US3909142A - Coupling assembly for stressing tendons of multi-span concrete structures - Google Patents

Coupling assembly for stressing tendons of multi-span concrete structures Download PDF

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Publication number
US3909142A
US3909142A US416687A US41668773A US3909142A US 3909142 A US3909142 A US 3909142A US 416687 A US416687 A US 416687A US 41668773 A US41668773 A US 41668773A US 3909142 A US3909142 A US 3909142A
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United States
Prior art keywords
coupling device
strands
deflector
assembly
anchoring
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Legal status (The legal status 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 status listed.)
Expired - Lifetime
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US416687A
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English (en)
Inventor
Eric Thornton Surr
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CCL Systems Ltd
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CCL Systems Ltd
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Publication date
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Publication of US3909142A publication Critical patent/US3909142A/en
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    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T24/00—Buckles, buttons, clasps, etc.
    • Y10T24/39—Cord and rope holders
    • Y10T24/3909—Plural-strand cord or rope
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T403/00—Joints and connections
    • Y10T403/70—Interfitted members
    • Y10T403/7045—Interdigitated ends

Definitions

  • a continuous tendon consisting of a plurality of strands or wires is made up in sections, the strands or wires of each section being coupled or connected together by mechanical means.
  • One such means comprises a coupling bar or a tubular sleeve where all the strands or wires of the tendon are to be tens'ioned simultaneously, or coupling sleeves for each strand or wire where the' strands or wires of the tendonare to be stressed individuallyf
  • Another means is that disclosed in our prior British Pat. No. 1,288,343 and its Patent of Addition No. 1,335,895, wherein a coupling device is formed witha plurality of central apertures to receive and anchor one end of the wires or strands of one sectionof a tendon,
  • a coupling assembly for the stressing tendons of multispan post-tensioned concrete structures comprising a coupling device having centrally'disposed axiallyextending means for anchoring one end of the wires or strands of one section of the stressing tendon, and other means formed on the periphery thereof for anchoring one end of the wires or strands of an adjacent section of the stressing tendon, a'wireor strand deflector attached to the coupling device to extend in the same general direction as the wires or strands'of said adja cent section of the stressingten don, and a reducing ele device to extend in the same general direction as the wire or strand deflector, the arrangement being such that, in use, the wires or strands of said adjacent section ment attached to the outer periphery of the coupling are disposed between the deflector and the reducing element.
  • the deflector and the reducing element are both preferably of frusto-conical formation and the shapes thereof are such that the external surface of the deflector and the internal surface of the reducing element determine the bending angle of the wires or strands.
  • FIG. 1 is a longitudinal section through a coupling assembly according to the invention
  • FIG. 2 is a section on the line 22 of FIG. I.
  • FIG. 3 is a section corresponding to part of FIG. 1 showing a modification.
  • FIGS. 1 and 2 of the drawings there is shown a coupling assembly comprising a coupling de vice 1 consisting of an annular bearing plate 2 formed with an integral flange 3, and a disc-like bearing plate 4 positioned over the bore 5 of the annular bearing plate 2 to engage one face of the latter.
  • a plurality of transverse bores 6 of conical formation are provided to extend through the plate 4 and are each adapted, in use, to receive a wire or strand, indicated at S, of one section of the tendon.
  • the bores 6 are each formed to receive, in addition to the wire or strand S, a wedge device 7 by which the wire or strand is anchored in the bearing plate.
  • the wedge devices 7 are of known construction and each comprise two or more arcuate wedge elements which are positioned between the bore 6 and the wire or strands.
  • the peripheral edge of the flange 3 of the bearing plate 2 is formed with a plurality of transverse recesses or grooves 8 which are of a width to receive a single wire or strand, indicated at S, of the next adjacent section of the tendon.
  • the number of grooves or recesses 8 correspond to the number of bores 6 and will of course vary with the number of wires or strands in the tendon.
  • the ends of the strands S extend through the bores 6 and are anchored in the bores, as hereinbefore described, by the wedge devices 7.
  • the strands S' however are held in position in the grooves or recesses 8 by means of anchoring fittings 9 which are secured to the ends of the strands.
  • the anchoring fittings 9 may each comprise a compression fitting of known construction consisting of a cylindrical sleeve one end of which is formed with an inwardly directed annular flange, and an insert received in the sleeve, the insert being provided with at least two longitudinally disposed slots and being knurled or otherwise roughened, both internally and externally, to increase friction between the insert and the wire or strand. After positioning the sleeve is compressed onto the wire or strand to provide a permanent fitting.
  • anchoring fitting 9 may comprise a so-called barrel and wedge type fitting consisting of a cylindrical barrel having a frusto-conical bore to receive a wire or strand and a plurality of wedge elements which grip and anchor the wire or strand in the barrel thereby providing an end fitting which can, if necessary, be removed from the wire or strand.
  • a hard metal washer is positioned between each fitting 9 and the face of the bearing plate flange 3. The washers 10 are passed over the ends of the strands before the fittings 9 are fixed thereon.
  • the coupling assembly further comprises a wire or strand deflector 11 of generally frusto-conical formation.
  • the deflector 11 is preferably of cast iron and is supported at one end by being fitted over the plate 4.
  • the sizes of the plate 4 and the deflector 11 are such that the portions of the strands S in the vicinity of the coupling device I extend parallel to the axis of the assembly and are not therefore subjected to bending at the points where they leave their co-acting anchoring fittings 9 which are also disposed parallel to the axis of the assembly.
  • That portion of the deflector 11 away from the coupling device 1 is arcuately tapered to present a support surface which corresponds to the permissable bending angle of the strands S, the angle depending on the diameter of the strands.
  • a reducing element 12 Surrounding the strands S is a reducing element 12 of generally frusto-conical formation.
  • the wide end of the element 12 is positioned over the coupling device 1 and the narrow end thereof is arcuately tapered, in the opposite sense to that of the deflector 1 l, to present a surface which corresponds to the permissable bending angle of the strands S.
  • the extreme narrow end of the element 12 corresponds to the size of the main duct of the structure through which the tendon passes.
  • the deflector 11 has the particular advantage that it serves to distribute the load transmitted from the strands S back into the previous span of the structure, and the S formation imparted to the strands S has the advantage that it reduces the length of the whole assembly compared with the prior art assemblies, and thus reduces the size of the voids in the structure.
  • the reducing element 12 is provided with a grout pipe 13 and is preferably formed of a synthetic plastics glass fibre reinforced material. However, and other suitable materials such as metal may be used provided only that the element is sufficiently rigid to withstand the pressure of the concrete which is poured over it to form the structure prior to the tensioning of the strands S.
  • the first span of the structure which is partly indicated at 14, terminates at the coupling point in a conventional tube unit 15 which is cast into the concrete, and which is connected by conventional ducting to a further tube unit cast into the concrete at the other end of the structure.
  • the bearing plate 4 is then temporarily attached to thetube unit 15 by means of bolts (not shown) which are positioned in lugs 16 provided on the plate 2.
  • the strands S are then tensioned either individually or collectively and anchored in position by the wedge devices 7.
  • the bolts holding the coupling device are then released and, using the same bolts, a grouting cover is positioned over the projecting ends of the anchored strands to form a sealed cavity around the wedge devices.
  • Grout is then injected into the grout cover and flows, via grout holes (not shown) into the ducting whereby the tendon is grouted in the normal manner.
  • the grout cover is then removed leaving a covering of grout indicated at 17, the coupling device being held in position against the tube unit 15 of the structure with the bearing plate 4 spaced from the structure bythe bearing plate 2.
  • the deflector 11 is placed in position.
  • the reducing element is threaded over the. ends of the strands and the anchoring fittings 9 and washers 10 are then applied to one end of each of the strands S. and the other ends of the strands are threaded through the main ducting of said next section or span.
  • the strands complete with the fittings 9 are then placed around the deflector 11 and the fittings 9 are placed in their respective slots to take up the positions shown in the drawings.
  • the strands are held in position by tape or other. binding and the reducing element 12 is then pushed axially towards the anchorage thereby forcing the strands to adopt the S-shaped formation which occurs when the element 12 is in its final position as shown in the drawings.
  • the angle of deviation of the strand, or the radii through which the strand bends should be approximately 15 to the horizontal.
  • maximum radius that can be utilised is dependent on the force required to position the reducing element be fore stressing. It will be appreciated that this will be forced axially towards the anchorage and it should be possible for two men to finally position the reducing element with the use of excessive force.
  • different sizes of strand diameter and construction are used in pre-stressed concrete anchorages, because of this, the number of strands in any anchorage will vary and therefore the geometric determination of the angle forming the S configuration must be a compromise between the maximum S configuration, giving maximum reduction in length, and minimum S configuration giving greatest ease of assembly.
  • the concrete is poured into the second section of the structure thus covering the element 12 enclosing the coupling device.
  • the second section of the tendon is tensioned and subsequently grouted in the same manner as that hereinbefore described, the load in this case being taken by the fittings 9 and transmitted by the first section coupling device to the first section of the tendon.
  • the coupling device 1 is provided as a single block element which is cut away at 18 to receive the deflector 1 l.
  • the block may be solid or it may be formed with a recess as indicated by dot dash lines 19.
  • the assembly of this embodiment is constructionally and operationally the same as that described with reference to FIGS. 1 and 2.
  • the deflector 11 has been described as being of cast iron, it will be understood that the invention is not limited in this respect.
  • the deflector may be of pre-cast concrete or any other material having sufficient strength to withstand the inward radial pressure applied thereto.
  • a coupling assembly for the stressing of multi-span post-tensioned concrete structures comprising a coupling device having centrally disposed axially extending means for anchoring one end of strands of one section of a stressing tendon in a first direction, and other means formed on and about the periphery of said coupling device for anchoring one end of strands of an adjacent section of said stressing tendon in an opposite direction, a strand deflector operatively associated with said coupling device and extending beyond said coupling device in the same general direction as said strands of said adjacent section of said stressing tendon, said strand deflector extending generally from said other anchoring means and sloping radially inwardly therefrom, and a reducing element fitted over said coupling device adjacent said other anchoring means and extending beyond said coupling device in the same direction as that of said deflector, said deflector having a portion adjacent said coupling device generally corresponding in outline to adjacent portions of said reducing element whereby strands of said adjacent section adapted
  • a coupling assembly for the stressing of multi-span post-tensioned concrete structures comprising an annular coupling device having a bore, said device having centrally disposed axially extending anchorage means for anchoring one end of strands of one section of a stressing tendon, and other anchoring means formed on andabout the periphery of said annular coupling device for anchoring one end of strands of an adjacent section of said stressing tendon, a strand deflector of truncated cone shape attached at one end to said coupling device and extending beyond said coupling device in the same general direction as said strands of said adjacent section of said stressing tendon, said deflector having a portion adjacent said coupling device lying substantially parallel with the axis of the assembly and the remainder of said deflector being of convex tapered formation, a reducing element of truncated cone shape fitted at one end over said coupling device and extending beyond said coupling device in the same direction as that of said deflector, said reducing element
  • said centrally disposed anchorage means comprise a plurality of tapered holes formed in said coupling device, said tapered holes being formed to receive said strands and retaining wedges which anchor said strands in said holes.

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  • Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Reinforcement Elements For Buildings (AREA)
  • Tents Or Canopies (AREA)
  • Ropes Or Cables (AREA)
US416687A 1972-12-05 1973-11-16 Coupling assembly for stressing tendons of multi-span concrete structures Expired - Lifetime US3909142A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB5607072A GB1364212A (en) 1972-12-05 1972-12-05 Coupling assembly for the stressing tendons of multi span post tensioned concrete structures

Publications (1)

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US3909142A true US3909142A (en) 1975-09-30

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US416687A Expired - Lifetime US3909142A (en) 1972-12-05 1973-11-16 Coupling assembly for stressing tendons of multi-span concrete structures

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US (1) US3909142A (xx)
JP (1) JPS4996524A (xx)
AT (1) AT331475B (xx)
BE (1) BE808271A (xx)
BR (1) BR7309329D0 (xx)
CH (1) CH577087A5 (xx)
DE (1) DE2360667A1 (xx)
ES (1) ES421146A1 (xx)
FR (1) FR2212843A5 (xx)
GB (1) GB1364212A (xx)
IT (1) IT1008070B (xx)
NL (1) NL7316411A (xx)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4121325A (en) * 1976-12-06 1978-10-24 Triple Bee Prestress (Proprietary) Limited Cable anchoring and coupling equipment
US4674801A (en) * 1985-02-06 1987-06-23 Allied Corporation Energy absorber having a limited stroke
WO2015073436A1 (en) * 2013-11-12 2015-05-21 Vectorsum, Inc. Composite sucker rod assembly for underground wells
US20150300452A1 (en) * 2014-04-22 2015-10-22 Richard V. Campbell Advanced Stranded Cable Termination Methods and Designs
CN105881736A (zh) * 2016-06-04 2016-08-24 中铁十九局集团第五工程有限公司 后张预应力箱梁钢绞线的穿线装置及其穿线方法
CN111779284A (zh) * 2020-07-20 2020-10-16 孔瑞扬 一种钢绞丝预应力锚固工艺
US20220412089A1 (en) * 2021-06-03 2022-12-29 Zhejiang Province Institute Of Architectural Design And Research Anchor assembly having pre-stressed mandrel

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2657202C3 (de) * 1976-12-17 1979-05-23 Dyckerhoff & Widmann Ag, 8000 Muenchen Kopplungsstelle für ein nachspannbares Bündelspannglied für Spannbeton
DE7714915U1 (de) * 1977-05-11 1977-08-18 Philipp Holzmann Ag, 6000 Frankfurt Kopplung fuer spannglieder in spannbetonkonstruktionen
US4223497A (en) * 1978-06-26 1980-09-23 Ccl Systems Limited Coupling assembly
FR2519673A1 (fr) * 1982-01-11 1983-07-18 Freyssinet Int Stup Elements allonges en beton precontraint, assemblables bout a bout
DE3224702C2 (de) * 1982-07-02 1986-01-16 Dyckerhoff & Widmann AG, 8000 München Vorrichtung zum Verankern und Koppeln eines Bündelspannglieds für Spannbeton
GB2127512B (en) * 1982-09-11 1986-11-19 Paul Francis Hope Reinforcing bar coupling system
DE3320992A1 (de) * 1983-06-10 1984-12-13 Polensky & Zöllner GmbH & Co., 6000 Frankfurt Kopplung fuer spannglieder
IT8422084V0 (it) * 1984-06-05 1984-06-05 Ponteggi Est Spa Testata di ancoraggio di accoppiamento per realizzazione di manufatti in calcestruzzo precompressi a cavi scorrevoli.
DE3440220A1 (de) * 1984-11-03 1986-05-07 Philipp Holzmann Ag, 6000 Frankfurt Zweiteilige kopplung fuer keilverankerte buendelspannglieder
WO2015148951A1 (en) 2014-03-28 2015-10-01 Steelcase Inc. Transparent panel system for partitions
KR101646866B1 (ko) * 2015-01-23 2016-08-09 서울시립대학교 산학협력단 데크 단부에서 긴장 정착시킨 장스팬 내화 데크의 긴장재 정착시스템 및 그 시공방법
CN109423949A (zh) * 2017-08-24 2019-03-05 中冶长天国际工程有限责任公司 一种分段式预应力钢绞线的连接装置及连接方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3405490A (en) * 1967-01-10 1968-10-15 Robert R. La Marr Anchor structure for posttensioned tendons
US3450829A (en) * 1966-11-03 1969-06-17 Bunker Ramo Process for salvaging armored cable and structure used for the same
US3449876A (en) * 1968-02-21 1969-06-17 George H Howlett Tendon anchorage
US3775811A (en) * 1972-07-26 1973-12-04 Preformed Line Products Co Appliance for linear bodies
US3795949A (en) * 1968-11-06 1974-03-12 Pre Stress Pioneers Ltd Post-stressing of reinforced concrete structures

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3450829A (en) * 1966-11-03 1969-06-17 Bunker Ramo Process for salvaging armored cable and structure used for the same
US3405490A (en) * 1967-01-10 1968-10-15 Robert R. La Marr Anchor structure for posttensioned tendons
US3449876A (en) * 1968-02-21 1969-06-17 George H Howlett Tendon anchorage
US3795949A (en) * 1968-11-06 1974-03-12 Pre Stress Pioneers Ltd Post-stressing of reinforced concrete structures
US3775811A (en) * 1972-07-26 1973-12-04 Preformed Line Products Co Appliance for linear bodies

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4121325A (en) * 1976-12-06 1978-10-24 Triple Bee Prestress (Proprietary) Limited Cable anchoring and coupling equipment
US4674801A (en) * 1985-02-06 1987-06-23 Allied Corporation Energy absorber having a limited stroke
WO2015073436A1 (en) * 2013-11-12 2015-05-21 Vectorsum, Inc. Composite sucker rod assembly for underground wells
CN105874149A (zh) * 2013-11-12 2016-08-17 吊装解决方案美国股份有限公司 用于地下井的复合材料抽油杆组件
US20150300452A1 (en) * 2014-04-22 2015-10-22 Richard V. Campbell Advanced Stranded Cable Termination Methods and Designs
US10578191B2 (en) * 2014-04-22 2020-03-03 Bright Technologies, Llc Advanced stranded cable termination methods and designs
CN105881736A (zh) * 2016-06-04 2016-08-24 中铁十九局集团第五工程有限公司 后张预应力箱梁钢绞线的穿线装置及其穿线方法
CN111779284A (zh) * 2020-07-20 2020-10-16 孔瑞扬 一种钢绞丝预应力锚固工艺
CN111779284B (zh) * 2020-07-20 2022-02-18 河北科讯通信器材有限公司 一种钢绞丝预应力锚固工艺
US20220412089A1 (en) * 2021-06-03 2022-12-29 Zhejiang Province Institute Of Architectural Design And Research Anchor assembly having pre-stressed mandrel
US11821208B2 (en) * 2021-06-03 2023-11-21 Zhejiang Province Institute Of Architectural Design And Research Anchor assembly having pre-stressed mandrel

Also Published As

Publication number Publication date
DE2360667A1 (de) 1974-06-06
GB1364212A (en) 1974-08-21
NL7316411A (xx) 1974-06-07
ATA1013573A (de) 1975-11-15
ES421146A1 (es) 1976-05-01
BE808271A (fr) 1974-06-05
FR2212843A5 (xx) 1974-07-26
CH577087A5 (xx) 1976-06-30
BR7309329D0 (pt) 1974-09-05
AT331475B (de) 1976-08-25
IT1008070B (it) 1976-11-10
JPS4996524A (xx) 1974-09-12

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