Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
Systems and Methods of Concrete Apparatus with
Incorporated Lifter
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation in part application of U.S
patent
application Ser. No. 14/492,431 filed on September 22, 2014, which is a
divisional application of U.S. patent application Ser. No. 12/421,337 filed
on April 9, 2009, entitled "Systems and Methods of Concrete Apparatus
with Incorporated Lifter," which are all incorporated by reference herein.
TECHNICAL FIELD
[0002] The present disclosure is generally related to concrete
fabrication and,
more particularly, is related to precast concrete apparatus.
BACKGROUND
[0003] Precast concrete is a form of construction, where concrete is cast
in a
reusable mold or "form" which is then cured in a controlled environment,
transported to the construction site and lifted into place. In contrast,
standard concrete is poured into site specific forms and cured on site.
Precast stone is distinguished from precast concrete by using a fine
aggregate in the mixture so the final product approaches the appearance
of naturally occurring rock or stone.
[0004] By producing precast concrete in a controlled environment
(typically
referred to as a precast plant), the precast concrete is afforded the
opportunity to properly cure and to be closely monitored by plant
employees. Many states across the United States require a precast plant
to be certified (either by NPCA or PCI) for a precast producer to supply
their product to a construction site sponsored by State and Federal
Departments of Transportation (DOTs).
[0005] Ancient Roman builders made use of concrete and soon poured the
material into molds to build their complex network of aqueducts, culverts
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and tunnels. Modern uses for precast technology include a variety of
architectural and structural applications featuring parts of or an entire
building system. Precast architectural panels are also used to clad all or
part of a building facade, free-standing walls used for landscaping,
soundproofing and security walls. Storm water drainage, water and
sewage pipes and tunnels make use of precast concrete units. The
advantages of using precast concrete is the increased quality of the
material, when formed in controlled conditions, and the reduced cost of
constructing large forms used with concrete poured on site.
[0006] There are many different types of precast concrete forming systems
for
architectural applications, differing in size, function and cost.
SUMMARY
[0007] Example embodiments of the present disclosure provides systems of
concrete apparatus with incorporated lifter. Briefly described, in
architecture, one example embodiment of the apparatus, among others,
can be implemented as follows: a reinforcement cage; and at least one
lifter, the at least one lifter an incorporated lengthened portion of the
reinforcement cage.
[0008] Example embodiments of the present disclosure can also be viewed
as
providing systems of concrete apparatus with incorporated lifter. In this
regard, one embodiment of such a system, among others, can be broadly
summarized by the following: a concrete mold configured to accept: a
reinforcement cage, the reinforcement cage comprising at least one lifter,
the at least one lifter an incorporated lengthened portion of the
reinforcement cage; and concrete for molding around the reinforcement
cage.
[0009] Example embodiments of the present disclosure can also be viewed
as
providing systems of concrete apparatus with incorporated lifter. In this
regard, one embodiment of such a system, among others, can be broadly
summarized by the following: a reinforcement cage comprising at least
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one lifter, the at least one lifter an incorporated lengthened portion of the
reinforcement cage; and a concrete mold configured to accept the
reinforcement cage.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a diagram of an example embodiment of a concrete device.
[0011] FIG. 2 is a diagram of an example embodiment of a reinforcement
structure with incorporated lifter used in the concrete device of FIG. 1.
[0012] FIG. 2A is a diagram of an example embodiment of the lifter of
F1G.2
incorporated by interweaving in an over and under method.
[0013] FIG. 3 is a diagram of an example embodiment of the concrete
device of
FIG. 1 with the lifter of FIG. 2.
[0014] FIG. 4 is a diagram of an example embodiment of the concrete
device of
FIG. 3 with the lifter removed at the outer circumference of the concrete
device.
[0015] FIG. 5 is a flow diagram of an example embodiment of a method of
manufacturing the concrete device of FIG. 3.
[0016] FIG. 6 is a flow diagram of an example embodiment of a method of
using
the concrete device of FIG. 3.
[0017] FIG. 7 provides a diagram of a reinforcement cage with rebar
installed.
[0018] FIG. 8 provides a length-wise cut-away diagram of a concrete pipe
with
lifting cable installed.
[0019] FIG. 9 provides a cross-wise cut-away diagram of a round concrete
pipe
with lifting cable installed.
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[0020] FIG. 10 provides a diagram of a reinforcement cage with lifting
cable
installed.
[0021] FIG. 11 provides a diagram of a reinforcement cage with spacer
installed.
[0022] FIG. 12 provides a diagram of a formed concrete structure with
lifting
cable installed.
[0023] FIG. 13 provides a cross-wise cut-away diagram of an arch concrete
pipe
with lifting cable installed.
[0024] FIG. 14 provides a diagram of a formed concrete structure with a
coated
lifting cable installed.
DETAILED DESCRIPTION
[0025] Embodiments of the present disclosure will be described more fully
hereinafter with reference to the accompanying drawings in which like
numerals represent like elements throughout the several figures, and in
which example embodiments are shown. Embodiments of the claims may,
however, be embodied in many different forms and should not be
construed as limited to the embodiments set forth herein. The examples
set forth herein are non-limiting examples and are merely examples
among other possible examples.
[0026] Concrete is the world's most commonly used building material. In
its
simplest form, concrete may be a mixture of paste and aggregates. The
material (paste) used to manufacture concrete pipe may be composed
principally of cement and water, and may be used to coat the surface of
the fine and coarse aggregates. The cement may be a closely controlled
chemical combination of calcium, silicon, aluminum, iron, and small
amounts of other compounds, to which gypsum may be added in the final
grinding process to regulate the setting time of the concrete. The
cements chemistry comes to life in the presence of water. Soon after the
cement and water are combined, hydration occurs and the paste hardens
and gains strength to form a rock-like mass, the concrete. During
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hydration, a node forms on the surface of each cement particle. The node
grows and expands until it links up with nodes from other cement particles
or adheres to adjacent aggregates. Within this process lies the key to
concrete--it's plastic and malleable when newly mixed and strong and
durable when hardened.
[0027] The character of the concrete may be determined by the quality of
the
paste. The strength of the paste, in turn, may depend on the ratio of water
to cement. The water-cement ratio is the weight of the mixing water
divided by the weight of the cement. High-quality concrete may be
produced by lowering the water-cement ratio as much as possible without
sacrificing the workability of fresh concrete. Generally, using less water
produces a higher quality concrete provided the concrete is properly
placed, consolidated, and cured. Typically, a mix may be about 10 to 15
percent cement, 60 to 75 percent aggregate and 15 to 20 percent water.
Entrained air in many concrete mixes may also take up another 5 to 8
percent.
[0028] Almost any natural water that is drinkable and has no pronounced
taste or
odor may be used as mixing water for concrete. However, some waters
that are not fit for drinking may be suitable for concrete. Specifications
usually set limits on chlorides, sulfates, alkalis, and solids in mixing water
unless tests can be performed to determine what effect the impurity has
on various properties.
[0029] The type and size of the aggregate mixture depends on the
thickness and
purpose of the final concrete product. A continuous gradation of particle
sizes is desirable for efficient use of the paste. In addition, aggregates are
preferably clean and free from any matter that might affect the quality of
the concrete.
[0030] Curing may begin after the exposed surfaces of the concrete have
hardened sufficiently to resist marring. Curing ensures the continued
hydration of the cement and the strength gain of the concrete. Concrete
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surfaces may be cured by steam or water. The longer the concrete is kept
moist, the stronger and more durable it will become. The rate of hardening
may depend upon the composition and fineness of the cement, the mix
proportions, and the moisture and temperature conditions. Most of the
hydration and strength gain may take place within the first month of
concrete's life cycle, but hydration continues at a slower rate for many
years. Concrete continues to get stronger as it gets older.
[0031] Precast concrete products may be cast in a factory setting.
Precast
concrete products may benefit from tight quality control achieved at a
production plant. Precast concrete pipe may be produced in highly
controlled plant environments under rigid production standards and
testing specifications. Previous methods of moving precast concrete pipe
have involved leaving a hole in the precast concrete pipe, inserting a
lifting means in the hole and using the lifting means to move the precast
concrete pipe into position. After the precast concrete pipe was moved
into position, the lifting means was removed and the hole is plugged. The
hole may be a source for leaking and weakness in the precast concrete
pipe. However, using the apparatus and methods of precast concrete
device with incorporated lifter disclosed herein, the hole in the concrete
pipe is eliminated such that the concrete pipe isn't weakened, and is
actually strengthened compared to the previous lifting methods.
[0032] FIG. 1 provides an example embodiment of precast concrete pipe
100. It
should be noted that, although an example of a concrete pipe is used in
this disclosure, the methods and systems disclosed herein may be
applicable in any type of precast concrete device. Concrete pipe 100 is
shown with a first end 120 and a second end 110. Although this pipe is
shown as a hollow pipe, the pipe could be solid, or the device could
alternatively be a precast culvert, pullbox, catch basin, retaining wall,
manhole sections, and building panel, as non-limiting examples. Concrete
pipe 100 is shown to be straight and circular, but may be elliptical, arched,
bent, and curved, as non-limiting examples.
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[0033] FIG. 2 provides an example embodiment of reinforcement system 200.
This example embodiment of reinforcement system 200 comprises
reinforcement cage 230 with a first open end 220 and a second open end
210. Reinforcement cage 230 may be constructed of steel, fiber, and
fiber-reinforced plastic as non-limiting examples. As provided in FIG. 2A,
lifter 240 is incorporated to provide lifting functionality after concrete is
poured around reinforcement cage 230. Lifter 240 is placed such that lifter
240 protrudes past the outer diameter of concrete pipe 100. Lifter 240
may be separate from reinforcement cage 230 or it may be an integrated
part of reinforcement cage 230. Lifter 240 may be incorporated into
reinforcement cage 230 by interweaving in an over and under method.
Lifter 240 extends out from reinforcement cage 230, and may be a
lengthened piece of reinforcement cage 230 or a slackened piece of
reinforcement cage 230 as non-limiting examples. Lifter 240 may be
comprised of galvanized steel or any other material which is strong
enough to support the weight of concrete pipe 100. Regarding the use of
the galvanized lifter cable, the galvanized cable will not rust and it is easy
to use. Additionally, no further attachments are necessary.
[0034] Reinforcement system 200 is placed in a concrete mold (not shown)
and
concrete is poured into the mold encasing reinforcement system 200.
Once the concrete is poured into the mold, lifter 240 may be folded down
until the mold is removed and lifter 240 springs up for lifting. FIG. 3
provides concrete pipe 100 after the mold has been removed with lifter
240 protruding from concrete pipe 100. Lifter 240 makes for a safe and
easy way to lift, transport, and lay concrete pipe 100.
[0035] After pipe 100 is laid in a desired position, lifter 240 may be
left in
position. In an alternative embodiment, however, lifter 240 may be
removed. FIG. 4 provides concrete pipe 100 with the protruding section of
lifter 240 detached at points 410, 420 on the outer surface of concrete
pipe 100. If lifter 240 is a galvanized cable, lifter 240 may be severed with
a cable cutter or other detachment means. By severing lifter 240 at the
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outer surface of concrete pipe 100, lifting holes and water leakage may be
reduced or substantially eliminated.
[0036] FIG. 5 provides a flow chart of an example embodiment of method
500 of
manufacturing a concrete device with an incorporated lifter. In block 510
of method 500, a casting mold is provided. In block 520, a reinforcement
structure is provided in the casting mold. In block 530, a lifter is provided,
the lifter protruding from the reinforcement structure. In block 540,
concrete is poured into the casting mold such that the lifter protrudes from
the concrete.
[0037] FIG. 6 provides method 600 of using a concrete device with
incorporated
lifter. In block 620 a precast concrete device is placed, the precast
concrete device comprising an incorporated cable lifter. In block 620, the
cable lifter is detached at the perimeter of the precast concrete device.
[0038] In an example embodiment of a method of installing a lifter, first
a
reinforcement cage is formed. Example standards for cages include but
are not limited to ASTM C-76, AASHTO M170, ASTM 0-506, and
AASHTO M-206. After the reinforcement cage is formed, rebar may be
attached to further reinforce the area where the lifter is installed. Table 1
provides example sizes and placements based on the size of a round
pipe, for example, in reference to the round pipe of FIG. 7 Reinforcement
cage 730 comprises spigot end 710 and bell end 720. The spigot end of a
first pipe may fit into the bell end of a second pipe. Rebar pieces 735 may
be sized and located per Table 1, though other sizing and locations may
be used. In Table 1, Round Size is the diameter of a round pipe, Rebar
Size is the size of the rebar material, Rebar Length is the length of the
rebar material, and Rebar Spacing is the space between the attachment
of more than one piece of rebar.
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Rebar Rebar
Round Size Rebar Size
Length Spacing
12" #3 10"-18" 6"
15" #3 10"-18" 6"
18" #3 10"-18" 6"
24" #3 10"-18" 6"
30" #3 10"-18" 6"
Table 1.
[0039] When the rebar size and location is determined, the rebar may be
welded
to one or more of the circumferential bars (that go around the cage), but
preferably at least two. In an example embodiment, the rebar is welded on
the inside of the circumferential bars the inside of the longitudinal bars.
However, in an alternative embodiment, the rebar is welded on the
outside of the circumferential bars. When multiple cages are used in a
structure, the rebar may be welded on the inside of the circumferential
bars of the inside cage. In an alternative embodiment with multiple cages,
the rebar may be welded on the inside of the circumferential bars of the
outside cage. Although, the spacing of the rebar may match the vertical
bar spacing of the reinforcing cage, the spacing may also differ. In an
example embodiment, the rebar is attached to the reinforcing cage by
welding. In an alternative embodiment, the rebar may be tied, clipped, or
secured in any manner to hold it in place on the reinforcing cage.
Although, #3 and #4 bars are listed in Table 1, the rebar sizes and lengths
may vary depending on the application. Table 1 is listed merely for
guidance.
[0040] The lifting cable diameter and length may be chosen according to
Table 2,
as a non-limiting example. In Table 2, Round Size is the diameter of a
round pipe, Cable Diameter is the diameter of the lifting cable, Cable
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Length is the length of the lifting cable, and B and C wall refers to the wall
thickness of the pipe (such as A, B, and C, where B and C are the most
common). A lifting cable may be used in all three wall thicknesses.
Round Size Cable Diameter Cable Length
12"
15"
18" 3/8 44" (B-wall)
54" (C-wall)
24"
30"
:
-
= reti .
14 N- ".,':t7 AAA 1sa
Table 2.
The lifting cable may be woven into the reinforcing cage, behind the
added rebar, and over and under each horizontal bar between the vertical
(circumferential) bars. A weaving method may be used so that the lifting
cable does not easily pull out of the concrete. The weaving makes it
tighten down and "grab" itself. Alternative methods of holding the cable in
the concrete include a cable clamp and welding the lifting cable to the
reinforcement cage.
[0041] In an example embodiment, the lifting cable forms a loop or
lifting eye as
shown in FIG. 8, in which lifting eye/loop/lifting cable 840 protrudes
beyond the outside of walls 850. In an example embodiment, lifting eye
840 is positioned at the midpoint between spigot end 810 and bell end
820. When laying pipe, the balance of the pipe should be tilted towards
the spigot end. The offset of the lifting point from the midpoint of the pipe
may achieve the desired tilting. The size and length of the cable may be
determined according to Table 3 as a non-limiting example. In Table 3,
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Size is the inside diameter of the pipe, Wall is the wall thickness, Length
is the length of the pipe (and may vary), D-1 is distance from outside wall
of the pipe to the inside of the lifting cable, D-2 is the distance from the
end of the bell of the pipe to the center of the lifting cable, Cable Dia. is
the diameter of the lifting cable, Cable Length (B Wall) is 44", and Cable
Length (C Wall) is 54".
Awl I U-1' " tt:/ I = õ It t
4 4 1 = 44
i";
õõ.
I ;4! 1 = 4,1
=
=='.= 44
. , = .
:===. I
fl =`.
' 4
, . = .
:==
Table 3
FIG. 9 provides a cross-sectional view of an example round pipe structure
with lifting cable 940 protruding from pipe wall 950.
[0042] In an example embodiment, as provided in FIG. 10, lifting cable
1040 is
attached to reinforcing cage 1030 by cable ties such as cable ties 1060,
1070. Cable tie 1060 attaches lifting cable 1040 to reinforcing cage 1030
at the rebar attachment. Cable tie 1070 attaches lifting cable 1040 to
reinforcing cage 1030 at or near the end of the cable. Lifting cable 1040
may be tied to reinforcing cage 1030 at both pieces of rebar and at both
ends.
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[0043] In an example embodiment, as provided in FIG. 11, one or more
spacers
1180 are added to reinforcing cage 1130 to ensure proper coverage. Both
interior and exterior spacers may be added. If two cages are used, the
cages may use spacers to keep the cages at acceptable distances apart.
Cage diameters may be adjusted within specification to ensure the
additional rebar and lifting eye achieves the proper cover. In an example
embodiment, reinforcing cage 1130 inside the concrete pipe has proper
cover to the surface of the concrete. To achieve proper cover between the
cage and the surface, one or more spacers 1180 are used to hold the
cage in place. Spacers may also be used to hold the cages a proper
distance apart from one another when multiple cages are used.
[0044] After the reinforcement cage is prepared, the reinforcing cage is
located
within a concrete form (cage may be placed within a form or the form may
be placed over the cage), and concrete is poured in the form. In an
example embodiment, the concrete form is removed before the concrete
is fully set. When the pipe mold is filled and vibrated, a header is applied
to the casted pipe and the pipe is stripped from the mold. In an example
implementation, the pipe is let to set for more than 2 minutes on a small
size pipe, but typically no more than 20 minutes on larger sizes. Once the
concrete form is removed, the cable will pop out or spring out of the
concrete, leaving a small void where the lifting cable rested while the
structure was being cast. Once the lifting cable has popped out, the void
left by the cable may be filled. In an example embodiment, the void is
filled with the same concrete mix used in the casting of the structure. The
void may be filled such that the surface of the structure is flush with no
visible indentation present as provided in FIG. 12, with lifting cable 1240
protruding from concrete structure 1250.
[0045] FIG. 13 provides a cross-sectional view of an arch pipe concrete
structure
with lifting cable 1340 protruding from sidewall 1350.
[0046] FIG. 14 provides an example embodiment of concrete structure 1450
with
coated lifting cable 1440. In an example embodiment, the cable is coated
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with plastic to prevent against water following the cable to the inside of the
concrete, and, potentially, to the reinforcing cage. Although plastic is used
as an example, other non-limiting example coatings include rubber,
powder coating, or any other protective coating. The coating may extend
the entire length of the cable or it may only cover the exposed cable that
extends from the concrete.
[0047] Although the present disclosure has been described in detail, it
should be
understood that various changes, substitutions and alterations can be
made thereto without departing from the spirit and scope of the disclosure
as defined by the appended claims.
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