EP0516140A1 - Seil zum Vorspannen von Betonkörpern - Google Patents

Seil zum Vorspannen von Betonkörpern Download PDF

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Publication number
EP0516140A1
EP0516140A1 EP92109078A EP92109078A EP0516140A1 EP 0516140 A1 EP0516140 A1 EP 0516140A1 EP 92109078 A EP92109078 A EP 92109078A EP 92109078 A EP92109078 A EP 92109078A EP 0516140 A1 EP0516140 A1 EP 0516140A1
Authority
EP
European Patent Office
Prior art keywords
strand
wires
central
radius
wire
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.)
Withdrawn
Application number
EP92109078A
Other languages
English (en)
French (fr)
Inventor
Henry Vilhelm Lönnberg
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.)
DALSBRUK Oy AB
Rannila Steel Oy
Original Assignee
DALSBRUK Oy AB
Rannila Steel Oy
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 DALSBRUK Oy AB, Rannila Steel Oy filed Critical DALSBRUK Oy AB
Publication of EP0516140A1 publication Critical patent/EP0516140A1/de
Withdrawn legal-status Critical Current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
    • D07B2201/2016—Strands characterised by their cross-sectional shape
    • 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
    • D07B2201/2047—Cores
    • D07B2201/2048—Cores characterised by their cross-sectional shape
    • 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
    • D07B2201/2047—Cores
    • D07B2201/2052—Cores characterised by their structure
    • D07B2201/2059—Cores characterised by their structure comprising wires
    • D07B2201/206—Cores characterised by their structure comprising wires arranged parallel to the axis
    • 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 a strand for prestressing of concrete components, which strand is made up of at least one central wire and of a plurality of surface wires twined around it, the central wire or wires running substantially without spiral in the longitudinal direction of the strand.
  • Prestressing strands are used in concrete structures in order to obtain pretensioning in the concrete by producing tensile stress in the strand before the casting of the concrete structure.
  • a strand is made up of six individual surface wires twined around a central wire.
  • the pretensioning of the strand is of an order of 50-70 % of the ultimate strength.
  • Concrete components such as hollow-core slabs are manufactured by slipforming in casting machines, specifically made for that purpose, onto form tables 90-150 meters long, from which they are after a very short hardening period sawn into components of predetermined length. When releasing the pretensioning the concrete has not yet reached its final strength.
  • Finnish patent application 873196 describes an arrangement in which the surface wires are polygonal and are twined about their longitudinal axis during or after the profiling. Thereby a relatively large adhesion surface is obtained between the outer wires and the concrete, and at the same time, under the effect of the twining, the shape of the strand is made varied in the direction of the spiral, in which case the slipping of the strand in the direction of the screw line of the strand spiral becomes more difficult. Thereupon compressive stress is produced in the concrete under the effect of discontinuity, and the stress considerably promotes the adhesion of the strand by expanding the area of effect of the stress.
  • the manufacture of a strand such as this requires machines of a quite specific type for working the surface wire by drawing, the production speed of these machines being presumably quite slow, and so the manufacture will be relatively expensive and may also involve many problems with manufacturing technology.
  • Finnish patent 73039 proposes a structure in which the core of the strand is made up either of two wires twined around one another, the basis of their cross section being a circle, or of one wire twined about its own axis, the cross section of the wire being flattened, and of surface wires twined around this core, in which case the direction of the spiral of the core is opposite to that of the spiral of the outer wires.
  • the changes of the cross sectional shape in the direction of the spiral of the outer wires are extensive, and the adhesion to concrete is excellent.
  • the manufacture of a strand such as this is, however, quite expensive, since it presupposes two successive stranding steps, one for the core and the other for the surface wires.
  • a corresponding double strand has also been described in the publication US-3 032 963, although by using a triple-wire core. Its targeted use is not the reinforcing of concrete but of automobile tires.
  • Publication DE-2 044 665 also describes an automobile-tire reinforcement cable which is made up of a multiple-wire core, the wires running in the longitudinal direction of the wire, and of surface wires twined around this core.
  • the cable additionally contains a tie wire wound around the surface wires, the tie wire preventing the unwinding of the strand.
  • the stranding is relatively loose, in which case the outer wires remain in the plane of the circle constituting the envelope, and a change of the cross sectional area in the direction of the spiral of the outer wires has not been achieved. It would evidently not have much significance in a material as elastic as rubber; in the targeted use concerned the aim seems to be simply to achieve a maximally large surface area for the steel cable.
  • the object of the present invention is to provide a strand the cross section of which in the direction of the spiral of the surface wires varies considerably, thus making it possible for the stress transferred from the strand to the concrete mass to spread over a large area in the concrete, which will thus prevent a screw line slip of the strand. It is a further object of the invention to provide a strand of this type which could be manufactured by conventional stranding machines and in one stranding step. This means that the above-mentioned change in the cross section must not be based on a separate stranding of the core or on a specific spiral of the surface wires.
  • the surface wires are hardened considerably even before the stranding step, and the stranding is made tight, in which case the surface wires will follow quite closely the shape of the core, it is one object of the invention that the surface wires will at no point of the stranding be subjected to excessive deformation such as bending, which would reduce the strength of the strand.
  • the strand can be manufactured in one step by conventional stranding machines, while nevertheless obtaining a cross section varied in the direction of the spiral of the strand, in which case the strand will have excellent adhesion to the concrete mass.
  • the strand can be made from conventional hard surface-wire having a round cross section, without the surface wires being damaged during the stranding and the subsequent thermomechanical relaxation.
  • Figure 1 depicts a cross section of one embodiment of the strand according to the invention.
  • Figure 2 depicts a cross section of another embodiment of the strand according to the invention.
  • Figure 3 depicts one preferred embodiment of the core of the strand according to the invention.
  • Figure 4 depicts another preferred embodiment of the core of the strand according to the invention.
  • the structural principle of the strand 10 according to the invention can be seen in Figures 1 and 2.
  • the surface wires 1 of the strand are wires which have a circle as the basis for their cross section, but which may have commonly used surface textures, ridges or grooves to improve adhesion.
  • the surface wires 1 are thus of the type conventionally used in strands, and they are not described here in greater detail.
  • the core of the strand is made up of two separate central wires 2 and 3, which have a circle-based cross-sectional shape, the radius B3 of one central wire 2 being greater than the radius C3 of the other central wire 3.
  • These two central wires 2, 3 of different sizes run without spiral in the longitudinal direction of the strand 10.
  • the larger-radius central wire 2 constitutes the cross section of the core for one side of the outer surface of the strand and the smaller-radius central wire 3 for the other side.
  • the cross section is thus made up of a combination of sections of two circles having different radii R2 and R1, and is thus not rotationally symmetric with respect to any axis.
  • the cross section of the envelope 6 of the strand 10 hereby has only one symmetry plane 11 or 12 at the most, which have been shown in figures 1 and 2. No other symmetry planes or lines can be found in the envelope of the strand. It is clear that the strand according to the invention can also be of the kind that it has no symmetry plane at all.
  • the outer surface of the strand is thus made up of a first cylindrical surface Y1 having the radius R1 and of a second cylindrical surface Y2 having the radius R2, and the distance between the center lines of these cylindrical sections is the sum of the radii of the central wires, i.e. B3 + C3.
  • the strand is thus in the longitudinal direction a combination of two parallel cylindrical surfaces, but the surface wires run helically relative to the cylindrical axes, their cross-sectional area changing periodically as viewed in their spiral direction.
  • the radius B3 of one central wire is preferably 5-15 % greater than the radius C3 of the other central wire 3.
  • the proportions of the thicknesses of the central wires may be also other than those described above, for example one of the wires may be thicker than the other two, in which case a strand with an envelope closely resembling the embodiment of Figure 1 is obtained. All the three central wires may also be of different sizes, although in this case defining the effective radii for the cylinder sections will be somewhat more difficult. Thus, preferably the radius of at least one central wire is 5-30 % greater or smaller than the radii of the other central wires. The functioning of such a strand in concrete is, however, always the same when the dimensioning of the central wires is correctly selected.
  • Figure 3 depicts one preferred single-wire variant of the central-wire combination of Figure 1 for the core
  • Figure 4 depicts another preferred single-wire variant of the three-wire core of Figure 2.
  • the single-wire core 4, 5 is triangular in shape and preferably substantially an isosceles, the apex angle of which is ⁇ or respectively ⁇ .
  • the apex angle is the angle between the straight lines tangent to the rounding of the apex of the triangular shape and to the roundings of the other angles.
  • the rounding radii of the angles of the triangles are B1 and C1 in the case of Figure 3 and B2 and C2 in the case of Figure 4.
  • This design of the central wire 4 is, however, considerably more flexible, since the distance S1 between the center points of the circles B1 and C1 can be selected freely and is in this case smaller than the sum of the radii. Furthermore, since the tangent surfaces 7 can be designed not only straight in the manner depicted but also cylindrically convex or in some other shape, it is easy in accordance with the principle of the invention to obtain for the central wire a shape which produces a sufficiently great cross-sectional difference in the direction of the spiral and at the same time a sufficiently small deformation in the surface wire. To illustrate this, a circle having radius A has been drawn around the central wire 4, tangent to the wire.
  • the apex angle ⁇ is an acute angle.
  • the apex angle ⁇ may also be an obtuse angle, as in the case of Figure 4.
  • the angles on the side opposite the apex angle ⁇ of the triangular central wire 5 have been rounded using radius B2, the distance S2 between the center points of the corresponding circles being greater than the sum of the radii.
  • the rounding radius C2 of the apex angle is smaller than the radii B2.
  • the roundings B2 and C2 are within a range of 40 % - 120 % of the radius of the outer wires and preferably 60 % - 105 % of the radius Z of the outer wires.
  • the sides of the triangular central wire 5 are curved cylindrically outward, in which case the deviations D3 and D2 between the circle drawn using radius A around the central wire and sides 8 and 9 of the central wire will be sufficiently small so that excessive deformation is not produced in the outer wires.
  • These deviations D2 and D3 are, as above, approx. 5 % - 45 % of the radius A of the circle drawn around the wire, and preferably approx. 10 % - 30 % of this circle radius A.
  • the rounding radii B2 and the side 8 constitute the core of the envelope having the greater radius R2 according to the invention, and the smaller rounding C2 generates the core of the cylindrical envelope having the smaller radius R1.
  • the circles B2 may be even further apart from each other, or they may intersect each other.
  • circle C2 may be located further away from the circles B2, or it may intersect both of them.
  • the curvatures of the sides 8 and 9 must in each case be designed so that the dimensions D2 and D3 will be within the given range.
  • the radii B2 and C2 must simultaneously be of the defined magnitude. Understandably, intermediate forms of the embodiments of Figures 3 and 4 can be obtained easily by imagining that the circles B2 in Figure 4 are moved gradually towards each other until they coincide, whereupon the implementation of Figure 3 has been arrived at.
  • One further intermediate form is a shape of the type of an equilateral triangle, which may contain any of the roundings described below.
  • the circles B2 which constitute one basis for the rounding may either intersect each other, be tangent to each other or be separated from each other as in the figure. It is clear that also with an alternative in which the radii of the circles B2 are smaller than the radius of circle C, the envelope according to the invention is obtained for a strand. This is understandable for the reason that the greater radius R2 of the envelope is based on the joint effect of the two circles B2 and the side 8 between them, this effect having simply to be effectively greater than the third circle C2.

Landscapes

  • Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Braiding, Manufacturing Of Bobbin-Net Or Lace, And Manufacturing Of Nets By Knotting (AREA)
  • Ropes Or Cables (AREA)
EP92109078A 1991-05-31 1992-05-29 Seil zum Vorspannen von Betonkörpern Withdrawn EP0516140A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI912638 1991-05-31
FI912638A FI88819C (fi) 1991-05-31 1991-05-31 Spaennlina foer betongelement

Publications (1)

Publication Number Publication Date
EP0516140A1 true EP0516140A1 (de) 1992-12-02

Family

ID=8532622

Family Applications (1)

Application Number Title Priority Date Filing Date
EP92109078A Withdrawn EP0516140A1 (de) 1991-05-31 1992-05-29 Seil zum Vorspannen von Betonkörpern

Country Status (2)

Country Link
EP (1) EP0516140A1 (de)
FI (1) FI88819C (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4432128A1 (de) * 1994-09-09 1996-06-05 Dyckerhoff & Widmann Ag Verfahren zum Herstellen eines Ankerelements für einen Erd- oder Felsanker, Felsbolzen oder dergleichen aus einer Litze aus verdrillten Stahldrähten
WO2002020945A3 (en) * 2000-09-05 2002-09-06 Michael Malkoski Mobile system for manufacturing and installing reinforcing members
CN104499321A (zh) * 2014-12-16 2015-04-08 天津银龙预应力材料股份有限公司 一种中空预应力钢绞线

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB299586A (en) * 1927-09-26 1928-11-01 American Chain & Cable Co A new or improved wire strand and process for making the same
DE656123C (de) * 1935-06-19 1938-01-29 Paul Kintschel Sektorfoermige Litze fuer Drahtseile
US3778993A (en) * 1971-12-07 1973-12-18 M Glushko Method of manufacturing twisted wire products
DE2941541A1 (de) * 1979-10-13 1981-04-23 Continental Gummi-Werke Ag, 3000 Hannover Drahtseil als verstaerkungselement fuer gummi- oder kunststoffartikel

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB299586A (en) * 1927-09-26 1928-11-01 American Chain & Cable Co A new or improved wire strand and process for making the same
DE656123C (de) * 1935-06-19 1938-01-29 Paul Kintschel Sektorfoermige Litze fuer Drahtseile
US3778993A (en) * 1971-12-07 1973-12-18 M Glushko Method of manufacturing twisted wire products
DE2941541A1 (de) * 1979-10-13 1981-04-23 Continental Gummi-Werke Ag, 3000 Hannover Drahtseil als verstaerkungselement fuer gummi- oder kunststoffartikel

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
RESEARCH DISCLOSURE no. 319, November 1990, EMSWORTH (GB) pages 1 - 5; 'Steel cord construction' *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4432128A1 (de) * 1994-09-09 1996-06-05 Dyckerhoff & Widmann Ag Verfahren zum Herstellen eines Ankerelements für einen Erd- oder Felsanker, Felsbolzen oder dergleichen aus einer Litze aus verdrillten Stahldrähten
DE4432128C2 (de) * 1994-09-09 2001-09-06 Dyckerhoff & Widmann Ag Verfahren zum Herstellen eines Ankerelements für einen Erd- oder Felsanker, Felsbolzen oder dergleichen aus einer Litze aus verdrillten Stahldrähten
WO2002020945A3 (en) * 2000-09-05 2002-09-06 Michael Malkoski Mobile system for manufacturing and installing reinforcing members
US6863476B2 (en) 2000-09-05 2005-03-08 Langford Industries, Ltd. Mobile system for manufacturing and installing reinforcing members
CN104499321A (zh) * 2014-12-16 2015-04-08 天津银龙预应力材料股份有限公司 一种中空预应力钢绞线

Also Published As

Publication number Publication date
FI912638A (fi) 1992-12-01
FI88819B (fi) 1993-03-31
FI88819C (fi) 1993-07-12
FI912638A0 (fi) 1991-05-31

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