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
  • D07B1/08—Ropes or cables built-up from metal wires, e.g. of section wires around a hemp core the layers of which are formed of profiled interlocking wires, i.e. the strands forming concentric layers
• • 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

Definitions

• the invention relates to a strand for stressed concrete structures, and to a process for its production.
• strands are used for pre- stressed, or after-stressed (reinforced) concrete structures to take up the stretching foree.
• These are formed generally with three to seven pieces of 2 to 5 mm thick cold drawn individual steel wires, so-called “elementary filaments” to cable-type strand with the use of twisting (stranding) machine.
• These strands transmit the stretching force to the concrete structure through adhesion, or anchorage between the strand and the concrete.
• the experts have been trying to find a solution for a long time, whereby adhesion or holding power of the strands to the concrete could be improved, since this way the stretching foree could be increased, which would be particularly desiralsle especially in case of high load bearing stresse ⁇ concrete structures, or long spans.
• Such strands and cables are already known from the British patent specification No. 1 194 758 and GPR patent specification No. 1 659 265, where evenly distributed (periodic) profiling of small depth is produced by rolling after cold drawing on the surface of the covering wires of the strand, just as in case of the simple concrete reinforcing rods.
• the adhesive capacity of- the strand in the concrete is improved by the periodic profiling formed with such indentation, i.e. "the anchoring length" will be shorter, however the increased risk of cracking or breakage must be reckoned with in the elementary filaments at the corners of the indentations upon the bending and torsional stresses arising during loading of the strand.
• the arrangement of the periodic surface profiles within the strand is incidental, in other words, the "functional" cross section surfaces of the sections perpendicular to the longitudinal axis of the strand are different from each other, consequently the stress conditions arising during loading are also different.
• the invention is aimed at the elimination of above shortcomings, i.e. at the realization of such strand for stressed reinforced concrete structures, whereby the adhesion to concrete can be improved, and at the same time identical stress conditions can be assured in all strand cross sections.
• strand which has a twist formed with at least three wires provided with surface profiling.
• the surface profiling of the wires is formed as non-circular cross section-profile continuously passing through the wire in longitudinal direction.
• the cross section profile of the wires continuously passing through in longitudinal direction may suitably be a polygonal profile, preferably a rounded regular hexagon. This enables a very simple production.
• such construction is also conceivable, where the cross section profile of the wires continuously parsing through in longitudinal direction is formed as such circular or polygonal cross section, which is provided with groove-like recesses and/or rib-like extensions evenly distributed along the circumference.
• the starting point was such conventional process, where first the surface profiling of the wires is formed with cold deformation, then at least three wires are formed to strand with simultaneous twisting.
• the essence of the process according to the invention is that the surface profiling of the wires is formed by drawing through drawplate of non-circular, preferably rounded hexagonal cross section. It is advisable to form the wires by turning around their longitudinal axis during or after formation of the profile, but before twisting. It is expedient if the turning direction of the wires coincides with the subsequent twisting direction of the strand. Furthermore, it is preferable if the pitch of the twisting is selected to the multiple, suitably at least to tenfold of the pitch of wire-turning.
• the invention is described in detail with the aid of drawing, showing the cross section of the strand according to the invention given by way of example, and drawn to enlarged scale.
• the strand denoted with reference number 1 in this case consists of a round central wire 2, (i.e. "supporting core wire") and tangentially surrounding six covering wires 3.
• the covering wires 3 in contact with the concrete in built-in state have non-circular cross section profile continuously passing through in longitudinal direction for the purpose of increased adhesion to the concrete, and establishing indentical stress conditions in all strand cross sections.
• the covering wires 3 are of regular hexagonal cross section, rounded on the corners.
• the diameter of central wire 2 is marked with D 2
• diameter of the circle drawable into the hexagon in case of the cover wire is marked with D 3
• diameter of the circle drawable around the hexagon with DA and the embracing facedistance of strand 1 with L 1 , while its distance between centres is marked with L 2 .
• the diameter D 2 of the central wire 2 is selected to 4.26 mm, and the diameter D 3 of the covering wires 3 to 4.11 mm.
• the production technology of the central wire 2 and covering wires 3 is essentially conventional.
• the production of the covering wires 3 according tothe invention only the last step of the cold deformation is different, where special drawplate of hexagonal opening cross section was used to obtain the required cross section.
• the covering wire 3 is turned around its longitudinal axis (naturally this can be dispensed with in given case) while passing through the drawplate.
• the pitch of wire-turning is determined by the pitch of the drawplate.
• the drawplate was embedded as to be capable to turn around the advanced wire.
• the twist i.e. the strand 1 is formed on a conventional twisting machine with the central wire 2 and six covering wires 3.
• the turning direction of the covering wires 3 was selected to be identical with the direction of twisting, furthermore the pitch of twisting was selected to about tenfold of the turning pitch.
• any cross section of the strand is identical, consequently the arising stress conditions too are identical.
• the surface area increased according to the periodic profiling results in improved anchoring capacity of the strand 1, consequently the load bearing capacity of the strand 1 and its safety factor are also increased.
• the use of steel, i.e. material is less for the strand provided with covering wires of helical hexagon cross section according to the invention.
• the central wire 2 is omitted.
• even the central wire may be identical with the covering wires.
• any other non-circular profile can also be used with similar result, e.g. as polygonal cross sections, thus regular pentagon, octogon, etc.
• such circular or polygonal profile too may come into question at least for the covering wires, which is provided with groove- like recesses passing through in longitudinal direction, and/or rib-like, or web-like extensions passing through in longitudinal direction.
• the cold deformation of the three latter ones may be accomplished in any other way, e.g. by rolling.

Landscapes

• Engineering & Computer Science (AREA)
• Architecture (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Reinforcement Elements For Buildings (AREA)
• Ropes Or Cables (AREA)
• On-Site Construction Work That Accompanies The Preparation And Application Of Concrete (AREA)
• Sewage (AREA)
• Curing Cements, Concrete, And Artificial Stone (AREA)
• Polishing Bodies And Polishing Tools (AREA)
• Heat Treatment Of Steel (AREA)
• Diaphragms For Electromechanical Transducers (AREA)
• Disintegrating Or Milling (AREA)
• Preparation Of Clay, And Manufacture Of Mixtures Containing Clay Or Cement (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (2)

Family

ID=10968173

Family Applications (1)

Country Status (9)

Families Citing this family (1)

Family Cites Families (6)

• 1985
  • 1985-11-26 HU HU854511A patent/HU204312B/hu not_active IP Right Cessation
• 1986
  • 1986-11-18 WO PCT/HU1986/000060 patent/WO1987003322A1/en not_active Ceased
  • 1986-11-18 DE DE8686906911T patent/DE3683769D1/de not_active Expired - Lifetime
  • 1986-11-18 EP EP86906911A patent/EP0247130B1/de not_active Expired - Lifetime
  • 1986-11-18 FI FI873196A patent/FI873196L/fi not_active Application Discontinuation
  • 1986-11-18 AT AT86906911T patent/ATE72282T1/de not_active IP Right Cessation
  • 1986-11-26 CS CS864786A patent/CS274284B2/cs unknown
  • 1986-11-26 DD DD86296685A patent/DD259228A1/de not_active IP Right Cessation
• 1987
  • 1987-07-24 NO NO873118A patent/NO873118L/no unknown

Non-Patent Citations (1)

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