EP0071292B1 - Vorspannseile für Betonkonstruktionen - Google Patents

Vorspannseile für Betonkonstruktionen Download PDF

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Publication number
EP0071292B1
EP0071292B1 EP82200892A EP82200892A EP0071292B1 EP 0071292 B1 EP0071292 B1 EP 0071292B1 EP 82200892 A EP82200892 A EP 82200892A EP 82200892 A EP82200892 A EP 82200892A EP 0071292 B1 EP0071292 B1 EP 0071292B1
Authority
EP
European Patent Office
Prior art keywords
strand
prestressing
modulus
stroke length
diameter
Prior art date
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
Application number
EP82200892A
Other languages
English (en)
French (fr)
Other versions
EP0071292A1 (de
Inventor
Bruno Hauzenberger
C.D. De Waal
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Estel Nederlandse Draadindustrie Bv
Original Assignee
Estel Nederlandse Draadindustrie Bv
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
Priority claimed from NL8200195A external-priority patent/NL180449C/xx
Application filed by Estel Nederlandse Draadindustrie Bv filed Critical Estel Nederlandse Draadindustrie Bv
Priority to AT82200892T priority Critical patent/ATE13324T1/de
Publication of EP0071292A1 publication Critical patent/EP0071292A1/de
Application granted granted Critical
Publication of EP0071292B1 publication Critical patent/EP0071292B1/de
Expired legal-status Critical Current

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Classifications

    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B1/00—Constructional features of ropes or cables
    • D07B1/06—Ropes or cables built-up from metal wires, e.g. of section wires around a hemp core
    • D07B1/0693—Ropes or cables built-up from metal wires, e.g. of section wires around a hemp core having a strand configuration
    • 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
    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B2201/00—Ropes or cables
    • D07B2201/20—Rope or cable components
    • D07B2201/2015—Strands
    • D07B2201/2024—Strands twisted
    • D07B2201/2025—Strands twisted characterised by a value or range of the pitch parameter given
    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B2501/00—Application field
    • D07B2501/20—Application field related to ropes or cables
    • D07B2501/2015—Construction industries
    • D07B2501/2023—Concrete enforcements

Definitions

  • the invention relates to prestressing strand for concrete structures comprising at least one central core wire and outer wires helically enveloping the core wire.
  • Such strands (known e.g. from GB-A-1424672) are often used as reinforcing elements in prestressed concrete structures, in which they offer the possibility of being inserted in curved channels in the concrete structure.
  • the channels are formed by enveloping tubes of steel or another material, which are precast into the concrete structure.
  • a commonly used type of prestressing strand comprises six equally thick outer wires and one single core wire the diameter of which is between 2 and 5 per cent greater than that of the outer wires. This last feature is of importance in order to obtain a construction of strand with a good coherence in which the outer wires fit against the core wire.
  • the strand form as described above is the one most used for prestressing strands, the invention is not restricted to this specific strand construction, but it also relates to other strand constructions of the type indicated at the outset.
  • a prestressing strand having a single core wire and six outer wires is illustrated in longitudinal view and in cross section respectively.
  • Fig. 1 also there is indicated the pitch of the helices in which each of the outer wires lies.
  • this pitch S is referred to by the expression "stroke length".
  • Fig. 2 it is indicated that by the diameter of the strand is understood the greatest cross-sectional dimension D. It is usual to express the stroke length as a multiple of the diameter.
  • the stroke length S mostly varies between 12 and 18 times the diameter.
  • the invention is based on the concept that for prestressing strands investigations have not yet been carried out in order to find the most suitable strand construction in practice.
  • the tension condition and the deformation condition of a prestressing strand in a curved configuration, in which the strand is subjected to transverse forces and frictional forces, is highly complex, and is dependent on a great number of factors which are related to the properties of the material and the production methods for the strand.
  • the modulus of deformation in the use of prestressing strand in curved channels, is very sensitive to the stroke length of the strand. More particularly, the invention consists in that a considerably better consistency between the modulus of deformation and the modulus of elasticity is obtained when the stroke lengths of the prestressing strand is chosen between 20 and 150 times the greatest diameter of the cable. It is remarkable that these limits are considerably higher than those which hitherto have been used in the art. It must be assumed that, with the greater stroke length the core wire can be more completely tensioned over its whole length and can cooperate as a load bearing element.
  • the prestressing strand must sufficiently remain a unit in order that slip occurring between the core wire and the outer wires is prevented, since this slip has a result that the core wire is no longer fully under load.
  • the rate at which slipless transfer of tension between strand and wedge anchors is possible is given by the expression "grip efficiency". It has been found that both as to the modulus of deformation and as to the grip efficiency, strands within the limits given above for the stroke length of between 20 and 150 D are considerably more satisfactory than known reinforcing strands. It has been found, in this connection, that no slip occurs between the core wire and the outer wires.
  • the prestressing strand is of the type described above, in which there are six equally thick outer wires and a single core wire with a diameter 2 to 5 percent greater than that of the outer wires, it has been found that especially good results are obtained by choosing a stroke length of 20 to 100 times the diameter of the strand. Particularly preferred is a stroke length of between 22 and 50 times the cable diameter.
  • reference numeral 1 indicates a concrete plate with a thickness of 22 cm.
  • the length of the curved channel part L2 is consequently 507 cm.
  • a support beam 2 is located, with at the left hand side a wedge anchoring 5 for a strand and at the right hand side a similar wedge anchoring 5 behind a hydraulic press 4.
  • the tensioned strand then consists of a straight piece L1 of a length of 175 cm, a curved piece of a length of L2 of 507 cm and another straight piece of length L3 of 210 cm.
  • the tests were carried out with the most common prestressing strand of thickness D of 0.5 inches (12,7 mm). First the strand was brought under nominal tension, in order to stretch it sufficiently, whereupon the tension force was increased up to a value near the usual full load value used in tension technology. During the increase of the tension force, the elongation and the tension force in the strand were measured continuously.
  • the strand was considered to be divided in elements, and for each element the stress and strain conditions were calculated with the application of a frictional force between the channel wall and the prestressing strand.
  • the stress and strain conditions were calculated with the application of a frictional force between the channel wall and the prestressing strand.
  • these friction coefficients were introduced into the calculation so that it was possible to determine by calculation, what tension forces should be present in the strand, on the basis of the total measured extension of the strand between the anchors 5. This value was compared with the actual tension forces obtained, from which a value could be obtained for the modulus of deformation in each test performed.
  • Fig. 5 The values thus found by measurements and calculation for the modulus of deformation are set out in Fig. 5.
  • the stroke length S is set out on the horizontal axis, expressed in mm and also as a multiple of the cable diameter D.
  • the diameter D was measured separately.
  • the modulus of deformation is set out, expressed in kN/mm 2 .
  • a horizontal line shows the level of 201 kN/mm 2 , which represents the value of the modulus of elasticity E of the wire material used.
  • the tests were performed with strands having stroke lengths of respectively 210, 290, 470 and 550 mm. The measured points were connected by straight lines to one another although of course a continuous line would result if more tests were performed with more varying values of the stroke length.
  • the hatched area shows the area in which known strands are found. It is clear that the modulus of deformation for greater stroke length is considerably greater than for the known stroke lengths.
  • the factor K (and thus also the modulus of deformation), for strands with a small stroke length diminishes when the curvature of the channel through which the strand is inserted increases. Also, it is clear from this figure that this relationship to the curvature is much less sensitive if the stroke length is increased. For values of the stroke length of 400 to 500 mm (32 to 40 D), the factor K is hardly influenced by the shape of the channel, which means that when the strand is tensioned the elongation imposed on the strand is a reliable measure for the tension which can be expected in the concrete structure.

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  • Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Reinforcement Elements For Buildings (AREA)
  • Curing Cements, Concrete, And Artificial Stone (AREA)

Claims (3)

1. Vorspannseil für Betonkonstruktionen mit zumindest einem zentralen Kerndraht und den Kerndraht schraubenförmig umhüllenden Außendrähten, dadurch gekennzeichnet, daß die sogenannte Schlaglänge des Bewehrungsseiles zwischen dem 20- und dem 150-fachen des größten Seildurchmessers ausgewählt ist.
2. Vorspannseil nach Anspruch 1 des Typs, welcher sechs gleichdicke Aussendrähte und einen einzigen Kerndraht mit einem 2 bis 5 % größeren Durchmesser als der der Außendrähte umfaßt, dadurch gekennzeichnet, daß die Schlaglänge zwischen 20- und 100-mal dem Seildurchmesser ist.
3. Vorspannseil nach Anspruch 2, dadurch gekennzeichnet, daß die schraubenförmige Länge 22- bis 50-mal dem Durchmesser ist.
EP82200892A 1981-07-25 1982-07-14 Vorspannseile für Betonkonstruktionen Expired EP0071292B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT82200892T ATE13324T1 (de) 1981-07-25 1982-07-14 Vorspannseile fuer betonkonstruktionen.

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
CH482381 1981-07-25
CH4823/81 1981-07-25
NL8200195 1982-01-20
NL8200195A NL180449C (nl) 1982-01-20 1982-01-20 Voorspanstreng voor betonconstructies.

Publications (2)

Publication Number Publication Date
EP0071292A1 EP0071292A1 (de) 1983-02-09
EP0071292B1 true EP0071292B1 (de) 1985-05-15

Family

ID=25696352

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82200892A Expired EP0071292B1 (de) 1981-07-25 1982-07-14 Vorspannseile für Betonkonstruktionen

Country Status (4)

Country Link
EP (1) EP0071292B1 (de)
DE (1) DE3263527D1 (de)
ES (1) ES275168U (de)
NO (1) NO157985C (de)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB8333845D0 (en) * 1983-12-20 1984-02-01 British Ropes Ltd Flexible tension members
ES2206037B2 (es) * 2002-09-23 2005-04-01 Nork 2, S.L. Cable para aparatos elevadores.

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE483351C (de) * 1926-07-27 1929-10-01 Felten & Guilleaume Carlswerk Verfahren zur Herstellung von Tragkoerpern fuer Haengebruecken aus schweren Tragseilen groesserer Abmessungen
US1822189A (en) * 1929-05-01 1931-09-08 Felten & Guilleaume Carlswerk Method of reducing the extension of wire ropes
CH170415A (de) * 1933-09-14 1934-07-15 Salvisberg Theodor Torsionsfreies Litzenseil.
GB1424672A (en) * 1972-04-25 1976-02-11 Gkn Somerset Wire Ltd Wire strand
BE824403A (fr) * 1973-05-17 1975-05-02 Cordon d'acier a profilage helicoidal

Also Published As

Publication number Publication date
EP0071292A1 (de) 1983-02-09
DE3263527D1 (en) 1985-06-20
ES275168U (es) 1984-03-01
NO822545L (no) 1983-01-26
NO157985C (no) 1988-06-22
NO157985B (no) 1988-03-14

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