Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
INTERMEDIATE ANCHOR ASSEMBLY
CROSS-REFERENCE TO RELATED U.S. APPLICATIONS
[0001] This application is a nonprovisional application which claims priority
from U.S.
provisional application number 63/000,356, filed March 26, 2020, which is
incorporated by
reference herein in its entirety.
TECHNICAL FIELD/FIELD OF THE DISCLOSURE
[0002] The present disclosure relates generally to anchors for use in post-
tensioning concrete,
and specifically to intermediate anchors for post-tensioning tendons.
BACKGROUND OF THE DISCLOSURE
[0003] Many structures are built using concrete, including, for instance,
buildings, parking
structures, apaiiments, condominiums, hotels, mixed-use structures, casinos,
hospitals, medical
buildings, government buildings, research/academic institutions, industrial
buildings, malls,
bridges, pavement, tanks, reservoirs, silos, foundations, sports courts, and
other structures.
[0004] The concrete may be poured into a concrete form. The concrete form may
be a form
or mold into which concrete is poured or otherwise introduced to give shape to
the concrete as
it sets or hardens thus forming a concrete member.
[0005] Prestressed concrete is structural concrete in which internal stresses
are introduced to
reduce potential tensile stresses in the concrete resulting from applied
loads; prestressing may
be accomplished by post-tensioned prestressing or pre-tensioned prestressing.
In post-tensioned
prestressing, a post-tensioning tendon embedded in the concrete is tensioned
after the concrete
has attained a specified strength. The post-tensioning tendon may include for
example and
without limitation, anchorages, a tension member, sheathing, and ducts. The
tension member
may be constructed of a suitable material exhibiting tensile strength that can
be elongated
including, for example, reinforcing steel or composite material, in the form
of single or multi-
strand cable.
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[0006] A post-tensioning tendon generally includes an anchorage at each end.
The tension
member is fixedly coupled to a fixed anchor positioned at one end of the post-
tensioning tendon,
sometimes referred to as the "fixed-end" or "dead end" anchor, and is stressed
at the other
anchor, sometimes referred to as the "stressing-end" or "live end" anchor.
[0007] The tension member is stressed by pulling the tension member through
the stressing
anchor; when the pulling force is released, the anchors grip the tension
member and retain the
tension member in tension. In some instances, the anchors grip the tension
member using
wedges, so that the gripping force increases when the tension on the tension
member increases.
[0008] In some instances, it may be desirable to pour a long concrete slab in
sections. In such
instances, the sections are poured sequentially, with each pour section curing
and being post-
tensioned before the next, adjacent section is poured. In such instances, the
anchors between
adjacent slabs are known as "intermediate anchors." Because intermediate
anchors typically
entail an interruption of the sheathing that otherwise protects the tension
member from
corrosion, and because intermediate anchors are ultimately fully embedded in
concrete,
intermediate anchors need to be able to inhibit the ingress of liquid that may
cause corrosion.
SUMMARY
[0009] The present disclosure provides for an intermediate anchor assembly.
The
intermediate anchor assembly includes an encapsulated anchor having a front
encapsulation
extension and a rear encapsulation extension. The intermediate anchor assembly
also includes
a cap, the cap having an outer surface and a front tube having a proximal end,
a distal end, an
outer surface, and an inside diameter that is greater than the outer diameter
of a tension member.
In addition, the intermediate anchor assembly includes a front adapter having
a proximal end
and a distal end, wherein the proximal end sealingly couples to the outer
surface of the cap, and
wherein the distal end sealingly couples to the outer surface of the proximal
end of the front
tube. The intermediate anchor assembly includes a rear tube having a proximal
end, a distal
end, an outer surface, and an inside diameter that is greater than the outer
diameter of the tension
member. In addition, the intermediate anchor assembly includes a rear adapter
having a
proximal end and a distal end, wherein the proximal end sealingly couples to
the rear
encapsulation extension, and wherein the distal end sealingly couples to the
outer surface of the
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proximal end of the rear tube. Further, the intermediate anchor assembly
includes a first split
seal sealingly fit between the tension member and the distal end of the front
tube and a second
split seal sealingly fit between the tension member and the distal end of the
rear tube.
[00010] The present disclosure also includes method for using an intermediate
anchor
assembly. The method includes providing a first concrete form assembly, the
first concrete form
assembly including a first concrete form, a first anchor affixed to the first
concrete form, and a
tension member extending through the first concrete form and the first anchor.
The method also
includes installing an intermediate anchor assembly on the tension member. The
intermediate
anchor assembly includes an encapsulated anchor having a front encapsulation
extension and a
rear encapsulation extension. In addition, the intermediate anchor assembly
includes a cap, the
cap having an outer surface and a front tube having a proximal end, a distal
end, an outer surface,
and an inside diameter that is greater than the outer diameter of the tension
member. The
intermediate anchor assembly also includes a front adapter having a proximal
end and a distal
end and a rear tube having a proximal end, a distal end, an outer surface, and
an inside diameter
that is greater than the outer diameter of the tension member. The
intermediate anchor assembly
also includes a rear adapter having a proximal end and a distal end. The
method further includes
affixing the encapsulated anchor to the first concrete form and coupling the
rear tube to the rear
adapter, coupling the rear adapter to the rear encapsulation extension, and
inserting a split seal
between the tension member and the distal end of the rear tube. In addition,
the method includes
placing concrete in the first concrete form so as to embed the first anchor
and the encapsulated
anchor in a first concrete pour and removing the first concrete form from
first concrete pour.
The method further includes inserting wedges into the encapsulated anchor,
coupling the cap to
the front encapsulation extension, coupling the front adapter to the cap,
coupling the front tube
to the front adapter, and inserting a second split seal between the tension
member and the distal
end of the front tube. The method includes providing a second concrete form
assembly adjacent
to the first concrete pour; the second concrete form assembly including a
second concrete form
and a third anchor affixed to the second concrete form, wherein the tension
member extends
through the third anchor and the second concrete form. Also, the method
includes placing
concrete in the second concrete form so as to embed the cap, front adapter,
front tube, second
split seal and third anchor in a second concrete pour.
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BRIEF DESCRIPTION OF THE DRAWINGS
[00011] FIG. 1 is a cross section of an intermediate anchor assembly
consistent with at least
one embodiment of the present disclosure.
[00012] FIG. 2 is a cross section of a cap of an intermediate anchor assembly
consistent with
at least one embodiment of the present disclosure.
[00013] FIG. 3 is a cross section of an alternative embodiment of the cap of
an intermediate
anchor assembly shown in FIG. 2.
[00014] FIGS. 4-6 are cross-sections illustrating steps in a method for using
an intermediate
anchor assembly consistent with at least one embodiment of the present
disclosure.
DETAILED DESCRIPTION
[00015] It is to be understood that the following disclosure provides many
different
embodiments, or examples, for implementing different features of various
embodiments.
Specific examples of components and arrangements are described below to
simplify the present
disclosure. These are, of course, merely examples and are not intended to be
limiting. In
addition, the present disclosure may repeat reference numerals or letters in
the various examples.
This repetition is for the purpose of simplicity and clarity and does not in
itself dictate a
relationship between the various embodiments or configurations discussed.
[00016] Referring to FIG. 1, in some embodiments, intermediate anchor assembly
10 may
include front tube 18, front adapter 12, cap 20, anchor 14, rear adapter 32,
and rear tube 28.
Tension member 50 may extend through intermediate anchor assembly 10. Tension
member 50
may be cylindrical and include strand 52 and sheathing layer 58 surrounding
strand 52.
[00017] Anchor 14 may include anchor body 15 at least partially surrounded by
encapsulation
40 (referred to herein as an "encapsulated anchor"). Anchor body 15 may
include bore 43
therethrough and frustoconical surface 17 adjacent the bore. One or more
wedges 19 may be
received within bore 43 and positioned adjacent frustoconical surface 17. The
one or more
wedges 19 may grip tension member 50 when a rearward (leftward, as drawn)
force is applied
to tension member 50. Encapsulation 40 may include a front encapsulation
extension 42 and a
rear encapsulation extension 44. Front encapsulation extension 42 may be
annular. Front
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encapsulation extension 42 may or may not include a male or female engagement
mechanism
such as threads or bayonet tabs or a groove or ridge for securing a snap-fit
with an adjacent
component.
[00018] Cap 20 may mechanically couple to front encapsulation extension 42 and
may include
a female or male engagement mechanism, such as threads, bayonet tabs, one or
more grooves,
or one or more ridges that corresponds to and engages the engagement mechanism
on front
encapsulation extension 42. Cap seal 23 may be disposed between cap 20 and
front
encapsulation extension 42 such that cap seal 23 sealingly engages at least
one of anchor body
or encapsulation 40 when cap 20 is coupled to front encapsulation extension
42. Cap seal 23
10 may be an 0-ring or may be annular.
[00019] Referring to FIG. 2, cap 20 may include frustoconical pocket-forming
wall 22, base
26, anchor-receiving portion 27, anchor seat 29, and end wall 36. A
longitudinally extending
gripping head 24 having a cable-opening 34 therethrough may extend from end
wall 36.
Gripping head 24 may be used to facilitate gripping, rotation, placement, or
removal of cap 20.
15 In some non-limiting embodiments, gripping head 24 may be hexagonal. In
other embodiments
and as illustrated in FIG. 3, cap 20 may not include a gripping head and may
have instead end
wall 36 with cable-opening 34 therethrough. As further shown in FIG. 3, base
26 may include
encapsulation-engaging boss 37 that frictionally engages front encapsulation
extension 42. In
still other embodiments, one or more of the foregoing elements may not be
present in cap 20, or
cap 20 may comprise one or more elements in a different configuration from
what is illustrated.
[00020] With further reference to FIG. 1, front and rear tubes 18, 28 may each
be made of a
polymer and may have an inside diameter that is greater than the outer
diameter of tension
member 50. Front and rear tubes 18, 28 may each have a proximal end 18a, 28a,
respectively,
and a distal end 18b, 28b, respectively. Front and rear tubes 18, 28 may each
be positioned over
tension member 50 by sliding anchor 14 from an end of tension member 50 to a
desired location
on tension member 50. Split seal 54a may be received on proximal ends 18a and
28a and split
seal 54b on distal ends 18b, 28b.
[00021] Each of split seals 54a, 54b may be a split seal having a longitudinal
slit that enables
split seals 54a, 54b to be applied to a tension member from the side, i.e.,
the cylindrical face,
without requiring access to an end of tension member 50. Split seals 54a, 54b
may be made of
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an elastomer, elastomeric foam, rubber, silicone, or other deformable sealing
material. Split
seals 54a, 54b may be sized to fit in an annular space between proximal ends
18a, 28a and
tension member 50 and distal tube ends 18b, 28b and tension member 50. In some
embodiments, split seals 54a, 54b may each have seal body 56 and seal head 57.
The inside
diameter of each seal body 56 may be the same as, less than, or greater than
the outer diameter
of tension member 50 and the outer diameter of each seal body 56 may be the
same as or greater
than the inside diameter of tubes 18, 28. Split seals 54a, 54b may be in a
compressed state when
positioned in the annular space between front or rear tube 18, 28 and tension
member 50. Split
seals 54a, 54b can be applied to the side of tension member 50 and then slid
along the tension
member and into the annular space between front or rear tube 18, 28 and
tension member 50.
[00022] In certain embodiments, front adapter 12 and rear adapter 32 may be
sleeves. Front
adapter 12 may include a proximal end 12a and a distal end 12b. Rear adapter
32 may include
a proximal end 32a and a distal end 32b. Front adapter 12 and rear adapter 32
may each be
made of an elastomer, rubber, silicone, or other suitably deformable sealing
material. Proximal
ends 12a, 32a of each adapter 12, 32 may have a larger inside diameter than
the inside diameter
of distal ends 12b, 32b. Thus, by way of example, proximal end 12a may be
sized to sealingly
couple to the outer surface of cap 20. Proximal end 32a may be sized to
sealingly couple to the
outer surface of rear encapsulation extension 44. Similarly and by way of
example, distal end
12b may be sized to sealingly couple to the outer surface of front tube 18 and
distal end 32b
may sealingly couple to the outer surface of rear tube 28. In some
embodiments, frictional
engagement is achieved by ensuring that one or more of each adapter end, 12a,
12b, 32a, 32b
has a smaller inside diameter than the outer diameter of the element with
which it couples, so
that the adapter is elastically deformed when it is frictionally coupled to
that element.
[00023] In addition or alternatively, in some embodiments, each proximal
adapter end 12a, 32a
may include engagement feature 59, such as threads, one or more snap-in tabs,
bayonet tabs, or
grooves or ridges. In the embodiment illustrated in FIG. 1, engagement feature
59 on proximal
adapter end 12a is a snap-in that engages slot 61 formed on cap 20 and the
engagement feature
on proximal adapter end 32a is a snap-in tab that engages a slot 63 formed in
rear encapsulation
extension 44. If present, each engagement feature 59 may retain the
frictionally coupled
elements in a desired relative position and reduce the likelihood of
decoupling.
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Date Recue/Date Received 2021-03-25
[00024] In some embodiments, each proximal tube end 18a, 28a may include an
engagement
feature, such as threads, snap-in tabs, bayonet tabs, or grooves or ridges. In
the embodiment
illustrated in FIG. 1, the engagement feature on proximal tube end 18a is a
slot 41 that engages
a snap-in tab 39 formed on front adapter 12 and the engagement feature on
proximal tube end
28a is a slot that engages a snap-in tab formed on rear adapter 32. If
present, each engagement
feature may retain the frictionally coupled elements in a desired relative
position and reduce the
likelihood of decoupling.
[00025] As illustrated in FIG. 1, tension member 50 may extend through the
interior of
intermediate anchor system 10. When the components of intermediate anchor
assembly 10 are
assembled, intermediate anchor assembly 10 may provide a liquid-tight seal
from distal tube
end 18b to distal tube end 28b.
Operation
[00026] Referring now to FIG. 4, to install an intermediate anchor in the
course of creating a
concrete construction member, concrete form 80 having tension member 50
extending
therethrough may be provided. A first anchor 82 may be positioned at one end
of tension
member 50. First anchor 82 may be attached to concrete form 80 by any suitable
fasteners and
may include any suitable fixed-end anchor or stressing-end anchor. If a pocket
is desired, pocket
former 84 may be installed between anchor 14 and concrete form 80.
[00027] At the other end of tension member 50, an intermediate anchor assembly
10 in
accordance with the embodiments described above may be used. As described
above, cap 20
may include a pocket forming element; if not and if a pocket is desired, a
separate pocket former
84 may be installed between anchor 14 and concrete form 80, as at first anchor
82.
[00028] In some embodiments, selected components of intermediate anchor
assembly 10 may
be applied to tension member 50 as tension member 50 is installed in concrete
form 80.
Specifically, in some embodiments, rear tube 28, rear adapter 32, anchor 14,
and cap 20 may be
threaded onto an end of the tension member 50 and slid along tension member 50
to the desired
location. Anchor 14 may be affixed to concrete form 80 by any suitable means,
including by
way of example, fasteners that may be placed through holes in anchor
encapsulation 40. A first
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split seal 54b may also be applied and slid along tension member and into the
space between
rear tube 28 and tension member 50.
[00029] Some or all of the components of intermediate anchor assembly 10 may
be pre-
assembled prior to delivery to the pour site or may be assembled at the pour
site. For example,
components of intermediate anchor assembly 10 that are adapted to be
mechanically coupled,
such as rear tube 28, rear adapter 32, and anchor 14, may be provided in
either a coupled or
decoupled state. Split seals 54 may be but are not necessarily included in or
with the pre-
assembly. If included, split seals 54 may be removed before initiation of some
installation steps.
[00030] Still further, because intermediate anchor assembly 10 is adapted for
use at the
interface between a first concrete pour and a second, adjacent concrete pour,
portions of
intermediate anchor assembly 10 may be installed before a first concrete pour
in concrete form
80 and portions of intermediate anchor assembly 10 may be installed between
the first pour and
a second pour. Tension member 50 may extend through both concrete pours.
[00031] By way of example and referring to FIGS. 5 and 6, once anchors 82, 14
have been
installed in concrete form 80, a first concrete pour 83 may be poured into
concrete form 80.
Once first concrete pour 83 has cured to a desired degree, concrete form 80
may be removed
and a second concrete form 80' can be assembled so as to abut first concrete
pour 83. Second
concrete form 80' may include a third anchor 13 positioned on tension member
50. If desired,
cap 20 may be decoupled from anchor 14 and slid along tension member 50 so as
to allow access
to the anchor bore. If present, the pocket former may be removed. Wedges 19
may be seated
in anchor 14 prior to tensioning tension member 50. Once wedges 19 are seated
and tension
member 50 has been tensioned, cap 20 may be recoupled to the anchor 14. With
cap 20
recoupled to the anchor, front adapter 12 and front tube 18 may be slid along
tension member
50 and into engagement with cap 20. Alternatively, cap 20, front adapter 12,
and front tube 18
may be coupled together as a preassembly prior to engagement with anchor 14. A
second split
seal 54a may be slid into the space between front tube 18 and tension member
50.
[00032] With second split seal 54a in place, intermediate anchor assembly 10
may be
considered fully assembled. In some embodiments, in the fully assembled state,
intermediate
anchor assembly 10 may include no internal voids. In some embodiments, in the
fully assembled
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state, intermediate anchor assembly 10 may provide a fluid-tight seal along
the entire portion of
tension member 50 that is enclosed therein, i.e. between first and second
split seals 54b, 54a.
[00033] With intermediate anchor assembly 10 fully assembled, the portion of
tension member
50 in first concrete pour 83 may be tensioned. With second concrete form 80'
and third anchor
13 in place, a second concrete pour 85 may be poured. Intermediate anchor
assembly 10 thus
allows intermediate tensioning and provides corrosion protection for tension
member 50 at the
interface between first and second concrete pours 83, 85. Tensioning of the
portion of tension
member 50 embedded in first concrete pour 83 may occur before or after pouring
or tensioning
of second concrete pour 85. If second concrete pour 85 has not occurred,
tensioning of the
portion of tension member 50 in first concrete pour 83 may be accomplished at
either end of
first concrete pour 83. If second concrete pour 85 occurs before the portion
of tension member
50 in first concrete pour 83 has been tensioned, the portion of tension member
50 in first
concrete pour 83 may be tensioned at first anchor 82.
[00034] The foregoing outlines features of several embodiments so that a
person of ordinary
skill in the art may better understand the aspects of the present disclosure.
Such features may be
replaced by any one of numerous equivalent alternatives, only some of which
are disclosed
herein. One of ordinary skill in the art should appreciate that they may
readily use the present
disclosure as a basis for designing or modifying other processes and
structures for carrying out
the same purposes or achieving the same advantages of the embodiments
introduced herein. One
of ordinary skill in the art should also realize that such equivalent
constructions do not depart
from the spirit and scope of the present disclosure and that they may make
various changes,
substitutions, and alterations herein without departing from the spirit and
scope of the present
disclosure. Unless expressly so indicated, the sequential recitation of steps
in the claims that
follow is not intended to indicate or require that the claims must be
performed in the recited
sequence.
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