End structure, and method for manufacturing end structure

Abstract

To provide an end structure including a metallic cap for protecting an end of a PC steel material.SOLUTION: An end structure comprises a PC steel material, a fixing tool gripping the PC steel material, a bearing plate supporting the fixing tool, a metallic cap covering the end of the PC steel material, the fixing tool and the bearing plate, a metallic bolt inserted into a bottomed bolt hole provided so as to pass through the cap and the bearing plate and made from a metal more valuable than the bearing plate and a resin arranged between the bolt and the bolt hole.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an end structure and a method for manufacturing an end structure. [Background technology]

[0002] Patent Document 1 describes a grout cap that grips both ends of a PC steel wire inserted into a sheath tube installed inside a PC member, covers a PC steel wire anchor that holds the PC steel wire in a tensile state, and liquid-tightly covers the anchor, A fixing flange is provided around the periphery of the opening for receiving the fixing tool using a transparent or semi-transparent resin material, and the tip side is formed into a hemispherical shape, and the fixing tool is integrally molded into a hat shape as a whole, The present invention discloses a grout cap for a PC steel wire fixing device, which is characterized in that a number of convex portions are arranged on the outer peripheral surface at intervals around the axis, and any one of the convex portions is selected and configured to allow post-machining of a grout injection port and a screw hole for connecting an exhaust port to the convex portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-131956 A Summary of the Invention [Problem to be solved by the invention]

[0004] Concrete structures are weak in terms of tensile strength. Therefore, prestressing steel strands and other prestressing steel materials are used to apply compressive strength to concrete structures in advance, control the tensile stress when the concrete structure receives a load, and prevent cracks from occurring.

[0005] After tension is applied to the prestressing tendon using a jack or the like, the ends of the prestressing tendon are gripped by anchors and the anchors are supported by bearing plates installed on the concrete structure, thereby fixing the tendon to the concrete structure.Then, caps as disclosed in Patent Document 1 are placed on the ends of the prestressing tendon, and grout is injected between the caps and the ends of the prestressing tendon to protect the ends of the prestressing tendon.

[0006] However, resin caps are not strong enough and may be damaged by contact with flying objects, etc., and there are problems with strength. In addition, resin is easily degraded by ultraviolet rays, etc., and the deterioration progresses quickly over time, and there are problems with durability. For this reason, when using a resin cap, the installed cap itself needs to be further embedded in concrete, and the cap cannot be used in an environment exposed to the outside air.

[0007] Therefore, there has been a demand for an end structure using a metal cap that can be used even in an environment exposed to the outside air.

[0008] Therefore, an object of the present disclosure is to provide an end structure that includes a metal cap to protect the end of a prestressing steel member. [Means for solving the problem]

[0009] According to one aspect of this embodiment, a PC steel material and A fixing tool that holds the PC steel material; A support plate for supporting the fixing tool; A metal cap that covers the end of the PC steel member, the fixing device, and the support plate; a metal bolt inserted into a bottomed bolt hole provided to pass through the cap and the support plate, the metal bolt being made of a more noble metal than the support plate; An end structure is provided having the bolt and a resin disposed between the bolt hole. Effect of the Invention

[0010] According to the present disclosure, an end structure can be provided that includes a metal cap that protects the end of a PC steel member. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view of an end structure according to one embodiment of the present disclosure. [Diagram 2] FIG. 2 is an enlarged view of area A in FIG. [Diagram 3] FIG. 3 is an explanatory diagram of the cap. [Figure 4] FIG. 4 is a flow diagram of a method for manufacturing an end structure according to one embodiment of the present disclosure. [Diagram 5] FIG. 5 is an explanatory diagram of the filling step. [Figure 6A] FIG. 6A is an explanatory diagram of a method for evaluating the relationship between the viscosity of a resin and the occurrence of liquid leakage. [Figure 6B] FIG. 6B is an explanatory diagram of a method for evaluating the relationship between the viscosity of the resin and the occurrence of liquid leakage. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The embodiments for carrying out the invention are described below.

[0013] [Description of the embodiments of the present disclosure] First, the embodiments of the present disclosure will be described. In the following description, the same or corresponding elements are denoted by the same reference numerals, and the same description thereof will not be repeated.

[0014] (1) An end structure according to one embodiment of the present disclosure includes a PC steel material and A fixing tool that holds the PC steel material; A support plate for supporting the fixing tool; A metal cap that covers the end of the PC steel member, the fixing device, and the support plate; a metal bolt inserted into a bottomed bolt hole provided to pass through the cap and the support plate, the metal bolt being made of a more noble metal than the support plate; The bolt has a resin disposed between the bolt and the bolt hole.

[0015] According to an embodiment of the end structure of the present disclosure, the end structure can include a metal cap.

[0016] When the end structure includes a metal cap, the metal cap has superior strength and durability compared to a resin cap. Therefore, there is no need to bury the cap in concrete or the like as in the case of the resin cap described above. However, in this case, since the bolt fixing the cap to the support plate is also exposed to the outside air, it is preferable to use a bolt made of a metal more noble than the support plate in order to improve the corrosion resistance of the bolt. However, in this case, the support plate may be severely corroded near the contact point between the bolt and the support plate, and the force of the bolt fixing the cap may be reduced. Therefore, the inventor of the present invention conducted an investigation and found that the corrosion occurs due to the infiltration of moisture into the contact point between the support plate, which is a metal with a different ionization tendency, and the bolt.

[0017] Therefore, in an end structure according to one embodiment of the present disclosure, by disposing resin between the bolt and the bolt hole provided to pass through the cap and the support plate, it is possible to suppress the infiltration of moisture into the bolt hole, resulting in an end structure with high durability.

[0018] (2) The resin may be one or more types of resin selected from acrylic and silicone resins.

[0019] By using one or more types of resin selected from acrylic and silicone resins as the resin, the space between the bolt and the bolt hole can be sufficiently filled, making it possible to particularly suppress the intrusion of water.

[0020] (3) The bolt may be made of stainless steel.

[0021] By using stainless steel for the bolts, rust formation on the bolts is suppressed and durability is increased.

[0022] (4) The cap may be made of stainless steel.

[0023] By making the cap out of stainless steel, rust formation on the cap is suppressed and durability is increased.

[0024] (5) The stainless steel may be one or more selected from the group consisting of SUS304, SUS305, SUS312, SUS316, and SUS347.

[0025] By using the above stainless steel, strength and corrosion resistance can be particularly improved.

[0026] (6) The support plates may be made of carbon steel.

[0027] By making the support plate from carbon steel, it is possible to create a support plate with excellent strength and hardness, which can support the tension introduced into the PC steel for a long period of time.

[0028] (7) A rubber packing is provided between the support plate and the cap, The bolt holes may be provided through the cap, the packing, and the bearing plate.

[0029] By disposing a packing between the support plate and the cap, leakage of the filler from between the support plate and the cap can be suppressed when filling the area surrounded by the support plate and the cap with the filler. Also, since the support plate and the cap can be configured not to be in direct contact with each other, electrolytic corrosion between the support plate and the cap can be prevented. Furthermore, the packing and the resin can particularly increase the airtightness of the space between the bolt and the bolt hole, and more reliably prevent water from entering the space between the bolt and the bolt hole.

[0030] (8) The bolt hole has a threaded portion, which is a region on an inner surface of the bolt hole having a thread groove that engages with the threads of the bolt, and a non-threaded portion, which is a region closer to an opening of the bolt hole than the threaded portion, In at least a portion of the non-threaded portion, the resin may be filled between the bolt and the bolt hole.

[0031] The threaded portion can be provided on the support plate. Therefore, in at least a part of the non-threaded portion that is disposed closer to the opening of the bolt hole than the support plate, resin is filled between the bolt and the bolt hole, thereby making it possible to particularly suppress the infiltration of water into the contact portion between the support plate and the bolt.

[0032] (9) A method for manufacturing an end structure according to one embodiment of the present disclosure includes an installation step of installing a metal cap to cover an end of a PC steel member, a fastener that grips the end side of the PC steel member, and a support plate that supports the fastener; a filling step of filling a bottomed bolt hole provided so as to pass through the support plate and the cap with resin; a tightening process of inserting a metal bolt made of a metal more noble than the support plate into the bolt hole and tightening the bolt to fix the cap to the support plate; and a wiping step of wiping off the resin overflowing in the tightening step.

[0033] According to the manufacturing method of an end structure according to one aspect of the present disclosure, an end structure including a metal cap can be manufactured.

[0034] In addition, according to a manufacturing method for an end structure according to one embodiment of the present disclosure, resin can be placed between the bolt and the bolt hole provided to pass through the cap and the support plate, thereby suppressing the infiltration of moisture into the bolt hole and obtaining an end structure with high durability.

[0035] (10) In the filling step, the resin may be filled by being forced into the bolt hole using a rod-shaped body.

[0036] Even if the viscosity of the resin to be filled is high, a sufficient amount of resin can be filled in the bolt hole by pushing the resin into the bolt hole using a rod-shaped body. Therefore, when the bolt is inserted in the tightening process and the resin hardens, a sufficient amount of resin can be filled between the bolt and the bolt hole. This makes it possible to suppress the intrusion of moisture into the bolt hole and to provide an end structure with high durability.

[0037] (11) In the filling step, a graduated syringe may be used to inject and fill the bolt hole with an amount of the resin according to the capacity of the bolt hole.

[0038] By measuring the capacity of the bolt hole in advance and injecting and filling the bolt hole with an amount of resin according to the capacity of the bolt hole using a graduated syringe, it is possible to prevent insufficient filling of the resin and excessive overflow of the resin during the tightening process. Also, by injecting and filling the bolt hole with resin while checking that no air has been mixed in with the resin in the graduated syringe, it is possible to fill the bolt hole with a sufficient amount of resin and ensure that there are no visible bubbles inside the resin.

[0039] (12) The method may further include a coating step of coating at least a portion of the bolt to be inserted into the bolt hole with the resin before the fastening step.

[0040] By also applying resin to the shaft portion of the bolt, which is the portion that is inserted into the bolt hole, it is possible to more reliably fill the space between the bolt and the bolt hole with resin.

[0041] (13) In the filling step, the resin filled into the bolt hole may have a viscosity of 1300 mPa·s or more and 50000 mPa·s or less.

[0042] When the viscosity of the resin is 1,300 mPa s or higher, it is possible to prevent the resin from leaking from the bolt hole even when the bolt hole is formed horizontally, and it is possible to more reliably fill the space between the bolt and the bolt hole with resin.

[0043] Furthermore, when the viscosity of the resin is 50,000 mPa·s or less, the resin can be easily filled into the bolt hole, and the resin can be more reliably filled into the space between the bolt and the bolt hole.

[0044] [Details of the embodiment of the present disclosure] Specific examples of an end structure and a method for manufacturing an end structure according to one embodiment of the present disclosure (hereinafter, referred to as the present embodiment) will be described below with reference to the drawings. Note that the present invention is not limited to these examples, but is indicated by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims. 1. End structure An example of the configuration of an end structure of this embodiment will be described with reference to Figures 1 to 3. Note that each figure is a schematic diagram used to explain the arrangement of members, etc., and does not accurately show the size ratio of each member, etc.

[0045] In addition, the end structure is a structure for fixing and protecting the end of the PC steel member installed in a concrete structure, and refers to a structure including the PC steel member, fixing device, support plate, cap, and bolts for fixing the cap, as described below.

[0046] Fig. 1 is a cross-sectional view of the end structure of this embodiment, taken along a plane passing through the central axis of the PC steel member 12. Fig. 2 is an enlarged view of an area A in Fig. 1. Fig. 3 is a perspective view of the cap.

[0047] The end structure 10 of this embodiment can have a PC steel member 12, a fixing device 14 that holds the PC steel member 12, a support plate 15, a cap 17, a metal bolt 191, and resin 22 arranged between the bolt 191 and the bolt hole 21, as shown in Figures 1 and 2.

[0048] Each member of the end structure of this embodiment will be described below. (1) Components of the end structure (1-1)PC steel material The PC steel member 12 is a tendon for introducing prestress to apply compressive force to the concrete structure 11, and may be a PC steel strand made of multiple strands twisted together, a PC steel rod, etc. The PC in the PC steel strand etc. stands for prestressed concrete.

[0049] For example, as shown in FIG. 1, a PC steel member 12 can be placed inside a concrete structure 11 with a sheath 13 interposed therebetween.

[0050] 1 shows an example in which the end structure 10 includes one PC steel member 12, but is not limited to this embodiment. The fastener 14 may also be configured to fix multiple PC steel members 12, in which case the end structure 10 may include multiple PC steel members 12. (1-2) Fixture The fixing device 14 can be arranged on the end 12A side of the PC steel member 12 and can grip the PC steel member 12. The configuration of the fixing tool 14 is not particularly limited as long as it can grip and fix the end 12A side of the PC steel material 12. As the fixing tool 14, for example, a fixing tool having a female cone and a male cone can be used.

[0051] The fixing device 14 is preferably made of a material having sufficient strength and hardness to grip and support the PC steel material 12, and may be made of steel, for example. It is particularly preferable that the fixing device 14 be made of carbon steel.

[0052] The carbon steel used for the fixing device 14 is not particularly limited, but one or more types selected from chromium-molybdenum steel (SCM material), ductile cast iron (FCD material), general structural rolled steel (SS material), welded structural rolled steel (SM material), mechanical structural carbon steel (SC material), etc. can be suitably used.

[0053] For example, when the fixing device 14 has a female cone and a male cone, it is particularly suitable to use chromium molybdenum steel (SCM material) or carbon steel for mechanical construction (SC material) as the female cone, and chromium molybdenum steel (SCM material) or the like as the male cone. (1-3) Support plate The support plate 15 may also be called a casting plate or an anchor plate. The support plate 15 is a thick piece of steel, and supports the fasteners 14 to which a force is applied toward the concrete structure 11 by the tension introduced into the PC steel 12, and can support the tension introduced into the PC steel 12 through the fasteners 14. The support plate 15 can be partially embedded in the concrete structure 11 as shown in FIG. 1, or can be disposed on the surface of the concrete structure 11. The support plate 15 is preferably formed of a material having sufficient strength and hardness to support the fasteners 14 and the like, and can be made of steel, for example. The support plate 15 is particularly preferably made of carbon steel. By making the support plate 15 of carbon steel, the support plate 15 can be made of excellent strength and hardness, and can support the tension introduced into the PC steel 12 for a long period of time.

[0054] The carbon steel used for the support plate 15 is not particularly limited, but one or more types selected from chromium-molybdenum steel (SCM material), ductile cast iron (FCD material), general structural rolled steel (SS material), welded structural rolled steel (SM material), mechanical structural carbon steel (SC material), etc. can be suitably used. (1-4) Cap Cap 17 is provided to protect components arranged near the end of PC steel 12, such as prestressing steel 12, fixing device 14, and support plate 15. For this reason, cap 17 can be arranged so as to cover end 12A of PC steel 12, fixing device 14, and support plate 15, as shown in Fig. 1. Cap 17 is preferably arranged so as to cover all exposed surfaces of end 12A of PC steel 12, fixing device 14, and support plate 15, but some parts, such as the side surface of support plate 15, may be exposed and not covered by cap 17.

[0055] As described above, a resin cap has been used in the past, but the strength of the resin cap is insufficient and may be broken by contact with flying objects, etc., and there is a problem in terms of strength. In addition, since resin is easily deteriorated by ultraviolet rays, etc., the deterioration progresses quickly over time, and there is a problem in terms of durability. For this reason, the end structure 10 of this embodiment can use a metal cap 17. That is, an end structure including a metal cap can be obtained. By making the cap 17 from metal, the strength and durability of the cap 17 and the end structure 10 can be increased compared to a resin cap.

[0056] Cap 17 only needs to protect end 12A of PC steel 12 from flying objects and the like, and does not need to have the high strength and hardness of fixing device 14 or support plate 15. However, since cap 17 is exposed to the outside air, it is preferable that cap 17 be made of a metal having excellent corrosion resistance, and more preferably, for example, a metal made of a more noble metal than support plate 15. It is even more preferable that cap 17 be made of, for example, stainless steel. Making cap 17 out of stainless steel can suppress the formation of rust on cap 17 and increase durability.

[0057] The stainless steel is not particularly limited, and may be, for example, one or more selected from SUS 304, SUS 305, SUS 312, SUS 316, and SUS 347. By using the above stainless steel, strength and corrosion resistance can be particularly improved.

[0058] The shape of the cap 17 is not particularly limited as long as it can cover the end 12A of the PC steel 12, the fixing device 14, and the support plate 15 as described above, but it can have a cylindrical shape with an upper surface 17A as shown in Figures 1 and 3. In Figures 1 and 3, the upper surface 17A is a flat horizontal surface, but it is not limited to such a shape, and the upper surface 17A can also have a dome shape or the like that is convex on the upper side, i.e., on the opposite side to the area that houses the end 12A of the PC steel 12, etc.

[0059] As shown in Figure 3, the cap 17 can have a body portion 171 that accommodates the end portion 12A of the PC steel material 12, the fixing device 14, etc., and a flange portion 172 having a bolt hole 21 through which a bolt 191 for fixing to the support plate 15 can be passed.

[0060] 1, the inside of the cap 17 can be filled with the filler 18. For this reason, the cap 17 can also have a first filler introduction hole 1731 and a second filler introduction hole 1732 so that the filler 18 can be introduced into the area surrounded by the cap 17 and the support plate 15 after the cap 17 is fixed to the support plate 15. The first filler introduction hole 1731 and the second filler introduction hole 1732 can have, for example, a tubular shape and can be provided on the upper surface 17A of the cap 17.

[0061] Furthermore, the PC steel bars 12 may have optical fibers or the like, and in this case, it is necessary to connect the optical fibers or the like of the PC steel bars 12 to external equipment. For this reason, if necessary, a through hole or the like can be provided on the top surface 17A of the cap 17 or on the side surface of the body 171 of the cap 17 to take the optical fibers or the like out of the cap 17 and connect them to external equipment.

[0062] When filling the internal space of cap 17 with filler, the filler is introduced from first filler introduction hole 1731, and air in the internal space of cap 17 can be discharged from second filler introduction hole 1732. Then, by discharging the filler from second filler introduction hole 1732, it can be confirmed that filling of filler 18 into the internal space of cap 17 is completed. (1-5) Bolts, bolt holes, washers The end structure 10 can have metal bolts 191 for fixing the cap 17. By using the metal bolts 191, the cap 17 can be fixed to the support plate 15 with sufficient strength.

[0063] When the end structure includes a metal cap 17, the metal cap 17 has superior strength and durability compared to a resin cap. Therefore, there is no need to bury the cap in concrete or the like as in the case of a resin cap. However, when a metal cap 17 is used, the bolt that fixes the cap 17 to the support plate 15 is also exposed to the outside air, so from the viewpoint of increasing the corrosion resistance of the bolt, it is preferable to use a metal bolt made of a more noble metal than the support plate 15. The bolt 191 is preferably made of, for example, stainless steel. By making the bolt 191 out of stainless steel, the occurrence of rust on the bolt 191 can be suppressed and durability can be increased.

[0064] The stainless steel is not particularly limited, and may be, for example, one or more selected from SUS 304, SUS 305, SUS 312, SUS 316, and SUS 347. By using the above stainless steel, strength and corrosion resistance can be particularly improved.

[0065] Bolt 191 can be inserted through cap 17 and support plate 15, i.e., into bolt hole 21 provided continuously through cap 17 and support plate 15. For this reason, bolt hole 21 is provided in cap 17 and support plate 15. When packing 16, which will be described later, is provided, bolt hole 21 will also be provided in packing 16. Then, bolt 191 can be fixed by fitting the thread of bolt 191 into thread groove 151 provided on inner surface 21B of bolt hole 21.

[0066] Bolt hole 21 can be a bottomed bolt hole having bottom 21A, i.e., a blind hole. By making bolt hole 21 bottomed, it is possible to prevent moisture from entering from any place other than the bolt insertion hole. Bottom 21A of bolt hole 21 can be provided within support plate 15 as shown in FIG. 2.

[0067] The number of bolts 191 that the end structure 10 has is not particularly limited, and may be any number. In order to fix the cap 17 to the support plate 15 with sufficient force and to bring the cap 17 into close contact with the support plate 15, it is preferable to dispose a plurality of bolts 191 on the flange 172 of the cap 17 along the circumferential direction of the flange 172, for example, three or more bolts 191 are preferably provided. However, if an excessive number of bolts 191 are provided, the installation work of the cap 17 will take time, so it is preferable that the number of bolts 191 is ten or less. Depending on the number of bolts 191, bolt holes 21 can be provided in the flange 172 of the cap 17 and the support plate 15.

[0068] The size of bolt 191 is not particularly limited, but may be one or more sizes selected from, for example, M8, M9, and M10. Bolt hole 21 may have a size corresponding to the bolt to be used.

[0069] However, as described later, it is preferable to place resin 22 between bolt 191 and bolt hole 21. For this reason, it is preferable to have a gap at least partially between the side surface of the shaft portion of bolt 191 and the inner surface of bolt hole 21 so that resin 22 can be filled when bolt 191 is inserted into bolt hole 21. In particular, it is more preferable that a gap that is continuous in the depth direction of bolt hole 21 is generated between the side surface of the shaft portion of bolt 191 and the inner surface of bolt hole 21 when bolt 191 is inserted into bolt hole 21. The gap that is continuous in the depth direction of bolt hole 21 here includes a gap that is formed continuously in the depth direction so as to follow an uneven surface such as a thread or a screw groove. Therefore, it is preferable to select the size of bolt 191 and bolt hole 21 so that the above gap is generated.

[0070] The end structure 10 may also have a washer 192 between the bolt 191 and the flange 172 of the cap 17. When the washer 192 is provided, it is preferable to use a metal washer made of a more noble metal than the support plate 15 for the washer 192 in order to improve corrosion resistance. The washer 192 is preferably made of, for example, stainless steel. By making the washer 192 out of stainless steel, rust generation on the washer 192 can be suppressed and durability can be improved.

[0071] The stainless steel is not particularly limited, and may be, for example, one or more selected from SUS 304, SUS 305, SUS 312, SUS 316, and SUS 347. By using the above stainless steel, strength and corrosion resistance can be particularly improved. (1-6) Resin As described above, from the viewpoint of increasing the corrosion resistance of the bolts 191 that fix the cap 17 to the support plate 15, it is preferable to use bolts made of a metal more noble than the support plate 15. In this case, however, severe corrosion may occur in the support plate 15 near the contact point between the bolts 191 and the support plate 15, and the force of the bolts 191 to fix the cap 17 may decrease. As a result of investigations, the inventors of the present invention found that the corrosion occurs due to the infiltration of moisture into the contact point between the support plate 15, which is a metal with a different ionization tendency, and the bolts 191.

[0072] Therefore, in the end structure of this embodiment, by disposing resin 22 between the bolt 191 and the bolt hole 21 provided to pass through the cap 17 and the support plate 15, it is possible to suppress the infiltration of moisture into the bolt hole 21, resulting in an end structure with high durability.

[0073] Resin 22 may be arranged so as to prevent moisture from entering bolt hole 21. For example, resin 22 is preferably arranged so as to prevent water from entering the contact area between support plate 15 and bolt 191.

[0074] For this reason, it is preferable that resin 22 be disposed at least in bolt hole 21 on the opening 21C side of bolt hole 21 relative to support plate 15.

[0075] 2, the bolt hole 21 can have a threaded portion 211 which is a region where a thread groove 151 that fits with the threads of the bolt 191 is provided on an inner surface 21B of the bolt hole 21, and a non-threaded portion 212 which is a region closer to the opening 21C of the bolt hole 21 than the threaded portion 211. In this case, it is preferable that resin 22 is filled between the bolt 191 and the bolt hole 21 in at least a part of the non-threaded portion 212.

[0076] 2, threaded portion 211 can be provided on support plate 15. For this reason, in at least a portion of non-threaded portion 212 arranged closer to opening 21C of bolt hole 21 than support plate 15, resin 22 is filled between bolt 191 and bolt hole 21, thereby making it possible to particularly suppress the infiltration of water into the contact portion between support plate 15 and bolt 191.

[0077] That resin 22 is filled between bolt 191 and bolt hole 21 in at least a portion of non-threaded portion 212 means that, for example, when observed at multiple cross sections perpendicular to the longitudinal direction of the shaft of bolt 191, resin 22 is filled in that portion on at least one of the faces.

[0078] It is preferable that resin 22 does not contain visible bubbles inside. When resin 22 does not contain visible bubbles inside, the strength of resin 22 is increased, and infiltration of water into the space between bolt 191 and bolt hole 21 can be particularly suppressed.

[0079] As described below, a graduated syringe can be used to inject and fill bolt hole 21 with an amount of resin 22 that corresponds to the capacity of bolt hole 21. At this time, by injecting and filling bolt hole 21 with resin 22 while checking that no air has been mixed into the resin in the graduated syringe, it is possible to fill bolt hole 21 with a sufficient amount of resin 22 and to ensure that resin 22 does not contain any visible bubbles.

[0080] The resin 22 is not particularly limited as long as it can fill the space between the bolt 191 and the bolt hole 21 and prevent water from entering.

[0081] For example, one or more types of resin selected from acrylic and silicone resins can be used as resin 22. By using one or more types of resin selected from acrylic and silicone resins as resin 22, the space between bolt 191 and bolt hole 21 can be sufficiently filled with the resin, and water intrusion can be sufficiently suppressed.

[0082] Furthermore, the viscosity of the resin 22 before curing is preferably 1300 mPa·s or more and 50000 mPa·s or less, and more preferably 1300 mPa·s or more and 13000 mPa·s or less.

[0083] Resin 22 can be filled, for example, in bolt hole 21, and then bolt 191 can be inserted into bolt hole 21, thereby filling the space between bolt 191 and bolt hole 21. When inserting bolt 191 into bolt hole 21, resin 22 can also be applied to the shaft portion of bolt 191, which is the portion that is inserted into bolt hole 21. However, the orientation of bolt hole 21 changes depending on the installation position of PC steel material 12, and for example, it may be formed horizontally as shown in Figures 1 and 2, or it may be formed tilted from the horizontal.

[0084] When the viscosity of resin 22 before hardening is 1300 mPa·s or more, even when bolt hole 21 is formed so as to be horizontal, leakage of resin 22 from bolt hole 21 is prevented, and resin 22 can be more reliably filled in the space between bolt 191 and bolt hole 21.

[0085] Furthermore, when the viscosity of resin 22 before hardening is 50,000 mPa·s or less, resin 22 can be easily filled into bolt hole 21, and resin 22 can be more reliably filled into the space between bolt 191 and bolt hole 21.

[0086] The viscosity can be measured by an Ubbelohde viscometer in accordance with JIS Z 8803 (2011) at a temperature of 25° C. Unless otherwise specified, the viscosity in this specification is the viscosity measured under the above measurement conditions.

[0087] The time required for resin 22 to harden is preferably 24 hours or less, and more preferably 18 hours or less. When the time required for hardening is 24 hours or less, it is possible to prevent resin 22 from flowing out of bolt hole 21 after filling bolt hole 21 with resin and inserting and tightening the bolt until resin 22 hardens. This is because a sufficient amount of resin 22 can be filled between bolt 191 and bolt hole 21.

[0088] Furthermore, if the time required for hardening is 24 hours or less, the resin 22 will harden and lose its fluidity from the next day after the bolts are inserted and tightened. Therefore, by checking the condition the day after construction, it is possible to ensure that the resin 22 does not flow out of the bolt holes 21.

[0089] There is no particular lower limit to the time required for resin 22 to harden, but taking into consideration the ease of filling bolt holes 21, it is preferably 30 minutes or more, and more preferably 1 hour or more.

[0090] The resin 22 is cured when the resin no longer adheres to the fingertip when the surface of the resin test piece is lightly touched with the fingertip. The time required for curing refers to the time required for the resin to no longer adhere to the fingertip when the surface of the resin test piece is touched with the fingertip after the resin test piece is produced. (1-7) Gasket A rubber packing 16 may be provided between the bearing plate 15 and the cap 17. In this case, the bolt holes 21 are provided so as to pass through the cap 17, the packing 16, and the bearing plate 15.

[0091] By disposing the packing 16 between the support plate 15 and the cap 17, when the filler 18 is filled into the area B surrounded by the support plate 15 and the cap 17, it is possible to suppress leakage of the filler 18 from between the support plate 15 and the cap 17. Also, since the support plate 15 and the cap 17 can be configured not to be in direct contact with each other, it is possible to particularly prevent electrolytic corrosion from occurring between the support plate 15 and the cap 17. Furthermore, the packing 16 and the above-mentioned resin 22 particularly increase the airtightness of the space between the bolt 191 and the bolt hole 21, and it is possible to more reliably prevent water from entering the space between the bolt 191 and the bolt hole 21.

[0092] The material of the packing is not particularly limited, but is preferably an elastic material having elasticity, for example, a polymer material can be suitably used. The packing 16 can be made of one or more types of rubber selected from, for example, chloroprene rubber, nitrile rubber, hydrogenated nitrile rubber, fluororubber, silicone rubber, ethylene propylene rubber, urethane rubber, etc. (1-8) Filler Filler 18 can be filled and placed in the area surrounded by cap 17 and support plate 15. By placing filler 18, corrosion of fastener 14 in cap 17 and support plate 15 can be suppressed.

[0093] The material of the filler 18 is not particularly limited, and various fillers can be used, for example, one or more types selected from epoxy resin, pre-grout resin, wax, cement grout, asphalt, and the like. 2. Manufacturing method of end structure Next, a method for manufacturing the end structure of this embodiment will be described. According to the method for manufacturing the end structure of this embodiment, the end structure already described can be manufactured. Therefore, the description of the matters already described will be omitted.

[0094] The manufacturing method of the end structure of this embodiment can be carried out according to the flow chart 40 shown in Figure 4, and can include the following installation process (S1), filling process (S2), tightening process (S3), and wiping process (S4).

[0095] Each step will be described below. (1) Installation process (S1) In the installation process (S1), a metal cap 17 can be installed to cover the end 12A of the PC steel 12, the fixing device 14 that grips the end 12A side of the PC steel 12, and the support plate 15 that supports the fixing device 14.

[0096] When packing 16 is installed between support plate 15 and cap 17, installation of packing 16 can also be performed in the installation step (S1).

[0097] When installing cap 17 in the installation process, the position of cap 17 can be adjusted so that bolt holes 21 provided in support plate 15 and cap 17 become continuous holes. When packing 16 is provided, the positions of packing 16 and cap 17 can be adjusted so that bolt holes 21 provided in support plate 15, packing 16, and cap 17 become continuous holes. (2) Filling process (S2) Filling process (S2) In the filling step (S2), the bottomed bolt hole 21 provided so as to pass through the support plate 15 and the cap 17 can be filled with the (pre-cured) resin 51.

[0098] In the filling step (S2), for example, as shown in FIG. 5, resin 51 can be filled so as to fill bolt hole 21, that is, to fill up to opening 21C of bolt hole 21.

[0099] For example, one or more types of resin selected from acrylic and silicone resins can be used as resin 51. By using one or more types of resin selected from acrylic and silicone resins as resin 51, the space between bolt 191 and bolt hole 21 can be sufficiently filled, and water intrusion can be sufficiently suppressed.

[0100] Furthermore, the viscosity of resin 51 is preferably 1300 mPa·s or more and 50000 mPa·s or less, and more preferably 1300 mPa·s or more and 13000 mPa·s or less.

[0101] After resin 51 is filled so as to fill bolt hole 21 as described above, bolt 191 is inserted, thereby filling the resin into the space between bolt 191 and bolt hole 21. When inserting bolt 191 into bolt hole 21, resin 51 can also be applied to the shaft of bolt 191. However, the orientation of bolt hole 21 changes depending on the installation position of PC steel material 12, and for example, it may be formed so as to be horizontal as shown in Fig. 5, or it may be formed so as to be tilted from the horizontal.

[0102] When the viscosity of resin 51 is 1300 mPa·s or more, even when bolt hole 21 is formed horizontally, leakage of resin 51 from bolt hole 21 is prevented, and resin 51 can be more reliably filled in the space between bolt 191 and bolt hole 21.

[0103] Furthermore, when the viscosity of resin 51 is 50000 mPa·s or less, resin 51 can be easily filled into bolt hole 21, and resin 51 can be filled into the space between bolt 191 and bolt hole 21 more reliably.

[0104] The inventors of the present invention evaluated the relationship between the viscosity of resin 51 and the occurrence of liquid leakage using the instruments and procedures shown in FIGS. 6A and 6B.

[0105] Specifically, first, as shown in Fig. 6A, resin 51 was filled into support plate 61, which is arranged, for example, along the vertical direction and has bolt holes 62 with openings 621 at the top. Then, it was rotated 90 degrees along arrow C so that bolt holes 62 were horizontal as shown in Fig. 6B. When the type of resin 51 filled into bolt holes 62 was changed and bolt holes 62 were made horizontal as shown in Fig. 6B, a study was conducted to determine whether or not resin 51 leaked from openings 621.

[0106] As a result, when the viscosity of the resin before curing was 1300 mPa s or more, as shown in Fig. 6B, no leakage of resin from opening 621 was observed even when bolt hole 62 was horizontal, and the same was true when it was rotated so that opening 621 was facing downward. In other words, it was confirmed that by using resin 51 with the above viscosity, leakage of resin from the bolt hole can be prevented and the space between bolt 191 and bolt hole 21 can be more reliably filled.

[0107] In the filling step (S2), resin 51 can also be filled by forcing it into bolt hole 21 using rod-shaped body 52, as shown in FIG.

[0108] Even if the viscosity of the resin to be filled is high, a sufficient amount of resin can be filled in the bolt hole by pushing the resin into the bolt hole using a rod-shaped body, and when the bolt is inserted in the tightening process and the resin hardens, a sufficient amount of resin can be filled between the bolt and the bolt hole. This makes it possible to suppress the infiltration of moisture into the bolt hole and to produce an end structure with high durability.

[0109] In particular, when the viscosity of resin 51 is 30,000 mPa·s or more, the viscosity is high and it may be difficult to fill bolt hole 21 with resin 51. In contrast, by forcing resin 51 into bolt hole 21 using rod-shaped body 52 as described above, resin 51 can be easily filled into bolt hole 21.

[0110] Although there are no particular limitations on rod-shaped body 52, it is preferable that at least a portion of it can be inserted into bolt hole 21. For this reason, when rod-shaped body 52 has a cylindrical shape, it is preferable that diameter D52 of the surface facing bolt hole 21 is smaller than diameter D21 of bolt hole 21 on the opening 21C side.

[0111] Also, in the filling step (S2), a graduated syringe can be used to inject and fill bolt hole 21 with an amount of resin that corresponds to the capacity of bolt hole 21.

[0112] By measuring the capacity of bolt hole 21 in advance and using a graduated syringe to inject and fill bolt hole 21 with an amount of resin according to the capacity of bolt hole 21, it is possible to prevent insufficient filling of resin and excessive overflow of resin in the tightening step (S3) described below. Also, by injecting and filling resin 22 into bolt hole 21 while checking that no air has been mixed in with the resin in the graduated syringe, it is possible to fill bolt hole 21 with a sufficient amount of resin 22 and to ensure that resin 22 does not contain any visible bubbles.

[0113] As the graduated injector, for example, a syringe-type injector can be used, and it is preferable that at least a part of the injector is transparent so that the resin inside can be seen.

[0114] The resin and other details such as the suitable curing time have already been explained, so the explanation will be omitted here. (3) Fastening process (S3) In the tightening step (S3), a metal bolt 191 made of a metal more noble than the support plate 15 is inserted into the bolt hole 21, and the cap 17 can be fixed to the support plate 15 by tightening the bolt 191.

[0115] Note that resin 51 may also be applied to the shaft portion of bolt 191 before it is inserted into bolt hole 21. In other words, a coating step may be further included before the tightening step (S3), in which resin is applied in advance to at least the shaft portion of bolt 191, which is the portion to be inserted into bolt hole 21.

[0116] In the application step, for example, the resin can be applied by putting the resin in a cup or the like and immersing the shaft portion of the bolt 191 in the resin in the cup.

[0117] By applying resin 51 also to the shaft portion of bolt 191, which is the portion that is inserted into bolt hole 21, resin 51 can be filled in the space between bolt 191 and bolt hole 21 more reliably. (4) Wiping process (S4) In the wiping step (S4), resin 51 that overflowed in the tightening step (S3) can be wiped away. Since resin 51 was filled so as to fill bolt hole 21 in the filling step (S2), inserting bolt 191 into bolt hole 21 and tightening it in the tightening step (S3) causes resin 51 to overflow from bolt hole 21. By seeing resin 51 overflowing in this way, it can be confirmed that a sufficient amount of resin 51 has been filled in the space between bolt 191 and bolt hole 21.

[0118] According to the method for manufacturing an end structure of this embodiment, an end structure including a metal cap can be manufactured.

[0119] In addition, in the manufacturing method of the end structure of this embodiment, resin can be placed between the bolt and the bolt hole provided to pass through the cap and the support plate, thereby suppressing the infiltration of moisture into the bolt hole, and resulting in an end structure with high durability. (5) Other processes The manufacturing process of the end structure of this embodiment may further include a filler filling step of filling a filler into the cap 17. The filling method of the filler and suitable fillers that can be used have already been described, so a description thereof will be omitted here. EXAMPLES

[0120] The present invention will be described below with reference to specific examples, but is not limited to these examples.

[0121] Of the following Experimental Examples 1 to 3, Experimental Examples 1 and 2 are working examples, and Experimental Example 3 is a comparative example. [Experimental Example 1] (1) Fabrication of end structure An end structure 10 having the structure shown in FIGS. 1 and 2 was produced.

[0122] Specifically, an end structure 10 was produced having a PC steel member 12, a fixing device 14, a support plate 15, a cap 17 covering the end portion 12A of the PC steel member 12, the fixing device 14, and the support plate 15, a bolt 191 for fixing the cap 17, and resin 22 arranged between the bolt 191 and the bolt hole.

[0123] As the PC steel material 12, a PC steel strand was used.

[0124] The fixing device 14 is made of carbon steel, has a male cone and a female cone, and grips the end 12A side of the PC steel material 12.

[0125] The bearing plate 15 is made of carbon steel and supports the fastener 14 .

[0126] 1 and 3, the cap 17 has a shape including a body portion 171 with a flat upper surface 17A and a flange portion 172. A first filler introduction hole 1731 and a second filler introduction hole 1732 are provided on the upper surface 17A.

[0127] The bolt 191 and the washer 192 are made of stainless steel, specifically, SUS304.

[0128] As the resin 22, an acrylic resin with a viscosity of 1300 mPa·s was used.

[0129] According to the flow chart 40 shown in FIG. 4, the film was produced in the following procedure. (1) Installation process (S1) A cap 17 was placed so as to cover the end 12A of the PC steel 12, the fixing tool 14 gripping the end 12A side of the PC steel 12, and the support plate 15 supporting the fixing tool 14. At this time, a packing 16 made of chloroprene rubber was placed between the support plate 15 and the cap 17.

[0130] The support plate 15, the packing 16, and the flange portion 172 of the cap 17 are provided with bottomed bolt holes 21, and the packing 16 and the cap 17 are aligned so that the bolt holes 21 in the support plate 15, the packing 16, and the cap 17 form continuous holes.

[0131] The PC steel members 12 are installed inside the concrete structure 11 via a sheath 13, and tension is applied to them beforehand. (2) Filling process (S2) Resin 51 was filled into bottomed bolt hole 21 provided to pass through support plate 15, packing 16, and cap 17. At this time, as shown in Fig. 5, resin 51 was filled using a graduated syringe so as to fill bolt hole 21, that is, to fill up to opening 21C of bolt hole 21. When filling resin 51 using the graduated syringe, the resin was injected and filled into the bolt hole while checking that no air had been mixed into the resin in the graduated syringe.

[0132] Bolt holes 21 were horizontal as shown in Figs. 1 and 2, and when resin 51 was filled into bolt holes 21, no leakage was observed and the filling could be completed easily.

[0133] Four bolt holes 21 are provided at equal intervals along the circumferential direction of flange 172 of cap 17, and resin was filled into all of bolt holes 21. Bottom 21A of bolt hole 21 is provided within support plate 15, and thread groove 151 into which bolt 191 fits is provided on inner surface 21B of bolt hole 21 within support plate 15. The sizes of bolt 191 and bolt hole 21 are selected so that when bolt 191 is inserted into bolt hole 21, a continuous gap through which resin can flow is generated between the side surface of the shaft of bolt 191 and the inner surface of bolt hole 21 along the depth direction of bolt hole 21. (3) Fastening process (S3) Bolt 191 with washer 192 attached was inserted into bolt hole 21, and bolt 191 was tightened to fix cap 17 to support plate 15. The above-mentioned resin was also applied to the shaft of bolt 191 before insertion into bolt hole 21. The resin was applied to the shaft of bolt 191 by putting the resin in a cup and immersing the shaft of bolt 191 in the resin in the cup. (4) Wiping process (S4) Resin 51 that overflowed from bolt holes 21 in the tightening step (S3) was wiped off with a rag. Since a sufficient amount of resin overflowed from each of bolt holes 21, it can be said that resin has filled the space between bolt 191 and bolt hole 21 in at least a part of non-threaded portion 212 shown in FIG.

[0134] After the bolt 191 was tightened and the resin hardening time (24 hours) had elapsed, it was confirmed that the resin sealing material was not leaking from around the bolt 191.

[0135] Thereafter, cement, which is a filler, was filled into the region B inside the cap 17 through the first filler introduction hole 1731 (filler filling step). (2) Evaluation A rust test was carried out in which seawater was sprayed onto the outer surface of the end structure 10, and it was confirmed whether rust was observed after 1000 hours had elapsed.

[0136] No rust was observed even after 1000 hours, confirming that the end structure obtained was usable even in an environment exposed to the outside air. [Experimental Example 2] An end structure 10 was produced and evaluated in the same manner as in Experimental Example 1, except that a silicone-based resin (silicone sealant) with a viscosity of 30,000 mPa·s and a curing time of 24 hours was used in the filling step (S2).

[0137] Since silicone resin has a high viscosity, the resin was filled into the bolt hole by pushing it using a rod-shaped body 52. ​​The rod-shaped body 52 used had a cylindrical shape, and the diameter D52 of the surface facing the bolt hole 21 was smaller than the diameter D21 of the bolt hole 21 on the opening 21C side.

[0138] As a result of the rust test, no rust was observed even after 1000 hours, and it was confirmed that the end structure obtained could be used even in an environment exposed to the outside air. [Experimental Example 3] The filling step (S2) was not performed, and in the tightening step (S3), bolt 191 with washer 192 attached was inserted and tightened in a state in which bolt hole 21 was not filled with resin. Therefore, no resin was disposed between bolt 191 and bolt hole 21. In addition, since resin was not filled, the wiping step (S4) was not performed either.

[0139] Except for the above points, the end structure 10 was produced in the same manner as in Experimental Example 1, and was evaluated.

[0140] As a result of the rusting test, rusting was confirmed near the tip of the bolt 191. Therefore, it was confirmed that the force fixing the cap 17 may decrease if it is exposed to the outside air for a long period of time. [Explanation of symbols]

[0141] 10 End structure 11 Concrete Structures 12 PC steel material 12A PC steel end 13 Sheath 14 Fixture 15 Bearing plate 151 Thread groove 16 Packing 17 Cap 17A Top 171 Torso 172 Flange 1731 1st filler introduction hole 1732 2nd filler introduction hole 18 Filling material 191 Volts 192 Washer Area A B area 21 Bolt holes D21 diameter 21A Bottom of bolt hole 21B Inner surface of bolt hole 21C Bolt hole opening 211 Threaded part 212 Non-threaded part 22 Resin 40 Flow Diagram S1 Installation process S2 Filling process S3 Tightening process S4 Wiping process 51 Resin (before hardening) 52 Rod-shaped body D52 diameter 61 Bearing plate 62 Bolt holes 621 Opening C Arrow

Claims

1. PC steel material, A fixing tool that holds the PC steel material; A support plate for supporting the fixing tool; A metal cap that covers the end of the PC steel, the fixing device, and the support plate; a metal bolt inserted into a bottomed bolt hole provided to pass through the cap and the support plate, the metal bolt being made of a more noble metal than the support plate; An end structure having a resin disposed between the bolt and the bolt hole.

2. The end structure according to claim 1 , wherein the resin is one or more types of resin selected from acrylic and silicone resins.

3. 3. An end structure according to claim 1 or claim 2, wherein the bolts are made of stainless steel.

4. An end structure according to any one of claims 1 to 3, wherein the cap is made of stainless steel.

5. 5. The end structure according to claim 3 or 4, wherein the stainless steel is at least one selected from the group consisting of SUS304, SUS305, SUS312, SUS316 and SUS347.

6. The end structure according to any one of claims 1 to 5, wherein the support plate is made of carbon steel.

7. A rubber packing is provided between the support plate and the cap, The end structure according to any one of claims 1 to 6, wherein the bolt holes are provided so as to pass through the cap, the packing, and the support plate.

8. the bolt hole has a threaded portion which is a region on an inner surface of the bolt hole having a thread groove for engaging with the threads of the bolt, and a non-threaded portion which is a region closer to an opening of the bolt hole than the threaded portion, The end structure according to claim 1 , wherein the resin is filled between the bolt and the bolt hole in at least a part of the non-threaded portion.

9. an installation process of installing a metal cap so as to cover the end of the PC steel, the fixing tool that grips the end side of the PC steel, and the support plate that supports the fixing tool; a filling step of filling a bottomed bolt hole provided so as to pass through the support plate and the cap with resin; a tightening process of inserting a metal bolt made of a metal more noble than the support plate into the bolt hole and tightening the bolt to fix the cap to the support plate; and a wiping step of wiping off the resin that has overflowed in the tightening step.

10. The method for manufacturing an end structure according to claim 9 , wherein in the filling step, the resin is filled by forcing it into the bolt hole using a rod-shaped body.

11. 11. The method for manufacturing an end structure according to claim 9 or 10, wherein in the filling step, a graduated syringe is used to inject and fill the bolt hole with an amount of the resin according to the capacity of the bolt hole.

12. The method for manufacturing an end structure according to any one of claims 9 to 11, further comprising a coating step of coating at least a portion of the bolt to be inserted into the bolt hole with the resin before the tightening step.

13. The method for manufacturing an end structure according to any one of claims 9 to 12, wherein the resin filled into the bolt hole in the filling step has a viscosity of 1300 mPa·s or more and 50000 mPa·s or less.

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