U.S. patent application number 10/256757 was filed with the patent office on 2003-05-15 for apparatus and method for improving quality of elevated concrete floors.
Invention is credited to Kieranen, Carl B., Pietila, Mark A., Quenzi, Philip J., Stein, Russ, Tipping, Eldon.
Application Number | 20030089050 10/256757 |
Document ID | / |
Family ID | 23270298 |
Filed Date | 2003-05-15 |
United States Patent
Application |
20030089050 |
Kind Code |
A1 |
Tipping, Eldon ; et
al. |
May 15, 2003 |
Apparatus and method for improving quality of elevated concrete
floors
Abstract
A device and method for measuring an initial camber of a beam
includes a support member positionable at a beam of a structure.
The support member includes a laser receiver for receiving a laser
reference plane at a first location when the support member is
positioned at an end of the beam and at a second location when the
support member is positioned at a central region of the beam. The
initial camber of the beam is then derived by determining a
difference between the first and second locations on the laser
receiver. A loose shoring system provides an adjustable length
support section and a positive stop for limiting deflection of the
beam at a desired amount generally equal to the measured initial
camber of the beam. The stop is adjustable to set a gap
approximately equal to the expected deflection or initial camber of
the beam as desired.
Inventors: |
Tipping, Eldon; (Plano,
TX) ; Quenzi, Philip J.; (Atlantic Mine, MI) ;
Stein, Russ; (Houghton, MI) ; Pietila, Mark A.;
(Atlantic Mine, MI) ; Kieranen, Carl B.; (Laurium,
MI) |
Correspondence
Address: |
VAN DYKE, GARDNER, LINN AND BURKHART, LLP
2851 CHARLEVOIX DRIVE, S.E.
P.O. BOX 888695
GRAND RAPIDS
MI
49588-8695
US
|
Family ID: |
23270298 |
Appl. No.: |
10/256757 |
Filed: |
September 27, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60325984 |
Sep 28, 2001 |
|
|
|
Current U.S.
Class: |
52/127.2 |
Current CPC
Class: |
E04G 2025/042 20130101;
E04G 25/06 20130101; E04G 25/061 20130101; E04G 11/48 20130101;
E04G 25/065 20130101; G01C 15/006 20130101 |
Class at
Publication: |
52/127.2 |
International
Class: |
E04G 021/04; E04G
021/26 |
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. A measuring system for measuring an initial camber in a beam,
said measuring system comprising: a laser reference generator
operable to generate a laser reference; a laser receiver operable
to receive said laser reference; and a support member, said laser
receiver being positionable on said support member, said support
member having an end adapted to removably mount to a portion of the
beam, said laser receiver being positioned on said support member
to receive said laser reference at a first location when said
support member is positioned at an end portion of a beam, said
laser receiver being operable to receive said laser reference at a
second location when said support member is positioned at a
generally central portion of the beam, a vertical distance between
said first and second locations defining the initial camber in the
beam.
2. The measuring system of claim 1, wherein said end of said
support member is adapted to removably mount to an upper surface of
the beam, said support member hanging downward from the upper
surface of the beam.
3. The measuring system of claim 1, wherein said support member
comprises an adjustable support member which is adjustable in
length to adjust a position of said laser receiver relative to said
end of said support member.
4. The measuring system of claim 1, wherein said laser receiver is
adjustably positioned on said support member and is adjustable
relative to said end of said support member to position said laser
receiver to receive said laser reference at said first
location.
5. The measuring system of claim 1 including a leveling device on
said support member for indicating when said support member is
positioned generally vertical.
6. The measuring system of claim 1, wherein said first location
comprises an average location of at least two first locations when
said support member is mounted at at least two end portions.
7. A method for measuring an initial camber of a beam supported at
opposite ends, said method comprising: generating a laser reference
at a preset level; comparing a first distance between an end
portion of the beam and said preset level with a second distance
between a generally central portion of the beam and said preset
level; and determining an initial camber of the beam at said
generally central portion by determining a difference between said
first and second distances.
8. The method of claim 7 including: positioning a laser receiver at
a support member; positioning said support member at an end portion
of the beam; receiving said laser reference at a first receiving
location on said laser receiver when said support member is
positioned at an end portion of the beam, said first distance being
defined between the end portion of the beam and said first
receiving location on said laser receiver.
9. The method of claim 8 including adjusting one of said laser
reference and said laser receiver relative to the end of the beam
and receiving said laser reference at said first location on said
laser receiver.
10. The method of claim 8 including: positioning said support
member at a generally central portion of the beam; and receiving
said laser reference at a second receiving location on said laser
receiver when said support member is positioned at the generally
central portion of the beam, said second distance being defined
between the generally central portion of the beam and said second
receiving location on said laser receiver.
11. The method of claim 10, wherein determining a difference
between said first and second distances comprises determining a
vertical distance between said first and second locations on said
laser receiver.
12. The method of claim 10, wherein positioning said support member
at the beam comprises positioning an end portion of said support
member at the beam, whereby said support member hangs downward from
the beam.
13. The method of claim 10 including adjustably positioning said
laser receiver along said support member relative to said end
portion of said support member to receive said laser reference.
14. The method of claim 10 including adjusting a length of said
support member to adjust a position of said laser receiver relative
to said end portion of said support member to receive said laser
reference.
15. The method of claim 10 including leveling a portion of said
support member with a leveling device on said support member to
position said support member in a generally vertical
orientation.
16. The method of claim 8, wherein receiving said laser reference
at a first location comprises receiving said laser reference at
multiple first locations by attaching said support member to at
least two end portions of at least one beam.
17. The method of claim 16 including averaging said multiple first
locations to determine an average first location and measuring the
difference between said average first location and said second
location.
18. The method of claim 7 including: positioning a measuring device
at a support member; positioning said support member at an end
portion of the beam; receiving said laser reference at a first
receiving location on said measuring device when said support
member is positioned at an end portion of the beam, said first
distance being defined between the end portion of the beam and said
first receiving location on said measuring device.
19. The method of claim 18, wherein receiving said laser reference
at a first location comprises receiving said laser reference at
multiple first locations by attaching said support member to at
least two end portions of at least one beam.
20. The method of claim 19 including averaging said multiple first
locations to determine an average first location and measuring the
difference between said average first location and said second
location.
21. The method of claim 7 including supporting the generally
central portion of the beam to limit deflection of the beam beyond
a predetermined amount while the beam is loaded.
22. The method of claim 21, wherein said predetermined amount is
approximately equal to said difference between said first and
second distances.
23. The method of claim 22 including: providing an adjustable
support device comprising an adjustable support section, a biasing
member for biasing said support section toward an extended position
and a positive stop member; positioning said adjustable shoring
device at the generally central portion of a beam and between a
lower surface of the beam and the support surface, said biasing
member extending said support section to retain said support
section between the lower surface of the beam and the support
surface; and setting an initial gap of said positive stop member to
be approximately equal to said predetermined amount.
24. The method of claim 23 including: placing uncured concrete on
the beams while said adjustable support device is positioned at the
generally central portion of the beam; and limiting downward
deflection of the beam with said positive stop member when the beam
has deflected said predetermined amount in response to the placing
of the uncured concrete.
25. The method of claim 24 including removing said adjustable
support device from the generally central portion of the beam after
the placed concrete has at least partially cured.
26. An adjustable shoring device which is adjustable in length and
positionable between a generally central portion of a beam and a
support surface below the beam, said adjustable shoring device
being configured to limit downward deflection of the beam to a
predetermined amount while the beam is loaded, said adjustable
shoring device comprising: a telescoping support section which is
extendable and compressible to adjust an overall length of said
support section, said support section being positionable at a
generally central portion of a beam and between a lower surface of
the beam and the support surface; a biasing member for biasing said
support section toward an extended position, said biasing member
biasing said support section toward said extended position to
generally removably secure said support section in place between
the lower surface of the beam and the support surface, said biasing
member being compressible to allow compression of said support
section toward a compressed position; and a positive stop to limit
compression of said support section, said positive stop defining an
initial gap, said support section, said biasing member and said
initial gap being compressible in response to downward deflection
of the beam, said positive stop limiting compression of said
support section when said initial gap is closed.
27. The adjustable shoring device of claim 26, wherein said support
section is adapted to engage the lower surface of the beam at one
end and the support surface at the other end.
28. The adjustable shoring device of claim 26, wherein said support
section is adapted to engage a shore member at one end and one of
the beam or the support surface at the other end.
29. The adjustable shoring device of claim 26, wherein said support
section is adapted to be attached in a middle portion of an
adjustable shore member.
30. The adjustable shoring device of claim 26, wherein said
positive stop comprises a collar and a stop member, said positive
stop limiting compression of said support section when said collar
engages said stop member.
31. The adjustable shoring device of claim 30, wherein said collar
comprises an adjustable collar which is adjustable along said
support section to adjust said initial gap, said initial gap being
defined between said stop member and said collar.
32. The adjustable shoring device of claim 26 including a
monitoring device positioned along said support section, said
monitoring device being operable to monitor an amount of
compression of said support section as concrete is placed on the
beam.
33. The adjustable shoring device of claim 26, wherein said support
section comprises a telescoping support section comprising an outer
member and an inner member, said outer member receiving said inner
member at a receiving end of said outer member.
34. The adjustable shoring device of claim 33, wherein said
positive stop comprises an adjustable stop collar at said receiving
end of said outer member and a stop member on said inner member,
said initial gap being defined between said stop member and said
stop collar.
35. The adjustable shoring device of claim 26 including a laser
receiver positioned at said support section, said laser receiver
being operable to receive a laser reference at a preset level.
36. The adjustable shoring device of claim 35, wherein said
positive stop is adjustable to adjust said initial gap in response
to a comparison between a first distance between an end portion of
the beam and said preset level and a second distance between the
generally central portion of the beam and said preset level.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority of U.S. provisional
application, Ser. No. 60/325,984, filed Sep. 28, 2001 by Tipping et
al. for APPARATUS AND METHOD FOR IMPROVING QUALITY OF ELEVATED
CONCRETE FLOORS, which is hereby incorporated herein by reference
in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates generally to a method for
placing concrete on elevated decks and surfaces and, more
particularly, to a method for allowing the placing and screeding of
concrete to form the elevated concrete slabs which result in
substantially flatter and more level floor surfaces of
substantially uniform thickness.
BACKGROUND OF THE INVENTION
[0003] Steel beams and girders, which are designed and then
assembled together to form a support structure, are commonly used
to create elevated decks and floors, such as for multistory
buildings and the like. Typically, the horizontal steel I-beams are
often specified by the building designers to be pre-cambered or
arched or curved slightly to have an upwardly curved initial form.
This is done in an effort to anticipate the normal, expected
deflection of the beams, and to counteract the strain of the floor
loads that they are designed to support. To form the elevated
floor, corrugated sheet metal decking material is typically placed
over the horizontal I-beams and girders. Steel bars and wire mesh
may be laid out in designated patterns over the corrugated decking
to serve as reinforcement. This material is normally supported on
small supports or "chairs" to ensure that it is held at the correct
height within the concrete as the concrete cures. The addition of
and location of these materials add greatly to the strength of the
final product.
[0004] Concrete is then placed and screeded over the arrangement to
form a slab of the specified thickness. Typically, the specified
camber of the beams and girders is 80% of the estimated deadload
deflection. For example, for a typical beam having an unsupported
span of thirty feet (9.14 m), the load deflection may be
approximately one inch (25.4 mm) to one and one half inches (38.1
mm) at the center of the beam. An approximate deflection tolerance
range of plus approximately one-half inch (13 mm), or minus
approximately zero inches may be typical. Often, the beams may not
deflect as much as anticipated under the design load, or the beams
may deflect beyond what is expected. The ideal amount of deflection
is that which allows the production of a flat and level concrete
floor of uniform thickness.
[0005] As the reinforcement materials and concrete are placed over
the corrugated metal decking, the mid sections of the beams and
girders deflect downward under the weight of the materials. With
the variables involved in estimating the required camber in the
beams, and the variable nature of the actual deflection of the
beams under load, each contribute to complicate the usefulness and
accuracy of using known concrete screeding methods on decks.
Conventional methods of screeding which are used to strike off,
level, and otherwise smooth the concrete, often result in a floor
that is either not flat, not level, or not of uniform thickness. In
extreme cases, all three desired specifications are compromised in
the final outcome, resulting in an inferior quality floor.
[0006] In order to counteract an excessive amount of camber in the
horizontal I-beams, concrete is often pre-placed within each bay
(the area enclosed by four adjacent columns) to cause an initial
anticipated downward deflection of the beams and girders. It is
then possible to strike-off the concrete to a uniform thickness
over the sheet metal decking. However, when enough concrete is
added to ensure an adequate amount of material for the strike off
process, the excess weight may cause an over-deflection of the
support structure in certain areas. This results in low areas of
the floor caused by over deflection of the support structure, which
may not again recover even after the concrete is stuck off to a
uniform thickness. Should more concrete be added to fill in these
low areas, the additional weight may cause further deflection of
the support structure. This results in a slab or floor which is
perhaps more flat and level, but is now no longer of uniform
thickness. This also consumes more concrete and adds to the cost of
materials.
[0007] One commonly proposed method to obtain a uniform thickness
of concrete on an elevated deck is to use pre-fabricated metal
structures or stands that have support legs which rest directly on
the corrugated sheet metal decking. A small plate is held in
position at the desired concrete thickness above the metal deck.
The screeding process then relies on these stands as a height
gauge. Some devices may even ride along the top surface of the
stands, similar to the methods used for slabs on grade, prior to
implementation of mechanized laser screeding. The stands may later
be removed before the concrete cures and the remaining holes are
filled and refinished.
[0008] Another method of obtaining a uniform thickness of concrete
on an elevated deck is to provide an ongoing series of small
pre-screeded areas ahead of the actual screeding process. A hand
trowel is used to strike off a roughly twelve inch (30 cm) diameter
area of the pre-placed concrete. The height of each wet screed pad
is determined by using a pre-established laser transmitter set-up
at the site, and a hand-held laser receiver mounted to a
grade-stick. These "wet screed pads" are created at the desired
thickness of concrete as a height gage. A hand-screeding method
will use these pads as a reference. First, two pads are made about
ten feet apart. Then, a 2.times.4 or similar straight edge is used
to strike off approximately a 12 inch (30 cm) wide by 10 foot (3 m)
long surface between the two twelve inch (30 cm) diameter pads. Two
of these 12 inch (30 cm) wide by 10 foot (3 m) long "surface-pads"
are then struck off parallel to each other at a distance roughly
equal to the width of the handheld screed being used. The concrete
is then struck off between these two parallel surfaces using the
"surface-pads" as guides for the hand held screed. Excess material
must be raked and shoveled away by at least one and often two or
more workers. Low spots as well must be filled in by the workers,
prior to the action of the hand-screed.
[0009] While either of these strike-off methods may provide a floor
or slab of generally uniform thickness on a supported deck, these
methods often result in over-deflection of the beams due to the
excess weight of concrete being placed in the bays prior to the
screeding process (concrete weighs approximately 137 lbs. per cubic
foot (2194.7 kg/cubic meter)). Since the concrete must be "placed
high" to assure that there is enough material before screeding,
over-deflection of the beams and support structure can result in a
bay which has a low area in the center. This is referred to as
"ponding" in the industry. To counteract ponding, additional
concrete has to be placed in the center area to bring the slab back
up to the specified grade and eliminate the ponding effect. This
solution, however, may result in substantially more concrete being
used to accomplish the desired result, as well as a slab that is
not of uniform thickness. In some cases, this solution to ponding
may result in up to 30% more concrete usage, adding significantly
to the cost of the construction project.
[0010] In order to counteract the ponding effect of a floor, in a
most basic way, 4.times.4 inch (10.times.10 cm) wood shores or
support posts may be temporarily placed vertically as columns
between the beams and girders of the floor or slab under
construction and the finished floor below. Shoring posts have been
used for many years in the construction industry as temporary
columns used to help support building materials such as formwork
and corrugated decking while the concrete is in the process of
being placed and cured. There are a wide variety of shoring posts
available in the industry. Some are simple wood or metal posts,
which are chosen in size for a cross-sectional load carrying
capacity and are simply cut to the desired length. Specially
designed adjustable shoring posts are also available. These posts
may utilize screw-jack threads or telescopic sections with various
types of locking mechanisms or through-pins. Overall lengths for
all posts may vary widely, typically depending upon the need, such
as from approximately 7 feet (2.13 m) or less to as much as
approximately 15 feet (4.57 m) or more. The more specialized shores
can be joined together using mechanical elements both vertically
and horizontally to create supports of added height, capacity, and
stability.
[0011] The shoring posts help to support the beams and girders of
the subject floor as they become loaded. The shores are simply cut
to length and fitted between the cambered beams and the finished
level below. In some cases, the shores may be selected and
installed to provide a small gap between the shores and the beams.
With current methods, the gap is estimated or roughly measured to
be approximately equal to the amount of designed initial camber of
the beam at each particular location. In this way, the shoring
columns are expected to limit the estimated deflection of the beams
and girders, and enhance the finished surface of the floor itself.
However, the shores must be secured to the beam or support surface
or otherwise held in place to prevent the shore from falling over
during the placing process until the beam has deflected
sufficiently so that the shore is pressed between the beam and the
lower support surface. It is also difficult to accurately measure
the amount of camber in the beams and to set the shore length
appropriately.
[0012] Under ideal conditions, if the beams are pre-cambered
perfectly, and the correct weight of reinforcing materials and
concrete are added to cause the beams to deflect downward to the
desired grade, the final surface of the floor can more easily be
made to be flat, level, and of uniform thickness. When this occurs,
all three desired specifications can be more easily achieved,
resulting in a higher quality floor installed at or near the
estimated cost. Unfortunately, ideal conditions are not always
available to allow this to occur with consistency.
[0013] Accordingly, there is a need in the art for an improved
method and tools for providing a flat, level decking of uniform
thickness. The method should employ the correct amount of
pre-camber needed for the horizontal I-beams. The tools should
provide a means to verify the elevation position of each beam in
their respective installed locations, and provide a means to set-up
and accurately install an improved temporary shoring to limit beam
deflection at various support locations along the beams. The
improved temporary shoring preferably should remain in place until
the concrete on the floor above has been struck-off, finished, and
allowed to cure to the desired strength. The method and tools
should consistently account for the pre-camber in the beams and
help provide flat and level elevated concrete floors of uniform
thickness, high quality, and predictable cost.
SUMMARY OF THE INVENTION
[0014] The present invention is intended to provide a loose shoring
system which sets a basis to improve the quality of any concrete
floor which is installed and supported by elevated steel beams,
girders, and decking materials. This is accomplished by
anticipating and measuring the camber in the beams or supporting
members, and limiting the final deflection of the supporting
members of the floor where it is possible to do so. The shoring
system of the present invention consists of both methods and tools
which ultimately leads to higher quality concrete floors of a
desired flatness and consistent thickness than has been typically
achieved in the elevated deck and multi-floor construction
industry. This invention is a sum combination of improvements in
existing tools, support work and on site measurements, and
application of laser-based measurement technology, and may be used
to provide feedback to structural engineers for development of
architectural structural specifications.
[0015] According to a first aspect of the present invention, a
loose shoring system for controlling a degree of deflection of a
beam of a structure includes an adjustable shoring device which is
adjustable in length and positioned between a generally central
portion of the beam and a support surface below the beam. The
adjustable shoring device includes a positive stop to limit
downward deflection of the beam at a desired point. The amount of
deflection allowed is preferably approximately equal to an initial
amount of camber or upward curvature in the beam prior to placing
concrete on the deck or surface above the beam. The adjustable
shoring device is adjustable in length such that it may be placed
snuggly between a lower surface of the beam and the lower support
surface prior to any downward deflection of the beam, in order to
remain in place without any additional bracketry or supports prior
to placing the concrete. The adjustable shoring device is then
adjustable in length or compressible to allow for a predetermined
amount of downward deflection of the beam as concrete is placed on
the deck or surface above the beam. Preferably, a plurality of
shoring devices may be placed beneath a plurality of beams and/or
girders. Additionally, multiple shoring devices may be positioned
at different locations along one or more beams and girders.
[0016] According to another aspect of the present invention, a
device, system and method for measuring the height of the top of an
I-beam functions in relation to an established laser plane
reference. The I-beam height measurement device is used to
determine the actual amount of pre-camber at various places along
the length of a beam. It is also used to establish height
relationships between various horizontal beams at their respective
end points, where they are attached to vertical columns. The
purpose for this is to establish whether or not the beams are at
the correct elevation. If not, this would provide measured data to
on-site workers, who can then decide on an ideal average for the
finished grade, according to the desired floor specifications as it
is created from poured concrete or like materials.
[0017] According to another aspect of the present invention, a
measuring system for measuring an initial camber in a beam
comprises a laser reference generator operable to generate a laser
reference, a laser receiver operable to receive the laser
reference, and a support member. The laser receiver is positionable
on the support member, which has an end adapted to removably mount
to a portion of the beam. The laser receiver is positionable on the
support member to receive the laser reference at a first location
when the support member is positioned at an end portion of a beam.
The laser receiver is operable to receive the laser reference at a
second location when the support member is positioned at a
generally central portion of the beam. The measuring system is
configured such that a vertical distance between the first and
second locations defines the initial camber in the beam.
[0018] In one form, the end of the support member is adapted to
removably mount to an upper surface of the beam, such that the
support member hangs downward from the upper surface of the
beam.
[0019] Preferably, the support member comprises an adjustable
support member which is adjustable in length to adjust a position
of the laser receiver relative to the end of the support member.
Optionally, the laser receiver is adjustably positioned on the
support member and is adjustable relative to the end of the support
member to position the laser receiver to receive the laser
reference at the first location.
[0020] According to another aspect of the present invention, a
method for measuring an initial camber or curvature of a beam
supported at opposite ends comprises positioning a laser receiver
at a beam, generating a laser reference at a preset level and
comparing a first distance between an end portion of the beam and
the preset level with a second distance between a generally central
portion of the beam and the preset level. An initial camber of the
beam at the generally central portion is determined by determining
a difference between the first and second distances.
[0021] In one form, the method includes positioning the laser
receiver at a support member and positioning the support member at
an end portion of the beam. The laser receiver receives the laser
reference at a first receiving location on the laser receiver when
the support member is positioned at an end portion of the beam. The
first distance is defined between the end portion of the beam and
the first receiving location on the laser receiver. The method may
include positioning the support member at a generally central
portion of the beam and receiving the laser reference at a second
receiving location on the laser receiver when the support member is
positioned at the generally central portion of the beam. The second
distance is defined between the generally central portion of the
beam and the second receiving location on the laser receiver. The
difference between the first and second distance is then determined
by determining a vertical distance between the first and second
receiving location on the laser receiver.
[0022] Optionally, the method may include supporting the generally
central portion of the beam to limit deflection of the beam beyond
a predetermined amount while the beam is loaded. The predetermined
amount is approximately equal to the difference between the first
and second distances. Preferably, an adjustable support device is
provided which includes an adjustable support section, a biasing
member for biasing the support section toward an extended position
and a positive stop member. The adjustable shoring device is
positioned at the generally central portion of a beam and between a
lower surface of the beam and the support surface. The biasing
member extends the support section to retain the support section
between the lower surface of the beam and the support surface. An
initial gap of the positive stop member is set to be approximately
equal to the predetermined amount.
[0023] The method may include placing uncured concrete on the beams
while the adjustable support device is positioned at the generally
central portion of the beam and limiting downward deflection of the
beam with the positive stop member when the beam has deflected the
predetermined amount in response to the placing of the uncured
concrete. The adjustable support device may then be removed from
the generally central portion of the beam after the placed concrete
has at least partially cured.
[0024] According to yet another aspect of the present invention, an
adjustable shoring device is adjustable in length and positionable
between a generally central portion of a beam and a support surface
below the beam. The adjustable shoring device is configured to
limit downward deflection of the beam to a predetermined amount
while the beam is loaded and includes a telescoping support
section, a biasing member and a positive stop. The support section
is extendable and compressible to adjust an overall length of the
support section and is positionable at a generally central portion
of a beam and between a lower surface of the beam and the support
surface. The biasing member biases the support section toward an
extended position to generally removably secure the support section
in place between the lower surface of the beam and the support
surface. The biasing member is compressible to allow compression of
the support section toward a compressed position. The positive stop
limits compression of the support section and defines an initial
gap. The support section, the biasing member and the initial gap
are compressible in response to loading and downward deflection of
the beam. The positive stop limits compression of the support
section when the initial gap is closed.
[0025] Therefore, the present invention provides a measurement
device and method which provides an accurate measurement of an
initial camber of a beam of an elevated deck or surface. The
measurement device is operable in response to or in conjunction
with a laser plane reference and provides an easy and accurate
measurement of the initial camber of the beams. The present
invention also provides for a loose shoring device or system which
is operable to temporarily shore or support a generally central
portion of a beam while concrete is placed thereon. The shoring
device is secured in place between the beam and the lower support
surface and allows downward deflection of the beam to a generally
level orientation, while limiting or substantially precluding
further downward deflection beyond the generally level orientation.
The present invention thus provides a measuring and shoring system
which is operable to determine the initial camber of a beam and to
limit deflection of the beam to that amount as concrete is placed
thereon.
[0026] These and others objects, advantages, purposes and features
of the present invention will become apparent upon review of the
following specification in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a perspective view of multiple adjustable shoring
columns in accordance with the present invention, as implemented on
a plurality of beams and girders of a single elevated bay;
[0028] FIG. 2 is perspective view of one of the adjustable shoring
columns of FIG. 1;
[0029] FIG. 3 is an upper perspective view of the adjustable
shoring device of FIGS. 1 and 2;
[0030] FIG. 4 is a lower perspective view of the adjustable shoring
device of FIGS. 1-3;
[0031] FIG. 5 is a side elevation of the adjustable shoring device
of FIGS. 1-4, showing an initial gap at a stop member of the
shoring device;
[0032] FIG. 6 is another side elevation of the adjustable shoring
devices of FIGS. 1-5, showing an initial gap approximately equal to
the beam camber;
[0033] FIGS. 7A and 7B are side elevations and partial sectional
views of the adjustable shoring device of FIGS. 1-6, as implemented
at a center region of a beam;
[0034] FIG. 8 is a side elevation of a camber measurement device in
accordance with the present invention;
[0035] FIG. 9 is a sectional view of an adjustable attachment
assembly for use with a conventional shore member in accordance
with the present invention;
[0036] FIGS. 10A and 10B are side elevation and partial sectional
views of the adjustable attachment of FIG. 9, as implemented at a
lower end of a conventional shoring column;
[0037] FIGS. 11A and 11B are side elevation and partial sectional
views of the adjustable attachment of FIG. 9, as implemented at an
upper end of a conventional shoring column;
[0038] FIG. 12 is a side elevation and partial sectional view of
another adjustable attachment assembly similar to that of FIG. 9,
and including an indicator assembly thereon; and
[0039] FIG. 13 is a side elevation and partial sectional view of a
mid-mount adjustable attachment assembly in accordance with the
present invention, which mounts to a middle region of an existing
shoring post.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0040] Referring now to the drawings and the illustrative
embodiments depicted therein, a loose shoring system 10 is
positioned at the beams 12 and girders 14 of an elevated flooring
bay 16 in a newly constructed high-rise or other building (FIG. 1).
One or more bays define the building or structure. Each bay 16 is
defined by a plurality of vertical I-beams or columns 18 which
support the ends 12a, 14a of the beams 12 and girders 14 about the
perimeter of the bay. The structure may be a building which
comprises multiple levels, such that the vertical columns 18
support a level of beams 12 and girders 14 above one or more lower
levels or above a support surface 20 (which may be a floor or slab
as shown in FIGS. 5 and 6 or an elevated deck as shown in FIGS. 1,
7A, 7B, 10A, 10B, 11A and 11B). A corrugated metal deck 22 or the
like is placed over the beams and girders of each bay prior to
placing concrete at or in the bay. An angle iron 24 or the like is
provided around the perimeter of the targeted area to contain the
concrete at the edges of the slab. The loose shoring system of the
present invention is applicable to conventional beams 12 and
girders 14, which are typically I-beams. Although the shoring
system of the present invention is applicable to both beams and
girders of the bays of a building, for the sake of brevity and
clarity the following discussion refers to the shoring system of
the present invention only as being implemented at one or more
beams. This is intended to refer to both the beams and girders of
each bay of the building or structure, since the shoring system of
the present invention is equally applicable to both the beams and
girders of the structure. The I-beams are often initially cambered
such that they have an initially upwardly curved center region 12b,
14b, which roughly approximates a normal mid-section deflection of
the beams under load stress and strain between their fixed ends
12a, 14a as the concrete is placed on the deck surface of the
respective bays.
[0041] Loose shoring system 10 includes one or more adjustable
shoring devices 26 positioned beneath one or more of the beams 12
of the building or structure. The adjustable shoring devices are
positioned between a lower surface 12c (FIGS. 1, 7A, 7B, 10A, 10B,
11A and 11B) of the beam 12 and the support surface or floor 20.
The adjustable shoring devices 26 are operable to snuggly fit
between the lower surface 12c of the beams 12 and the support
surface 20, yet are compressible to allow for a predetermined
amount of deflection of the beam as concrete is placed and cured
thereon. The adjustable shoring devices 26 further provide a
positive stop 43 to limit their compression and, thus, to limit
deflection of the beams, at the predetermined amount. This limits
or substantially precludes over deflection of the beams, which may
result in ponding or other problems with the concrete that is
poured and cured on the deck surface on top of the beams. Each
adjustable shoring device 26 may include a laser receiver 28 for
receiving a laser beam from a laser plane generator 30, which may
be a column mounted laser transmitter positioned at one of the
vertical columns 18 or an otherwise supported laser transmitter
positioned at a tripod or other support 30a at the building or
structure. The laser plane generator 30 and receivers 28 provide
for proper positioning and adjusting of the adjustable shoring
devices to ensure that the beams deflect the appropriate amount
when the concrete is placed and cured above the beams, as discussed
in detail below.
[0042] As best shown in FIGS. 2-6, 7A and 7B, adjustable shoring
device 26 includes a telescoping post or tube or support section
32, which includes an inner tube or support section 32a and an
outer tube or support section 32b. Inner tube section 32a is
slidably received through a receiving end 32e of outer tube section
32b and is slidable and adjustable or movable within outer tube
section 32b. A biasing member or compression spring 34 (FIGS. 2, 3,
5, 6, 7A and 7B) is positioned within outer tube 32b and functions
to bias inner tube 32a toward an extended position. A spring stop
pin or reaction pin 36 is positioned through one of a plurality of
holes 32c through outer tube 32b to hold one end of the compression
spring 34 in position within the outer tube 32b. An end of inner
tube 32a within outer tube 32b then pushes against the compression
spring 34, whereby the compression spring 34 compresses or extends
as the overall length of tube 32 is adjusted via movement of inner
tube 32a within outer tube 32b. The telescoping tubes may be formed
from any known type of tubing, and may be circular or square in
cross section or may be other shapes as desired. The outer tube 32b
is a hollow tube for receiving the inner tube 32a therein, while
the inner tube may be hollow or solid and may include an end plate
for engaging the compression spring, in order to prevent the spring
from sliding within the inner tube.
[0043] Adjustable shoring device 26 preferably further includes an
adjustable pull down handle 38, which is fixedly mounted or secured
to outer tube 32b, such that manual movement of handle 38 by an
operator functions to compress compressible spring 34 to shorten
the length of adjustable shoring device 26. At opposite ends of the
telescoping tube 32 are a pair of bearing pads or base and top
plates 35a, 35b, for bearing against the lower support surface 20
and the lower surface 12c of the beam 12, respectively.
[0044] Adjustable shoring device 26 further includes the positive
stop or stop member 43, which preferably includes a screw
adjustable collar 40, which is threadedly positioned at a threaded
portion or threads 32f (FIGS. 7A and 7B) of a receiving end 32e of
outer tube 32b and extends downwardly therefrom to provide a stop
collar at a lowermost portion of receiving end 32e of outer tube
32b. Although shown as being at a lowermost portion of outer tube
32b, clearly, telescoping tube 32 could be reversed such that stop
collar 40 is positioned at an uppermost portion of a lower, outer
tube, without affecting the scope of the present invention. The
positive stop 43 further includes a stop pin 42 positioned through
a selected pair of holes 32d through inner tube 32a, such that a
lower end of adjustable collar 40 contacts stop pin 42 to limit or
stop further compression of the tubes 32 and spring 34 after the
beam and adjustable shoring device have deflected and moved the
selected amount, as discussed below.
[0045] During use and operation of adjustable shoring device 26,
adjustable shoring device 26 is positioned beneath a beam 12, such
as in a generally central portion 12b of the beam, or spaced along
the beam, depending on how many adjustable shoring devices are
desired along a particular beam. In order to position the
adjustable shoring device 26 at the beam, the pull down handle 38
is pulled or moved downwardly to compress compressible spring 34
within tube 32, in order to shorten the overall length of
adjustable shoring device 26, such that it may easily be positioned
between the lower surface 12c of the beam 12 and the support floor
20. When adjustable shoring device 26 is positioned at the
appropriate location beneath the beam, the handle 38 is released to
allow the spring 34 to expand and, thus, to allow the overall
length of the adjustable shoring device 26 to increase until
adjustable shoring device 26 is positioned tightly between the
lower surface 12c of the beam 12 and the support surface 20 (as
shown in FIG. 7A). The spring pin 36 may be moved or adjusted along
the holes 32c in outer tube 32b to adjust the amount of compression
in spring 34 and thus the amount of force it may take to position
or move the adjustable shoring device once it is positioned beneath
the beam. Once in position, stop pin 42 is positioned in the
openings 32d in inner tube 32a which are closest to or at an
appropriate distance from the lower end of the adjustable collar
40. The amount of vertical offset of the beam from horizontal due
to the initial camber in the beam is then determined and a gap 41
(FIGS. 6 and 7A) between the adjustable collar 40 and pin 42 is set
to be approximately equal to the initial amount of the vertical
offset or camber (shown as DIM A in FIG. 7A). The gap 41 is
adjusted by rotating collar 40 around the threaded portion of outer
tube 32b, whereby collar 40 moves up or down along threaded portion
32f of receiving end 32e of outer tube 32b.
[0046] As concrete is placed on the deck surface 22 above the beams
12, the beams supporting the deck surface begin to deflect downward
toward a horizontal position. As the beams deflect downward, the
compression spring 34 compresses to allow the overall length of
adjustable shoring device 26 to shorten. As the overall length
shortens, the outer tube 32b moves downward along the inner tube
32a, such that the adjustable collar 40 moves toward the stop pin
42. When the beam has deflected the appropriate amount, the lower
end of the stop collar 40 contacts the stop pin 42 and limits or
substantially precludes any further downward movement of the outer
tube 32b and thus of the beam, such that the beam is held in its
optimal, substantially level and horizontal position (as shown in
FIG. 7B), while the concrete is placed and cured at the deck
surface. The concrete then has a generally uniform thickness over
decking material or surface 22.
[0047] Preferably, the gap 41 of the positive stop 43 (i.e. the gap
between the adjustable collar 40 and the stop pin 42) is set to the
actual amount of camber in the beam and not just an estimated
amount. In order to determine the actual amount of camber in the
beam, the laser receiver 28 and laser plane generators 30 may be
implemented. For example, laser plane generator 30 may be set up at
an arbitrary height along one of the columns of the bay. Steel
tape, a measuring stick or other measurement device or measuring
member or the like (not shown) may then be used to measure the
distance from the laser plane 31 generated by the laser plane
generator 30 to the bottom of the corrugated metal deck 22 (which
is at the same level as the top surfaces 12d of the beams 12) at
each column 18 of the bay 16. Optionally, and preferably, a laser
range finder (shown as part of laser receiver 28) may be used to
measure the distance from the laser plane 31 generated by the laser
plane generator 30 to the bottom of the corrugated metal deck 22
(or top of beam) at each column 18 of the bay 16. An average
distance from the laser plane 31 to the bottom of the metal deck 22
(or top of beam) may then be determined by averaging these
measurements (the average distance may be manually calculated or
may be automatically calculated by pressing an "average" button or
the like on the rangefinder or laser receiver, without affecting
the scope of the present invention). The laser receiver 28 may then
be positioned or zeroed along the adjustable shoring device 26
until it is aligned with the laser plane 31. The laser range finder
may then measure the distance from the laser plane 31 to the bottom
of the metal deck 22 at each particular adjustable shoring device
26. The difference between the measurements at the column and the
measurement at each adjustable shoring device 26 is approximately
the camber in the beam at that particular location. The adjustable
collar 40 may then be adjusted so that the initial gap 41 between
collar 40 and stop pin 42 is at least approximately equal to the
measured initial beam camber. A laser receiver 28 may be positioned
at each shoring device 26 (as shown in FIG. 1), or a single laser
receiver (or more than one laser receiver) may be removably
positioned at the shoring device at a fixed or predetermined or
designated mounting position at each shoring device and moved from
one shoring device to the next while taking a measurement at each
shoring device, without affecting the scope of the present
invention.
[0048] Therefore, the adjustable shoring device 26 of the present
invention provides for a easy and accurate method for measuring the
actual initial camber of the beam at the particular location of the
shoring device and provides a means for controlling and limiting
deflection of the beam, such that the beam does not deflect past
the amount of the actual initial camber in the beam. Accordingly,
ponding and other problems associated with placing, screeding and
curing concrete on an elevated deck surface are substantially
reduced. The end result is a deck surface which is flat, smooth and
of uniform thickness throughout, without requiring the additional
conventional manual labor processes.
[0049] Referring now to FIG. 8, a beam or camber measuring device
50 is operable to measure an amount of camber in a beam via a laser
reference plane 31 generated by a laser plane generator (not shown
in FIG. 8). The measurement device 50 includes a telescoping rod 52
and a laser receiver 54. The telescoping rod 52 includes an upper
hook member 56, which may be placed or hooked over top of an upper
surface 12d of the I-beam 12, as shown in FIG. 8. Telescoping rod
52 includes an inner tube or rod 52a and an outer tube or rod 52b
and a locking member or collar 58, which is operable to secure the
inner tube 52a relative to outer tube 52b to lock the overall
length of the telescoping rod 52 at a desired length. Laser
receiver 54 further includes calipers 54a or means for measuring a
change in location of the laser plane 31 as received by the laser
receiver 54, and preferably includes a digital readout 54b of this
difference. Measurement device 50 may further include a level 60
for determining when the telescoping rod 52 is oriented generally
vertically, in order to provide a more accurate camber
measurement.
[0050] During use, measurement device 50 incorporates the laser
plane generator 30 which is operable to generate the laser
reference plane 31 at an arbitrary height beneath the beams of the
deck. The measurement device 50 is positioned toward an end of a
beam and the laser receiver is moved along the outer tube 52b, or
the outer tube 52b is moved along the inner tube 52a, until the
laser plane 31 is received at a desired location on the laser
receiver 54. The laser receiver 54 is then secured in position on
the outer tube 52b and/or the outer tube 52b is secured relative to
the inner tube 52a, in order to substantially fix the distance
between the upper hook 56 and the laser receiver 54. The
measurement device 50 may be moved to the ends of other beams
and/or girders in the bay, whereby any discrepancy in height
between those ends may be averaged to determine an average end
height relative to the laser plane. The position of the laser
receiver relative to the upper hook member 56 may then be adjusted
such that the laser reference plane 31 intercepts or is received by
the laser receiver 54 at a desired location corresponding to the
average height at the ends of the beams.
[0051] Once the average height or average relative position of the
upper surface of the ends of the beams to the laser receiver is
determined, measurement device 50 may be positioned toward a mid
section or other desired location along a particular beam. The
laser plane then intercepts or is received by the laser receiver at
a different location, since the generally central region of the
cambered beam would be at a higher location than the ends of the
beam, due to the initial camber or upward curvature of the beam.
The amount of camber or upward curvature of the beam may then be
measured due to the change in location of the laser plane 31 on the
laser receiver 54. This may be read via the digital readout 54b at
laser receiver 54, and provides a measurement of the actual camber
of the beam at each desired location along the beam. This process
may be repeated for other locations along the beam and for other
beams of the particular bay.
[0052] Once the amount of camber at a particular location along the
beam is determined, an appropriate shoring device may be positioned
there to limit movement or deflection of the beam at an amount
generally equivalent to its initial camber. The appropriate shoring
device may be an adjustable shoring device, such as adjustable
shoring device 26, discussed above, or may be a conventional
shoring column cut or otherwise formed to the desired length,
without affecting the scope of the present invention. It is further
envisioned that an adjustable shoring attachment may be connected
to an existing shoring column to provide for adjustability of the
shoring column and to allow for the appropriate amount of
deflection of the beam, as discussed below with respect to FIGS.
9-12, without affecting the scope of the present invention.
[0053] Referring now to FIGS. 9-12, an adjustable shoring
attachment 70 may be positioned at a lower end 72a or an upper end
72b of an existing shoring column 72 and may be adjustable to allow
for the appropriate amount of deflection of the beam at its
particular location. Adjustable shoring attachment is spring loaded
or otherwise biased to allow for easy implementation of the shoring
column without the brackets and supports previously required to
hold the shoring column in position prior to placing the concrete.
Adjustable shoring attachment 70 includes a telescoping tube
section 74, which further includes an inner tube section 74a and an
outer tube section 74b which slidably engage one another to adjust
the overall length of the tube section 74 and thus of the
adjustable shoring attachment 70. A compression spring 76 or other
biasing member is positioned within the tube sections 74a, 74b, in
order to bias the attachment 70 toward its extended position. Inner
tube 74a includes and inner stop 75a and is slidable within outer
tube 74b, which further includes an outer stop 75b at its lower or
receiving end. The inner and outer stops 75a, 75b prevent over
extension and unintentional disassembly of the tube section 74 when
transporting the adjustable attachment 70 and setting up the
adjustable attachment 70 at an appropriate location. As shown in
FIG. 9, a spacer sleeve 77 is preferably positioned within outer
tube 74b and around inner tube 74a, and functions to contact outer
stop 75b and inner stop 75a to limit extension of tube section 74.
This ensures that, even at full extension of tube section 74, the
outer and inner tubes overlap a sufficient amount to prevent
bending or binding of the tubes as they are loaded.
[0054] Adjustable attachment 70 further includes a pair of base
plates 78a, 78b, which are positioned at opposite ends of the tube
section 74 for engaging the existing shoring column 72 at one end
and the support surface 20 or lower surface 12c of the beam 12 at
the other end of the adjustable attachment 70. For example, as
shown in FIGS. 9, 10A, 10B and 12, lower base plate 78a engages
support surface 20, while upper base plate 78b engages a lower end
72a of the existing shoring column 72. Alternately, as shown in
FIGS. 1A and 1B, adjustable attachment 70 may be positioned at an
upper end 72b of shoring column 72, such that lower base plate 78a
engages upper end 72b of shoring column 72, while upper base plate
78b engages a lower surface of the beam 12. As shown in FIG. 9, a
weld joint 78c may occur at the junction of base plate 78a and
inner tube 74a. In such a situation, a stop collar 79 may be
positioned around the weld joint 78c at base plate 78a to provide a
flat upper surface for outer stop 75b to engage when the beam has
deflected the desired amount, as discussed below. The stop collar
79 preferably includes a beveled edge to fit around the weld joint,
such that the lower surface of the stop collar 79 engages the flat
upper surface of the base plate 78a.
[0055] Similar to the tube sections of adjustable shoring device
26, the tube sections of the adjustable attachment 70 may be square
or circular in cross section or may be other shapes as desired,
without affecting the scope of the present invention. As shown in
FIGS. 9-12, both the inner and outer tube sections are hollow to
allow the biasing member or compression spring to extend the entire
length of the adjustable attachment to engage the opposed surfaces
of the base plates. However, a spring stop pin or plate or the like
may be provided at the outer tube and/or the inner tube to engage
an end of a shorter spring, without affecting the scope of the
present invention.
[0056] After the amount of camber at the particular location for
the shoring column 72 and adjustable attachment 70 is determined,
such as via the measuring methods discussed above with respect to
measuring device 50, the shoring column 72 may be adjusted in
length via conventional methods, such as via cutting or forming the
shoring column to the desired length or via known pin and threaded
collar adjustment means. The length of shoring column 72 is
adjusted such that when the adjustable attachment 70 is positioned
at an end of the shoring column 72, the distance between outer stop
75b and stop collar 79 at base plate 78a (and/or the distance
between inner stop 75a and base plate 78b) is approximately equal
to the amount of initial camber in the beam at that position (shown
as a gap 81 in FIG. 9). The compression spring 76 then functions to
bias the adjustable attachment 70 toward its extended position, in
order to press the shoring column upward against the beam (or
downward against the floor, depending on where adjustable
attachment 70 is positioned) to hold the shoring column 72 and
extendable attachment 70 in position between the beam 12 and
support surface 20 prior to placing concrete at the deck 22 above
the beam 12 (as shown in FIGS. 10A and 11A). As concrete is placed
on the deck surface 22 above beam 12, the beam deflects downward
and compresses the compression spring 76 as outer stop 75b moves
toward stop collar 79 at base plate 78a and/or inner stop 75a moves
toward base plate 78b. When the appropriate amount of deflection
has occurred in the beam 12, outer stop 75b and/or inner stop 75a
contacts stop collar 79 and/or base plate 78b, respectively, and
prevents further compression of the tubes 74, and thus
substantially precludes or limits further downward deflection of
the beam 12, whereby the beam is then positioned in its
substantially horizontal and level orientation for further placing,
smoothing and/or curing of concrete on the deck surface above the
beams (as shown in FIGS. 10B and 11B).
[0057] Referring now to FIG. 12, the adjustable attachment 70 may
optionally include a monitoring device 80 to assist with setting
the travel dimension (shown at 83 in FIG. 12) and for monitoring
progress in the amount of deflection of the beam as the concrete is
placed on the deck surface above the beam. In the illustrated
embodiment, the monitoring device 80 includes a graduated measuring
rod 81 and indicator 82. The measuring rod 81 is fixedly mounted to
base plate 78a and extends upwardly therefrom and through a
passageway or guide 78d in the opposite base plate 78b. A stop
collar 84 may be positioned along measuring rod 81 to indicate the
point at which deflection of the beam will stop due to the outer or
inner stop contacting the opposite base plate and thus limiting or
precluding any further deflection of the beam. Measuring rod 81 may
further include a scale or indicator 81a along an upper portion of
measuring rod 81, whereby an indicating point or needle 82a of
indicator 82 functions to indicate the amount of deflection of the
beam or movement of base plate 78b while concrete is placed and
cured on the deck surface above the beam. Placing of the concrete
may then be adjusted in response to the amount of deflection
occurring while the concrete is being placed, since that amount of
deflection may be accurately monitored via monitoring device
80.
[0058] Referring now to FIG. 13, a mid-mount adjustable shoring
attachment 90 is shown mounted at or near a middle region of an
existing shoring post 92. Similar to adjustable attachment 70,
mid-mount adjustable attachment 90 includes a telescoping tube
section 94 having an inner tube section 94a and an outer tube
section 94b. A compression spring 96 is positioned within tube
section 94 and between a pair of base plates 98a, 98b.
[0059] The existing shoring post 92 is preferably a telescoping
shoring post and includes an inner post section 92a and an outer
post section 92b. The inner post section 92a extends through the
mid-mount spring attachment 90 and into the outer tube section 92b
at the opposite end of the attachment 90. The existing shoring post
further includes an adjustment collar 100 and post plate 102 for
adjusting the overall length of the shoring post 92. Once the
amount of camber at the desired location along the beam is known,
such as via measurement of the camber via the above discussed
means, the length of the shoring post may be adjusted such that the
gap 91 between plate 98b and an end 94c of outer tube section 94b
of adjustable attachment 90 and/or between plate 98a and an end 94d
of inner tube section 94a, is substantially equal to the amount of
camber in the beam at that location. The amount of compression of
the adjustable attachment and thus the amount of deflection of the
beam is thus limited to at least approximately the amount of camber
in the beam, since further deflection will be limited or precluded
via engagement of the ends 94c, 94d with plates 98b, 98a,
respectively. It is further envisioned that inner tube 94a may
further include a monitoring device or a visible scale on its outer
surface 94e for monitoring the amount of deflection as the concrete
is placed at the deck surface above the beam or beams.
[0060] Therefore, the present invention provides a means for
measuring the actual amount of camber in a beam via laser plane
generating devices and further provides a means for limiting
deflection of the beam to an amount substantially equal to the
measured camber. The present invention further provides for an
adjustable shoring system which may be easily placed at the desired
location beneath the beam and which is easily held in place beneath
the beam via a biasing member exerting a force at the lower surface
of the beam. The shoring system is thus positioned at, and
maintained at, its desired location beneath the beam without
requiring any additional bracketry or mounting devices to secure it
in position. Also, the present invention provides for a means for
easily monitoring and adjusting the amount of deflection for the
particular location along the beam. The present invention further
provides for an adjustable attachment which is adaptable for use
with existing shoring posts and which again allows for easy
positioning of the shoring posts at the desired location and
limiting of deflection of the beam to a desired, predetermined
amount. The desired amount of deflection is substantially equal to
the initial camber in the beam, which may be an estimated value,
design specification of the beam, or a measured value, such as via
any of the measuring means in accordance with the present
invention.
[0061] Changes and modifications in the specifically described
embodiments may be carried out without departing from the
principles of the present invention, which is intended to be
limited only by the scope of the appended claims as interpreted
according to the principles of patent law.
* * * * *