CA2126980A1

CA2126980A1 - Fibrous composite rope and method of manufacturing the same

Info

Publication number: CA2126980A1
Application number: CA 2126980
Authority: CA
Inventors: Toshiroh Kido; Yoshifumi Nishimura; Kenichi Yamashita; Susumu Yamamoto; Ikuo Tanaka
Original assignee: Individual
Current assignee: Sumitomo Electric Industries Ltd
Priority date: 1992-12-28
Filing date: 1993-12-27
Publication date: 1994-07-07
Also published as: NO943156L; EP0633348A1; EP0633348A4; NO943156D0; WO1994015015A1

Abstract

Abstract The present invention provides a fibrous composite rope suitably used as a prestressing member for PC structures. The present invention features in one aspect such a fibrous composite rope. excellent in mechanical strength, fabiricated by heating the thermosetting resin-impregnated fiber cores so as to semicure the resin, then wrapping a primary wrapping and a secondary fiber bundles around the periphery of each said fiber core, stranding a plurality of the resultant fiber cores together into a rope form, and subsequently heating the stranded rope to complete the curing. In another aspect, the present invention provides a fibrous composite rope, in which either the primary or secondary wrapping fiber bundle is wound with wrapping clearance so as to form a rugged peripheral surface to improve adhesion to an anchoring means, as is required for a prestressing member.

Description

r~ 2 1 2 6 ~ 8 O

Patent Specification Fibrous Composite RoPe and Method of M~nufacturing the Same ` .

Technical Field The Present invention relates to a fibrous composite roPe for use in prestressing members of PC (prestressed concrete) structures in the civil engineering and construction industry or strengthening or reinforcing members -for power or communication cables, etc., and more particularly to such a fibrous roPe which is obtained bY stranding a PluralitY of fibrous cores or strands impregnated with a thermosetting resin. The "rope" herein referred to is a generic term including in its meaning all ropes, cords and the like stranded materials.
Background Arts ~ ~-Heretofore, an overwhelmingly maior part of Prestressing members for PC
structures has been shared bY steel in the civil engineering and construction industrY.' ~ '' !; `'~.
Many improvements have been proposed in such steel-based structural prestressing members, among which Japanese Patent Publication No. Hei 3-28,551 typically discloses one of the most advanced one. NamelY, it discloses a prestressing member featuring a high corrosion resistance, good anchorage and ~ ~`
workability due to its synthetic resin coating.
Honever, since such a Prestressing member comprises stranded steel wires .. ..
as its base material, it is heavY in weight and cannot be free from problems caused by magnetism, and if its resin coating is damaged the stranded wires will corrode, resulting in the loss of required mechanical proPerties.
Meanwhile, there are known various cords and ropes fabricated of fibers or fibrous YarnS. Among those, the fibrous composite ropes disclosed in Japanese Patent Publication No. Sho 62-18,679 is known as having a high tensile strength. The disclosed fibrous composite rope is obtained by imPregnating a fiber core with a thermosetting resin, covering the outer PeripherY of the 2~ 2~9~
- `~

impregnated core with a fiber braid after applying drYing powder onto the periphery, and subsequentlY heating the covered core to cure the $hermosetting resin.
In the technique disclosed in Japanese Patent Publication cited immediately above, in which drying powder is used to prevent the thermosetting resin impregnated into the fiber core from leaking therefrom, the drYing Powder must be applied uniformly in a well controlled quantity, thus renderir,g the process or production control difficult. If such leakage of the thermosetting resin cannot be prevented, the leaked thermosetting resin will cause such fiber cores to be adhesivelY bonded to each other when theY are brought together in a later stranding or twisting process, consequentlY to suPpress their relative movements, resulting in reduced mechanical strength and flexibility of the resultant rope. Further, the existence of the drying powder will not have a desirable effect on integral adhesion of the thermosetting resin of the fiber core to the fibrous yarns of the braid covering the core. Besides, the thermosetting resin of the fiber core will substantially lose its plasticity when cured, rendering the twisting difficult. and so that a roPe stranded of such rigidified cores would have its cores loosened when cut for use.

D i sc I osure of the I nvent i on With a view to solving the aforementioned problems of the prior art, the inventors aimed at forming a prestressing material by usin~ fiber-based materials having a high tensile strength and low elongation such as carbon fiber, glass fiber and aramid fiber, instead of using. as base material, stranded steel wires which is not only heavY in weight but poor in corrosion resistance.
The inventors have undertook a series of experiments and research works to successfullY obtain a fibrous comPOsite roPe having sufficient mechanical proPerties and satisfiable anchorage to mortar. resins or other anchoring bodies to which the roPe is embeddedlY anchored.
Namely, according to one aspect of the present invention, there is --` 212~)9~0 :
provided a fibrous composite rope comprising a pluralitY of fiber cores stranded together, each of said cores being impre~nated with a thermosetting resin and having a fiber bundle wrapped around the ~eripherY thereof in one winding direction without clearance between the sides of adjacent turns of the bundle, namely, without wrapping clearance.
Preferably, the present fibrous comPOSite rope may be fabiricated bY
first heating the thermosetting resin-imPregnated fiber cores so as to semicure the resin, then wrapping said fiber bundle around the periphery of each said fiber core in one winding direction without wrapping clearance, stranding a plurality of the resultant fiber cores together into a rope form, and subsequentlY heating the stranded rope to finalize the curing.
For preventin~ leakage of the thermosetting resin from the fiber core without semicuring the resin but merelY by wrapping the fiber bundle around its periPherY in such a manner that no clearance remains between the sides of adjacent turns of the bundle, it would be necessarY to strictly control the manufacturing conditions by for examPle thickening the fiber bundle and controlling its winding force within an appropriate range during the wrapping process. Too thick fiber bundle will increase the diameter of the resultant rope, resulting in reduced tensile strength Per cross-sectional area.
According to another aspect of the present invention, there is provided a fibrous composite rope comprising a PluralitY of fiber cores stranded together, each of said cores being imPregnated with a thermosetting resin and having as a primary wrapping member said fiber bundle wrapped around the Periphery thereof in one winding direction without wrapPing clearance and further having as a secondarY WraPPing member a fiber bundle wrapPed around the periphery of said primary wrapping member in the oppsite winding direction thereto without wrapping clearance.
Preferebly, the fibrous comPosite rope according to the second aspect of the present invention maY be fabiricated bY first heating the thermosetting resin-impregnated fiber cores so as to semicure the resin, then wrapping said 2 ~ 0 fiber bundle of said PrimarY wrapping member around the peripherY of each saidfiber core in one winding direction without clearflnce between the sides of adjacent turns of the bundle, further wrapPing said fiber bundle of said secondary wrapping member around the periPherY of said PrimarY wrappin8 member in the opposite winding direction thereto without wrapping clearance, stranding a PluralitY of the resultant fiber cores together into a roPe form. and subsequently heating the stranded rope to finalize the curing.
Either of the aforementioned methods may be modified to ioprove integral adheshion of the fiber core to the fiber bundle wrapping the same, for example, by applying a thermosetting resin to the wrapping fiber bundle internally thereof, or by controlling the semicured state of the thermosetting resin-impregnated fiber core so as to cause the resin to Penetrate into the the wrapping fiber bundle.
Instead of applying drying Powder onto the periPheral surface of fiber core for preventing the thermosetting resin impregnated into the core as in the prior art, the method of the present invention first semicure the thermosetting resin and then wrap the fiber bundle around the core in one winding direction without clearance between the sides of adiacent turns of the fiber bundle.
Since it is impossible to prevent the thermosetting resin from leaking in its liquid state and since application of the drying powder is not preferable for the aforementioned reason. the thermosetting resin is first semicured to obtain a highly viscous state which facilitates working. In addition, wraPPing the fiber bundle around the fiber core ensures the prevention of resin leakage.
Further, according to the present invention, wrapping the secondarY
fiber bundle around the foregoing wrapping fiber bundle in the opPosite winding direction thereto produces a bidirectionally wrapped fiber core, which allows fabrication of a fibrous composite rope from torsion-free fiber cores. That is to say, wraPping the fiber bundle around the fiber core only in one direction will rather tends to give rotation to the core, leaving a torsion therein. Such a torsion would act to impede even and uniform elongation of constituent fibers ` 2~3~ :

and consequentlY deteriorate mechanical Properties of the resultant roPe.However, according to the second aspect of the present invention. the secondarY
wrapping fiber bundle is wrapped around the PrimarY fiber bundle in the opposite winding direction thereto without clearance bet~een the sides of adiacent turns of the fiber bundle, therebY to give counterrotation to the core so as to offset the torsion.
In any of the foregoing two aspects of the invention, the present fibrous comPosite roPe is fabricated bY stranding together a plurality of fibrous cores impregnated with a thermosetting resin around which is wrapped a fiber bundle without wrapping clearance, so that spiral peripheral grooves of the roPe formed between adiacent cores thereof would not be slackened . Thus, when used as a prestressing member, the Present roPe will exhibit strong adhesion to anchoring bodies.
If a wedge and a wedge support are used for anchoring a rope end, a fibrous composite rope exhibiting Poor adhesion tends to slide on the wedge surface and, in some cases, maY slip off the wedge. Even if such a roPe exhibiting poor adhesion is anchored by inserting its end in a pipe, Pouring a mortar or resin into the pipe to fill the surrounding space of the rope end and curing the mortar or resin, the end tends to slide against such a mortar or resin to occasionallY slip off the anchoring Pipe. Thus, it is difficult to anchor such a rope with a practicably short anchoring length. Meanwhile, regarding the individual fiber cores constituting the roPe which are poor in adhesion, relative slippage may occur between their Primary and secondary wrapping members or between the wrapping members and the base core, occasionallY
resulting in complete slipping off.
Further, according to still another aspect of the present invention, for far improving the adhesion of roPe to anchoring bodies, either of the primary or secondary wraPPing member maY be wound so as to follow a screw thread-like pattern, namelY, with a wrapping clearance between adiacent turns of the wrapping member or fiber bundle for obtaining rugged surfaces.

2 1 ~

In this manner. wrapping either of the PrimarY or secondarY fiber bundle with adiacent turns of the bundle spaced apart from each other brings about a rugged peripheral surface, increasing the pullout resistance at anchoring means to the extent that the rope end can be securely prevented from slipping off when the rope is used as ~ prestressing member for PC structures.
For the aspect of the present invention described last hereinabove, which of the primary and secondarY wrapping members or fiber bundles may be wound with adjacent turns of the fiber bundle spaced apart from each other. For example, the primarY wrapping member (inside) may be wound without wraPPing clearance, followed by the secondary wrappin~ member (outside) which is wound ujth adjacent turns thereof sPaced apart from each other, and vice versa. In either case, the resultant fiber core can have a rugged PeriPheral surface.
Further according to the lastly aspect of the invention. since one of the primary or secondary fiber bundles is wrapped without clearance between the sides of adiacent turns of thereof in the opposite winding direction to that of the other bundle, leakage of the thermosetting resin as well as torsion can be effectively prevented in the resultant fiber core. Any such residual torsion existing in the fiber core would impede even and uniform longitudinal elongation of the constituent fibers and lead to deteriorated mechanical proPerties of the resultant rope. The present invention can successfully solve these problems.
Brief DescriPtion of the Dra~ings FIG. I is a schematic diagram showing a manufacturing process used in a Preferred example of the Present invention, with FIG. I(A) showing the former half of the Process and FIG. I(B) the latter half;
FIG. 2 is a perspective view showing a state in which a fiber bundle is RraPPed around the peripherY of a fiber core in one winding direction without clearance between the sides of adjacent turns of the bundle according to the Prefeferred example of the Present invention;
FIG. 3 is a schematic drawing showing a manufacturing Process used in a second and third examples of the present invention, with FIG. 2(A) showing the I

212~
, ~ .

former half of the process and FIG. 2(B) the latter half;
FIG. 4(A) is a perspective view showing a state in which a primary and a secondary fiber bundles are wrapped around the Periphery of a fiber core in two opposite winding directions, respectivelY, without clearance between the sides of adjacent turns of the respective bundles according to the second preferred example of the present invention, while FIG. 4(B) is a like PersPeCtiVe view showing a state in which the PrimarY fiber bundle is wrapped around the periphery of the fiber core in one winding direction without wrapping clearance, followed by wrapping the secondary fiber bundle in the opposite direction with adjacent sides theleof spaced apart from each other, according to the third preferred example of the present invention.
FIG. 5 is a drawing showing partially in section a tensile tester used for tesiting the fibrous composite rope according to the present invention to mesure pullout resistance (adhesion) to an anchoring body.
Best Mode CarrYing out the Invention ExamPle I
When using the fibrous composite rope of the Present invention as a prestres sing member for PC structures, the third example to be described herein later is most preferable for securing sufficient adhesion with a shorter anchoring length. However, the description will be made in the order of the first, second and third examples, because such order would be appropriate for exactly understanding the present invention.
~ ith reference to FIG. 1, especially to FIG. I(A), showing a manufacturing process according to the first preferred examPle, initiallY a PluralitY of aramid resin fibers or Yarns of such fibers having a high tensile strength and low elongation are unwound from the respective feed reels I and bundled into a fiber core A. The fiber core A is then fed into a thermosetting resin bath 2 to be impregnated with a thermosetting resin (e.g., unsaturated polYester or epoxy resin). The impregnated fiber core is then passed through a die (or forming mold) 3 to be reduced to a Predetermined outside diameter and to ' 2126~8~

remove excess resin, and is subsequentlY fed into a heater 4. In the heater,the fiber core is heated at about 90C for about 30 seconds to cure the thermosetting resin, and then fed into a wrapping machine 5, where a fiber bundle or bunndled yarn 10 (FIG. 2) is wrapped around the periPheral surface of the fiber core A in one windin~ direction ~ithout clearance between the sides of adjacent turns of the bundle. A thermosetting resin. which may be the same or different from the aforesaid thermosetting resin, may be apPlied onto the fiber bundle 10 on its side coming inside when wraPPed, for furthering integral adhesion to the core A. In FIG. 2, is shown the fiber core A wraPped with the fiber bundle 10 without clearance between the sides of its aiacent turns, namely, without ~raPping clearance. The resultant fiber core is wound up on a take-up reel 6.
Thereafter, as shown in FIG. I(B), a plurality of such wrapped fiber cores A are un~ound from the respective reel 6 to be fed into a stranding machine 7, where theY are stranded together. The resultant stranded roPe A is then heated in a heater 8 to finalaize or comPlete the curing of the semicured thermosetting resin, and is subsequently wound uP on a take-up reel 9.
Thus, by wrapping the fiber core with the fiber bundle without clearance between its adjacent turns while the thermoseting resin being still in its seeicured state, it is Possible according to the present invention to surely prevent leakage of the thermosetting resin without using a drying Powder as in the prior art and to Prevent adiacent fiber cores from directlY bonding to each other during the stranding Process also as in the prior art. Further, protuberances on the rope surface or like unseemlY external appearance caused b leaked resin can be eliminated according to the Present invention.
ExamPle 2 Now ~3ith reference to FIG. 3, esPeciallY to FIG. 3(A), showing a manufacturing process according to the first Preferred example, initiallY a plurality of aramid resin fibers or yarns of such fibers having a high.tensile strength and low elongation are unNound from the resPective feed reels 1 and - 8 ~ ~ :~
, ,. :, 2 ~

bundled into a fiber core A. The fiber core A is then fed into a thermosetting resin bath 2 to be impregnated with a thermosetting resin (e.g., unsaturated polyester or epoxy resin). The impregnated fiber core is then passed through a die (or forming mold) 3 to be reduced to 8 Predetermined outside diameter and to re~ove excess resin, and is subsequentlY fed into a heater 4. In the heater, the fiber core is heated at about 90~C for about 30 seconds to cure the thermo setting resin, and then fed into a urapping machine 5A, where a fiber bundle or bundled yarn 10 is wraPPed AS a PrimarY ~rapPing member around the peripheral surface of the fiber core A in one winding direction uithout clearance between the sides of adjacent turns of the bundle. Then, the fiber core A is fed into another wrapping machine 5B, where another fiber bundle 10, as a secondary wrapping member, is wrapped around the fiber core A also without wrapping clearance but in the winding direction opposite to that of the primary wrappin~
member. A thermosetting resin, which may be the same or different froo the aforesaid thermosetting resin, maY be aPPlied onto the fiber bundle 10 on its side coming inside when wrapped, for furthering integral adhesion to the core A.ln FIG. 4(A), is shown the fiber core A urapped with the primarY and secondarY
fiber bundles 10 without clearance between the sides of its aiacent turns. The resultant fiber core is wound up on a take-up reel 6.
Thereafter, as shown in FIG. 3(B~. a plurality of such wrapped fiber cores A are unwound from the respective reel 6 to be fed into a strandin machine 7, where they are stranded together. The resultant stranded rope A is then heated in a heater 8 to finalaize or comlete the curing of the semicured thermosetting resin, and is subsequently wound up on a take-up reel 9.
Thus, bY wraPPing the fiber core uith the fiber bundle without wraPPing clearance while the thermoseting resin being still in its semicured state, it is possible according to the present invention to surely prevent leakage of the thersosetting resin to Prevent adjacent iiber cores from directly bonding to each other during the stranding Process as in the prior art. Further, in this preferred examPle, the bidirectional wrapPing effectively eliminates torsion of _ g _ 2~2~

the fiber core.
As a material for the fiber core of the Present invention, carbon fiber, glass fiber or the like may be used in addition to the aforementioned aramid resin fiber. Also, the wrapping fiber bundle used for the present invention may be made of an aramid resin fiber, vinylon fiber or polYester fiber. For a prestressing member for PC structures. it is preferable to use an aramide fiber to improve alkali resistance of the resultant rope.
ExamPle 3 In the similar manner, the Process of the aforementioned Example 2 shown in FIG . 3 is repeated. except that a secondary wrapping fiber bundle is wound by the wrapping machine 5B with its adjacent turns spaced apart from each other on a primarY wrapping fiber bundle wound by the wrapping machine 5A without clearance between the sides of adjacent turns of the bundle in the windin direction opposite to that of the secondary wrapping member. In this example, the resultant core has a rugged peripheral surface.
In FIG. 4(B), is shown the resultant fiber core of Example 3 comprising the primary wrapPing fiber bundle IOA wound inside without wrapping clearance and the secondary wrapping fiber bundle IOB wound around the periphery of the PrimarY fiber bundle in the oPposite direction thereto with its adjacent turns spaced aPart from each other. Either one of the wrapping fiber bundles which is wound with wrapping clearance (fiber bundle IOB in the instant example) may vary from the other bundle which is wound without clearance (bundle IOA in the instant example) in at least one of a grouP of items including the number of fibers or yarns, shaPe, Pitch, or wrapping tension of the bundle.
Like the aforementioned Exaples I and 2, a thermosetting resin, which maY be the same or different from the aforesaid thermosetting resin, maY be applied onto these fiber bundles IOA and/or IOB on their sides coming inside when wrapped, for furtherin8 integral adhesion to the core A.
Further, the mode of winding the primarY and secondary wrapping members may be reversed from Example 3, namerY, the Primary member disPosed inside may 2~ ~6~
. .
be wound with wrapping clearance, followed by winding the secondarY member without ~rapping clearance. In addition, a third fiber bundle may be ~raPPed around the PeriPherY of such a fiber core that is bidirectionallY wrapped with fiber bundles as in Example 2. In such a case, the resultant fiber core would have an increased diameter.
In the same manner as in the aforementioned Examples I and 2, a plurality of resultant fiber cores having a rugged PeriPheral surface are then stranded together and heated to be formed into a fibrous composite material havin~ a rugged outer peripheral surface and exhibiting good adhesior. to anchoring means, as intended bY the present invention. Differential height between the top and bottom of the rugged PeriPheral suraface of the wrapped fiber core, as viewed in its cross section, is apploximatelY 0.5 mm in Example 3, although it may preferably ranges from approximately 0.3 to 0.8 mm.
Tensile Test By using the processes of the aforementioned Examples I and 2, 7 wrapped fiber cores, each 4.2 mm across, were stranded together to fabricate samples of fibrous composite roPes of the respective preferred examples. The base fiber core was PrePared bY bundling 18 aramid resin fibers of 6,000 deniers, and the core was impregnated with a thermosetting resin, the Proportion of fiber to thermosetting resin being 65 ~ by volume of fiber. As the thermosetting resin, a vinyl ester resin was used, and an arami resin fiber as the wrapping fiber.
Each sPecimen of the fibrous composite ropes has its oPPosite ends secured to a tensile tester and its tensile load was measured. The tensile -tester used is shown in FIG. 5. As shown in the drawing, the tester had a pair of cylindrical anchoring iigs or fixtures, in which the oPPosite ends of the specimen 13 was inserted and mortar 11 was filled to fix the respective ends.
Then, the tester exerted a tension on the sPecimen bY Pulling the same in the ~
opposite directions, and the maximum tensile load was measured for evaluation. ;``
In FIG. 5, the reference numeral 14 denotes a crosshead, 15 a Plate, and 16 a rubber plug, respectively. ~ ~
- 1 1 - " `

2~ 26~0 As described hereinabove, the specimen of Example 1 was prepared by using fiber cores each wrapped with onlY a primarY fiber bundle wound in one direction therearound without winding clearance, and the sPecimen of ExamPle 2 ~as prepared bY using fiber cores which are obtained by further wrapping a secondary fiber bundle around the resultant fiber core of Example 1 in the opposite winding direction without wrapping clearance. For comparison, another specimen was prepared, as a comparative example. bY wrapping only a primary fiber bundle in one winding direction without wrapping clearance around a thermosetting resin-imPregnated base fiber core without semicuring the resin, and stranding together a pluralitY of such wrapped fiber cores with the resin leaked out to the surfaces.
Each specimen was set on the tester under the following conditions and tested for tensile load.
Anchoring iig size: 30 mm l.D., SOO mm long Jig filler: mortar cured for 5 daYs The test results are given below. The specimens of the preferred examples all showed a significantily higher tensile load than the comparative example. This evidently shows good applicabilitY of the preferred examples of the Present invention to a prestressing member for PC structures and to reinforcing members for power and communication cables.
Specimens Tensile load (kN) Example 1 165 Example 2 175 Comparative examPle 100 This improvement achieved in the preferred examPles of the present invention would be attributable to positive prevention of the resin leakage by wrappin~ the peripherY of the thermosetting resin-imPregnated fiber core with the fiber bundle in the semicured state of the resin and to prevention of slackening of the periPheral spiral grooves of the rope by completing the curing of the semicured resin after stranding. EspeciallY, in Example 2 emPloYing ' r~

2 ~ 0.

bidirectional wrapping, torsion of the fiber cores is prevented to effectively further the improvement.
Adhesion Test Except the anchorin~ 12 had a shorter length, the same equipment as that in the aforementioned tensile test was used to measure a tensile load, as a allo~able tensile load, at which the specimen had its end slipped off the anchoring jig. In this test. were used a sPecimen of Example 3-1, as one Preferred example, prepare by using fiber cores IYrapPed with a PrimarY fiber bundle without wrapping clearance and a secondary fiber bundle with wraPPin clearance, and a specimen of Example 3-2, as another preferred example, prepared in a manner reverse to Example 3-1, namely, bY using fiber cores wrapped with a PrimarY fiber bundle with wrapping clearance, followed by a secondary fiber bundle wrapped without clearance~ Besides, a comparative example was prePared in the same manner as in the preceding tensile test, namely, wrapping only a primary fiber bundle in one winding direction without wrapping clearance around a thermosetting resin-impregnated base fiber core without semicuring the resin, and stranding together a pluralitY of such wrapped fiber cores~
The anchorin~ s were set as follows:
Jig size: 30 mm l.D., 200 mm long Jig filler: mortar cured for 5 daYs The test results are as shown below, where the allowable tensile load is given in terms of index based on the allowable tensile load of the comparative example taken as the reference index 100. The preferred examples, particularly, Example 3-1 adoPting the secondary fiber bundle wound with wrapping clearance exhibits excellent adhesion.
SPecimens Allowable tensile load ~1 Example 3-1 180 Example 3-2 140 Comparative examPle 100 Industrial APPI icabi I ity : ~ .

2126~Q

As fullY described hereinbefore, lhe Present invention provides a fibrous composite roPe having superior mechanical Properties, fabricated bY &
novel method in which leakage of the thermopsetting resin imPregnated in the fiber core can be Prevented without fail, so that adjacent cores are prevented from being directlY bonded to each other in the subsequent stranding stage.
Particularly, in the present invention, the drying Powder used in the Prior art for preventing leakage of the thermosetting resin impregnated in the fiber core can be eliminated together v,ith the process steP for its application to the fiber core.
Furthermore, bidirectional w.apping of the fiber bundles can PreVent torsion of wrapPed fiber cores, resulting in a fibrous composite rope having more excellent mechanical properties. Besides, if either the primarY or secondary wrapping member is wound with wrapping clearance in the bidirectional wrapping configuration, high adhesion can be assured to anchoring means.
Heretofore, an overwhelmin81y major part of Prestressing members for PC
structures has been shared bY steel. Meanv,hile, the fibrous composite roPe according to the Present invention has a high tensile strength comparable with PC steel members in addition to such features as high corrosion resistance, nonmagnetizability and light weight which are not provided by PC steel members.
Thus, the Present invention has expectedly an increasinglY wide applications, including :grine structures, PC structures for linegr :otors. etc.

';
~' .~

.~

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A fibrous composite rope comprising a plurality of fiber cores stranded together, each of said cores being impregnated with a thermosetting resin and having a fiber bundle wrapped around the periphery thereof in one winding direction without wrapping clearance.

2. A method of manufacturing a fibrous composite rope, comprising the steps of first heating the thermosetting resin-impregnated fiber cores so as to semicure the resin, then wrapping a fiber bundle around the periphery of each said fiber core in one winding direction without wrapping clearance, stranding a plurality of the resultant fiber cores together into a rope form, and subsequently heating the stranded rope to finalize the curing.

3. A fibrous composite rope comprising a plurality of fiber cores stranded together, each of said cores being impregnated with a thermosetting resin and having as a primary wrapping member a fiber bundle wrapped around the periphery thereof in one winding direction without wrapping clearance and having as a secondary wrapping member another fiber bundle wrapped around the periphery of said primary wrapping member in the oppsite winding direction thereto without wrapping clearance.

4. A method of manufacturing a fibrous composite material, comprising first heating the thermosetting resin-impregnated fiber cores so as to semicure the resin, then wrapping a fiber bundle as a primary wrapping member around the periphery of each said fiber core in one winding direction without wrapping clearance, further wrapping another fiber bundle as a secondary wrapping member around the periphery of said primary wrapping member in the opposite winding direction thereto without wrapping clearance, stranding a plurality of the resultant fiber cores together into a rope form, and subsequently heating the stranded rope to finalize the curing.

5. A fibrous composite rope comprising a plurality of fiber cores stranded together, each of said fiber cores being impregnated with a thermosetting resin and having as a primary wrapping member a fiber bundle wrapped around the periphery thereof in one winding direction without wrapping clearance find having as a secondary wrapping member another fiber bundle wrapped around the periphery of said primary wrapping member in the oppsite winding direction thereto with wrapping clearance so as to form a rugged peripheral surface.

6. A method of manufacturing a fibrous composite material, comprising first heating the thermosetting resin-impregnated fiber cores so as to semicure the resin, then wrapping a fiber bundle as a primary wrapping member around the periphery of each said fiber core in one winding direction without wrapping clearance, further wrapping another fiber bundle as a secondary wrapping member around the periphery of said primary wrapping member in the opposite winding direction thereto with wrapping clearance so as to form a rugged peripheal surface, stranding a Plurality of the resultant fiber cores together into a rope form, and subsequently heating the stranded rope to finalize the curing.

7. A fibrous composite rope comprising a plurality of fiber cores stranded together, each of said fiber cores being impregnated with a thermosetting resin and having as a primary wrapping member a fiber bundle wrapped around the periphery thereof in one winding direction with wrapping clearance to consequently form a rugged peripheral surface and having as a secondary wrapping member another fiber bundle wrapped around the periphery of said primary wrapping member in the oppsite winding direction thereto without wrapping clearance.

8. A method of manufacturing a fibrous composite material, comprising first heating the thermosetting resin-impregnated fiber cores so as to semicure the resin, then wrapping a fiber bundle as a primary wrapping member around the periphery of each said fiber core in one winding direction with wrapping clearance to consequently form a rugged peripheral surface, further wrapping another fiber bundle as a secondary wrapping member around the periphery of said primary wrapping member in the opposite winding direction thereto without wrapping clearance, stranding a plurality of the resultant fiber cores together into a rope form, and subsequently heating the stranded rope to finalize the curing.

9. A prestressing member for PC structures, comprising a fibrous compositerope as set forth in any one of the preceding claims 1, 3, 5 or 7.