WO2006112805A1 - Systeme de precontrainte non colle - Google Patents

Systeme de precontrainte non colle Download PDF

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Publication number
WO2006112805A1
WO2006112805A1 PCT/US2003/004997 US0304997W WO2006112805A1 WO 2006112805 A1 WO2006112805 A1 WO 2006112805A1 US 0304997 W US0304997 W US 0304997W WO 2006112805 A1 WO2006112805 A1 WO 2006112805A1
Authority
WO
WIPO (PCT)
Prior art keywords
concrete
post
void
stainless steel
tubular structure
Prior art date
Application number
PCT/US2003/004997
Other languages
English (en)
Inventor
Jacques Gulbenkian
Original Assignee
Jacques Gulbenkian
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Jacques Gulbenkian filed Critical Jacques Gulbenkian
Priority to AU2003217590A priority Critical patent/AU2003217590A1/en
Publication of WO2006112805A1 publication Critical patent/WO2006112805A1/fr

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
    • E04C5/08—Members specially adapted to be used in prestressed constructions
    • E04C5/12—Anchoring devices
    • E04C5/122—Anchoring devices the tensile members are anchored by wedge-action
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
    • E04C5/08—Members specially adapted to be used in prestressed constructions
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
    • E04G21/00—Preparing, conveying, or working-up building materials or building elements in situ; Other devices or measures for constructional work
    • E04G21/12—Mounting of reinforcing inserts; Prestressing

Definitions

  • the present invention relates to a post-tensioning system for concrete, and more particularly to an unbonded post-tensioning system wherein the post-tensioning tendons are removable and replaceable for inspection and maintenance.
  • Post-tensioning of concrete structures has been known in the art for many years.
  • tendons are placed through a concrete structure and then tensioned using hydraulic jacks in order to place the concrete structure under compression. Examples of various post-tensioning systems are shown in, for example, U.S. Patent Nos. 3,225,499, 5,271,199, and 5,299,445.
  • a post-tensioning system for concrete structures comprises a tubular structure configured and dimensioned to provide a continuous void through a concrete structure, first and second anchor members disposed at opposite ends of the tubular structure, and at least one stainless steel strand extending through the tubular structure and secured under tension between the anchor members.
  • the anchor members are mounted to close and maintain the void with the void being unfilled such that the strand may be easily removed and replaced for inspection and maintenance.
  • a method for post-tensioning concrete structures is provided.
  • steps include assembling a continuous tubular structure within a concrete structure form, the continuous tubular structure opening at opposite ends of the form, pouring concrete into the form and permitting it to cure while maintaining a void through the continuous tubular structure, inserting at least one stainless steel strand through the void, tensioning and anchoring said at least one stainless steel strand at opposite ends of the concrete structure, and maintaining the void unfilled.
  • the strand may be inserted before or after the concrete is poured.
  • the method may further include periodically removing at least one stainless steel cable, inspecting the cable, and re-tensioning and anchoring said cable. The cable may be replaced if necessary.
  • a post-tensioned concrete structure comprises a poured concrete member, a tubular structure defining a void through the concrete member and at least one tensioned stainless steel strand passing through the void and anchored at opposite ends of the structure.
  • the void is preferably unfilled such that the cable may be removed and inspected.
  • anchor members are secured to the stainless steel strand at each end of concrete structure.
  • FIG. 1 is a cross-sectional view of one end of a post-tensioning system according to the present invention
  • FIG. 2 is a cross-sectional view of a socket for use in connection with the present invention
  • FIG. 3 is a partial side view of a duct for use in connection with the present invention
  • FIG. 4 is an end view of an assembled anchor according to the present invention
  • FIG. 5 is a cross-sectional view through line V-V in FIG. 4.
  • FIG. 6 is a cross-sectional view of a structure according to the present invention.
  • post-tensioning system 10 includes duct 12 received in socket 14.
  • the duct and socket create a passageway through subsequently poured concrete through which post- tensioning strands 16 are placed.
  • Strands 16 are anchored using anchor 18 employing
  • cover 20 may be employed in a preferred embodiment, hi one embodiment cover 20 is a flexible boot made of a material such as heavy rubber. Cover 20 is anchored to the concrete by retaining ring 22 and bolts
  • covers made of other materials including poured concrete or steel caps, may be employed.
  • strands 16 comprise a twisted seven-wire stainless steel cable.
  • Each wire maybe about 0.2 inches in diameter, such that the strand has an overall diameter of about 0.6 inches.
  • Preferred stainless steels include 0 ASTM A 368, types 316 or 304..
  • the twisted wires may have a helical pitch of 8 to 9 inches.
  • Utilizing stainless steel strands according to the present invention reduces or eliminates corrosion such that the use of grout, grease or other filler materials are not required for protection of 5 the cables. Thus, as described below, strands may be removed, inspected, and reassembled/replaced as part of regular maintenance of the system.
  • Socket 14 is shown in greater detail in FIG. 2.
  • Socket 14 may comprise central tubing member 28 onto which end plates 30 and 32 are welded.
  • tubing member 28 may comprise a 3-3/4 inch OD, 0.180 inch wall thickness 0 AISI 1020 tubing.
  • Tubing member 28 may be about 9 to 10 inches long.
  • End plates 30 and 32 may comprise 1 inch thick ASTM A36 steel plates approximately 6 to 7 inches square.
  • Plate 32 has a central hole 34 sized to receive duct 12 as shown in FIG. 1.
  • Plate 30 is provided with a larger central opening 36, sized to provide clearance for strand 16 passing therethrough as shown in FIG. 1.
  • 5 Duct 12 is shown in detail in FIG. 3.
  • duct 12 is a 2-1/2 inch OD, 19 gauge, AISI 1010 galvanized steel tube. Alternatively, other materials such as plastic pipe may be used. At one end an enlarged bell 26 is provided so that adjoining sections may be slip-fit together. Duct 12 may be provided in any convenient length. In a further alternative embodiment duct 12 is not used, hi such an embodiment, the void is maintained through the concrete without the duct, for example by drilling through hardened concrete.
  • wedges 19 clamp strands 16 into anchor 18.
  • Wedges 19 are conically shaped, preferably from AISI 8620 case-hardened steel.
  • each wedge is approximately 1-1/8 inch in length, having a large end diameter of approximately 1.25 inches and a small end diameter of approximately 0.8 inches.
  • the central bore through each wedge 19 is approximately 0.6 inches in diameter and lined with sharp spiral threads at approximately 23 threads per inch.
  • appropriately spaced knurls maybe used, for example at a pitch of 1/19 and height of about 0.046 inches.
  • two half wedges 19 make up a wedge assembly.
  • the half wedges have a thickness which preferably leaves a parting line opening 38 between the half wedges 19 when they are compressed around the tendon.
  • the width of opening 38 is approximately 3/32 - 1/8 of an inch, hi the illustrated embodiment, seven strands (each made up of seven twisted wires) are used to form a seven- stranded, parallel-lay post-tensioning cable or tendon.
  • Anchor 18 includes a number of openings corresponding to the number of strands to be used in the system.
  • openings 40 include a tapered portion mated with wedges 19 and a straight portion permitting each strand 16 to pass therethrough.
  • the wall of the tapered portion of openings 40 has a pitch of about 1 :5 to 1 :8.
  • a person of ordinary skill in the art may design suitable combination of wedges and openings to compress and secure the strands based on the teachings provided herein.
  • a system according to the invention may be utilized as follows. Prior to pouring concrete structure, the duct and sockets are placed in the concrete forms, for example as shown in FIG. 1. Concrete is then poured and permitted to dry. Once the concrete has set, strands 16 are passed through the duct and socket. Alternatively, the strands may be placed at an earlier point in the process. The strands are then inserted through anchor 18 and tensioned utilizing hydraulic jacks as known in the art. It will be appreciated that FIG. 1 illustrates one end of the post-tensioning system according to the invention and that the same parts will typically be provided on an opposite end of the structure to be post- tensioned.
  • a suitable extra length of strand is left extending from the anchor at at least one end.
  • the wedges may be removed and the strand withdrawn.
  • a strand Once a strand is removed, it may be inspected for corrosion or other degradation and replaced or reinserted as appropriate.
  • the strands may be reinserted or replaced by following the procedure for initial assembly.
  • the present invention has the advantages of reducing corrosion and permitting non-destructive
  • an original structure such as a bridge deck
  • member 100 may have comprised a central concrete member, such as member 100.
  • Member 100 may comprise a cantilevered, hollow box construction.
  • the structure has been increased in width by adding T-sections 104 25 to the ends of member 100.
  • the T-sections may have a width of about 20 feet.
  • the new T-sections 104 are prefabricated or cast-in-situ with ducts (not shown) positioned to mate with the ducts in original member 30 100. T-sections 104 are placed in position adjacent member 100 and new strands of appropriate length are passed through the extended ducts and re-tensioned. Other suitable connections may be made as required for structural soundness in the particular application.
  • the present invention thus permits integral post-tensioning of modified structures without a complete rebuilding of the structure.

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  • Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Reinforcement Elements For Buildings (AREA)

Abstract

Cette invention concerne un système de précontrainte non collé et un procédé correspondant. L'invention concerne également des structures en béton utilisant un système de précontrainte non collé. Selon le mode de réalisation décrit dans cette invention, un vide est crée et conservé à travers la structure en béton; ce vide sert à recevoir au moins un toron en acier inoxydable (16) tendu. Le vide contenant le câble est maintenu à l'état non rempli. Des torons (16) peuvent ainsi être retirés et examinés, et insérés ou replacés si nécessaire. Le mode de réalisation décrit dans cette invention présente l'avantage de réduire la corrosion et de permettre un examen non destructeur et le remplacement de torons individuels (16).
PCT/US2003/004997 2002-02-15 2003-02-19 Systeme de precontrainte non colle WO2006112805A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2003217590A AU2003217590A1 (en) 2002-02-15 2003-02-19 Unbonded post-tensioning system

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US35740902P 2002-02-15 2002-02-15
US60/357,409 2002-02-15

Publications (1)

Publication Number Publication Date
WO2006112805A1 true WO2006112805A1 (fr) 2006-10-26

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Family Applications (1)

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Country Status (2)

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AU (1) AU2003217590A1 (fr)
WO (1) WO2006112805A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ITMI20101604A1 (it) * 2010-09-03 2012-03-04 Ttm Tension Technology S R L Ancoraggi da post tensione per cavi multi-trefolo ad alta protezione alla corrosione
CN101629441B (zh) * 2008-07-18 2012-11-21 柳州欧维姆机械股份有限公司 复合式锚垫板及其制作方法
CN108104854A (zh) * 2018-01-05 2018-06-01 中铁五局集团第四工程有限责任公司 一种速凝高强快速张拉锚索的注浆施工方法
US11583296B2 (en) 2017-12-13 2023-02-21 Embody Orthopaedic Limited Guide for positioning a resurfacing head implant

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104963518A (zh) * 2015-07-22 2015-10-07 中铁十一局集团桥梁有限公司 一种用于拆除预应力钢绞线的火焰切割退锚方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3778869A (en) * 1971-03-15 1973-12-18 American Stress Wire Corp Apparatus for detensioning stranded cable
US4410162A (en) * 1980-08-16 1983-10-18 Dyckerhoff & Widmann Aktiengesellschaft Recoverable form part for use in the region where a tendon is anchored in a prestressed concrete component
US5720139A (en) * 1996-02-26 1998-02-24 Sorkin; Felix L. Method and apparatus for installing a multi-strand anchorage system

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3778869A (en) * 1971-03-15 1973-12-18 American Stress Wire Corp Apparatus for detensioning stranded cable
US4410162A (en) * 1980-08-16 1983-10-18 Dyckerhoff & Widmann Aktiengesellschaft Recoverable form part for use in the region where a tendon is anchored in a prestressed concrete component
US5720139A (en) * 1996-02-26 1998-02-24 Sorkin; Felix L. Method and apparatus for installing a multi-strand anchorage system

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101629441B (zh) * 2008-07-18 2012-11-21 柳州欧维姆机械股份有限公司 复合式锚垫板及其制作方法
ITMI20101604A1 (it) * 2010-09-03 2012-03-04 Ttm Tension Technology S R L Ancoraggi da post tensione per cavi multi-trefolo ad alta protezione alla corrosione
US11583296B2 (en) 2017-12-13 2023-02-21 Embody Orthopaedic Limited Guide for positioning a resurfacing head implant
CN108104854A (zh) * 2018-01-05 2018-06-01 中铁五局集团第四工程有限责任公司 一种速凝高强快速张拉锚索的注浆施工方法
CN108104854B (zh) * 2018-01-05 2019-06-28 中铁五局集团第四工程有限责任公司 一种快速张拉锚索的注浆施工方法

Also Published As

Publication number Publication date
AU2003217590A1 (en) 2006-11-01

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