JP4843383B2 - Composite PC steel and composite PC steel stranded wire - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a composite PC steel material and a composite PC steel stranded wire that are used as components of a prestressed concrete structure and the like, and have improved consumption (absorption) ability to frame energy due to external forces such as earthquakes and strong winds acting on the structure. .

When prestressed concrete structures, especially precast and prestressed concrete columns and beam joints, are subjected to frame energy due to external forces such as earthquakes and strong winds, tensile is used as a means to increase the energy consumption (absorption) of the frame energy Steel and mixed cables are known . Tensile steel this is that tensile steel material of tensile steel material and the low strength of high strength in the longitudinal direction is configured to co-exist.

Mixed-cable, bonding the end faces of PCa beam on the left and right sides of the column via the column to the other fixing up position is inserted into the sheath tube disposed tensioning and fixing of the beam from the fixing position of one of the beams Used for junction structure. Then, this mixed cable is inserted into the sheath tube arranged in the beam at the fixing position, the PC steel stranded wire and the reinforcing bar as the tension material are inserted, the PC steel stranded wire is tensioned, and the column and the beam are crimped. PC steel stranded wire is fixed to the fixing tool with a wedge, and grout material is injected into the sheath tube without applying tension to the reinforcing bar, and the PC steel stranded wire and the reinforcing bar are integrated with the column and beam. It is configured to resist the bending stress generated by the tensile force of the PC steel stranded wire and the reinforcing bar.

The above-mentioned tensile steel materials and mixed cables are used by being embedded in the bending members of columns and beams. In that case, it is necessary to fill around the cable with grout (cement milk), and accordingly, when tensile steel materials are embedded in concrete bending members There is a problem that can only be applied to. Recently, however, bridges and various structures have been increasingly used for structures that bear earthquake force with out-cables that can be easily expanded and reinforced, and brace structures. Cables used in such structures Are often not filled with grout, and often cannot be accommodated by the above prior art tensile steel or mixed cables.

  In such a situation, on the condition that the cable surroundings are not filled with grout, for example, when a tensile steel material made of only low-strength steel is used as an out-cable brace for bridges and various structures, it is likely that earthquakes, winds, etc. Out-cable braces yield due to tensile force due to disturbance, and tensile steel does not resist compressive force. Therefore, energy is consumed (absorbed) when the initial tensile force is applied, but not consumed (absorbed) thereafter. . Another problem is that the residual deformation is large.

  On the other hand, when a tensile steel material made only of high strength steel is used as an out cable brace for a bridge or various structures, the out cable brace remains within the elastic range, so there is no energy consumption (absorption) due to disturbance. For this reason, even if the cable surroundings are not filled with grout in the field, the energy consumed by the frame due to disturbances such as earthquakes and strong winds, that is, the energy acting on the joints of the bridges and various structures, etc. is absorbed. Development of a tensile steel material that can prevent the collapse of objects and the like is desired.

  As shown in FIG. 6 (a), the behavior of the different strength steel mixed stranded wire called the above mixed cable is the same as the outer periphery of the core wire of the high strength steel stranded wire 1 ′ using PC steel. When unloading a PC steel stranded wire, which is composed of multiple strands of a high strength steel stranded wire 1 'and a low strength steel stranded wire 2' such as a reinforcing bar, after applying a tensile load of repeated load, The high strength steel stranded wire 1 'is elastically stretched, the low strength steel stranded wire 2' is plastically stretched to the same length, and when unloaded, the high strength steel stranded wire 1 'is elastically shrunk, and the low strength steel stranded wire 2' is The ideal behavior is to shrink the same length by plastic shrinkage without buckling.

However, in the different-strength steel mixed stranded wire, the high-strength steel stranded wire 1 ′ and the low-strength steel stranded wire 2 ′ are not deformed in the same manner due to the difference in strength between the strands. In particular, as shown in FIG. 6B, there are many problems in the process of unloading after applying a tensile axial force. Since the strength difference is large, the low-strength steel stranded wire 2 ′ may yield, and may not follow the shrinkage of the high-strength steel stranded wire 1 ′, and only the low-strength steel stranded wire 2 ′ may be stretched. Because there is. Further, as shown in FIG. 6 (c), at the time of unloading, the low-strength steel stranded wire 2 ′ may enter the compression region and bulge in the outer circumferential direction, which may cause a buckling phenomenon. Therefore, unless measures are taken to prevent such a phenomenon from being applied to the different strength steel mixed stranded wire, a different strength steel mixed stranded wire capable of sufficient energy consumption (absorption) cannot be obtained.
In addition, even when cement milk is injected and the periphery of the mixed strand of different strength steel is hardened, the low strength steel strand 2 'of the mixed strand of different strength steel is connected to the outer periphery of the cable at the joint or cracked portion of the concrete. It is desirable to take the same measures as it may cause swelling in the direction and buckling.

  In consideration of the above-mentioned problems, the present invention provides a bridge or other structure as a tensile steel material that consumes (absorbs) or attenuates energy caused by disturbances such as earthquakes and strong winds without filling the cable with grout. It is an object of the present invention to provide a composite PC steel material and a composite PC steel stranded wire that can be used for an out cable and a brace material.

As a means for solving the above-mentioned problem, the present invention is a composite PC steel material in which the steel materials are expanded and contracted and the energy of the tensile load is attenuated with respect to repeated tensile loads by combining different strength steel materials having different elastic limits. Each steel material constituting the composite PC steel material is provided with an elastic deformation restraint material that restrains deformation in the axial direction and the radial direction or only in the radial direction between the steel materials, and the steel material having a low elastic limit against repeated tensile loads, The composite PC steel material is configured such that the two steel materials are constrained by a deformation constraining material so as to cause plastic elongation or plastic shrinkage equivalent to the expansion and contraction of the steel material having a high elastic limit.

As another means for solving the above-mentioned problem, steel strands of different strengths having different elastic limits are combined, and the core wire in the center of the sectional view is surrounded and arranged to twist other steel strands of different strengths on the outside. In a composite PC steel stranded wire in which the steel stranded wire expands and contracts with respect to repeated tensile loads and attenuates the energy of the tensile load, each steel stranded wire constituting the composite PC stranded wire has an axis between each steel stranded wire. the elastic deformation restraint member for restraining the deformation in the direction of the direction and the radial or radial only provided, repeatedly steel strand low elastic limit to tensile loading, stretching the same plastic steel strand of the high elastic limit It can be set as the structure of the composite PC steel strand wire which restrained between both steel strand wires by a deformation | transformation restraint material so that elongation or plastic shrinkage may be produced.

  The composite PC steel material and composite PC steel stranded wire of the present invention configured as described above, when used in a bridge or a joint of various structures, etc., are not subject to disturbances such as earthquakes and strong winds without having to be filled with grout around the cable. It is possible to absorb (consume) the energy consumed by the frame, that is, the energy acting on the joints of the bridge and various structures, and prevent collapse of the bridge and various structures. The composite PC steel material and the composite PC steel stranded wire preferably have a frame energy consumption capacity set to a predetermined level or more by a deformation restraining material. In this case, the composite PC steel material and the composite PC steel stranded wire frame energy consumption (absorption) It is desirable to set the equivalent viscous damping constant representing the performance to 5% or more.

The frame energy consumption (absorption) ability is evaluated using an equivalent viscous damping constant as an evaluation index. The equivalent viscous damping constant (h _eq ) is the most accurate value, including the dynamic evaluation of the damping state, of how much the vibration generated by disturbances such as earthquakes acts on the structure. This is a damping constant used for elastic analysis, replacing the equivalent viscous damping (damping proportional to speed) shown in

  In the above composite PC steel stranded wire, a composite PC steel stranded wire in which a deformation restraining material of granular material such as carborundum (trade name of silicon carbide) containing carbon is disposed on the outer peripheral surface of the core wire of the steel stranded wire. Is desirable. Further, in addition to the above-mentioned granular deformation restraining material, a composite PC in which a high elastic material such as a carbon fiber sheet containing carbon is used as a deformation restraining material and arranged on the outer periphery of a plurality of steel strands surrounding the core wire of the steel strand. It can also be a steel stranded wire. Moreover, it can also be set as the composite PC steel strand wire which has arrange | positioned the filler like a curable composition which has an epoxy resin as a main component so that the outer periphery of the cross section of steel strand wire may be enclosed as a deformation | transformation restraint material.

The composite PC steel material and composite PC steel stranded wire of the present invention are a combination of steel materials of different strengths and steel stranded wires having different elastic limits, and each steel material constituting the composite PC steel material and the composite PC stranded wire, and each steel material in the steel stranded wire. An elastic deformation restraining material that restrains deformation in the axial direction and the radial direction or only in the radial direction between the steel strands is provided, and the steel material and the steel strand wire with a low elastic limit are subjected to repeated tensile loads. Since both steel and steel strands are constrained by a deformation restraint so as to cause plastic elongation or plastic shrinkage equivalent to the expansion and contraction of steel and steel stranded wire, it is combined with repeated tensile loads by the deformation restraint. By setting the frame energy consumption capacity of PC steel and composite PC steel strands to a predetermined level or higher, it is possible to prevent plastic expansion and contraction due to radial expansion, axial displacement, etc. of low-strength steel wires. I can do it. Therefore, as an out cable and brace material for bridges and other structures, composite PC steel and composite PC as tensile steel that can consume more than a predetermined amount of energy due to disturbances such as earthquakes and strong winds without filling grout around the cable Steel strands can be obtained.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1A is a cross-sectional view of (a) the PC steel material of the first embodiment and the PC steel stranded wire of the second embodiment, (b) an external perspective view of the PC steel material of the first embodiment, and (c) the second embodiment. The external appearance perspective view of each PC steel strand wire is shown. As shown in the drawing, both the composite PC steel A ₁ of the first embodiment and the composite PC steel stranded wire A ₂ of the second embodiment have a common cross section as shown in FIG. The composite PC steel material A ₁ of the embodiment includes a plurality (four in the illustrated example) of high strength steel materials 1 and a plurality (three in the illustrated example) of low strength steel materials 2, and the outer periphery of the high strength steel material 1 at the center. The other high-strength steel material 1 and the low-strength steel material 2 are in contact with each other through the carborundum 3 which is a deformation restraining material, and the other steel materials 1 and 2 are also alternately contacted with each other through the carborundum 3, so that all the steel materials are They are arranged so as to be integrated.

Further, the carborundum 3 on the outer periphery of the high-strength steel material 1 at the center has a particle size of 200 to 300 μm and has a hardness exceeding the Vickers hardness of 500 attached to the steel material surface. And the sheet | seat 4 (thickness about 0.6 mm) of a highly elastic material is arrange | positioned as a further deformation | transformation restraint material so that the outer periphery of the said other steel materials 1 and 2 may be enclosed, They are united so that the whole is united. As the deformation restraining material, in addition to carbon fiber (235 kN / mm ² ), glass fiber (70 GN / mm ² ), aramid fiber, and the like that can be formed into a sheet shape are preferable in addition to those that can be easily coated such as epoxy resin. . In particular, one having an elastic limit equal to or greater than that of PC steel is more preferable (steel 210 kN / mm ² ).

The high-strength steel material 1 and the low-strength steel material 2 are thick steel rods having a predetermined diameter or more, and extend linearly and parallel to each other as shown. The strength level of the high-strength steel material 1 is 2200 N / mm ² , and the strength level of the low-strength steel material 2 is 600 N / mm ² . The carborundum is used to constrain the deformation between the central and outer strands, and the carbon fiber is used separately to restrain the outer strands from expanding in the normal direction. . Carborundum is not absolutely necessary for exhibiting performance, and can be made of carbon fiber alone.

Composite PC steel strand A ₂ of the second embodiment, the enlarged section of the same composite PC steel A ₁ of the first embodiment, as shown in (c) diagram of Figure 1A, the high-strength steel material 1 The high-strength steel stranded wire 1 ′ is replaced with the low-strength steel material 2 and the low-strength steel stranded wire 2 ′ is used instead, and the whole is configured as a composite PC steel stranded wire. The same as in the first embodiment. Also in the second embodiment, similarly to the first embodiment, the carborundum 3 particles, which are deformation restraining materials, and the carbon fiber sheet 4 are arranged.

The composite PC steel material A _{1 and the} composite PC steel stranded wire A ₂ of each embodiment configured as described above are provided with particles of the carborundum 3 that is the deformation restraining material, and a sheet 4 of carbon fiber. Even if the surrounding area is not filled with grout or the like at the construction site and a tensile force exceeding a predetermined value is repeatedly applied as a load, the swelling in the outer peripheral direction and the deviation in the axial direction can be completely restrained. Therefore, when used as a deformation restraining material for joints of structures where external forces such as earthquakes and strong winds act as repeated loads, it is a material that can consume (absorb) sufficient frame energy in the frame structure. Can be used.

The frame energy consumption ability is evaluated using an equivalent viscous damping constant as an evaluation index. The equivalent viscous damping constant (h _eq ) is the most accurate value of how much an earthquake caused by a disturbance such as an earthquake is attenuated from the beginning to the end, including the dynamic evaluation of the attenuation state. This is a damping constant used for elastic analysis, replacing the equivalent viscous damping (damping proportional to speed) shown in The types of attenuation include external viscous attenuation, internal viscous attenuation, solid friction attenuation, and hysteresis attenuation. Of these attenuations, attention is focused on hysteresis attenuation.

Hysteresis is a damping that occurs when a structure is subjected to repeated loads in the inelastic region. When a structure member is unloaded after a tensile load is applied, the relationship between the tensile load and elongation of the member is shown in the figure. A curve drawn when applying a tensile load in (not shown) and a curve drawn when unloading a tensile load follow different paths to form a loop-like curve. The energy of the area surrounded by this loop-shaped curve is the energy consumed in one cycle, and this consumed energy is defined as the hysteresis decay. The area of the curve in the hysteresis damping is replaced with an equivalent triangular area, and the equivalent viscous damping constant h _eq is obtained. Hysteresis attenuation can be evaluated at 2 h _eq ωm using the equivalent viscous damping constant. The larger the damping constant, the greater the damping of the structure. Thus, an equivalent viscous damping constant can be used as an index indicating whether or not there is an effect of damping the vibration of the structure.

FIG. 1B shows a cross-sectional view and an external perspective view of a composite PC steel stranded wire A ₃ as a third embodiment. In this embodiment, the steel stranded wire is composed of different strength mixed steel stranded wires of the high strength steel stranded wire 1 ′ and the low strength steel stranded wire 2 ′ shown in FIG. 1A (c), and each stranded wire 1 ′, 2 In order to constrain the bulge in the outer peripheral direction and the displacement in the axial direction, the epoxy resin-filled coating layer 5 is filled between the strands and the strands of the strands 1 'and 2' to cover the whole. , Was produced. The resin is not limited as long as it can be coated. For example, those disclosed in Japanese Patent No. 2998146 and Japanese Patent Application Laid-Open No. 2001-3517 can be used. In particular, polyethylene and epoxy that are easy to extrude are preferable, and among them, epoxy that can be powder-coated is more preferable.

  In this example, instead of the carborundum 3 particles and the carbon fiber sheet 4 which are deformation constraint materials in the first and second embodiments, an epoxy resin is provided as the deformation constraint material, so that a tensile force of a predetermined value or more is repeated. Even when applied as a load, swelling in the outer peripheral direction and displacement in the axial direction can be restricted within a predetermined range. Therefore, when used as a deformation restraining material for joints of structures where external forces such as earthquakes and strong winds act as repeated loads, it is a material that can consume (absorb) sufficient frame energy in the frame structure. Can be used.

A high strength steel stranded wire 1 having a strand diameter of 5 mmφ and a strength level of 2200 N / mm ² using a strand for PC steel as the steel strand of the composite PC steel stranded wires A ₂ and A ₃ of the second and third embodiments. , Specimens a and b of composite PC steel stranded wire using 4 pieces of 'and 3 pieces of low-strength steel stranded wire 2' having a strand diameter of 5 mmφ and a strength level of 600 N / mm ² were respectively used in Examples 1, 2 Moreover, although not shown in figure, the test body c of the composite PC steel stranded wire which consists only of different strength mixed steel stranded wire of the same high strength steel stranded wire 1 ′ and low strength steel stranded wire 2 ′ as above is referred to as Comparative Example 1. Below, the test result performed with respect to the test body a and b of the composite PC steel strand wire of the said Examples 1 and 2 and the test body c of the said comparative example 1 is described.

  In the test, the ends of only the composite PC steel stranded wire of the test specimen a, the composite PC steel stranded wire of the test specimen b, and the composite PC steel stranded wire of the test specimen c of Comparative Example 1 were respectively placed in a 500 kN vertical tensile testing machine. Set and fix using a wedge that is normally used. Before explaining the results of this test, first, a tensile test was performed on this specimen c using the composite PC steel stranded wire of the specimen c (shown as a mixed strength mixed strand in the figure) in FIG. Schematic diagram showing the relationship between the tensile axial force by the test and the elongation of each of the different strength mixed steel stranded wire, the high strength steel strand and the low strength steel strand, which are the strands, of the expected diagram when Indicates.

  In this test, as shown in the drawing, a high strength steel strand is always elastic, and a low strength steel strand is subjected to repeated tensile force in the range of elastoplasticity. Since the different-strength mixed stranded wire is always in a state of receiving a tensile axial force, a prestress is applied, and after applying the tensile axial force to the center (B) of the amplitude, the unloaded position (O) is set as the initial state. Then, a tensile axial force is repeatedly applied between the amplitude CE from the initial state. This was repeated and the displacement was controlled with reference to the value of the strain gauge attached to the stranded wire. In an actual test, repeated loading is performed with a small amplitude up to the maximum amplitude.

  FIG. 3 shows the results of the same tests performed on the composite PC steel stranded wire of the test specimen a, the composite PC steel stranded wire of the test specimen b, and Comparative Example 1 in the same procedure as the basic test. (A) The figure is the test body a, (b) The figure is the test body b, (c) The figure is the test result of the test body c of Comparative Example 1. In the test of the test body a, when an initial load is applied and then a repeated load is applied, the hysteresis curve draws a loop CDEF, and the area during which the loop during loading and unloading is surrounded by the curves of CD and EF is large. As a result, energy consumption (absorption) is performed in the meantime. Therefore, it has been clarified that energy consumption is large, and that sufficient energy consumption can be achieved by restraining the bulging and axial displacement of the low-strength steel strands with carbon fibers and carborundum.

  In the composite PC steel stranded wire of the test body b, the loop is slightly drawn only in the first cycle, but after the second cycle, there is a bulge in the outer circumferential direction of the low-strength steel stranded wire, The history loop curves CD and EF are repeatedly traced, and the consumed energy is smaller than the specimen a, but the minimum necessary energy consumption is performed. In Comparative Example 1, after the initial load is applied, when the tensile force is weakened, the low-strength steel stranded wire starts to bulge in the outer circumferential direction, and the history curve repeatedly follows the curve CD. The energy consumed during one cycle corresponds to the area surrounded by the history curve CDEF, but in Comparative Example 1, no history loop is drawn and no energy consumption is obtained.

From the above, it is understood that the composite PC steel stranded wire of the test body a has a large energy consumption capability, and this energy consumption capability is evaluated by an equivalent viscous damping constant (h _eq ). The larger the damping constant, the greater the damping of the vibration of the structure subject to disturbance. FIG. 4 shows the degree of attenuation of the composition of the composite PC steel stranded wire. The horizontal axis represents the number of cycles at the maximum amplitude, and the vertical axis represents the equivalent viscous damping constant. The details of the equivalent viscous damping constant are as described above.

  As shown in FIG. 4, the composite PC steel stranded wire of the test body a swelled in the outer peripheral direction and restrained the deviation in the axial direction, and thus showed an equivalent viscous damping constant value of about 8% in all three cycles. It can be seen that sufficient energy consumption during disturbance can be obtained. In specimen b, the equivalent viscosity damping constant value of the first cycle is as much as 8.5%, but the swelling from the second cycle to the outer periphery of the low-strength steel strand was observed and decreased to 4.9%. The minimum value of 3% or more is shown as the equivalent viscous damping constant value, and the necessary minimum energy consumption is performed.

  On the other hand, in the different strength mixed steel stranded wire of the test body c, since no deformation restraining material is applied, the equivalent viscous damping constant is 2.6 to 0.9%, and there is almost no energy consumption (absorption). In general, when a PC steel stranded wire is used as a reinforcing member for a structural member, if the equivalent viscous damping constant is about 5% or more, it is said that a damping effect during an earthquake can be expected. Therefore, it can be seen that the composite PC steel stranded wire of the test bodies a and b provides the necessary damping effect, and the composite PC steel stranded wire of the test body c has an insufficient damping effect.

An example of partial modification of the feasible PC steel _a 1 ~a ₇ other than the above is shown in (d) of Figure of Figure 1A. In either case, the high-strength steel material (high-strength steel wire) 1 indicated by hatching and the low-strength steel material (low-strength steel wire) 2 indicated by white circles ○ have the same diameter or different diameters, or a partial arc cross section. And a member having a circular cross section. The number configuration of the strands is not particularly limited, but for these productions, those composed of 7, 10, 19 which can use the existing equipment for stranded steel such as JIS standards are preferable. The forms of a ₁ , a ₃ , and a ₅ having high energy consumption ability are more preferable.

The strand diameter is not particularly limited, but is preferably not more than φ32 mm, which is generally distributed, and more preferably not more than φ7 mm that can be processed into a stranded wire. Although the strands may be bundled in parallel, it is preferable to use a stranded wire that can be easily coiled. Although the cross-sectional shape of the strand is not limited, a circle or an ellipse that can be formed into a coiled and stranded wire is preferable. These PC steel materials (PC stranded wires) are also provided with deformation restraining materials (not shown) between the strands or on the outer periphery .

  The composite PC steel material and the composite PC steel stranded wire of the present invention are tensile steel materials that can attenuate the energy caused by disturbances such as earthquakes and strong winds without filling grout around the cable in the field. Can be widely used as an out cable and brace material for other structures.

(A) sectional view of composite PC steel material A ₁ and composite PC steel stranded wire A _{2 in} the _first and _second embodiments, (b) external perspective view of composite PC steel material A ₁ , (c) composite PC steel stranded wire A ₂ external perspective view of a cross-sectional view showing (d) is another feasible embodiment of the PC steel _a 1 ~a ₇ (A) sectional drawing of composite PC steel strand A3 of _3rd Embodiment, (b) external appearance perspective view Diagram showing the relationship between tensile axial force and elongation of steel stranded wire by a model test The figure of the test result about the composite PC steel strand of the test body a of an Example by the procedure similar to a model test, and the test body c of the comparative example 1 The figure which shows the extent of attenuation | damping of the composite PC steel strand of the test bodies a and b and the test body c of the comparative example 1 by an equivalent viscous damping constant ( _heq ). Figures showing application examples of composite PC steel and composite PC steel stranded wire ((a) brace, (b) seismic control partition, (c) out cable) Diagram explaining basic action of different strength steel stranded wire

Explanation of symbols

1 High-strength steel 1 'High-strength steel strand 2 Low-strength steel 2' Low-strength steel strand 3 Carborundum (silicon carbide)
4 Carbon Fiber Sheet A ₁ PC Steel A ₂ , A ₃ PC Steel Stranded Wire h _eq Equivalent Viscous Damping Constant

Claims (6)

Steel (1, 2) of elastic limit different heterologous strength combination, to repeated tensile load in the composite PC steel for attenuating the energy of the tensile load above steel (1, 2) is elastic (A ₁₎ the elastic deformation restraint member for restraining the deformation in the direction of only axial and radial direction or a radial direction between the steel (1, 2) to each steel constituting the composite PC steel (a ₁₎ is provided, the repeated the steel (2) of the low elastic limit to the tensile load, while the high elastic limit of the steel (1) of the telescopic equivalent plastic elongation or plastic shrinkage both steel by the deformation restriction member to produce a (1,2) Composite cable for bracing out cables and braces characterized by restraining the cable . Combine steel strands ( 1 ', 2 ') of different strengths with different elastic limits, and surround the core wire in the center of the cross section and twist other steel strands ( 1 ', 2' ) of different strengths outside In the composite PC steel stranded wire (A ₂ , A ₃ ) in which the steel stranded wire (1 ′, 2 ′) expands and contracts to attenuate the energy of the tensile load against repeated tensile loads , the composite PC Elastic deformation restraint that restrains deformation in the axial direction between each steel stranded wire and the radial direction or only in the radial direction on each steel stranded wire ( 1 ′, 2 ′ ) constituting the stranded wire (A ₂ , A ₃ ) the timber is provided, the steel wire strands of low elastic limit to the repeated tensile load 'in the steel strand of the high elastic limit (1 (2)' the to cause shrinkage expansion equivalent plastic elongation or plasticity) the deformation restriction member both steel strand (1 ', 2'), wherein between that which is adapted to restrain the Autoke Le, complex PC steel stranded wire for the brace. The out cable according to claim 1, wherein the low elastic limit steel material (2) is a core material, and the high elastic limit steel material (1) is disposed on an outer periphery of the low elastic limit steel material (2) . Composite PC steel for braces . The low elastic limit steel stranded wire (2 ') is a core wire, and the high elastic limit steel stranded wire (1') is disposed on the outer periphery of the low elastic limit steel stranded wire (2 '). Item 3. An out cable and a composite PC steel stranded wire for braces . The strength level of the steel material (1) with a high elasticity limit is 2200 N / mm ^2, and the strength level of the steel material (2) with a low elasticity limit is 600 N / mm ² , Composite PC steel for out cable and brace . Claims wherein the high elastic limit of the steel strand (1 ') the intensity level of the 2200N / mm ^2, the low elastic limit of the steel strand (2', characterized in that the intensity level of) was 600N / mm ² Item 5. An out cable or a composite PC steel stranded wire for brace .

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