US3654968A - Steel wire cage wire for chemically prestressed concrete pipe - Google Patents

Steel wire cage wire for chemically prestressed concrete pipe Download PDF

Info

Publication number
US3654968A
US3654968A US12363A US3654968DA US3654968A US 3654968 A US3654968 A US 3654968A US 12363 A US12363 A US 12363A US 3654968D A US3654968D A US 3654968DA US 3654968 A US3654968 A US 3654968A
Authority
US
United States
Prior art keywords
wire
concrete
expansion
cage
steel
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 - Lifetime
Application number
US12363A
Other languages
English (en)
Inventor
Katsuhisa Mizuma
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.)
Koshuha Netsuren KK
Original Assignee
Koshuha Netsuren KK
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 Koshuha Netsuren KK filed Critical Koshuha Netsuren KK
Application granted granted Critical
Publication of US3654968A publication Critical patent/US3654968A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L9/00—Rigid pipes
    • F16L9/08—Rigid pipes of concrete, cement, or asbestos cement, with or without reinforcement

Definitions

  • the present invention relates to a steel wire orrod for use in chemically prestressed concrete pipe, which is effective for controlling the expansion of the expansion concrete therein over a wide range and with approximately uniform stress.
  • expansion concrete is caused to compensate for shrinkage of the concrete during hardening.
  • a wire or rod restrains the force of the expansion so that a compressive stress occurs in the radial direction of the concrete during manufacture for the purpose of increasing the resistance of the pipe to external pressure.
  • the steel wire or rod is a member of a steel wire cage which is placed in a concrete frame during the manufacture of a concrete pipe.
  • the steel wire is spirally wound and fixed around the periphery of a group of steel rods arranged parallel to one another longitudinally along the wall of a concrete pipe, and the internal surface of the steel wire serves to restrain the expansion of the expansion concrete.
  • the width of the internal surface of the wire as wound spirally around the parallel steel rods to form the steel wire cage i.e., the plane at which the compressive stress is applied on the concrete, is larger than the diameter of a circular wire with the same cross sectional area; its thickness is smaller than such diameter; and such internal surface is provided with projections to be spot welded to the parallel rods in the formation of the steel wire cage.
  • FIG. 1 is a partial elevation of a known steel wire cage for use in chemically prestressed concrete pipe
  • FIG. 2 is a partial section of a chemically prestressed concrete pipe under manufacture
  • FIG. 3 is a section taken along line IIIIII of FIG. 2;
  • FIG. 4a is an elevation of a known wire for use in a steel wire cage of a chemically prestressed concrete pipe
  • FIG. 4b is a section taken along line IVb-IVb of FIG. 4a;
  • FIG. 40 is an oblique view of another known wire
  • FIG. 5a is an elevation of a steel wire in accordance with a first embodiment of the present invention.
  • FIG. 5b is a section taken along line VbVb of FIG. 5a;
  • FIG. 6a is a sectional illustration of the compressive stress created on concrete by the known wire illustrated in FIGS. 4a and 4b;
  • FIG. 6b is a sectional illustration of the compressive stress created on concrete by the novel wire illustrated in FIGS. 5a and 5b;
  • FIG. 7a is a partial section of the wire of FIGS. 5a and 5b positioned for spot welding;
  • FIG. 7b is a partial section of a wire of a second embodiment of the present invention positioned for spot welding
  • FIG. 8a is an elevation of the wire of the second embodiment
  • FIG. 8b is a section taken along line VIIIb-VIIIb of FIG. 8
  • FIG. 8c is a bottom view of the wire of FIG. 8a;
  • FIG. 9a is a section taken along line IXa-IXa of FIG. 9b illustrating a third embodiment of the present invention.
  • FIG. 9b is a bottom view of the wire of FIG. 9a;
  • FIG. 10a is a section taken along line XaXa of FIG. 10b illustrating a fourth embodiment of the present invention
  • FIG. 10b is a bottom view of thewire of FIG. 100;
  • FIG. 11a is a sectional illustration of the compressive stress created on concrete by the known wire illustrated in FIGS. 40 and 4b;
  • FIG. 11b is a sectional illustration of the compressive stress created on concrete by the novel wire illustrated in FIGS. 80, 8b and
  • FIG. 12 is a graph illustrating the relationship between steam curing time and steam temperature on a concrete pipe incorporating the novel wire of the present invention
  • FIG. 13a is a sectional illustration of a concrete pipe in accordance with the present invention undergoing a pressure test.
  • FIG. 13b is a longitudinal view, partially in section, of the arrangement of FIG. 13a.
  • FIG. 1 shows a known steel wire cage adapted to be placed in a concrete frame during the manufacture of chemically prestressed concrete pipe.
  • the concrete includes a desired quantity of expansion cement, for example, 10-17% by weight.
  • the frame is revolved whereby the concrete is hardened under the application of centrifugal force.
  • the expansion of the expansion cement is restrained by the internal surface of the wire which is part of the steel wire cage.
  • a compressive strees is applied in the radial direction of the concrete.
  • the steel wire cage is usually formed as follows.
  • the required number of steel reinforcing wires or rods 1 are arranged parallel to one another with their ends fixed to a holding means (not shown), and are spaced around the circumference of a drum 3.
  • the rods 1 can move and revolve continuously along the outer circumference of drum 3.
  • Around the outer circumference of rods 1 is spirally wound the hoop-reinforcing wire 2. This is done by relatively rotating the rod or the wire, i.e., by fixing either the group of steel rods or the hoop-reinforcing wire 2 and rotating the other.
  • the points 4 where each rod 1 and the hoop-reinforcing wire 2 contact are successively and automatically spot-welded by an electrode 5, which electrode is connected to a power source E.
  • the reinforcing rods 1 and the hooping wire 2 preferably are made of a steel including elements as listed in Table 1.
  • the thus formed wire cage is placed as shown in FIGS. 2 and 3 into a concrete frame 6.
  • a concrete mixture including 10-17% by weight of expansion cement is poured.
  • the concrete within section 6 of the frame is compacted under centrifugal force by rotating frame 6 together with rotating wheel 7, whereby the concrete is hardened to form a pipe.
  • Wheel 7 is caused to rotate by any known suitable means, not shown.
  • the pipe After steam curing, the pipe is demolded and then submitted to underwater curing to produce a chemically prestressed concrete pipe.
  • the concrete containing the expansion concrete expands; and through restraint of this expansion by the internal surface of the hooping wire 2, a compressive stress is imparted in the radial direction of the pipe, thereby increasing the resistance of the pipe to external pressure.
  • the conventional hooping wire consists of a steel rod or wire 2' circular in cross section.
  • the wire illustrated in FIG. 40 differs from that illustrated in FIGS. 4a and 4b in that the former has axial notches 8 cut on the periphery thereof. But, both are circular in cross section.
  • wire 2' is limited in the amount of stress it may impart to the concrete 9, as shown in FIG. 6a at f.
  • the stress applied to concrete 9 is not uniform over the periphery of the wire in contact with the concrete. More stress is applied at mid-portion C than at the ends. As a result, the concrete in contact with the mid-portion C may be fractured, resulting in a failure of the objective of the chemically prestressing manufacture, that is, to develop resistance to external pressure.
  • the plane is the internal surface which contacts the periphery of the rods 1 and restrains the concrete expansion.
  • the width of plane 10 is larger than the diameter of a circular wire having the same cross sectional area as wire 2", and the thickness of wire 2" is less than such diameter.
  • Plane 10 is preferably straight, however, it may be slightly concave or convex.
  • the top 14 is preferably formed in a mild arc.
  • a wire of this profile has remarkable advantages over the previously known circular wire. Namely, whereas the circular wire has a limited ability to create compressive stress on the concrete 9 as indicated by f in FIG. 6a; the wire with the shape shown in FIGS. 5a and 5b has a much greater stress creating ability as shown by f in FIG. 6b. Furthermore, the stress acting on concrete 9 is approximately uniform over the entire surface 10, and accordingly there is no likelihood of the concrete being fractured as before.
  • FIGS. 8a-8c A second embodiment of the present invention is shown in FIGS. 8a-8c and represents an improvement over the embodiment of the invention shown in FIGS. 5a and 5b.
  • FIG. 7a when the wire of FIGS. 5a and b is wound around rods 1, the entire width of surface 10 contacts the rods. Due to this relatively large surface to surface contact, the spot welding of wire 2" to rods 1 is difficult with existing wire cage spot welders. This is due to the fact that the larger contact area requires longer weld time. Additionally, care must be taken not to deteriorate the mechanical properties of the wire during such welding.
  • the wire of FIGS. 5a and b is acceptable and gives vastly improved results
  • the embodiment of FIGS. 8a-b represents an even more desirable wire.
  • the width of the plane for applying a compressive stress to the concrete i.e., the internal surface of the wire as wound spirally around the rods of the wire cage, is larger than the diameter of a circular wire having the same cross sectional area, and its thickness is smaller than such diameter. Also, the internal surface is provided with projections to facilitate spot welding during the formation of the wire cage.
  • the internal surface of the wire as spirally wound around the rods i.e., the plane 10 at which the compressive stress is applied to the concrete, is generally straight or midly curved in section and is provided at both ends with projections 13 and 13'. It is for the purpose of making the stress acting on the expansion concrete approximately even over the entire plane 10 that this plane 10 is formed straight or only midly curved.
  • the width 12 of plane 10 is larger than the diameter of .a circular wire with the same cross sectional area, and its thickness 11 is smaller than such diameter.
  • the top 14 is preferably formed in a mild arc. However, as illustrated in FIG. 5b, the top may be formed approximately straight in mid-portion, with both ends an ln thereof formed in mild arcs. As mentioned above, projections 13 and 13 enhance spot welding by providing relatively little surface to surface contact with rods 1, as shown in FIG. 7b.
  • Provision of these projections 13 and 13' at both ends of plane 10, as shown in FIG. 8b, is desirable because it enhances the bending rigidity of wire 2, and the formed cage when laid on the ground therefore sufiers less deflection.
  • the projections may satisfactorily be positioned within plane 10 symmetrically relative to the mid-point thereof as shown in FIG.
  • the preferred dimensions of the wire are, with reference to FIG. 8b: thickness 11, over 2.5 mm; width 12, at least 1.5 times the thickness 11; the curvature of the projections 13 and 13', l-2 R; height of the projections, 0.5-1.5 mm.
  • the upper limit of the thickness 11 may be 5 mm or more.
  • Width 12 may be less than 1.5 times the thickness 11, but better results would be obtained when it is more than 1.5 times the thickness.
  • the upper limit of width 12 normally need not exceed four times the thickness 11.
  • the projections 13 and 13 are less than 0.5 mm in height, then during the formation of the wire cage when the spot welder 5 presses the wire 2 against the steel rod 1, the part of the plane 10 of the wire other than the projections 13 and 13' is likely to touch the rod 1. This would cause a small molten area to be formed on the wire, thereby causing deterioration of the mechanical properties of the wire.
  • the projections may be over 1.5 mm in height.
  • the above-mentioned height would be sufficient to prevent the above-mentioned disadvantage during spot welding.
  • the chemical composition of the wire may be approximately the same as that of the known circular wire as listed in Table 1.
  • Raw steel of the above composition is held for 20 minutes at approximately 800 C.820 C. by the known method.
  • the steel is then drawn to the shape according to FIG. 8b, and thereafter it may be submitted to bluing.
  • Spot welding may be accomplished with a spot welding current of LOGO-1,200 A using a known steel wire cage forming machine without any deterioration of the mechanical properties of the wire.
  • Unit I Unit Unit fine aggrecoarse expansion gate aggregate cement 586 kg. 1,043 kg. 80 kg.
  • dial gauges 20 were vertically attached at 150 mm from both ends of each pipe; and strain gauges l9 and 19 were internally plastered at 300 mm from both ends of each pipe.
  • the cracking of the pipes was cv v s z .
  • the chemically prestressed concrete pipe having a steel wire cage including the known wire having a circular cross section developed the first crack under a test load of 6500 Kg/m.
  • the pipe having a cage including the wire as illustrated in FIGS. 8a-c and the same cross sectional area as the circular wire did not crack until a test load of 7500 Kg/m y asreached.
  • said means comprise two projections symmetrically located with respect to the midpoint of said surface, each projection being 0.5-1.5 mm high and the surface of which is curved in the order of l-2 R.
  • said means comprise a curved projection centered with respect to the midpoint of said surface, said projection being 0.5-1.5 mm high and the surface of which is curved in the order of l-2 R.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Reinforcement Elements For Buildings (AREA)
US12363A 1969-03-13 1970-02-18 Steel wire cage wire for chemically prestressed concrete pipe Expired - Lifetime US3654968A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP1857169 1969-03-13

Publications (1)

Publication Number Publication Date
US3654968A true US3654968A (en) 1972-04-11

Family

ID=11975295

Family Applications (1)

Application Number Title Priority Date Filing Date
US12363A Expired - Lifetime US3654968A (en) 1969-03-13 1970-02-18 Steel wire cage wire for chemically prestressed concrete pipe

Country Status (3)

Country Link
US (1) US3654968A (de)
DE (1) DE2012064C3 (de)
FR (1) FR2034873B1 (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3982565A (en) * 1973-08-30 1976-09-28 Nippon Hume Pipe Company Limited Prestressed concrete pipe
US4113823A (en) * 1974-04-24 1978-09-12 Nippon Hume Pipe Company Limited Method of manufacturing prestressed concrete pipe
US4702282A (en) * 1984-11-27 1987-10-27 Vianini Industria S.P.A. Reinforced conventional concrete pipe having an evenly distributed steel wire reinforcement

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US891234A (en) * 1908-06-23 Harry A Crane Reinforcing-bar for cementitious bodies.
US1255678A (en) * 1916-09-11 1918-02-05 William P Witherow Reinforcing-bar.
US1763360A (en) * 1927-01-22 1930-06-10 Otho V Kean Noncorrodible reenforced pipe
US1910643A (en) * 1930-08-22 1933-05-23 James H Sherrard Concrete pipe, pole, column, and the like
US2069280A (en) * 1928-06-18 1937-02-02 Karl R Schuster Composite structural steel and reenforced concrete construction
US2660199A (en) * 1947-05-01 1953-11-24 Gustaf A Montgomery Reinforced concrete conduit
US2870626A (en) * 1949-11-04 1959-01-27 Gillberg Johannes Reinforcing bars having depressed portions for use in concrete constructions

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US891234A (en) * 1908-06-23 Harry A Crane Reinforcing-bar for cementitious bodies.
US1255678A (en) * 1916-09-11 1918-02-05 William P Witherow Reinforcing-bar.
US1763360A (en) * 1927-01-22 1930-06-10 Otho V Kean Noncorrodible reenforced pipe
US2069280A (en) * 1928-06-18 1937-02-02 Karl R Schuster Composite structural steel and reenforced concrete construction
US1910643A (en) * 1930-08-22 1933-05-23 James H Sherrard Concrete pipe, pole, column, and the like
US2660199A (en) * 1947-05-01 1953-11-24 Gustaf A Montgomery Reinforced concrete conduit
US2870626A (en) * 1949-11-04 1959-01-27 Gillberg Johannes Reinforcing bars having depressed portions for use in concrete constructions

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3982565A (en) * 1973-08-30 1976-09-28 Nippon Hume Pipe Company Limited Prestressed concrete pipe
US4113823A (en) * 1974-04-24 1978-09-12 Nippon Hume Pipe Company Limited Method of manufacturing prestressed concrete pipe
US4702282A (en) * 1984-11-27 1987-10-27 Vianini Industria S.P.A. Reinforced conventional concrete pipe having an evenly distributed steel wire reinforcement

Also Published As

Publication number Publication date
DE2012064A1 (de) 1970-09-17
FR2034873B1 (de) 1975-12-26
DE2012064B2 (de) 1973-05-17
DE2012064C3 (de) 1973-12-06
FR2034873A1 (de) 1970-12-18

Similar Documents

Publication Publication Date Title
Ilki et al. Compressive behaviour of carbon fibre composite jacketed concrete with circular and non-circular cross-sections
Nematzadeh et al. Experimental study on modulus of elasticity of steel tube-confined concrete stub columns with active and passive confinement
KR20120031942A (ko) 양호한 고정성을 갖는 고 신장성 파이버
Warwaruk Strength and behavior in flexure of prestressed concrete beams
Nedwell et al. 26 INVESTIGATION INTO THE REPAIR OF SHORT SQUARE COLUMNS USING FERROCEMENT
US3654968A (en) Steel wire cage wire for chemically prestressed concrete pipe
O’Shea et al. High strength concrete in thin walled circular steel sections
US2579183A (en) Method for tensioning reinforcements
Scribner Delaying Shear Strength Decay In Reinforced Concrete Flexural Members Under Large Load Reversals.
US4113823A (en) Method of manufacturing prestressed concrete pipe
Gonnade et al. Experimental and computational study on concrete filled PVC plastic tubes placed in columns
US3411545A (en) Reinforced concrete pipe
US3088187A (en) Process of making elongated stressed concrete structures
Baqi et al. Experimental study of prestressed masonry flexural elements
Regan et al. THE PUNCHING RESISTANCE OF PRESTRESSED CONCRETE SLABS.
US3982565A (en) Prestressed concrete pipe
CN110887647A (zh) 一种薄壁离心混凝土钢管塔补强的方法
Thandavamoorthy Static and fatigue of high-ductility bars reinforced concrete beams
Hill Material Properties of the Grade 300 and Grade 270 Prestressing Strands and Their Impact on the Design of Bridges
Mansur et al. Ferrocement under combined bending and axial loads
JP3150927B2 (ja) 鉄筋コンクリート柱
US3300922A (en) Anchor assembly for prestressed concrete structures
US3411546A (en) Reinforced concrete pipe
RU2033505C1 (ru) Способ изготовления предварительно напряженного строительного элемента с внешней трубчатой обоймой
Mohamed et al. An experimental study of the behaviour of sleeved bolt connections in precast concrete frames