US3533203A - Compressed structural members - Google Patents

Compressed structural members Download PDF

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Publication number
US3533203A
US3533203A US856901A US3533203DA US3533203A US 3533203 A US3533203 A US 3533203A US 856901 A US856901 A US 856901A US 3533203D A US3533203D A US 3533203DA US 3533203 A US3533203 A US 3533203A
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concrete
percent
tensioning
strand
tension
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US856901A
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Herbert Corliss Fischer
Herbert Corliss Fischer Jr
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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

Definitions

  • the invention relates to novel prestressed structural elements and methods of their manufacture.
  • prestressing by maintaining a structural member in a precompressed condition may be utilized to increase its tensile strength and its strength in bending.
  • concrete a cast stone made primarily of portland cement, aggregate and water, has the property of great strength in compression.
  • it is weak in tension, causing it to be brittle and so subject to cracking and breakage when subjected to unexpected tension stresses, such as frequently occur in handling and assembling precase concrete elements prior to and during building construction.
  • Reinforcing however, has the distinct drawback in that it still permits the concrete to crack under tensions, although the steel reinforcing continues to hold the cracked pieces generally together. This is because the steel reinforcing must elongate as it takes up the load, but, because the elongation is more than the encasing concrete can stand, it cracks under the load.
  • Prestressing is largely a matter of precompressing the concrete element in those areas where tension stresses are anticipated. If enough precompression is stored up in the concrete element, there will be no tensile stresses under the design load. Under these conditions, the concrete, being under compression, loses its brittleness and behaves as a flexible and resilient material. A prestressed concrete element merely loses some of its precompression as it accepts its load, so that the actual compression stresses are reduced as the load increases, at least up to the design load.
  • prestressing of concrete has been accomplished in two ways; post-tensioning and pretensioning.
  • a steel rod or cable is tensioned to compress the concrete.
  • post-tensioning such is accomplished by casting a hole in the concrete element, and, after the concrete has set, placing a steel rod or cable through the hole and tensioning it to compress the concrete, leaving the tensioning elements exposed at the ends of the hole.
  • pretensioning a steel cable is tensioned as by hydraulic jacks and end anchors and the concrete poured around the steel while it is maintained in tension. After curing, the concrete will bond to the steel cable by reason of the grooves therein so that the end anchors can be cut 01T, the steel remaining in tension to maintain the surrounding concrete in compression and so prestress it.
  • prestressed concrete elements could be economically manufactured only at central locations :and trucked to the construction site, and their range of sizes and configurations was limited by the cost and availability of such equipment, especially when but a few of a particular concrete element was involved.
  • ⁇ Other materials such as synthetic organic plastic materials
  • ⁇ Other materials have similarly been prestressed by incorporating therein stressed, relatively inextensible elements, but all were subject to the Same difficulties enumerated above, namely, the practical difficulty in achieving optimum prestressing because of the low elongation of the prestressing elements, even when they are under high tension and the resulting inability to utilize them, particularly with low strength structural elements, especially of light weight materials such as wood and plastic.
  • the major object of the present invention is to provide novel prestressed structural elements and methods of manufacturing same not subject to the abovementioned difficulties.
  • Another object of the invention is to make possible the concealing of the reinforcing strands within the structural element, so that they are not exposed on the surface thereof.
  • Another object of the invention is to avoid the use of metal pretensioning elements with their known electrolytic and corrosion problems.
  • pretensioning elements of a class of materials long known in other uses but never heretofore considered to be practical as pretensioning elements.
  • These materials comprise well-known synthetic organic plastic polymers, such as nylon, polypropylene, and polyester, preferably in the form of highly elastic multifilament strands, twisted or untwisted, of moderate tensile strength as compared to steel, but uniquely capable of producing high compressive forces due to their high recoverable stretch or elongation, upwards of 10 to 20 percent, providing progressively increasing tension up to their breaking tension at their elastic limit.
  • multi-filament strands such as ropes
  • relatively rigid materials especially such light weight materials as light metals, plastic, wood, etc., capable of maintaining the tensioned strand at a relatively fixed length, particularly as to further elongation, to provide unusually light weight pretensioned structural elements.
  • FIGS. 1 and 2 are, respectively, plan and cross-sectional views of an internally prestressed structural element according to the invention
  • FIGS. 3 and 4 are, respectively, side and cross-sectional views of an externally prestressed structural ele ment according to the invention.
  • FIG. 5 shows a typical end product utilizing the structural element of FIGS. 3 and 4, and
  • FIG. 6 shows an internally prestressed tubular structural element.
  • the preferred embodiments of the invention provide compressed structural elements such as those shown in the drawings by compressing elements of conventional rigid materials such as metal, plastic, concrete, wood, etc., by means of internal or external fiber tensioning strands capable of dimensional change such as potentially high elastic stretch, of the order of at least about 5 to 10 percent, relatively to that of the material to be prestressed, with such strands being maintained at about 5 to 10 percent elongation in excess of their stabilized relaxed length and under tension of at least about 10 to 20 percent of its ultimate breaking strength.
  • the material to be prestressed be in a substantially rigid, non-yielding condition, that is, be relatively incompressible, when compressive forces are applied to it by the tensioning strand, so that the highly tensioned strand is in intimate contact with the rigid body and is maintained thereby at a relatively xed length so that it continuously maintains its compressive force to prestress the element.
  • the use of the non-metallic ber tensioning strands of the invention avoids the electrolytic and corrosion problems of metal, and has still other advantages as hereinafter set forth.
  • a wide variety of elastically contractible organic plastic strands may be utilized according to the invention including such organic plastic materials as nylon, polypropylene, and polyester, for example, as well as others, preferably in multi-filament, untwisted or twisted configurations as with rope or rovings.
  • Such strands have a usefully high tensile strength with a great amount of elastically recoverable extension, by which we mean that extension which repeatedly remains after the strand has been stretched a sufficient number of times to achieve a relatively stabilized relaxed length.
  • nylon rope, a preferred tensioning strand according to the invention has a breaking strength of about 36,000 p.s.i.
  • Such a material is uniquely useful as a prestressing element, especially for prestressing relatively light-weight rigid elements as of wood, aluminum, plastic, etc., which are very difficult to prestress with a material such as steel because the high tensile strength of steel makes it necessary to utilize extremely small prestressing elements which are diflcult to assemble and control.
  • Polyester and polypropylene ropes have somewhat lower breaking strengths, with elongations about half that of nylon, b ut are nevertheless highly useful in the practice of the invention. Other plastic materials with similar physical properties are also useful.
  • the potentially contractible tensioning strand of the inventiona may be incorporatedwith a non-rigid material such as unset concrete or plastic, while the concrete or plastic is in unset, yieldable condition usually by pouring it into or compressing it within a suitable form in which the tensioning strands are supported, after which the non-rigid body is allowed to set to a rigid condition and the tensioning strands then contracted or allowed to contract to compress the element.
  • the tensioning strand may be applied in tensioned condition externally of a rigid element to be compressively stressed with the tensioning strand in intimate contact therewith so that the stressed reinforcing element dimensionally changes to compressively stress such element.
  • the stressing of the tensioning strand after the previously non-rigid body has :sufficiently set may be accomplished on a temperature basis.
  • the curing of precast concrete elements is carried out by heating the form containing the concrete.
  • a tensioning strand can be selected in which a major proportion of its contraction occurs at a suitable temperature, below which the concrete cure can be initially carried out for substantial setting and bonding to the tensioning strand above which the tensioning strand will shrink to tension it and so compress the concrete element.
  • the invention may be applied to concrete made of Portland cement, using a wide variety of aggregates, as presently known to the art, not only the usual sand, gravel and stone aggregates, but also light weight aggregates lsuch as burnt clay, expanded blast furnace slag, pumice and expanded vermiculate, as well as air-entrained and foamed concrete.
  • FIGS. l and 2 a standard concrete test element (ASTM) generally designated constructed according to the invention.
  • ASTM standard concrete test element
  • a test specimen has a six inch square cross section and is twenty-one inches longa and was produced by incorporating tensioning elements 12, 14, 16, 18 with a normal Portland cement concrete having a strength in the range of 5,000- 6,000 p.s.i. compressive strength, as is known in the art and described, for example, in Design and Control of Concrete Mixtures, 10th ed., published by Portland Cement Association (1952)
  • the tensioning elements l2, 14, 16, 18 are multi-filament, heat-shrinkable polyester fibers having a recoverable stretch of about 10 percent, in which about a 10 percent shrinkage occurs upon heating to a temperature of about 300 degrees.
  • Precompressed structural elements may also be produced by using organic plastic multi-fiber strands, such as ropes, of the type described above which are capable of at least about 5' to 10 percent elongation and elastic recovery under tension of at least about 10 ⁇ to 20 percent of their ultimate breaking strength. This may be accomplished by tensioning one or more such ropes for example of nylon, and holding each by appropriate clamps 20, such as are shown and described ⁇ with reference to FIG. 6, pouring the concrete or other unset plastic body around the tensioned ropes, and allowing it to set while maintaining the ropes undertenson. Afterthe concrete has set, the tension on the ropes may be released to compress the concrete and the ends of the ropes may be cut off.
  • organic plastic multi-fiber strands such as ropes, of the type described above which are capable of at least about 5' to 10 percent elongation and elastic recovery under tension of at least about 10 ⁇ to 20 percent of their ultimate breaking strength.
  • This may be accomplished by tensioning one or more such ropes for example of nylon, and holding each by appropriate clamps 20,
  • Nylon ropes are particularly desirable in such application, not only because of their great elongation and the high compressive forces produced thereby, but also because they appear to react chemically with the concrete for firm bonding thereto.
  • the body 10 regardless of the rigid material of which it is cornposed may be stressed according to the invention by passing ropes 12, 14, 16, 18 through appropriate holes therein, tensioning said ropes to a condition equivalent to at least about 5 to 10 percent in excess of their stabilized relaxed length and under tension of at least about 10 to 20 percent of their ultimate breaking strength, and so maintaining them at a fixed length relatively to body 10 as by clamps 20.
  • FIGS. 3 and 4 an externally stressed structural member according to the invention in which a rigid body 2S, as of metal, wood or plastic, is stressed by a tensionedstrand 27 wrapped therearound, which may be in the form of, for example, an endless rope, roving or multiple turn-wound multifilamefnt strand.
  • strand 27 is of an extensible material pretensioned to at least about 5 to l0 percent in excess of its stable relaxed length and to a tension of at least about l0 to 20 percent of its breaking tension.
  • strand 27 need not wrap the body 25, but may extend along one or both sides thereof and be attached adjacent its end by any suitable means such as clamps 20.
  • FIG. 5 is shown a typical end product using the structural elements of FIGS. 3 and 4 as the side rails 32, 34 of an otherwise conventional ladder 30 having rungs 36.
  • the lader material is of hardwood although aluminum could be used as well.
  • Strand 27 is of nylon rope of 1A; inch diameter, extended to 40 percent of its stabilized relaxed length to develop a residual compressive force of about 700 pounds, about 1/3 of its ultimate breaking strength and is retained in a groove about the periphery of the side rails.
  • FIG. 6 is shown another structural member in the form of an aluminum tube 30 having a strand 32 elongated and stressed according to the invention passing through its center and held at its ends by known clamps, generally designated 20, having a conical body 22 for receiving the opened end of the multi-fiber strand 32 and clamping it by cooperation with a conical plug 23 held in position in body 22 by screw threads 24.
  • the internally stressed, tubular structural member of FIG. 6 is useful in a wide variety of end products, including supporting poles of many types including boat masts and ski poles, as well as for such highly stressed and flexible elements as helicopter rotor blades.
  • a 1/2 inch nylon or Dacron rope can be so elongated to about 10 percent in excess of its stabilized relaxed length with about a 400G-500() pound force as compared to a force five times higher needed to stretch at 1/2 inch steel cable about 1 percent.
  • This not only makes it possible to use simpler and cheaper prestressing machinery, but also at the same time to produce a more uniformly stressed product even of light weight concrete, Wood or aluminum, for example, and to distribute the stress throughout the element cross section by utilizing multiple strands as desired.
  • any required amount of pretensioning may be provided according to the invention by increasing the number of organic plastic fiber strands, and slippage may be virtually eliminated by coating the strands with a suitable adhesive such as an epoxy resin to provide any desired degree of bonding to maintain the tensioning strands in intimate contact with the body.
  • a stressed structural element composed at least in part of concrete comprising portland cement and aggregate and having integral non-metallic tensioning means in intimate contact with said element, said tensioning means comprising a multiplicity of organic plastic fibers having a recoverable stretch of at least 10 percent and having a tensile strength of at least about 10,000 p.s.i. with a decay factor of no more than about 1/3 over a period of years and having a plurality of non-terminated, curved portions permanently maintained in tensioned condition at a relatively fixed length and in initimate contact With said concrete at at least l percent elongation and under tension of at least percent of its ultimate breaking strength, providing concrete element containing a substantial proportion of non-terminated, curved stressed fibers effective to stress said element.
  • a stressed structural element composed at least in part of concrete comprising portland cement and aggregate and having integral non-metallic tensioning means in intimate contact with said element, said tensioning means comprising a multiplicity of organic plastic fibers having a recoverable stretch of at least 10 percent and having a tensile strength of at least about 10,000 p.s.i. with a decay factor of no more than about 1/3 over a period of years and having a plurality of portions permanently maintained in tensioned condition at a relatively iixed length and in initimate contact with said concrete at at least 10 percent elongation and under tension of at least 10 percent of its ultimate breaking strength, providing concrete element containing a substantial proportion of stressed fibers effective to stress said element.
  • a reinforced element including a rigid, non-yielding solid body having non-terminated reinforcing strand means composed of a multiplicity of synthetic organic plastic fibers having a recoverable stretch of at least l0 percent and having a tensile strength of at least about 10,000 p.s.i. extending continuously throughout a major portion of the length of said body concealed within the substance of said body including its ends and maintaining said body therebetween in compressed condition, said reinforcing strand means being permanently maintained at a relatively fixed length and in intimate association with said body at at least 10 percent elongation and under tension of at least 10 percent of its ultimate breaking strength to compress said body, providing an element reinforced with a substantial proportion of stressed fibers.
  • a reinforced element including a rigid, non-yielding solid body having reinforcing strand means composed of a multiplicity of synthetic organic plastic fibers having a recoverable stretch of at least 10 percent and having a tensile strength of at least about 10,000 p.s.i. extending continuously in a closed curve encircling said body and maintaining said body therewithin in compressed condi- Cil tion, the bers of said reinforcing strand means being permanently maintained at a relatively fixed length and in intimate association with said body at at least 10 percent elongation and under tension of at least l0 percent of its ultimate breaking strength to compress said body therewithin, providing an element reinforced with a substantial proportion of stressed fibers.
  • a reinforced element including a rigid, non-yielding solid body having reinforcing strand means composed of a multiplicity of synthetic organic plastic fibers having a high coefficient of contraction of at least 10 percent relatively to the coefficient of contraction of said body and maintaining said body therewithin in compressed condition, said reinforcing strand means being permanently maintained at a relatively fixed length and in intimate association with said body in elongated condition to compress said body therewithin, providing an element reinforced with a substantial proportion of stressed fibers.
  • a reinforced ladder including rigid, non-yielding solid side members having reinforcing strand means composed of a multiplicity of synthetic organic plastic fibers having a high coeficient of contraction of at least l0 percent relatively to the coefiicient of contraction of said body extending continuously in a closed curve encircling said side members in a longitudinal direction and maintaining said side members therewithin in compressed condition, said reinforcing strand means being permanently maintained at a relatively fixed length and in intimate association with said side members in elongated condition to compress said body therewithin, providing a ladder reinforced with a substantial proportion of stressed fibers.
  • a reinforced element including a rigid, non-yielding aluminum tube having longitudinally extending central reinforcing strand means composed of a multiplicity of synthetic organic plastic fibers having a high coefficient of contraction of at least 10 percent relatively to the coeflicient of contraction of said body extending continuously throughout the length of said tube internally thereof and maintaining said surrounding tube in compressed condition, said reinforcing strand means being permanently maintained at a relatively fixed length in elongated condition to compress said tube, providing an element reinforced with a substantial proportion of stressed bers.
  • a stressed structural element having a relatively rigid, incompressible body and tensioning means comprising a multiplicity of synthetic organic plastic fibers having a recoverable stretch of at least about 10 percent, and a tensile strength of at least about 10,000 p.s.i., said tensioning means being maintained at a relatively fixed length in intimate association with said body at -at least about 5 to 10 percent elongation and under tension of at least 10 percent of its ultimate breaking strength to compress said body.
  • FRANK L. ABBOTT Primary Examiner J. L. RIDGILL, JR., Assistant Examiner U.S. C1.

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  • Engineering & Computer Science (AREA)
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  • Civil Engineering (AREA)
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  • Ropes Or Cables (AREA)
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Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3813098A (en) * 1970-06-22 1974-05-28 H Fischer Prestressed elements
US3938288A (en) * 1973-03-06 1976-02-17 Regie Nationale Des Usines Renault Reinforcing device for automobile body
US3948010A (en) * 1971-12-17 1976-04-06 Sonneville Roger P Reinforcing device for an element of prestressed concrete
US4003450A (en) * 1974-04-25 1977-01-18 Kenngott Gmbh & Co. Kg Small structural building component
US4151244A (en) * 1975-03-11 1979-04-24 Small Edward B Method of manufacturing pre-cast concrete panels
US4615163A (en) * 1984-10-04 1986-10-07 Curtis Albert B Reinforced lumber
US4852690A (en) * 1988-12-05 1989-08-01 Simon Ladder Towers, Inc. Aerial ladder tower with pretensioned truss members
US4905793A (en) * 1989-09-26 1990-03-06 Paulson Dennis R Ladder bracket
US5768847A (en) * 1995-05-15 1998-06-23 Policelli; Frederick J. Concrete reinforcing devices, concrete reinforced structures, and method of and apparatus for producing such devices and structures
US20070204948A1 (en) * 2006-02-21 2007-09-06 Werner Co. Fiberglass reinforced plastic products having increased weatherability, system and method
US20090065302A1 (en) * 2006-02-21 2009-03-12 Werner Co. Fiberglass reinforced plastic products having increased weatherability, system and method
US20140102830A1 (en) * 2012-10-16 2014-04-17 Nasir U. Ahmed Fiberglass Reinforced Plastic Lightweight Heavy-Duty Ladder and Method of Making Same
US20140150359A1 (en) * 2011-07-18 2014-06-05 Rolf J. Werner Tower-shaped supporting structure
US20170217108A1 (en) * 2016-01-28 2017-08-03 Donald E. Wheatley Method of making a fiber reinforced hoop and anchors for a concrete reinforcement structure
CN111187022A (zh) * 2018-11-14 2020-05-22 王子国 一种腐蚀致型形状记忆纤维及其制备方法和应用
US20220170267A1 (en) * 2019-04-04 2022-06-02 Deutsche Institute Für Textil-Und Faserforschung Denkendorf Prestressed concrete body, method for the production thereof, and use of same

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2716225B1 (fr) * 1994-02-11 1996-05-03 Bernard Lyon I Universite Clau Ceinture composite de frettage, procédé pour sa fabrication, application à la constitution d'un corps massif et corps massif ainsi obtenu.

Citations (9)

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Publication number Priority date Publication date Assignee Title
GB452126A (en) * 1934-11-09 1935-05-18 Pierre Louis Boucherie New constructional or reinforcing elements
US2413990A (en) * 1943-01-25 1947-01-07 Eric P Muntz Process of making prestressed reinforced concrete
US2652093A (en) * 1949-03-02 1953-09-15 Gates Rubber Co Method of making reinforced rubber hose
US2821155A (en) * 1953-12-11 1958-01-28 Richard A Fisch Process of applying protective coatings
US2825117A (en) * 1952-06-20 1958-03-04 Bradford Dyers Ass Ltd Method and apparatus for treating sheet material
US2827414A (en) * 1953-08-11 1958-03-18 Tropi Sales Plastic material and method of preparing same
US2836529A (en) * 1954-05-03 1958-05-27 Hugh Adam Kirk Reinforced plastic
US2850890A (en) * 1951-06-04 1958-09-09 Rubenstein David Precast element and reinforced facing layer bonded thereto
US2859936A (en) * 1954-03-03 1958-11-11 Cincinnati Testing & Res Lab Compressor blade and method of forming same

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB452126A (en) * 1934-11-09 1935-05-18 Pierre Louis Boucherie New constructional or reinforcing elements
US2413990A (en) * 1943-01-25 1947-01-07 Eric P Muntz Process of making prestressed reinforced concrete
US2652093A (en) * 1949-03-02 1953-09-15 Gates Rubber Co Method of making reinforced rubber hose
US2850890A (en) * 1951-06-04 1958-09-09 Rubenstein David Precast element and reinforced facing layer bonded thereto
US2825117A (en) * 1952-06-20 1958-03-04 Bradford Dyers Ass Ltd Method and apparatus for treating sheet material
US2827414A (en) * 1953-08-11 1958-03-18 Tropi Sales Plastic material and method of preparing same
US2821155A (en) * 1953-12-11 1958-01-28 Richard A Fisch Process of applying protective coatings
US2859936A (en) * 1954-03-03 1958-11-11 Cincinnati Testing & Res Lab Compressor blade and method of forming same
US2836529A (en) * 1954-05-03 1958-05-27 Hugh Adam Kirk Reinforced plastic

Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3813098A (en) * 1970-06-22 1974-05-28 H Fischer Prestressed elements
US3948010A (en) * 1971-12-17 1976-04-06 Sonneville Roger P Reinforcing device for an element of prestressed concrete
US3938288A (en) * 1973-03-06 1976-02-17 Regie Nationale Des Usines Renault Reinforcing device for automobile body
US4003450A (en) * 1974-04-25 1977-01-18 Kenngott Gmbh & Co. Kg Small structural building component
US4151244A (en) * 1975-03-11 1979-04-24 Small Edward B Method of manufacturing pre-cast concrete panels
US4615163A (en) * 1984-10-04 1986-10-07 Curtis Albert B Reinforced lumber
US4852690A (en) * 1988-12-05 1989-08-01 Simon Ladder Towers, Inc. Aerial ladder tower with pretensioned truss members
US4905793A (en) * 1989-09-26 1990-03-06 Paulson Dennis R Ladder bracket
US5768847A (en) * 1995-05-15 1998-06-23 Policelli; Frederick J. Concrete reinforcing devices, concrete reinforced structures, and method of and apparatus for producing such devices and structures
US5846364A (en) * 1995-05-15 1998-12-08 Policelli; Frederick J. Reinforced concrete structure, reinforcing device, and method for producing same
US8418811B2 (en) * 2006-02-21 2013-04-16 Werner Co. Fiberglass reinforced plastic products having increased weatherability, system and method
US20090065302A1 (en) * 2006-02-21 2009-03-12 Werner Co. Fiberglass reinforced plastic products having increased weatherability, system and method
US20070204948A1 (en) * 2006-02-21 2007-09-06 Werner Co. Fiberglass reinforced plastic products having increased weatherability, system and method
US9266289B2 (en) * 2006-02-21 2016-02-23 Werner Co. Fiberglass reinforced plastic products having increased weatherability, system and method
US20140150359A1 (en) * 2011-07-18 2014-06-05 Rolf J. Werner Tower-shaped supporting structure
US9168701B2 (en) * 2012-10-16 2015-10-27 Abss Manufacturing Co., Inc. Fiberglass reinforced plastic lightweight heavy-duty ladder and method of making same
US20160040479A1 (en) * 2012-10-16 2016-02-11 Abss Manufacturing Co., Inc. Fiberglass Reinforced Plastic Lightweight Heavy-Duty Ladder and Method of Making Same
US20140102830A1 (en) * 2012-10-16 2014-04-17 Nasir U. Ahmed Fiberglass Reinforced Plastic Lightweight Heavy-Duty Ladder and Method of Making Same
US20170217108A1 (en) * 2016-01-28 2017-08-03 Donald E. Wheatley Method of making a fiber reinforced hoop and anchors for a concrete reinforcement structure
US10786951B2 (en) * 2016-01-28 2020-09-29 Donald E. Wheatley Method of making a fiber reinforced hoop and anchors for a concrete reinforcement structure
CN111187022A (zh) * 2018-11-14 2020-05-22 王子国 一种腐蚀致型形状记忆纤维及其制备方法和应用
CN111187022B (zh) * 2018-11-14 2023-07-14 王子国 一种腐蚀致型形状记忆纤维及其制备方法和应用
US20220170267A1 (en) * 2019-04-04 2022-06-02 Deutsche Institute Für Textil-Und Faserforschung Denkendorf Prestressed concrete body, method for the production thereof, and use of same
US12241250B2 (en) * 2019-04-04 2025-03-04 Deutsche Institute Für Textil-Und Faserforschung Denkendorf Prestressed concrete body, method for the production thereof, and use of same

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FR2058123A5 (fr) 1971-05-21
DE2040085A1 (de) 1971-03-18
BE754794A (fr) 1971-02-15

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