, the force required to drive anchor segment 134 into the
ground is less than the resistance provided by slab 100. Thus, slab
100 initially remains stationary as pier segment 128 is pushed into
the ground.
[0036] Because only one pier assembly 104 is driven at a time, a
substantial portion of the weight of slab 100 may provide the
counter force or weight necessary to drive pier assembly 104 into
the ground. For example, 20-30% of slab 100 may provide
counterforce while driving a single pier assembly 104. Indeed,
cables and reinforcements integral to slab 100 (not shown) may
effectively transfer force from a broad area of slab 100 to the one
pier assembly 104 which is being driven.
[0037] In some embodiments, wherein pier segment 128 includes a
length of pipe, such as steel pipe, pier segment 128 may be driven
into the ground as an empty cylinder, having a bore, and may or may
not later be filled with concrete. After driving a desired number
of pier assemblies 104, each to a desired depth, each pier assembly
104 may be topped by plate 152. Plate 152 may be used to distribute
a load across uppermost pier segment 138.
[0038] Referring to FIG. 5, when a plurality of pier segments 128
are stacked on top of each other, segments 128 may be joined
together by cable lock assembly 156. Cable lock assembly 156 may
include cable 158, cable lock 160, and cable top anchor 162. Cable
158 extends from cable top anchor 162 through uppermost pier
segment 138, through each pier segment 128 that may be present, to
anchor segment 134, wherein cable 158 is secured by cable lock
assembly 156.
[0039] In an exemplary embodiment, cable lock 160 is lowered into
the column of pier segments 128 and anchor segment 134 after pier
segments 128 and anchor segment 134 are pressed into the ground, as
described in U.S. Pat. No. 6,718,707. In this embodiment, a weight
(not shown) may be dropped from the surface onto the top of cable
lock 160 to initially set the anchor. Tension is then applied to
cable 158 to further set cable lock 160 within anchor segment 134.
Some embodiments may not use cable lock assembly 156.
Alternatively, cable lock 160 may be placed in anchor segment 134
prior to driving anchor segment 134 into the ground, and then cable
158 may later be passed through pier assembly 104 until it engages
cable lock 160.
[0040] Cable top anchor 162 may be placed on top of the uppermost
pier segment 138 in the pier assembly 104 and used as a "tie-off"
to maintain tension on cable 158. Cable top anchor may be recessed
from the surface of uppermost pier segment 138 such that, after
tensioning cable 158, cable top anchor 162 may sit flush with the
upper edge of the outer cylinder of uppermost pier segment 138 or
may sit flush with the top of plate 152. Alternatively, anchor 162
may sit slightly below uppermost pier segment 138 or top plate
152.
[0041] In some embodiments wherein pier assembly 104 is driven into
the ground as empty pipe, pier assembly 104 may subsequently be
filled with concrete 132. Concrete 132 may provide strength and
lateral support to pier assembly 104. In some embodiments, cable
158 may include a textured exterior surface such as, for example,
the exterior surface of a multi-strand cable. In these embodiments,
concrete 132 may engage the exterior surface as it cures. The
adhesion between concrete 132 and cable 158 may be strong enough to
maintain tension on cable 158 even if top anchor 162 or cable lock
160 fail some time after concrete 132 sets.
[0042] Referring to FIG. 6, U-shaped member 168 is a device that
may be used to transmit force from the top of pier assembly 104 to
jack 142. U-shaped bracket may be made from metal, such as steel,
or made from other materials having suitable strength. U-shaped
bracket may have base member 170 and legs 172 extending from base
member 170. U-shaped member 168 may be placed with the legs of the
"U" pointing down, such that legs 172 of the "U" contact plate 152
while base member 170 of the "U" contacts ram 144. In some
embodiments, base member 170 of U-shaped member 168 is attached to
ram 144. In embodiments that do not use plate 152, U-shaped bracket
168 may be installed between ram 144 and uppermost pier segment
138. Furthermore, in some embodiments, jack 142 may be positioned
such that ram 144 extends upwardly and thus contacts the upper
frame 148 of bracket 146 (FIG. 1). In these embodiments, U-shaped
bracket may be attached to the base of jack 142.
[0043] After connecting a jack 142 to each of the plurality of pier
assemblies 104, the plurality of jacks 142 are raised, either
simultaneously or in a coordinated fashion to raise all or portions
of slab 100. Because a plurality of jacks 142 are raised at one
time, the weight of slab 100 is distributed across the plurality of
jacks 142 and thus across a plurality of pier assemblies 104. Thus,
slab 100 rises up as each jack 142 exerts force, via brackets 116,
against slab 100 and lifts slab 100 away from the ground. Pier
assemblies 104 are not pressed deeper into the ground when slab 100
is lifted because the weight of slab 100 is no longer concentrated
on a single pier assembly 104. Indeed, slab 100 may begin to rise
with as little as, for example, 5-6 tons of pressure on each of one
or more jacks 142. Thus, slab 100 does not provide the, for
example, up to 25 tons of pressure required to drive pier assembly
142 deeper into the ground.
[0044] Referring to FIG. 1, retaining rod 164 may be used to
support slab 100 to allow removal of jack 142. Retaining rod 164
may be a metal rod, such as a steel rod, or a length of pipe.
Retaining rod 164 may be, for example, approximately 1-3 inches in
diameter, but may be any diameter. The diameter of retaining rod
164 is smaller than the interior dimensions of U-shaped member 168.
Indeed, length of legs 172 and the distance between legs 172 are
each longer than the diameter of retaining rod 164. Thus retaining
rod 164 may pass through the opening created by U-shaped member 168
when U-shaped member 168 is placed against a surface such as plate
152.
[0045] In operation, after raising the desired portions of slab
100, a retaining device such as retaining rod 164 is passed through
retainer hole 114 in one bracket 106 and over the top of topmost
pier segment 138 or plate 152, and then through hole 114 of the
opposite bracket 106. Rod 164 passes through the opening of
U-shaped member 168 and thus can be installed while jack 142 is
still pressing against pier assembly 104 (and thus holding slab 100
in an elevated position). The mid-point of retaining rod 164 is
generally centered above the top pier segment 128. Shims 174 may be
placed between the rod and the top of the pier 128 to maintain the
elevation of slab 100 after jack 142 is retracted and removed.
Because the opening of U-shaped member 168 is pointing down, ram
144 and U-shaped member 168 may be retracted away from pier segment
128 while retaining rod 164 is in place. When jack 142 is
retracted, the weight of slab is transferred through bracket
assembly 102 to retaining rod 164, shims 174, and ultimately to
pier assembly 104. Other retaining devices such as bolts, plates,
and the like may be used. Brackets 106 remain secured to the slab
after completion of lifting slab 100 and removal of jacks 142.
[0046] While the invention has been shown or described in only some
of its forms, it should be apparent to those skilled in the art
that it is not so limited, but is susceptible to various changes
without departing from the scope of the invention.
* * * * *