JP2021055399A - Cap suitable to multistrand type pre-grout pc steel material, and pc steel material with the same - Google Patents

Abstract

To prevent a grout material from leaking even when a multistrand type pre-grout PC steel material is taken up into a package to have a difference in peripheral length.SOLUTION: A cap 200 includes an outer cap 210 which has an inner diameter d (OUT) larger than an outer diameter D(S) of a sheath 130, and an inner cap 220 which has an outer diameter D (IN2) smaller than the inner diameter d (OUT) of the outer cap 210, and an inner diameter d (IN2) of the inner cap 220 is larger than an outer diameter D (K) of an assembly cable 110S. When the PC steel material is taken up with a grout material 120 charged in a space S formed of a PC steel material end face and the inner cap 220, a PC steel twisted wire 110IN protruding from an end of the sheath 130 is housed in this space S.SELECTED DRAWING: Figure 2

Description

The present invention relates to a PC steel material for prestressed concrete that introduces tension in a prestressed concrete post-tension system, and in particular, bundles a plurality of PC steel strands (strands) of 7 or more wires (7 is only an example). A grout material that coats the aggregated cable with a sheath formed of resin, metal, etc., and cures (after a few years) between the aggregated cable and the sheath after the aggregated cable is strained. The present invention relates to a cap suitable for a PC steel material (multi-strand type prestressed PC steel material) prefilled (including both a cement type and a resin type) and a PC steel material using the cap. In the present invention, "pre-filled" is synonymous with "pre-applied". Further, in the following, the PC steel material and the tension material may be described without distinction.

At present, in prestressed concrete girders using the post-tension method for bridges, a cable assembly in which a plurality of PC steel stranded wires are bundled is frequently used as an inner cable. The post-tension method is a method of introducing prestress by tensioning the PC steel stranded wire inserted into the sheath portion of the concrete member after the concrete strength is developed. The inner cable is a cable that introduces prestress by transmitting the tension force of the PC steel stranded wire by adhering to concrete.

As an example, the cable is an aggregate of 12 PC steel strands of 12.7 mm from 7 SWPR7BL, which is a class ^{B steel material (tensile strength of about 1,860 N / mm 2) in JIS G 3536.} In many cases, a cable or an aggregate cable in which 12 PC steel strands of 15.2 mm from 7 SWPR7BLs are bundled is used (a tension material using such an aggregate cable is called a multi-strand type described later).

In a prestressed concrete member using a general post-tension method, a polyethylene (resin) or metal sheath is placed before the concrete is placed (sheath placement work), and before or after the concrete is placed. After that, the assembly cable is inserted into this sheath, and after the strength of the concrete reaches the specified strength, the assembly cable is tensioned and fixed, and finally, the assembly cable is rust-proofed and the assembly cable and the concrete are separated. Grout material is injected between the assembly cable and the sheath for the purpose of adhesion integration treatment (grout filling work).

In such a post-tension method, in order to improve on-site workability by omitting the sheath placement work and the grout filling work, at the time of shipment from the PC steel manufacturing factory, one or more sheaths are used. Pre-grout type in which a liquid grout material (hardened after 2 to 3 years, but liquid when filled) is filled between the sheath and the PC steel stranded wire by inserting a PC steel stranded wire. There are PC steel materials.

Here, as a pre-grout type tensioning material using a PC steel stranded wire as a PC steel material, one PC steel stranded wire is inserted through one sheath and between the sheath and one PC steel stranded wire. A single-strand type tension material filled with grout material and a sheath having a large inner diameter are inserted with a plurality of PC steel strands, and a grout material is formed between the sheath and the plurality of PC steel strands. It is roughly classified into a filled multi-strand type tension material (PC steel material using the above-mentioned aggregate cable as an inner cable).

A prestressed type tensioning material for prestressed concrete that introduces tension in such a prestressed concrete post-tensioning method has been developed and filed by the applicant of the present application, and is published in JP-A-2018-165435 (Patent Document 1). It is disclosed.
The tension material for prestressed concrete disclosed in Patent Document 1 is a tension material for prestressed concrete that introduces tension force in the post-tension method of prestressed concrete, and is an aggregate cable composed of a plurality of PC steel stranded wires. Is coated with a sheath, and a grout material that hardens after tension of the aggregate cable is filled between the PC steel stranded wire and the PC steel stranded wire and between the PC steel stranded wire and the sheath. As the aggregate cable, a high-strength PC steel stranded wire capable of introducing a tension force equal to or higher than the 12-wire configuration of the PC steel stranded wire defined by JISG3536 in a 7-wire configuration is adopted.

By the way, including such a prestressed concrete tension material (PC steel material) (whether it is a prestressed type, not a prestressed type, a single strand type, or a multi-strand type), a PC At the time of shipment from a PC steel material manufacturing factory, the steel material is wound up to a diameter of, for example, about 1500 to 2000 mm and shipped as shown in FIGS. 3 to 5 of JP-A-6-219641 (Patent Document 2). ing.

JP-A-2018-165435 Japanese Unexamined Patent Publication No. 6-219641

The pre-grout type multi-strand tension material (PC steel material) disclosed in Patent Document 1 has been well received. Further, both the pregrout type single-strand type tension material and the multi-strand type tension material are cut to a predetermined length (the length corresponding to the length of the prestressed concrete to be tensioned), and the packing style disclosed in Patent Document 2, for example, is disclosed. It was shipped from a PC steel manufacturing factory. In this case, the pre-grout type is a substantially hollow cylinder (to achieve water stoppage) in order to prevent leakage of the unhardened liquid grout material filled between the sheath and the PC steel stranded wire. A cap (for example, made of polyethylene) having a shape and having one bottom closed (the other bottom was not closed and opened) was bonded to the sheath with an adhesive to seal both ends of the PC steel material.

However, there is no particular problem with the pre-grout type single-strand type tension material even if it is shipped using such a cap, but when the pre-grout type multi-strand type tension material is wound into a package, it is wound up. Due to the difference in circumference between the inside and outside of the diameter, the inner PC steel stranded wire (aggregate) at the winding diameter in the pregrout type multi-strand type tension material cut to a predetermined length. Of the multiple PC steel stranded wires forming the cable, the inner PC steel stranded wire at the take-up diameter) could break through one or both caps that sealed both ends.

That is, for a PC steel material (multi-strand) in which a plurality of strands are arranged, a cap for preventing the grout material from leaking because a shift occurs for each strand when the wound material is wound or untied and unfolded. Was sometimes damaged. As described above, when wound due to the difference in circumference, the strands placed on the inside protrude from the sheath end of the PC steel material, and the strands placed on the outside enter inside the sheath end of the PC steel material. Become. When the end of the pre-grout type multi-strand type tension material was sealed with a cap having the same specifications as the pre-grout type single-strand type tension material, the (inner) strand that protruded in this way broke through the cap. Or the adhesive may come off and the cap may come off. In addition, when the end is firmly stopped by suppressing the displacement of the strand in order to prevent the cap from being damaged in this way, problems such as deformation of the sheath and undulation or meandering of the cable occur. .. Needless to say, damage to the cap leads to leakage of the grout material. In addition, the swell of the cable may prevent the cable from being placed in a predetermined position, or the meandering of the cable may increase the friction between the PC steel material and the sheath, which may hinder the proper transmission of tension. .. Further, the deformation of the sheath may impair the adhesion between the concrete and the sheath.

The present invention has been developed in view of the above-mentioned problems of the prior art, and an object of the present invention is a cap attached to an end portion of a pre-grout type multi-strand type PC steel material, the PC steel material. A cap and its cap were used so that the grout material filled between the sheath and the plurality of PC steel strands would not leak out without damaging the cap attached to the end even if the cap was wound up. It is to provide PC steel materials.

In order to achieve the above object, the cap according to the present invention takes the following technical measures.
That is, the cap according to a certain aspect of the present invention is a cap suitable for a multi-strand type pregrout PC steel material that introduces a tension force in a post-tension system of prestressed concrete. The multi-strand type pre-grout PC steel material is a grout in which an aggregated cable composed of a plurality of PC steel strands is covered with a sheath, and the aggregated cable is hardened after tension of the aggregated cable between the aggregated cable and the sheath. The material is filled. The cap has a substantially hollow cylindrical shape, one of which is closed, and an outer cap having an inner diameter larger than the outer diameter of the sheath, and an outer cap provided inside the outer cap, which has a substantially hollow cylindrical shape. One bottom is closed and includes an inner cap having an outer diameter smaller than the inner diameter of the outer cap and an adhesive layer between the outer cap and the inner cap, and the inner diameter of the inner cap is the inner diameter. A space is formed by the end face of the PC steel material and the inner cap, which is larger than the outer diameter of the aggregate cable, and when the PC steel material is wound up with a predetermined diameter, it pops out from the end portion of the sheath. The inner PC steel stranded wire in diameter is housed in the space.

Preferably, the space can be configured to be filled with grout material.
More preferably, the outer diameter of the inner cap is substantially the same as the outer diameter of the sheath, so that the cut end face of the sheath and the end face on the opposite side of the bottom of the inner cap face each other to form the space. Can be configured in.
More preferably, the outer diameter of the inner cap is smaller than the inner diameter of the sheath, and the end face on the opposite side of the bottom of the inner cap is inserted into the gap between the assembly cable and the sheath to form the space. Can be configured to

More preferably, the outer diameter of the outer cap, which is the maximum diameter of the cap after the adhesive layer is cured and the outer cap and the inner cap are joined, is installed at a place where the PC steel material is applied. It can be configured to be smaller than the inner diameter of the insertion hole of the PC steel material in the tool or equipment.
Further, the PC steel material according to another aspect of the present invention is a multi-strand type pregrout PC steel material having any of the above-mentioned caps.

According to the present invention, it is a cap attached to an end portion of a pre-grout type multi-strand type PC steel material, and even if the PC steel material is wound up, the cap attached to the end portion is not damaged and a plurality of sheaths and a plurality of caps are attached. It is possible to provide a cap in which the grout material filled between the book and the PC steel stranded wire does not leak out, and a PC steel material using the cap.

It is sectional drawing of the end part of the PC steel material which provided this cap at the end part for explaining the cap which concerns on embodiment of this invention, (A) shows the PC steel material which provided with cap 200, (B). Indicates a PC steel material having a cap 300 different from the cap 200. FIG. 5A is a cross-sectional view of an end portion of a PC steel material when the PC steel material for explaining the action and effect of the cap according to the embodiment of the present invention is wound up with a predetermined diameter, and FIG. The PC steel material is shown, and (B) shows a PC steel material having a cap 300 different from the cap 200.

Hereinafter, the cap according to the embodiment of the present invention and the multi-strand type pregrout PC steel material provided with the cap (hereinafter, may be simply referred to as PC steel material) will be described in detail with reference to FIGS. 1 and 2. It should be noted that FIG. 1 is a cross-sectional view of a PC steel material end portion provided with this cap at the end portion for explaining the cap according to the present embodiment, and FIG. 2 shows the action and effect of the cap according to the present embodiment. It is sectional drawing of the end part of the PC steel material at the time of winding up the PC steel material for explanation with a predetermined diameter. 1 (A) and 2 (A) are cross-sectional views of the end portion of the PC steel material provided with the cap 200, and FIGS. 1 (B) and 2 (B) show the cap 300 different from the cap 200. It is sectional drawing of the provided PC steel material end portion.

With reference to these FIGS. 1 and 2, the cap 200 and the cap 300 according to the present embodiment and the PC steel material provided with the cap 200 or the cap 300 will be described. First, the PC steel material according to the present embodiment common to these caps 200 and 300 will be described.
The PC steel material according to the present embodiment is a multi-strand type pregrout PC steel material that introduces a tension force in the post-tension system of prestressed concrete. As shown in FIGS. 1 and 2, in this multi-strand type pregrout PC steel material, an aggregate cable 110S composed of a plurality of PC steel stranded wires 110 is covered with a sheath 130, and the aggregate cable 110S and the sheath S are combined. A grout material 120 that hardens after tension of the assembly cable 110S is filled between the two.

As the PC steel material according to the present embodiment, for example, the prestressed concrete tension material disclosed in Patent Document 1 developed, filed and published by the applicant of the present application can be adopted.
Next, the cap 200 and the cap 300 according to the present embodiment will be described with reference to these FIGS. 1 and 2. The cap 200 and the cap 300 will be described in detail later, but the outer diameter D (IN2) of the inner cap 220 of the cap 200 is substantially the same as the outer diameter D (S) of the sheath 130, and the inner cap 220 and the sheath The outer diameter D (IN3) of the inner cap 320 of the cap 300 is smaller than the inner diameter d (S) of the sheath 130, while the outer peripheral surface of the 130 is substantially flush with each other. Is different. For other structures (including PC steel) and the same structure, the cap 200 and the cap 300 are designated by the same reference numerals in FIGS. 1 and 2. The configurations with the same reference numerals will not be described repeatedly in order to have the same effect. More specifically, the cap 200 and the cap 300 differ only in the inner cap, the cap 200 includes the inner cap 220 instead of the inner cap 320, and the cap 300 includes the inner cap 320 instead of the inner cap 220. Is configured to include.

The cap 200 and the cap 300 have a substantially hollow cylindrical shape, and one bottom is closed (the other bottom is not closed and is open), and the inner diameter d is larger than the outer diameter D (S) of the sheath 130. An outer cap 210 provided with (OUT) and an outer diameter D provided inside the outer cap 210, which has a substantially hollow cylindrical shape, one of which is closed, and is smaller than the inner diameter d (OUT) of the outer cap 210. (IN2) (for cap 200) or inner cap 220 (for cap 200) or inner cap 320 (for cap 300) with outer diameter D (IN3) (for cap 300), and outer cap 210 It includes an adhesive layer 230 (to prevent the grout material 120 from leaking) between the inner cap 220 or the inner cap 320. The inner diameter d (IN2) of the inner cap 220 or the inner diameter d (IN3) of the inner cap 320 is larger than the outer diameter D (K) of the assembly cable 110S. The most characteristic feature is that the space S formed by the end face of the PC steel material (indicated by the arrow PC) and the inner cap 220 or the inner cap 320 is filled with the grout material 120, and the PC steel material is predetermined. The inner PC steel stranded wire 110IN at the winding diameter, which protrudes from the end of the sheath 130 when wound at the diameter, is accommodated in this space S. It should be noted that filling the space S with the grout material 120 is an optional configuration, and the cap according to the present invention may not be filled with the grout material 120 in the space S. That is, both the cap in which nothing is filled in the space S and the cap in which the space S is filled with a filler other than the grout material, the space S is filled with the grout material (between the aggregate cable 110S and the sheath S). A cap filled with the same grout material as the grout material 120 or a different grout material) is also within the scope of the present invention.

Like the cross-sectional view of the end of the PC steel material when the PC steel material is wound into a package shape with a predetermined diameter (for example, 1500 mm to 2000 mm) shown in FIGS. 2 (A) and 2 (B). Pregrout type multi-strand type tension material cut to a predetermined length due to the difference in circumference between the inner PC steel stranded wire 110IN and the outer PC steel stranded wire 110OUT in the winding diameter. The inner PC steel stranded wire 110IN at the winding diameter in the above (the inner PC steel stranded wire 110IN at the winding diameter among the plurality of PC steel stranded wires forming the aggregate cable) is free with respect to the grout material 120. One or one of the caps 200 or 300 that can be moved to and is housed in the space S (formed by the PC steel end face and the inner cap 220 or the inner cap 320) and has both ends of the PC steel sealed. It is possible to prevent it from breaking through both caps.

As described above, filling the space S with the grout material 120 is an arbitrary configuration, and when nothing is filled in the space S, the inner PC steel stranded wire 110IN is free in the space S. Needless to say, when this space S is filled with a filling other than grout material, the inner PC steel stranded wire 110IN can move freely with respect to this filling in the space S. This filling is selected so that it can be done, and if this space S is filled with a grout material different from the grout material 120 filled between the aggregate cable 110S and the sheath S, the inner PC steel. The different grout material is selected so that the stranded wire 110IN can move freely with respect to the different grout material in the space S.

By providing such a cap 200 or a cap 300, the following effects can also be exhibited.
-Even if the end of the PC steel material moves during winding, the sheath 130 is prevented from being deformed or damaged, and the cap 200 and the cap 300 are prevented from being damaged or removed.
-Since this PC steel material (multi-strand type pre-grout PC steel material) is placed before concrete placement, the internal pressure rises due to the influence of heat and shrinkage during concrete placement, and grout material leakage is likely to occur. The adhesive layer 230 makes it difficult for the grout material 120 to leak.
-Since the end portion of the PC steel material is not restrained, deformation of the sheath 130 of the PC steel material and swelling of the entire cable can be reduced.

Prior to placing concrete, a multi-strand type pregrout PC steel material provided with these caps 200 or 300 is arranged at a predetermined position for placing concrete, and the strength of the placed concrete reaches a predetermined strength. After that, the assembly cable is strained. Immediately before tensioning the assembly cable, these caps 200 or 300 are removed from the PC steel. Therefore, in the work up to tension, these caps 200 or caps 300 are attached to the PC steel material (continuously after shipment from the PC steel material manufacturing factory).

Here, in the cap 200 shown in FIGS. 1 (A) and 2 (A), the outer diameter D (IN2) of the inner cap 220 is substantially the same as the outer diameter D (S) of the sheath 130, and the sheath 130 is cut. A space S is formed by facing the end face and the open end face on the opposite side of the bottom of the inner cap 220. This state is shown by the circles in FIGS. 1 (A) and 2 (A). As shown by the circles, the outer diameter D (IN2) of the inner cap 220 of the cap 200 is substantially the same as the outer diameter D (S) of the sheath 130, and the outer peripheral surfaces of the inner cap 220 and the sheath 130 are substantially flush with each other. It has become.

Further, in the cap 300 shown in FIGS. 1 (B) and 2 (B), the outer diameter D (IN3) of the inner cap 320 is smaller than the inner diameter d (S) of the sheath 130 (and as described above). (Because the inner diameter d (IN3) of the inner cap 320 is larger than the outer diameter D (K) of the assembly cable 110S), the side opposite to the bottom of the inner cap 320 is opened in the gap between the assembly cable 110S and the sheath 130. The end face is inserted to form a space S. This state is shown by the circles in FIGS. 1 (B) and 2 (B). As shown by the circles, the outer diameter D (IN3) of the inner cap 320 of the cap 300 is smaller than the inner diameter d (S) of the sheath 130, and the inner cap 320 is inserted into the sheath 130.

Compared to the cap 200, the cap 300 has the end face of the inner cap 320 inserted in the gap between the assembly cable 110S and the sheath 130, so that the PC steel material and the space S are filled with the liquid before curing. It is preferable in that the leakage of the grout material 120 can be prevented more reliably (water stoppage can be realized more reliably).
Here, such an outer cap 210 and an inner cap 220 or an inner cap 320 are polyethylene resin (PE), polypropylene resin (PP), vinyl chloride resin (PVC), polystyrene (PS), steel material and the like, and are particularly limited. As the adhesive used for the adhesive layer 230 that joins these (outer cap 210 and inner cap 220 or inner cap 320), a heat-melt type hot melt adhesive, an epoxy resin type adhesive, etc. (Rapid connection) It is a polyethylene-based adhesive and the like, and is not particularly limited.

In the case of forming the adhesive layer 230 with such an adhesive, for example, if an outer cap 210 made of polyethylene resin is adopted and a hot melt adhesive is adopted for the adhesive layer 230, the outer is before the hot melt adhesive is cured. Since the cap 210 is freely deformable, it may expand in the direction of increasing diameter (such a situation also occurs with a cement-based adhesive, for example). In this way, the outer diameter D (OUT) of the outer cap 210, which is the maximum diameter of the cap 200 or the cap 300, is larger than the inner diameter of the insertion hole of the PC steel material in the tool or equipment installed at the place where the PC steel material is installed. If it becomes large (because the cap 200 and the cap 300 cannot be removed yet at this point), this PC steel material cannot be applied. Here, since the inner diameter d (OUT) of the outer cap 210 is larger than the outer diameter D (S) of the sheath 130 and the outer cap 210 inevitably has a wall thickness, the maximum diameter of the PC steel material provided with the cap is The outer diameter D (OUT) of the outer cap 210, which is the maximum diameter of the cap 200 or the cap 300, is larger than the sheath 120. Therefore, even if the PC steel material (sheath 120) without a cap can be inserted, a situation may occur in which the PC steel material (cap) with a cap cannot be inserted.

In order to avoid such a situation, when attaching these caps 200 or 300 to the PC steel material, more specifically, the inner cap 220 or the inner cap 320 is placed inside (which will form a space S). After filling a sufficient amount of grout material 120, insert the inner cap 220 or the inner cap 320 (so that the outer peripheral surfaces of the inner cap 220 and the sheath 130 are substantially flush with each other, or the inner cap 320 enters the sheath 130. Then, attach it to the end face of the PC steel material, and join the inner cap 220 or the inner cap 320 to the sheath 130 with an adhesive tape 212 coated with an adhesive on one side. Next, in order to form the adhesive layer 230, an adhesive is applied to the outer peripheral surface of the inner cap 220 or the inner cap 320, and the outer cap 210 is put on the inner cap 220 or the inner cap 320, if necessary. The outer cap 210 is joined to the sheath 130 with an adhesive tape 222 coated with an adhesive on one side.

After this, it is more than the outer diameter D (OUT) of the outer cap 210 so as to prevent the outer cap 210 from freely deforming and expanding in the diameter expansion direction until the adhesive (hot melt, cement-based) hardens. A steel pipe having a slightly larger inner diameter (about the inner diameter of the insertion hole of the PC steel material in the tool or equipment installed at the place where the PC steel material is applied) is attached to the outer cap 210 until the adhesive is cured. In this way, the outer diameter D (OUT) of the outer cap 210, which is the maximum diameter of the cap 200 or the cap 300 after the adhesive layer 230 is cured and the outer cap 210 and the inner cap 220 or the inner cap 320 are joined to each other. However, it is smaller than the inner diameter of the insertion hole of the PC steel material in the tool or equipment installed at the place where the PC steel material is installed (even if there is a limitation that the cap 200 and the cap 300 cannot be removed at this point). You will be able to construct PC steel materials.

As a confirmation, the PC steel material according to the present embodiment is a multi-strand type pregrout PC steel material provided with a cap 200 or a cap 300 having the above-mentioned characteristics.
As described above, according to the cap according to the present embodiment and the PC steel material provided with the cap (pre-grout type multi-strand type PC steel material), the cap attached to the end portion of the PC steel material even if it is wound up. The grout material filled between the sheath and the plurality of PC steel strands does not leak out without being damaged.

It should be noted that the embodiments disclosed this time are exemplary in all respects and are not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and it is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

The present invention is preferable for PC steel materials for prestressed concrete that introduce tension force in the post-tension method of prestressed concrete, and an aggregate cable in which a plurality of twisted wires (strands) of PC steel are bundled is a sheath formed of resin, metal, or the like. A PC steel material pre-filled with grout material that is coated and hardened (after a few years) after tensioning of the assembly cable between the assembly cable and the sheath is wound up and grouted as a packing form. It is particularly preferable in that the material does not leak.

110 PC Steel Strand 110S Aggregate Cable 120 Grout Material 130 Sheath 200 Cap 210 Outer Cap 212 Adhesive Tape 220 Inner Cap 222 Adhesive Tape 230 Adhesive Layer 300 Cap 320 Inner Cap

Claims (6)

A cap suitable for multi-strand type pregrout PC steel that introduces tension in the post-tension system of prestressed concrete.
The multi-strand type pre-grout PC steel material is a grout in which an aggregated cable composed of a plurality of PC steel strands is covered with a sheath, and the aggregated cable is hardened after tension of the aggregated cable between the aggregated cable and the sheath. Filled with wood,
The cap
An outer cap having a substantially hollow cylindrical shape with one bottom closed and an inner diameter larger than the outer diameter of the sheath.
An inner cap provided inside the outer cap, which has a substantially hollow cylindrical shape, one bottom of which is closed, and an outer diameter smaller than the inner diameter of the outer cap.
Includes an adhesive layer between the outer cap and the inner cap
The inner diameter of the inner cap is larger than the outer diameter of the assembly cable.
A space is formed by the end face of the PC steel material and the inner cap, and when the PC steel material is wound up with a predetermined diameter, the inner PC steel stranded wire at the winding diameter that protrudes from the end portion of the sheath is formed. A cap to be housed in the space. The cap according to claim 1, wherein the space is filled with a grout material. The outer diameter of the inner cap is substantially the same as the outer diameter of the sheath, and the space is formed by facing the cut end surface of the sheath and the end surface of the inner cap on the opposite side of the bottom. The cap according to claim 2. A claim that the outer diameter of the inner cap is smaller than the inner diameter of the sheath, and the end face on the opposite side of the bottom of the inner cap is inserted into the gap between the assembly cable and the sheath to form the space. 1 or the cap according to claim 2. The outer diameter of the outer cap, which is the maximum diameter of the cap after the adhesive layer is cured and the outer cap and the inner cap are joined, is a tool or a tool installed at a place where the PC steel material is applied. The cap according to any one of claims 1 to 4, which is smaller than the inner diameter of the insertion hole of the PC steel material in the equipment. A multi-strand type pregrout PC steel material having the cap according to any one of claims 1 to 5.

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