Technical Field/Field of the Disclosure
[0001] The present disclosure relates generally to post-tensioned, prestressed concrete
construction. The present disclosure relates specifically to methods for forming a
pocket in a post-tensioned, prestressed concrete member.
Background of the Disclosure
[0002] Many structures are built using concrete, including, for instance, buildings, parking
structures, apartments, condominiums, hotels, mixed-use structures, casinos, hospitals,
medical buildings, government buildings, research/academic institutions, industrial
buildings, malls, roads, bridges, pavement, tanks, reservoirs, silos, sports courts,
and other structures.
[0003] 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 tension member is tensioned after the concrete has
attained a desired strength by use of a post-tensioning tendon. The post-tensioning
tendon may include for example and without limitation, anchor assemblies, the tension
member, and sheathes. Traditionally, a tension member is constructed of a material
that can be elongated and may be a single or a multi-strand cable. Typically, the
tension member may be formed from a metal or composite material, such as reinforced
steel. The post-tensioning tendon conventionally includes an anchor assembly at each
end. The post-tensioning tendon is fixedly coupled to a fixed anchor assembly positioned
at one end of the post-tensioning tendon, the "fixed-end", and stressed at the stressed
anchor assembly positioned at the opposite end of the post-tensioning tendon, the
"stressing-end" of the post-tensioning tendon.
[0004] A pocket former may be used to prevent or restrict concrete from filling in the area
between the stressing-end anchor and the concrete form used to form the concrete member
to allow access to the stressing-end of the tendon once the concrete member is poured.
As understood in the art, the concrete form is a form or mold into which concrete
is poured or otherwise introduced to give shape to the concrete member as it sets
or hardens, thus forming the concrete member. Once the concrete has sufficiently hardened
and the concrete form is removed, the pocket former is removed from the concrete member.
In certain conventional uses, pocket formers are frustoconical in shape to facilitate
removal from the concrete member. Conventionally, once the tendon is stressed, the
pocket formed by the pocket former is filled with a material such as a cementitious
grout or concrete to, for example, provide fire protection and corrosion protection.
[0005] The document
DE 3123641 discloses the features of the preamble of claim 1.
Summary
[0006] The present disclosure provides for a method of forming a post-tensioned concrete
member, according to claim 1.
[0007] The method includes positioning a post-tensioning tendon within a concrete form,
the post-tensioning tendon including a tension member, fixed anchor, and a stressing
end anchor. The method also includes positioning a pocket former between the stressing
end anchor and the concrete form. The pocket former includes a pocket former body,
the pocket former body having an outer surface. The pocket former body has a tension
member channel therethrough. The pocket former also includes a collapsible element,
the collapsible element formed on the outer surface of the pocket former body. The
collapsible element extends radially outwardly from the pocket former body. The method
additionally includes inserting the tension member through the tension member channel
of the pocket former body and placing concrete into the concrete form such that the
post-tensioning tendon and the pocket former are encased in the concrete. The method
includes applying force to the pocket former body and collapsing the collapsible element
into the pocket former body. The method also includes forming a cavity within the
concrete by removing the pocket former body from the concrete.
Brief Description of the Drawings
[0008] The present disclosure is best understood from the following detailed description
when read with the accompanying figures. It is emphasized that, in accordance with
the standard practice in the industry, various features are not drawn to scale. In
fact, the dimensions of the various features may be arbitrarily increased or reduced
for clarity of discussion.
FIGS. 1A, 1B depict a partial cross section of a post-tensioning tendon within a concrete
form during stages of a concrete pouring procedure consistent with embodiments of
the present disclosure.
FIGS. 1C - IE depict an anchor consistent during stages of a concrete pouring procedure
consistent with embodiments of the present disclosure.
FIGS. 2A, 2B depict a pocket former not falling under the scope of the present invention.
FIGS. 3A, 3B depict a pocket former consistent with embodiments of the present disclosure.
FIG. 4 depicts a cross section of a pocket former not falling under the scope of the
present invention.
FIG. 5 depicts a cross section of a pocket former not falling under the scope of the
present invention.
Detailed Description
[0009] 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.
The scope of protection of the present invention is defined by the appended claims.
In addition, the present disclosure may repeat reference numerals and/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 and/or
configurations discussed.
[0010] When stressing concrete member 40, anchoring systems may be provided to hold the
tension member before and after stressing. In some embodiments, as depicted in FIGS.
1A, 1B, post-tensioning tendon 11 may be positioned within concrete form 21. Concrete
form 21 is a form into which concrete may be poured to form concrete member 40. Post-tensioning
tendon 11 includes a fixed end anchor 13, tension member 15, and stressing end anchor
17. In some embodiments, post-tensioning tendon 11 may also include a sheath positioned
about tension member 15 and one or more seals between the sheath and fixed end anchor
13, stressing end anchor 17. The sheath and seals may, for example, protect tension
member 15 from corrosion after concrete 23 (shown in FIG. 1B) is poured. Additionally,
the sheath and seals may, for example, prevent or retard concrete from ingressing
into tension member 15 and preventing or retarding the tensioning of tension member
15. In some embodiments, a seal for fixed end anchor 13 may be omitted. Fixed-end
anchor body 14 may be positioned within concrete form 21 such that fixed-end anchor
13 will be encased in concrete 23 after concrete is poured into concrete form 21.
In some embodiments, fixed end cap 19 may be positioned at distal end 41 of fixed
end anchor 13. Fixed end cap 19 may, in certain embodiments, protect tension member
15 from corrosion after concrete 23 is poured by preventing or retarding corrosive
or reactive fluids or concrete from contacting tension member 15.
[0011] Pocket former 100 is positioned between stressing end anchor body 18 and end wall
22 of concrete form 21. Pocket former 100 may prevent or restrict concrete 23 from
filling the space between stressing end anchor 17 and end wall 22, thus forming a
cavity or pocket in edge 42 of concrete member 40 formed by concrete 23 within concrete
form 21. Pocket former 100 allows access to tension member 15 from outside concrete
member 40 once concrete member 40 is sufficiently hardened and end wall 22 is removed.
[0012] In some embodiments, as depicted in FIG. 1C, pocket former 100 comprises pocket former
body 101. In some embodiments, pocket former body 101 may include a coupler for coupling
pocket former 100 to stressing end anchor 17. In some embodiments, pocket former body
101 may be hollow. The pocket former body 101 does include tension member channel
111 through which tension member 15 may pass when pocket former 100 is installed onto
stressing end anchor 17. In some embodiments, pocket former body 101 may be a cylindrical
or generally cylindrical member. Pocket former body 101 may be any shape suitable
for providing a pocket in concrete 23 to allow access to the end of tension member
15 including, but not limited to, cylindrical, frustoconical, prismatoidal, ellipsoidal,
or any combination thereof. Additionally, the cross-sectional shape of pocket former
body 101 may be any shape including, but not limited to, square, round, oblong, ovate,
ellipsoidal, triangular, polyhedral, or any combination thereof. As depicted in FIGS.
1C-E, pocket former body 101 may be frustoconical or otherwise tapered from pocket
former outer edge 125 to pocket former inner edge 130. In some embodiments, by tapering
pocket former body 101 from pocket former outer edge 120 to pocket former inner edge
130, removal of pocket former body 101 from concrete 23 may be accomplished more easily
than a non-tapered pocket former body. As depicted in FIG. 1D, when pocket former
body 101 is removed from concrete 23 (once concrete 23 has reached a sufficient strength),
cavity 101' is formed in concrete 23. The shape of cavity 101' does correspond with
the outside shape of pocket former body 101.
[0013] The pocket former 100 does further include one or more collapsible elements 103.
"Collapsible element," as used herein, refers to an attachment to or integrally formed
part of pocket former body 101 that collapses inward towards a pocket former body
101, such as shown in FIG. 1D, or pocket former interior, such as pocket former interior
230, as shown in FIG. 2B, when placed under compressive force. Collapsible elements
may be formed from such materials as plastic or metal. Non-limiting examples of collapsible
elements are described hereinbelow.
[0014] As depicted in FIGS. 1C-E, in some embodiments, collapsible element 103 is formed
on outer surface 120 of pocket former body 101. As depicted in FIGS. 1C-E, collapsible
element 103 extends radially outwardly from pocket former body 101. As depicted in
FIG. 1D, when pocket former 100 is removed from concrete 23, collapsible element 103
does collapse, compress, or otherwise deform towards pocket former body 101, allowing
pocket former 100 to be removed from concrete 23. After removal of pocket former 100,
keyway 103' may be formed in concrete 23 corresponding with the outside shape of pocket
former body 101 and collapsible element 103. As shown in FIG. 1D, keyway 103' is a
cavity within concrete 23.
[0015] With further direction to FIGS. 1C-E, once pocket former body 101 and collapsible
element 103 are removed from concrete 23, tension member 15 may be placed under tensile
stress. In some embodiments, stressing end anchor 17 may allow tension member 15 to
extend and be stressed against fixed end anchor 13, while preventing or restricting
retraction of tension member 15 once tension member 15 is stressed. In some embodiments,
tension member 15 may be cut to length such that tension member 15 does not, for example,
extend beyond edge 42 of concrete 23. In some embodiments, once tension has been applied
to tension member 15, cavity 101' and keyway 103' may, as depicted in FIG. IE, be
filled with filling material 105. Filling material 105 may be grout, a cementitious
chloride-free grout, or concrete. In some embodiments, a stressed end cap may be installed
over end 35 of tension member 15 to prevent or restrict filling material 105 from
entering stressing end anchor 17 and tension member 15. In some embodiments, keyway
103' may provide more surface area than in concrete 23 without keyway 103' and/or
one or more locking features into which filling material 105 may be placed, thus preventing
or restricting filling material 105 from delaminating or otherwise detaching from
or moving relative to concrete 23. In some embodiments, locking features may include,
for example and without limitation, textured surfaces, ridges, grooves, recesses,
or protrusions from or into concrete 23 adapted to prevent movement of filling material
105 relative to concrete 23. Such locking features may be formed, for example and
without limitation, by textured surfaces, ridges, grooves, recesses, or protrusions
formed on outer surface 120 of pocket former body 101.
[0016] FIGS. 1A-E depict embodiments in which collapsible element 103 is at least partially
annular and triangular in cross section, thus forming keyway 103' that is generally
annular and triangular.
[0017] In some embodiments, pocket former body 101 may be formed from a rigid material capable
of retaining its shape when concrete 23 is poured. In some embodiments, collapsible
element 103 may be formed from an elastic or pliable material that may allow collapsible
element 103 to deform, thus allowing easier removal from concrete 23 than if collapsible
element 103 were rigid. In some embodiments, collapsible element 103 may be formed
from multiple subcomponents. In some such embodiments, portions of collapsible element
103 may be formed from a rigid material, while other portions are formed from a more
pliable material.
[0018] Disclosed herein, but not falling under the scope of the present invention are pocket
formers of FIGS. 2A, 2B, pocket former 200 may include collapsible elements 203 and
pocket former body 201. Pocket former body 201 may include pocket former first portion
207 and pocket former second portion 209. Collapsible elements 203 may couple between
pocket former first portion 209 and pocket former second portion 207. In some embodiments,
pocket former 200 may be formed by injection molding. In some embodiments, collapsible
element 203 may be flexibly coupled to pocket former body 201 such that upon removal
from concrete 23, collapsible elements 203 may collapse, compress, or otherwise deform
inward to form collapsible element keyway 222 formed along lines 220 as depicted in
FIG. 2B. As further shown in FIG. 2B, upon application of compressive force, collapsible
elements 203 detach from pocket former second portion 209. In some embodiments, collapsible
pocket former 200 may further include pocket former bridge 205. Pocket former bridge
205 may couple pocket former second portion 209 to collapsible elements 203. Pocket
former bridge 205 may be less thick than the pocket former inner portion 209, allowing
pocket former bridge 205 to decouple from pocket former inner portion 209 when pocket
former 200 is removed from concrete 23. In other embodiments, pocket former bridge
205 may include cut or slit formed in pocket former body 201. Pocket former bridge
205 may seal against infiltration of concrete 23 into the interior of pocket former
200 while providing a structurally weakened area to allow, for example and without
limitation, separation between collapsible elements 203 and pocket former second portion
209. As depicted in FIGS. 2A, 2B, in some embodiments, pocket former bridge 205 may
be formed about at least a portion of the perimeter of collapsible elements 203 and
may serve to allow collapsible elements 203 to, as depicted in FIG. 2B, collapse into
the interior of pocket former 200.
[0019] As depicted in FIGS. 3A, 3B, pocket former 300 does include collapsible elements
303 positioned about and attached to pocket former body 301. The pocket former 300
does also include pocket former bridges 305. Pocket former bridges 305 are oriented
longitudinally along pocket former body 301 such that, when sufficient force is applied
to pocket former bridges 305, pocket former bridges 305 break and pocket former body
301 does separate into two or more longitudinal segments 306. Longitudinal segments
306 that are attached to collapsible elements 303 may then flex into the pocket former
interior 308 of pocket former 300, allowing removal of pocket former 300 from concrete
23. Although depicted as symmetrically arranged about pocket former body 301, pocket
former bridges 305 may be positioned in any configuration without deviating from the
scope of this disclosure.
[0020] As depicted in FIGS. 3A, 3B, collapsible elements 303 do extend radially outward
from exterior surface 310 of pocket former body 301. In some embodiments, the collapsible
elements exterior surface 311 may have a curved profile. In some such embodiments,
cross-sectional angle α of collapsible elements 303 may be smaller than longitudinal
angle β. In some such embodiments, because cross-sectional angle α is smaller than
longitudinal angle β, the retraction of collapsible elements 303 of pocket former
300 may be achieved by the rotation of pocket former 300. Because cross-sectional
angle α is smaller than longitudinal angle β, collapsible elements 303 may allow pocket
former 300 to rotate within concrete 23, while adding inward pressure on collapsible
elements 303, pushing collapsible elements 303 into pocket former body 301. This inward
force does cause the breakage of pocket former bridges 305. Although described as
longitudinal, pocket former bridges 305 may be of any geometry and pocket former bridges
305 may be utilized with curved collapsible elements 303 without deviating from the
scope of this disclosure.
[0021] A further alternative not falling under the scope of the present invention is disclosed
in FIG. 4, pocket former 400 may include pocket former body 401 and collapsible element
403. Pocket former body 401 may also include flex feature 407 that allows flexure
between collapsible element 403 and pocket former body 401. Flex feature 407 may,
for example and without limitation, be a thinner portion of pocket former body 401
than the remainder of pocket former body 401, different material of pocket former
body 401 than the rest of pocket former body 401, a hinge, a connection or a coupling,
and may allow collapsible element 403 to bend inward without separating from pocket
former body 401.
[0022] In some embodiments, collapsible elements 403 may be formed from a different material
than the rest of pocket former body 401. In some embodiments, collapsible elements
403 may be formed together with pocket former body 401 by, for example and without
limitation, injection molding, using a different material in the portions of the mold
corresponding to the collapsible elements 403 than the rest of pocket former body
401. In some embodiments, collapsible elements 403 may be formed separately from pocket
former body 401 and may be coupled thereto. In some embodiments, pocket former body
401 may be formed from a flexible material. In some embodiments, collapsible elements
403 may be formed from a rigid material, thus, for example and without limitation,
retaining the shape of collapsible elements 403 while allowing pocket former body
401 to flex when removed from concrete 23. In some embodiments, pocket former body
401 may be formed from a rigid material and collapsible elements 403 may be formed
from a flexible material. In some embodiments, a portion of pocket former body 401,
such as pocket former bridge 405 or flex fixture 407 may be formed from a flexible
material with pocket former body 401 and collapsible elements 403 formed from a rigid
material.
[0023] A further alternative not falling under the scope of the present invention is disclosed
in FIG. 5, collapsible elements 503 of pocket former 500 may be springedly coupled
to pocket former body 501 by spring mechanism 507. In some such embodiments, spring
mechanism 507 may include connecting member 511 mechanically attached or formed integrally
with pivot 510 and spring 509. Spring 509 may connect pivot 510 to pocket former body
501. Spring mechanism 507 may allow collapsible elements 503 to move radially inward
without breakage of pocket former 500. In some such embodiments, collapsible elements
503 may be biased into the outward position by spring 509. When removed from concrete
23, collapsible elements 503 may collapse inward into pocket former body 501. Once
pocket former 500 is removed from concrete 23, spring 509 may return collapsible elements
503 to the outward position, allowing pocket former 500 to be reused.
[0024] 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 and/or achieving
the same advantages of the embodiments introduced herein. The scope of protection
of the present invention is defined by the appended claims.
1. A method of forming a post-tensioned concrete member (40) comprising:
positioning a post-tensioning tendon (11) within a concrete form (21), the post-tensioning
tendon (11) including a tension member (15), fixed anchor (13), and a stressing end
anchor (17);
positioning a pocket former (100, 200, 300, 400, 500) between the stressing end anchor
(17) and the concrete form (21), the pocket former (100, 200, 300, 400, 500) including:
a pocket former body (101, 201, 301, 401, 501), the pocket former body (101, 201,
301, 401, 501) having an outer surface (120), the pocket former body (101, 201, 301,
401, 501) having a tension member channel (111) therethrough; and
a collapsible element (103, 203, 303, 403, 503), the collapsible element (103, 203,
303, 403, 503) formed on the outer surface (120) of the pocket former body (101, 201,
301, 401, 501), the collapsible element (103, 203, 303, 403, 503) extending radially
outwardly from the pocket former body (101, 201, 301, 401, 501);
inserting the tension member (15) through the tension member channel (111) of the
pocket former body (101, 201, 301, 401, 501);
placing concrete (23) into the concrete form (21) such that the post-tensioning tendon
(11) and the pocket former are encased in the concrete (23);
applying force to the pocket former body (101, 201, 301, 401, 501);
collapsing the collapsible element (103, 203, 303, 403, 503) toward the pocket former
body (101, 201, 301, 401, 501); and
forming a cavity (101') within the concrete (23) by removing the pocket former body
(101, 201, 301, 401, 501) from the concrete (23); optionally, further comprising after
forming a cavity (101'):
applying tensile stress to the tension member (15); and
filling the cavity (101') with filling material,
the method being characterised in that the pocket former (300) further comprises pocket former bridges (305), and in that the method further comprises:
applying force to the pocket former bridges (305); and
separating the pocket former body (301) into two or more segments.
2. The method of claim 1, wherein the pocket former bridges (305) are oriented longitudinally
along the pocket former body (301) and the method further comprises:
separating the pocket former body (301) into two or more longitudinal segments; optionally,
further comprising:
flexing the longitudinal segments into a pocket former interior (308).
3. The method of claim 1, wherein the pocket former body (101, 201, 301, 401, 501) is
tapered from a pocket former outer edge (125) to a pocket former inner edge (130).
4. The method of claim 1 or 3, wherein the collapsible element (103, 203) is generally
triangular in cross section.
5. The method of any one of claims 1, 3 or 4, wherein the outer surface of the pocket
former body (101, 201, 301, 401, 501) includes textured surfaces, ridges, grooves,
recesses, or protrusions.
6. The method of any one of claims 1 or 3 to 5, wherein the collapsible element (303,
403, 503) has an exterior surface (311) and wherein the exterior surface of the collapsible
element (303, 403, 503) has a curved profile; optionally, wherein the collapsible
element (303) has a cross-sectional angle α and a longitudinal angle β, and wherein
the cross-sectional angle α is smaller than the longitudinal angle β.
7. The method of claim 1, wherein the pocket former (200) further comprises a pocket
former bridge (205), wherein the pocket former bridge (205) couples the first portion
of the pocket former body (201) to the collapsible element (203); optionally, wherein
the pocket former bridge (205) is less thick than the inner portion of the pocket
former body (201); optionally, wherein the pocket former bridge (205) is formed about
at least a portion of the perimeter of the collapsible element (203).
8. The pocket former (200) of claim 7, wherein the pocket former bridge (205) includes
a slit between the collapsible element (203) and the pocket former body (201).
1. Verfahren zum Formen eines Spannbetonelements (40), umfassend:
Positionieren eines Spanngliedes (11) innerhalb einer Betonform (21), wobei das Spannglied
(11) ein Spannelement (15), einen festen Anker (13) und einen Anker (17) am Spannende
einschließt;
Positionieren eines Taschenformers (100, 200, 300, 400, 500) zwischen dem Anker (17)
am Spannende und der Betonform (21), wobei der Taschenformer (100, 200, 300, 400,
500) einschließt:
Einen Taschenformerkörper (101, 201, 301, 401, 501), wobei der Taschenformerkörper
(101, 201, 301, 401, 501) eine Außenfläche (120) aufweist, der Taschenformerkörper
(101, 201, 301, 401, 501) einen dort hindurch gehenden Spannelementkanal (111) aufweist;
und
ein klappbares Element (103, 203, 303, 403, 503), wobei das klappbare Element (103,
203, 303, 403, 503) auf der Außenfläche (120) des Taschenformerkörpers (101, 201,
301, 401, 501) geformt ist, sich das klappbare Element (103, 203, 303, 403, 503) aus
dem Taschenformerkörper (101, 201, 301, 401, 501) radial nach außen erstreckt;
Einführen des Spannelements (15) durch den Spannelementkanal (111) des Taschenformerkörpers
(101, 201, 301, 401, 501);
Platzieren von Beton (23) in die Betonform (21) derartig, dass das Spannglied (11)
und der Taschenformer in den Beton (23) eingeschlossen werden;
Anwenden von Kraft auf den Taschenformerkörper (101, 201, 301, 401, 501);
Zusammenklappen des klappbaren Elements (103, 203, 303, 403, 503) in Richtung des
Taschenformerkörpers (101, 201, 301, 401, 501); und
Formen eines Hohlraums (101') innerhalb des Betons (23) durch Entfernen des Taschenformerkörpers
(101, 201, 301, 401, 501) aus dem Beton (23); optional, ferner nach dem Formen eines
Hohlraums (101') umfassend:
Anwenden von Zugspannung auf das Spannelement (15); und
Füllen des Hohlraums (101') mit Füllmaterial,
wobei das Verfahren dadurch gekennzeichnet ist, dass der Taschenformer (300) ferner Taschenformerbrücken (305) umfasst, und das Verfahren
ferner umfasst:
Anwenden von Kraft auf die Taschenformerbrücken (305); und
Trennen des Taschenformerkörpers (301) in zwei oder mehr Segmente.
2. Verfahren nach Anspruch 1, wobei die Taschenformerbrücken (305) longitudinal entlang
des Taschenformerkörpers (301) orientiert sind und das Verfahren ferner umfasst:
Trennen des Taschenformerkörpers (301) in zwei oder mehr longitudinale Segmente; optional,
ferner umfassend:
Biegen der longitudinalen Segmente in einen Taschenformerinnenraum (308).
3. Verfahren nach Anspruch 1, wobei der Taschenformerkörper (101, 201, 301, 401, 501)
von einer äußeren Kante (125) des Taschenformers zu einer inneren Kante (130) des
Taschenformers verjüngt ist.
4. Verfahren nach Anspruch 1 oder 3, wobei das klappbare Element (103, 203) im Querschnitt
generell dreieckig ist.
5. Verfahren nach einem der Ansprüche 1, 3 oder 4, wobei die Außenfläche des Taschenformerkörpers
(101, 201, 301, 401, 501) strukturierte Oberflächen, Rippen, Nuten, Vertiefungen oder
Vorsprünge einschließt.
6. Verfahren nach einem der Ansprüche 1 oder 3 bis 5, wobei das klappbare Element (303,
403, 503) eine Außenfläche (311) aufweist und wobei die strukturierte Oberfläche des
klappbaren Elements (303, 403, 503) ein gekrümmtes Profil aufweist; optional, wobei
das klappbare Element (303) einen Querschnittwinkel α und einen Längenwinkel β aufweist,
und wobei der Querschnittwinkel α kleiner als der Längenwinkel β ist.
7. Verfahren nach Anspruch 1, wobei der Taschenformer (200) ferner eine Taschenformerbrücke
(205) umfasst, wobei die Taschenformerbrücke (205) den ersten Abschnitt des Taschenformerkörpers
(201) an das klappbare Element (203) koppelt; optional, wobei die Taschenformerbrücke
(205) weniger dick als der innere Abschnitt des Taschenformerkörpers (201) ist; optional,
wobei die Taschenformerbrücke (205) um zumindest einen Abschnitt des Umkreises des
klappbaren Elements (203) geformt ist.
8. Taschenformer (200) nach Anspruch 7, wobei die Taschenformerbrücke (205) einen Schlitz
zwischen dem klappbaren Element (203) und dem Taschenformerkörper (201) einschließt.
1. Procédé de formation d'un élément en béton post-contraint (40), consistant à :
positionner un toron de post-tension (11) dans un coffrage à béton (21), le toron
de post-tension (11) comprenant un élément de tension (15), un ancrage fixe (13) et
un ancrage extrême de contrainte (17) ;
positionner un dispositif de coffrage de poche (100, 200, 300, 400, 500) entre l'ancrage
extrême de contrainte (17) et le coffrage à béton (21), le dispositif de coffrage
de poche (100, 200, 300, 400, 500) comprenant :
un corps de dispositif de coffrage de poche (101, 201, 301, 401, 501), le corps de
dispositif de coffrage de poche (101, 201, 301, 401, 501) ayant une surface externe
(120), le corps de dispositif de coffrage de poche (101, 201, 301, 401, 501) étant
traversé par un canal d'élément de tension (111) ; et
un élément déformable (103, 203, 303, 403, 503), l'élément déformable (103, 203, 303,
403, 503) étant formé sur la surface externe (120) du corps de dispositif de coffrage
de poche (101, 201, 301, 401, 501), l'élément déformable (103, 203, 303, 403, 503)
s'étendant radialement vers l'extérieur par rapport au corps de dispositif de coffrage
de poche (101, 201, 301, 401, 501) ;
insérer l'élément de tension (15) par le canal d'élément de tension (111) du corps
de dispositif de coffrage de poche (101, 201, 301, 401, 501) ;
placer du béton (23) dans le coffrage à béton (21) de sorte que le toron de post-tension
(11) et le dispositif de coffrage de poche soient enrobés de béton (23) ;
appliquer une force au corps de dispositif de coffrage de poche (101, 201, 301, 401,501);
déformer l'élément déformable (103, 203, 303, 403, 503) vers le corps de dispositif
de coffrage de poche (101, 201, 301, 401, 501) ; et
former une cavité (101') dans le béton (23) en retirant le corps de dispositif de
coffrage de poche (101, 201, 301, 401, 501) du béton (23) ; le procédé consistant
éventuellement, après la formation d'une cavité (101'), à :
appliquer une contrainte de traction à l'élément de tension (15) ; et
remplir la cavité (101') avec un matériau de remplissage,
le procédé étant caractérisé en ce que le dispositif de coffrage de poche (300) comprend en outre des entretoises de dispositif
de coffrage de poche (305), et en ce que le procédé consiste en outre à :
appliquer une force aux entretoises de dispositif de coffrage de poche (305) ; et
séparer le corps de dispositif de coffrage de poche (301) en deux segments ou plus.
2. Procédé selon la revendication 1, dans lequel les entretoises de dispositif de coffrage
de poche (305) sont orientées longitudinalement suivant le corps de dispositif de
coffrage de poche (301), et le procédé consistant en outre à :
séparer le corps de dispositif de coffrage de poche (301) en deux segments longitudinaux
ou plus ;
et éventuellement consistant en outre à :
fléchir les segments longitudinaux en un intérieur de dispositif de coffrage de poche
(308).
3. Procédé selon la revendication 1, dans lequel le corps de dispositif de coffrage de
poche (101, 201, 301, 401, 501) est conique d'un bord externe de dispositif de coffrage
de poche (125) vers un bord interne de dispositif de coffrage de poche (130).
4. Procédé selon la revendication 1 ou 3, dans lequel l'élément déformable (103, 203)
a généralement une section transversale triangulaire.
5. Procédé selon l'une quelconque des revendications 1, 3 et 4, dans lequel la surface
externe du corps de dispositif de coffrage de poche (101, 201, 301, 401, 501) comporte
des surfaces texturées, des nervures, des cannelures, des évidements ou des protubérances.
6. Procédé selon l'une quelconque des revendications 1, 3 et 5, dans lequel l'élément
déformable (303, 403, 503) a une surface extérieure (311) et dans lequel la surface
extérieure de l'élément déformable (303, 403, 503) a un profil incurvé ;
éventuellement dans lequel l'élément déformable (303) a un angle de section transversale
α et un angle longitudinal β, et dans lequel l'angle de section transversale α plus
petit que l'angle longitudinal β.
7. Procédé selon la revendication 1, dans lequel le dispositif de coffrage de poche (200)
comprend en outre une entretoise de dispositif de coffrage de poche (205), l'entretoise
de dispositif de coffrage de poche (205) accouplant la première partie du corps de
dispositif de coffrage de poche (201) à l'élément déformable (203) ; éventuellement
dans lequel l'entretoise de dispositif de coffrage de poche (205) est moins épaisse
que la partie interne du corps de dispositif de coffrage de poche (201) ; éventuellement
dans lequel l'entretoise de dispositif de coffrage de poche (205) est formée autour
d'au moins une partie du périmètre de l'élément déformable (203).
8. Dispositif de coffrage de poche (200) selon la revendication 7, dans lequel l'entretoise
de dispositif de coffrage de poche (205) comprend une fente entre l'élément déformable
(203) et le corps de dispositif de coffrage de poche (201).