Intermediate anchoring device for newly installed or existing prestressing steel members and intermediate anchoring method using the same

Abstract

To provide an intermediate anchorage assembly suitably used for PC steel in a strained state and excellent in workability with a small number of parts.SOLUTION: An intermediate anchorage assembly 30 comprises a sleeve 100 separated detachably on PC steel B in a strained state and a wedge 140, wherein the sleeve 100 is separated into a sleeve piece 110 of an inner cylindrical side in a hollow cylindrical shape with a taper combined with a taper of the wedge 140 and a sleeve piece 120 of an outer cylindrical side in a hollow cylindrical shape which is arranged outside of the sleeve piece 110 of the inner cylindrical side so as to function as a sleeve by integrally assembling the sleeve 100 with the wedge 140 through connection of the sleeve piece 110 and the sleeve piece 120.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an intermediate fixing device that is suitably used for newly installed or existing PC steel members in a tensioned state, and an intermediate fixing construction method using the same. In the present invention, the terms wedge, cudgel, wedge, and wedge may be used, but they all have the same structure. In addition, the prestressing steel materials in the newly installed or existing prestressing steel materials (sometimes referred to as prestressing steel materials) that are the subject of the present invention include prestressing steel wires, prestressing steel bars, prestressing steel strands (PC steel strands), and prestressing steel materials whose outer surfaces are covered (coated) with resin (such as epoxy). [Background technology]

[0002] Some concrete structures have prestress introduced by the tension of embedded tendons. Such concrete structures may require partial removal for repair, reinforcement, renovation, etc. For example, part of the bridge girder in the width direction may be removed and the remaining part may be replaced with a new girder while maintaining traffic on the remaining part. Also, when part of the bridge girder in the axial direction, such as the girder end, deteriorates and requires repair, the girder end may be removed and new concrete may be poured to repair it. In addition, part of the building may be demolished.

[0003] In such a case, a continuous tendon is arranged between the part to be removed and the part to be left, and if prestress has been introduced, the middle part of the tendon is exposed and an intermediate fixing device is attached to fix it to the concrete of the part to be left. Then, the tendon in a state where tension has been introduced is maintained in the part to be left of the concrete structure, and the tendon in the part to be removed is cut and the concrete structure is removed.

[0004] For example, JP 2018-017029 A (Patent Document 1) discloses an intermediate fixing structure that fixes the tension material in the intermediate portion while tension is being applied to it. The intermediate fixing structure disclosed in Patent Document 1 is characterized in that a fixing block is formed by joining a pair of half blocks that are separable from each other, a tensioning material is inserted into a hollow hole formed between the pair of half blocks, the fixing block and the tensioning material are joined by a filler material that is filled between the tensioning material and the inner surface of the hollow hole and hardened, the fixing block is fixed to a structure so as to transmit the tension of the tensioning material, and a plurality of protrusions are formed on the outer surface of the portion of the tensioning material inserted into the hollow hole from metal that is adhered by metal spraying. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-017029 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, while it is possible to form a sleeve in the hollow hole in the intermediate fixing structure disclosed in the above-mentioned Patent Document 1 and combine this sleeve with a corresponding wedge to create an intermediate fixing device (an intermediate fixing device having a configuration in which the half sleeve is bolted together using a half sleeve and a half wedge), such an intermediate fixing device has a large number of parts, which makes it heavy and difficult to work with.

[0007] The present invention was developed in consideration of the above-mentioned problems of the prior art, and its object is to provide an intermediate fixing device with excellent workability that can be suitably used for newly installed or existing PC steel members in a tensioned state, and an intermediate fixing construction method using the same. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, the intermediate fixing device for newly installed or existing PC steel members and the intermediate fixing construction method using the same according to the present invention employ the following technical measures. That is, the intermediate fixing device for a newly or existing prestressing tendon according to one aspect of the present invention is an intermediate fixing device that is suitably used for a prestressing tendon in a tensioned state in the middle of a newly or existing concrete structure, and is fixed to two or more wedge pieces when viewed from a plane perpendicular to the longitudinal direction of the prestressing tendon. The present invention includes a divided wedge, and a sleeve divided into an inner sleeve piece having a taper that is combined with the wedge, and an outer sleeve piece provided outside the inner sleeve piece, and the inner sleeve piece and the outer sleeve piece have at least a notch into which the PC steel can be inserted as viewed from a plane perpendicular to the longitudinal direction of the PC steel, and the inner sleeve piece and the outer sleeve piece are joined together to form a sleeve that functions as a sleeve combined with the wedge. The outer sleeve piece may be, for example, a sheet made of FRP (Fiber Reinforced Plastics), and the inner sleeve piece and the outer sleeve piece may be integrated as a sleeve by wrapping the sheet-like outer sleeve piece around the outer periphery of the inner sleeve piece. In this case, the notch of the sheet-like outer sleeve piece is not an essential component.

[0009] Preferably, a key can be provided spanning a key groove provided on the outer peripheral surface of the sleeve piece on the inner tube side and a key groove provided on the inner peripheral surface of the sleeve piece on the outer tube side, and the sleeve piece on the inner tube side and the sleeve piece on the outer tube side can be joined together to form an integrated sleeve. More preferably, the sleeve piece on the inner tube side and the sleeve piece on the outer tube side can be configured so that they are integrated as a sleeve by screwing together a male thread provided on the outer peripheral surface of the sleeve piece on the inner tube side and a female thread provided on the inner peripheral surface of the sleeve piece on the outer tube side.

[0010] In addition, an intermediate fixing device for newly installed or existing PC steel members relating to another aspect of the present invention is an intermediate fixing device that is suitably used for PC steel members in a tensioned state in the middle of a newly installed or existing concrete structure, and includes a wedge divided into two or more wedge pieces when viewed from a plane perpendicular to the longitudinal direction of the PC steel member, and a sleeve having a taper that can be combined with the wedge and a slit portion through which the PC steel member can be inserted when viewed from a plane perpendicular to the longitudinal direction of the PC steel member, and is characterized in that the opposing wall surfaces in the slit portion are connected using a connecting member, thereby regulating the spacing of the slit portion when viewed from the perpendicular plane, and functions as a sleeve that can be combined with the wedge.

[0011] Preferably, the connecting member includes a female threaded hole provided in at least one of the opposing wall surfaces and a male screw passed through a hole provided in the other wall surface, and the male screw is screwed into the female threaded hole to connect the wall surfaces, thereby regulating the spacing of the slit portions as viewed from the vertical plane. More preferably, the sleeve further includes a flat plate joined to the sleeve at an end face in the direction in which the taper widens and which is perpendicular to the longitudinal direction of the PC steel, the plate having a cutout into which the PC steel can be inserted when viewed from a plane perpendicular to the longitudinal direction of the PC steel and into which a wedge protrusion provided at the end of the wedge in the direction in which the taper widens can protrude, and the plate can be configured so that by joining the end face of the sleeve, the wedge is positioned at a predetermined position on the sleeve and the wedge protrusion protrudes from the cutout of the plate.

[0012] More preferably, the wire clip further includes a three-dimensional wire clip, the wire clip having at least a straight portion in the sleeve corresponding to the longitudinal length of the PC steel, an arc portion which is fitted into a wedge groove provided on the outer periphery of the end of the wedge in the direction in which the taper widens, on the side of the sleeve where the taper widens relative to the straight portion, and an insertion piece which is fitted into a sleeve hole provided on the end face of the sleeve in the direction in which the taper narrows, which is perpendicular to the longitudinal direction of the PC steel, on the side of the sleeve where the taper narrows relative to the straight portion, so that the arc portion of the wire clip is fitted into the wedge groove and the insertion piece of the wire clip is fitted into the sleeve hole, so that the wedge is positioned at a predetermined position in the sleeve and the straight portion of the wire clip is arranged along the outer periphery of the sleeve.

[0013] According to yet another aspect of the present invention, there is provided an intermediate fixing method for a newly or existing prestressing tendon using an intermediate fixing device that is suitably used for a prestressing tendon in a tensioned state in an intermediate portion of a newly or existing concrete structure, the method comprising the steps of: The method includes a wedge divided into two or more wedge pieces when viewed from a plane perpendicular to the longitudinal direction of the PC steel, and a sleeve having a taper that can be combined with the wedge and a structure that can be attached to the PC steel in a tensioned state, and includes a step of chipping the concrete to expose the PC steel in a tensioned state when the PC steel to be fixed by the intermediate fixing device is embedded in concrete, and a step of attaching the two or more divided wedge pieces to the PC steel in a tensioned state so that the taper of the wedge narrows in the direction of the concrete to introduce compressive force. the sleeve having a structure that can be attached to the PC steel member so that the taper of the sleeve narrows in the direction of the concrete into which the compressive force is introduced; a sleeve functioning step of making the sleeve function as a sleeve that can be combined with the wedge; and an insertion step of inserting two or more wedge pieces that are attached to the PC steel member in the divided state into the sleeve that has been made to function as a sleeve, with the taper direction of the wedge and the taper direction of the sleeve aligned.

[0014] Preferably, the inserting step may be configured to insert the wedge into the sleeve manually by an operator without the use of a jack. Effect of the Invention

[0015] The intermediate fixing device for newly installed or existing PC steel members and the intermediate fixing method using the same of the present invention make it possible to provide an intermediate fixing device with excellent workability that is suitably used for newly installed or existing PC steel members that are in a tensioned state, and an intermediate fixing method using the same. [Brief description of the drawings]

[0016] [Figure 1]This is a diagram for explaining the application (division of work area) of an intermediate fixing device (intermediate fixing device 30) of an embodiment of the present invention to a newly constructed concrete structure (prestressed concrete member) in which the use is expected. [Diagram 2] A diagram for explaining the application (repair) of an intermediate fixing device (intermediate fixing device 30) of an embodiment of the present invention to an existing concrete structure (prestressed concrete member) in which the use is expected. [Diagram 3] 2A to 2C are diagrams for explaining a usage mode of an intermediate fixing device (intermediate fixing device 30) according to an embodiment of the present invention. [Figure 4] 1 is a plan view of (A) a sleeve 100 (corresponding to sleeve S) and (B) a wedge 140 (corresponding to wedge W) that configure the intermediate fixing tool 30. FIG. [Diagram 5] 5A is a plan view showing a state in which sleeve 100 (corresponding to sleeve S) in FIG. 4 functions as a sleeve that can be combined with wedge 140 (corresponding to wedge W), and FIG. 5B is a diagram for explaining the function of a shear key. [Figure 6] FIG. 5 is a diagram for explaining a procedure for attaching intermediate fastener 30 using sleeve 100 (corresponding to sleeve S) and wedge 140 (corresponding to wedge W) in FIG. 4 to a PC steel member. [Figure 7] 1A is a plan view of a sleeve 200 (corresponding to sleeve S) (different from sleeve 100) and (B) a wedge 240 (corresponding to wedge W) (different from wedge 140) that constitute the intermediate fixing device 30. FIG. [Figure 8] FIG. 8 is a diagram for explaining a procedure for attaching intermediate fastener 30 using sleeve 200 (corresponding to sleeve S) and wedge 240 (corresponding to wedge W) in FIG. 7 to a PC steel member. [Figure 9] This is a plan view showing the state in which sleeve S10, sleeve S11, or sleeve S20 (corresponding to sleeve S) that constitutes intermediate fixing device 30 (separate from sleeve 100 and sleeve 200) functions as a sleeve that can be combined with wedge W (same as wedge 140). [Figure 10]13 is a diagram showing the test results obtained by using test specimens to evaluate an intermediate fixing device 30 according to an embodiment of the present invention. FIG. [Figure 11] FIG. 11 is a diagram for explaining an intermediate fixing device according to a first modified example of an embodiment of the present invention. [Figure 12] 13A and 13B are diagrams illustrating an intermediate fixing device according to a second modified example of the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Below, we will provide a detailed explanation of an intermediate fixing device that is suitable for use with tensioned PC steel members that are applying compressive force to newly constructed or existing prestressed concrete members, and an intermediate fixing construction method that is suitable for use with newly constructed or existing prestressed concrete members using the intermediate fixing device, which is an embodiment of the present invention. In the figures referred to in the following description, in order to facilitate understanding of the present invention, parts that should be represented by their exterior rather than their interior may be represented as if looking through the interior, parts that should be represented by a cross section rather than an exterior may be represented by an exterior, parts that should be represented by an exterior rather than a cross section may be represented by a cross section, cross sections may not be hatched, non-cross sections may be hatched, detailed structures may be omitted, and the same components may not match between drawings due to the omission of detailed structures.

[0018] <Structures where intermediate anchors are expected to be used> First, referring to Figure 1, we will explain an example of a newly constructed concrete structure (PC structure, prestressed concrete member, concrete body) in which the intermediate fixing device (intermediate fixing device 30) of an embodiment of the present invention is expected to be used. In the case of a newly constructed concrete structure, the construction section may be divided due to restrictions on the amount of concrete that can be poured at one time, etc. In this case, the length of the tension members (PC steel members) for the later construction section is prepared, but they may be temporarily stored in coil form due to storage space restrictions, etc. In this case, the anchor cannot be inserted from the end (the end of the coil). In such a case, it is assumed that the intermediate anchor according to the present invention will be adopted as shown in Figure 1 as a method of introducing prestress into the concrete structure in the earlier construction section.

[0019] Next, referring to Figure 2, we will explain an example of an existing concrete structure (PC structure, prestressed concrete member, concrete body) in which the intermediate fixing device (intermediate fixing device 30) of an embodiment of the present invention is expected to be used. Existing concrete structures may require repairs due to deterioration over time, etc., and when such repairs are made, openings are often made (the concrete is chipped away to expose the prestressing tendons in the openings) to fasten the existing prestressing tendons. In this case, since both ends of the tendons (existing prestressing tendons) are embedded inside the concrete, fasteners cannot be inserted from the ends. In such cases, it is envisaged that an intermediate fastener according to the present invention will be used as shown in Figure 2 as a method of introducing prestress.

[0020] Fig. 3 shows an image of an intermediate anchor (intermediate anchor 30) according to the present invention being used in a new or existing concrete structure (PC structure, prestressed concrete member, concrete body). The intermediate anchor is attached to the existing prestressing steel member, which is in a tensioned state, to tension the existing prestressing steel member. We will now explain in detail the wedge W, which clamps the new or existing PC steel B on its inner surface and has a tapered outer surface, and the sleeve S, which has an inner surface that follows the tapered surface of the wedge W, that constitute the intermediate fixing device (intermediate fixing device 30) used in the construction method shown in Figures 1 to 3.

[0021] The materials used for the sleeves S and wedges W may be metals, resins, chemical fibers, etc., and are not particularly limited, but in the following description they will be described as being the type of metal commonly used as fixing devices for PC steel members. In the intermediate fixing device according to the present embodiment, the sleeve S is roughly classified into two types (the inner cylinder-outer cylinder type shown in Figs. 4 to 8 and the slit wall surface connection type shown in Fig. 9). There are two types of Wedge W (Wedge W differs only in the number of divisions, while Sleeve S has a significantly different structure). 4 to 6, a sleeve 100 (inner cylinder, outer cylinder type, shear key joint type) will be described as the sleeve S, and a wedge 140 (three-part type) will be described as the wedge W. 7 and 8, a sleeve 200 (an inner cylinder, outer cylinder type, screw-in type) will be described as the sleeve S, and a wedge 240 (split into two parts) will be described as the wedge W. With reference to FIG. 9, sleeves S10 and S20 (slit wall surface connection type) will be described as the sleeve S (wedge W in FIG. 9 is the same as wedge 240 (3-split)).

[0022] Furthermore, two modified examples that can be commonly used for these will be described with reference to FIGS. The following intermediate fixing devices that can be used as the intermediate fixing device according to the present invention are known. The intermediate fixing device is attached to the middle part of a tension member (PC steel material including PC steel bar) in which tension has already been applied and both ends are fixed to a structure, and fixes the tension member to a surrounding structure while maintaining the tension applied to the tension member. More specifically, the intermediate fixing device is attached to the middle part of a tension member (PC steel material including PC steel bar) in which tension has already been applied and both ends are fixed to a structure, and fixes the tension member to a surrounding structure while maintaining the tension applied to the tension member. More specifically, the intermediate fixing device is attached to the middle part of a tension member (PC steel material including PC steel bar) in which tension has already been applied and both ends are fixed to a structure, and fixes the tension member to a surrounding structure while maintaining the tension applied to the tension member. More specifically, the intermediate fixing device is attached to the middle part of a tension member (PC steel material including PC steel bar) in which tension has already been applied and both ends are fixed to a structure. More specifically, the intermediate fixing device is attached to the middle part of a tension member. In the following explanation, an intermediate fixing device in which a sleeve is formed in this hollow hole and combined with a wedge corresponding to this sleeve (the configuration in which a wedge is combined with a sleeve in the intermediate fixing device described in JP 2018-017029 A is a configuration in which a half sleeve and a half wedge are used to bolt the half sleeve, and this configuration is approximately equivalent to the intermediate fixing device described in JP 57-084220 A filed by one of the applicants of the present application) may be described as prior art or comparative example.

[0023] <1: Inner and outer cylinder type: Shear key joint type> First, the sleeve 100 and the wedge 140 will be described. Figure 4(A) shows a plan view of sleeve 100 that constitutes intermediate fixing device 30, Figure 4(B) shows a plan view of wedge 140, Figure 5(A) shows a plan view showing the state in which sleeve 100 (corresponding to sleeve S) shown in Figure 4 functions as a sleeve that can be combined with wedge 140 (corresponding to wedge W), Figure 5(B) shows a diagram explaining the function of the shear key in the state in which it functions as a sleeve, and Figure 6 shows a diagram explaining the procedure for attaching intermediate fixing device 30 to new or existing PC steel B exposed from a PC structure using sleeve 100 and wedge 140 so that sleeve 100 (corresponding to sleeve S) functions as a sleeve that can be combined with wedge 140 (corresponding to wedge W).

[0024] This intermediate fixing device 30 is composed of a sleeve 100 shown in Fig. 4(A) and a wedge 140 shown in Fig. 4(B) which is combined with the sleeve 100. Note that the side view (partial cross-sectional view) on the left side of Fig. 4(A) is a view seen from the direction of arrow X shown in the front view on the right side, and the side view on the left side and the front view on the right side of Fig. 4(B) are views of the wedge 140 formed by combining three divided wedge pieces. Here, the front view is a view seen from a plane perpendicular to the longitudinal direction of the new or existing prestressing steel B, and the side view is a view seen from a plane parallel to the longitudinal direction of the new or existing prestressing steel B (the same applies below).

[0025] As shown in Fig. 4(B), the wedge 140 is divided into two or more wedge pieces (here, it is divided into three pieces, that is, wedge piece 142, wedge piece 144, and wedge piece 146) when viewed from a plane perpendicular to the longitudinal direction of the new or existing prestressing steel B. Since it is divided in this way, it can be attached to the new or existing prestressing steel B. Furthermore, the wedge 140 is provided with a taper 140T by combining the three wedge pieces.

[0026] As shown in FIG. 4A, the sleeve 100 is assembled to the taper 140T of the wedge 140. The sleeve is divided into a hollow cylindrical inner sleeve piece 110 having a taper 100T that can be fitted to it, and a hollow cylindrical outer sleeve piece 120 that is joined to the inner sleeve piece 110 by a shear key K. An outer surface 116 of the inner sleeve piece 110 is provided with a key groove 118 that contains the shear key K, and an inner surface 126 of the outer sleeve piece 120 is provided with a key groove 128 that contains the shear key K. In addition, in order to prevent the shear key K from moving in the longitudinal direction of the PC steel B from the key groove, it is also preferable, for example, to provide a hole in the bottom of the key groove 118 of the sleeve piece 110 on the inner tube side to engage a protrusion provided on the shear key (furthermore, a female threaded hole is cut in the bottom of the groove and a female threaded hole that passes through the shear key K is cut, and the female threaded hole of the shear key K is screwed into the female threaded hole at the bottom of the groove by a fully threaded bolt (a bolt with a male thread cut along its entire length and a hexagonal hole on its end face, sometimes called a set screw) (shown by a dotted line on the shear key K). The sleeve piece 110 on the inner tube side and the sleeve piece 120 on the outer tube side have cutout portions (cutout portion 114 formed by cutting out a portion of the main body 112 in the sleeve piece 110 on the inner tube side and cutout portion 124 formed by cutting out a portion of the main body 122 in the sleeve piece 120 on the outer tube side) into which the new or existing PC steel B can be inserted when viewed from a plane perpendicular to the longitudinal direction of the new or existing PC steel B.

[0027] Furthermore, the sleeve piece 110 on the inner tube side and the sleeve piece 120 on the outer tube side have shear keys K contained in their respective key grooves 118 (sleeve piece 110 on the inner tube side) and key grooves 128 (sleeve piece 120 on the outer tube side), and by joining the sleeve piece 110 and the sleeve piece 120, they are integrated into sleeve 100 and function as a sleeve that can be combined with the wedge 140.

[0028] More specifically, the sleeve piece 110 has a main body 112 with a taper 100T at the center, through which the new or existing PC steel B is inserted (corresponding to the new or existing PC steel B to be inserted), and since a portion of the main body 112 is formed as a cutout portion 114, the taper 100T does not exist around the entire circumference, and only the portion of the cutout portion 114 is missing the taper 100T, but this does not affect the function of this intermediate fixing device 30.

[0029] Here, the function of the shear key K will be described with reference to Fig. 5. Fig. 5(A) shows a side view (left side) and a front view (right side) of the intermediate fixing device 30 composed of the sleeve 100 and the wedge 140 (more specifically, the shear key K) in a state in which the sleeve piece 110 and the sleeve piece 120 are joined together to be integrated as the sleeve 100 and function as a sleeve to be combined with the wedge 140. In the intermediate fixing device 30 shown in Figure 5(A) which is composed of a sleeve 100 (more specifically, the sleeve piece 110 on the inner tube side and the sleeve piece 120 on the outer tube side) and a wedge 140 (more specifically, the shear key K), when the wedge 140 clamps the newly installed or existing PC steel B and tension is applied to the newly installed or existing PC steel B, the wedge 140 bites into the sleeve piece 110 on the inner tube side due to a wedge effect (indicated by the black arrow in Figure 5(B)), and the cutout portion 114 tries to expand (the notch width of the cutout portion 114 tries to widen) (indicated by the curved arrow in Figure 5(B)). At this time, since the sleeve piece 110 on the inner cylinder side and the sleeve piece 120 on the outer cylinder side are joined via the shear key K (contained in each other's key grooves 118 and 128), the deformation of the sleeve piece 110 on the inner cylinder side (expansion of the notch portion 114) is transmitted to the sleeve piece 120 on the outer cylinder side via the shear key K due to the engagement of the shear key K, and the deformation of the sleeve piece 110 on the inner cylinder side (expansion of the notch portion 114) is borne by the sleeve piece 120 on the outer cylinder side. Therefore, the deformation of the sleeve piece 110 on the inner cylinder side is suppressed, the desired wedge effect is produced, and the desired tension can be applied to the new or existing PC steel B.

[0030] The intermediate anchor 30 having such a structure is attached to a new or existing prestressing steel member B as follows. When the prestressing steel member B to be fixed by the intermediate anchor is embedded in concrete, an exposure step of chipping the concrete and exposing the prestressing steel member B in a tensioned state is required before the wedge attachment step described below. As shown in FIG. 6A, the wedge 140 is divided into two or more wedge pieces (here, it is divided into three pieces, so that the three pieces are wedge piece 142, wedge piece 144, and wedge piece 145) so that the taper 140T of the wedge 140 narrows in the direction toward the surface (here, the direction shown in the side view of FIG. 3). The edge piece 146) is attached to the exposed new or existing PC steel B as a wedge attachment step (see the black arrow on the wedge side).

[0031] In the sleeve installation step, the divided sleeve pieces (here, because it is divided into two, two inner-cylinder-side sleeve pieces 110 and an outer-cylinder-side sleeve piece 120) are installed on the exposed new or existing PC steel B so that the narrowing direction of the taper 100T of the sleeve 100 is toward the surface (here, the direction shown in the side view of Fig. 3) (see the black arrow on the sleeve side). More specifically, the two inner-cylinder-side sleeve pieces 110 and the outer-cylinder-side sleeve piece 120 are brought close to the new or existing PC steel B from the left and right directions in Fig. 6(A) and installed.

[0032] Next, as shown in FIG. 6(B), in order to integrate the divided sleeve pieces (here, since the sleeve pieces are divided into two, the two inner sleeve pieces 110 and the outer sleeve piece 120) into the sleeve 100 and function as a sleeve to be combined with the wedge 140 (for the sleeve functioning step), the shear key K contained in the key groove 118 provided on the outer peripheral surface 116 of the inner sleeve piece 110 is inserted into the key groove 128 provided on the inner peripheral surface 126 of the outer sleeve piece 120 (reversely). The shear key K contained in the key groove 128 provided on the inner peripheral surface 126 of the sleeve piece 120 on the outer cylinder side may be contained in the key groove 118 provided on the outer peripheral surface 116 of the sleeve piece 110 on the inner cylinder side), and the sleeve piece 110 on the inner cylinder side and the sleeve piece 120 on the outer cylinder side are brought close to each other in the longitudinal direction of the new or existing prestressing steel B (either one or both are slid in the longitudinal direction of the new or existing prestressing steel B), and the sleeve piece 110 on the inner cylinder side and the sleeve piece 120 on the outer cylinder side are joined together. As a result, the divided sleeve pieces (here, the two sleeve pieces 110 on the inner cylinder side and the sleeve piece 120 on the outer cylinder side because they are divided into two) are integrated as a sleeve and can function as the sleeve 100 that can be combined with the wedge 140.

[0033] Finally, in an insertion step, two or more divided wedge pieces (in this case, three wedge pieces 142, 144 and 146, as the wedge is divided into three) attached to the exposed new or existing PC steel B are inserted into sleeve 100, which has been integrated and can function as a sleeve that can be combined with wedge 140, by aligning the orientation of taper 140T of wedge 140 with the orientation of taper 100T of sleeve 100. In this manner, the intermediate fixing device 30 is attached to the new or existing PC steel member B.

[0034] <2: Inner and outer cylinder type: Screw-on type> Next, the sleeve 200 and the wedge 240 will be described. Figure 7(A) shows a plan view of sleeve 200 that constitutes intermediate fixing device 30, Figure 7(B) shows a plan view of wedge 240, and Figure 8 is a diagram for explaining the procedure for attaching intermediate fixing device 30 to new or existing PC steel B exposed from a PC structure by using sleeve 200 and wedge 240 so that sleeve 200 (corresponding to sleeve S) functions as a sleeve that can be combined with wedge 240 (corresponding to wedge W).

[0035] This intermediate fixing tool 30 is composed of a sleeve 200 shown in Fig. 7(A) and a wedge 240 shown in Fig. 7(B) which is combined with the sleeve 200. Note that the side view (partial cross-sectional view) on the left side of Fig. 7(A) is a view seen from the direction of arrow X shown in the front view on the right side of Fig. 7(B), and the side view on the left side and the front view on the right side of Fig. 7(B) are views of the wedge 240 formed by combining two divided wedge pieces.

[0036] As shown in Fig. 7(B), the wedge 240 is divided into two or more wedge pieces (here, it is divided into two, so there are two wedge pieces 242 and 244) when viewed from a plane perpendicular to the longitudinal direction of the new or existing prestressing steel B. Since it is divided in this way, it can be attached to the new or existing prestressing steel B. Furthermore, the wedge 240 is provided with a taper 240T by combining the two wedge pieces.

[0037] As shown in FIG. 7A, the sleeve 200 has a taper 200T that is combined with the taper 240T of the wedge 240, and an inner sleeve having an external thread (male thread) 216. The sleeve piece 210 is divided into an outer tube side sleeve piece 220 having an inner thread (female thread) 226 that is screwed into an outer thread (male thread) 216 of the sleeve piece 210 on the inner tube side. The inner tube side sleeve piece 210 and the outer tube side sleeve piece 220 have cutouts (cutouts 214 in which a part of the main body 212 in the sleeve piece 210 on the inner tube side and cutouts 224 in which a part of the main body 222 in the sleeve piece 220 on the outer tube side) into which the new or existing PC steel B can be inserted when viewed from a plane perpendicular to the longitudinal direction of the new or existing PC steel B. Note that the cutouts into which the new or existing PC steel B can be inserted do not necessarily have to include the cutouts 224 into which the new or existing PC steel B can be inserted as long as the sleeve piece 210 on the inner tube side and the sleeve piece 220 on the outer tube side have a structure in which the sleeve piece 210 on the inner tube side and the sleeve piece 220 on the outer tube side can be joined. For example, the sleeve piece 220 on the outer tube side may be, for example, a sheet made of FRP, and the sleeve piece 210 on the inner tube side and the sleeve piece 220 on the outer tube side may be integrated as a sleeve by wrapping the sheet-like sleeve piece 220 on the outer periphery of the sleeve piece 210 on the inner tube side, and function as a sleeve that can be combined with the wedge 240. In this case, the notch 224 of the sheet-like sleeve piece 220 on the outer tube side is not an essential component. Furthermore, the sleeve piece 210 on the inner tube side and the sleeve piece 220 on the outer tube side are integrated as the sleeve 200 by screwing the outer thread (male thread) 216 and the inner thread (female thread) 226 together, and function as a sleeve that can be combined with the wedge 240.

[0038] More specifically, the sleeve piece 210 has a main body 212 with a taper 200T (corresponding to the new or existing PC steel B to be inserted) at the center, and since a part of the main body 212 is made into a cutout portion 214, the taper 200T does not exist around the entire circumference, and the taper 200T is absent only at the cutout portion 214, but this does not affect its function as an intermediate fixing device 30.

[0039] The intermediate anchor 30 having such a structure is attached to a new or existing prestressing steel B as follows. If the prestressing steel B to be fixed by the intermediate anchor is embedded in concrete, an exposure step of chipping the concrete to expose the prestressing steel B in a tensioned state is required before the wedge attachment step described below, as described above. As shown in Figure 8(A), two or more divided wedge pieces (here, two wedge pieces 242 and 244 because the wedge is divided into two) are attached to the exposed newly or existing PC steel B in the wedge attachment step so that the narrowing direction of taper 240T of wedge 240 is toward the surface (here, the direction shown in the side view of Figure 3) (see the black arrow on the wedge side).

[0040] In the sleeve installation step, the divided sleeve pieces (here, because it is divided into two, two inner-cylinder-side sleeve pieces 210 and an outer-cylinder-side sleeve piece 220) are installed on the exposed new or existing PC steel B so that the narrowing direction of the taper 200T of the sleeve 200 is toward the surface (here, the direction shown in the side view of Fig. 3) (see the black arrow on the sleeve side). More specifically, the two inner-cylinder-side sleeve pieces 210 and the outer-cylinder-side sleeve piece 220 are brought close to the new or existing PC steel B from the left and right directions in Fig. 8(A) and installed.

[0041] 8(B), in order to integrate the divided sleeve pieces (here, because it is divided into two, the two inner tube side sleeve pieces 210 and the outer tube side sleeve piece 220) as a sleeve 200 and function as a sleeve that can be combined with the wedge 240 (for the sleeve functioning step), the outer thread (male thread) 216 of the inner tube side sleeve piece 210 and the inner thread (female thread) 226 of the outer tube side sleeve piece 220 are screwed together. This allows the divided sleeve pieces (here, because it is divided into two, the two inner tube side sleeve pieces 210 and the outer tube side sleeve piece 220) to be integrated as a sleeve and function as the sleeve 200 that can be combined with the wedge 240.

[0042] Finally, the two or more divided wedge pieces (here, two wedge pieces 242 and 244 because they are divided into two) attached to the exposed new or existing PC steel B are integrated into a sleeve to be combined with the wedge 140 by matching the direction of the taper 240T of the wedge 240 with the direction of the taper 200T of the sleeve 200. The sleeve 200, which is now functional, is inserted as an insertion step. In this manner, the intermediate fixing device 30 is attached to the new or existing PC steel member B.

[0043] <3: Slit wall connection type> Both the intermediate fixing device 30 composed of the sleeve 100 and the wedge 140 and the intermediate fixing device 30 composed of the sleeve 200 and the wedge 240 described above are of the inner cylinder / outer cylinder type, but next, the intermediate fixing device 30 including the sleeve S10, the sleeve S11, and the sleeve S20 of the slit wall surface connection type will be described in detail below with reference to Fig. 9. Note that the wedge W shown in Fig. 9, which is combined with the sleeve S10, the sleeve S11, and the sleeve S20, is the same as the wedge 140 composed of the above-mentioned three divided wedge pieces, and therefore will not be described again here.

[0044] Fig. 9(A) shows a plan view of sleeve S10 using a headed hexagon socket bolt (hereinafter referred to as a cap bolt) T10 as a connecting member constituting intermediate fixing device 30, Fig. 9(B) shows a plan view of sleeve S11 using a headless hexagon socket bolt (fully threaded bolt, so-called set screw, hereinafter referred to as a fully threaded bolt) T20 as a connecting member, and Fig. 9(C) shows a plan view of sleeve S20 different from sleeve S10 and sleeve S11. Note that although sleeve S20 shown in Fig. 9(C) uses cap bolt T10 as a connecting member, fully threaded bolt T20 may also be used as a connecting member.

[0045] These slit wall connection types shown in Figure 9 differ from the inner tube outer tube type (split type) described above in that they have a taper that can be combined with a wedge W, and a slit portion into which new or existing PC steel B can be inserted when viewed from a plane perpendicular to the longitudinal direction of the new or existing PC steel B, and the opposing wall surfaces at this slit portion are connected using a connecting member, thereby regulating the spacing of the slit portion when viewed from the perpendicular plane, and they function as a sleeve that can be combined with the wedge W.

[0046] Although the sleeve S10 shown in FIG. 9(A) and the sleeve S11 shown in FIG. 9(B) have different connecting members (a cap bolt T10 in FIG. 9(A) and a fully threaded bolt T20 in FIG. 9(B)), the structure of the sleeve is the same except that the hole provided in portion B10 is hole H10 (sleeve S10) and female thread hole H11 (sleeve S11). The sleeves S10 and S11 have a hollow cylindrical shape with an eccentric hollow portion (in which the wedge 140 and the new or existing prestressing steel B are contained). Due to the eccentricity, the thicker side (the side where portion B10 and portion B12 are located) has a slit portion into which the new or existing prestressing steel B can be inserted, and the wall surfaces facing each other at the slit portion are connected by a connecting member.

[0047] When the connecting member is a cap bolt T10, like the sleeve S10 shown in Figure 9 (A), it has a female threaded hole H12 provided in at least one of the opposing wall surfaces (here, one of the wall surfaces) in the slit portion (here, the wall surface on the part B12 side) and a hole H10 provided in the other wall surface (here, the wall surface on the part B10 side), and the male thread of the cap bolt T10 passed through the hole H10 (not a threaded hole but a through hole) is screwed into the female threaded hole H12 to connect the opposing wall surfaces, thereby regulating the spacing of the slit portion as viewed from a vertical plane and functioning as a sleeve that can be combined with the wedge W.

[0048] In contrast, when the connecting member is a fully threaded bolt T20, as in the sleeve S11 shown in FIG. 9(B), the sleeve S11 has a female threaded hole H12 provided in at least one (here, both) of the opposing wall surfaces in the slit portion (here, the wall surface on the side of the portion B12) and a female threaded hole H11 provided in the other wall surface (here, the wall surface on the side of the portion B10). The male thread of the fully threaded bolt T20 threaded into the female threaded hole H11 is threaded into the female threaded hole H12, connecting the opposing wall surfaces, thereby restricting the spacing of the slit portion as viewed from a vertical plane and functioning as a sleeve that can be combined with the wedge W. In the sleeve S11 shown in FIG. 9(B), not only is a female threaded hole H12 provided on the portion B12 side, but also a female threaded hole H11 is provided on the portion B10 side, and a fully threaded bolt T2 is used as a connecting member. 9(A), in which a hole H10 is provided on the portion B10 side instead of a female threaded hole and a cap bolt T10 is used as the connecting member. In comparison with the sleeve S10 shown in FIG. 9(A), in which a cap bolt T10 is used as the connecting member, excessive tightening by the connecting member can be prevented.

[0049] Next, the sleeve S20 shown in FIG. 9(C) has a hollow prism shape with an eccentric hollow portion (in which the wedge 140 and the new or existing PC steel B are contained) compared with the sleeve S10 shown in FIG. 9(A) and the sleeve S11 shown in FIG. 9(B). That is, the sleeve S20 shown in FIG. 9(C) is different in that it has a hollow prism shape while the sleeve S10 shown in FIG. 9(A) and the sleeve S11 shown in FIG. 9(B) have a hollow cylindrical shape. And, the sleeve S20 is the same as the sleeve S10 and the sleeve S11 in that the sleeve S20 has a slit portion into which the new or existing PC steel B can be inserted on the thicker side (the side where the part B10 and the part B12 are located) due to the eccentricity, and the wall surfaces facing each other in the slit portion are connected by a connecting member, so that the interval of the slit portion as viewed from a vertical plane is regulated and the sleeve S20 functions as a sleeve to be combined with the wedge W.

[0050] More specifically, in the sleeve S20, as in the sleeve S10 shown in Fig. 9(A), the male thread of the cap bolt T10 passed through the hole H10 (not a screw hole but a through hole) is screwed into the female thread hole H12, and the opposing wall surfaces are connected to each other, so that the spacing of the slits as viewed from a vertical plane is regulated and the sleeve functions as a sleeve to be combined with the wedge W. As described above, the sleeve S20 shown in Fig. 9(C) uses the cap bolt T10 as the connecting member, but the fully threaded bolt T20 may be used as the connecting member. In this case, as in the sleeve S11 shown in Fig. 9(B), in the sleeve S20, the male thread of the fully threaded bolt T20 passed through the female thread hole H11 is screwed into the female thread hole H12, and the opposing wall surfaces are connected to each other, so that the spacing of the slits as viewed from a vertical plane is regulated and the sleeve functions as a sleeve to be combined with the wedge W.

[0051] The intermediate fixing device 30 having such a structure is attached to a new or existing prestressing steel B as follows. If the prestressing steel B to be fixed by the intermediate fixing device is embedded in concrete, an exposure step of chipping the concrete to expose the tensioned prestressing steel B is required before the wedge attachment step described below, as described above. Below, a description will be given of the case where the intermediate fixing device 30 shown in Fig. 9(A) is used. Although not shown, in the wedge installation step, two or more divided wedge pieces (in this case, it is divided into three, so that there are three wedge pieces 142, 144 and 146) are attached to the exposed new or existing PC steel B so that the narrowing direction of taper 140T of wedge 140 is toward the surface (here, the direction shown in the side view of Figure 3).

[0052] In a sleeve mounting step, a sleeve S10 with a slit portion is mounted on the exposed new or existing prestressing steel B so that the narrowing direction of the taper 100T of the sleeve 100 is toward the surface (here, the direction shown in the side view of Fig. 3). More specifically, the new or existing prestressing steel B is inserted through the slit portion of the sleeve S10 and mounted. Next, the male screw of the cap bolt T10 is passed through a hole H10 (not a threaded hole but a through hole) provided in a portion constituting one of the opposing wall surfaces of the slit portion of the sleeve S10, and is screwed into the female screw hole H12, so that the opposing wall surfaces are connected to regulate the spacing of the slit portion as viewed from a vertical plane, allowing the sleeve to function as a sleeve that can be combined with the wedge W (sleeve functioning step). In this way, in the sleeve S10 having a slit portion, the opposing wall surfaces of the slit portion are connected to regulate the spacing of the slit portion as viewed from a vertical plane, allowing the sleeve to function as a sleeve (here, sleeve 100) that can be combined with the wedge W.

[0053] Finally, the two or more divided wedge pieces (here, three wedge pieces 142, 144, and 146 because the wedge pieces are divided into three) attached to the exposed new or existing PC steel B are integrated and assembled into the wedge 140 by matching the direction of the taper 140T of the wedge 140 with the direction of the taper 100T of the sleeve 100. In the insertion step, the sleeve 100 is inserted into the sleeve 100 which can function as a sleeve to be inserted. In this manner, the intermediate fixing device 30 is attached to the new or existing PC steel member B.

[0054] <Evaluation> The evaluation of this intermediate fixing device 30 and the construction method using this intermediate fixing device 30 (intermediate fixing method) will be explained with reference to Figure 10, along with the results of testing using test specimens and reference weights (including wedges). Note that the prior art is an intermediate fixing device described in JP 2018-017029 A in which an intermediate fixing device having a configuration combining a sleeve and a wedge and tightened with four bolts is used as intermediate fixing device 30, with Example 2 being intermediate fixing device 30 shown in Figure 9(A), Example 3 being intermediate fixing device 30 shown in Figure 9(B), Example 4 being intermediate fixing device 30 shown in Figure 9(C), and Example 5 being intermediate fixing device 30 shown in Figures 4 to 6.

[0055] As shown in FIG. 10(A), compared to the prior art (two-piece sleeve, four fastening bolts, reference weight 8.8 kg), Example 2 (no split sleeve, two fastening bolts, reference weight 6.2 kg), Example 3 (no split sleeve, two fastening bolts, reference weight 6.1 kg), Example 4 (no split sleeve, two fastening bolts, reference weight 6.8 kg), and Example 5 (two-piece sleeve, two fastening bolts, reference weight 8.0 kg) showed a reduction in the number of parts, weight, and man-hours required for fastening, improving workability.

[0056] Next, the results of the performance verification test (static tensile test) are shown in FIG. 10(B). The test outline is as follows: a 32 mm PC steel bar (Type B No. 2) (as an example of PC steel material) is placed in a horizontal tensile testing machine, and a tensile test is performed with one end fixed to a fixing nut commonly used for PC steel bars and the other end fixed to the intermediate fixing device of the present invention. The maximum load during the test is recorded, and the fixing efficiency, which indicates the ratio of the maximum load to the standard maximum tensile load (949 kN) of the PC steel bar, is calculated.

[0057] The results of such tests are shown in Figure 10 (B). In Examples 2 to 4, the fixing efficiency was 100% or more, and the fracture position was the fixing nut, not the position of the intermediate fixing device according to the present invention, confirming sufficient performance as a fixing device. For Example 3, similar performance can be expected by using the same shape and bolt diameter as Example 2. For Example 5, although the fixing efficiency is smaller than the other examples, this is because the maximum load is determined by the destruction of the shear key K, and an increase in the fixing efficiency can be expected by reviewing the cross-sectional shape of the shear key K, etc. In this way, it is possible to provide an intermediate fixing device with excellent workability that can be suitably used for newly installed or existing PC steel members in a tensioned state, and an intermediate fixing construction method using the same.

[0058] <Modification> In the following, an intermediate fixing device according to a modified embodiment of the present invention (suitably used for tensioned PC steel in the middle of a new or existing concrete structure) will be described. The intermediate fixing device according to the first modified embodiment and the intermediate fixing device according to the second modified embodiment described below are intended to easily check and judge the construction status in order to set a wedge in a narrow and dark space, and more specifically, have a structure for easily checking the presence of the wedge itself and the maintenance of the set position of the wedge (prevention of falling off). Note that the intermediate fixing method suitable for use with tensioned PC steel in the middle of a new or existing concrete structure other than the confirmation of the presence of the wedge itself and the maintenance of the set position of the wedge (prevention of falling off) is the same as the above-mentioned description, and will not be repeated here. In the following, the same reference numerals are used for members (e.g., wedges, etc.) having the same structure as the above-mentioned structure, and the structure and action and effect are the same, so they will not be repeated here.

[0059] Furthermore, intermediate fixing devices according to the two modified examples shown below have the basic structure of the intermediate fixing device shown in FIG. 7, but as shown in FIG. 7, the sleeve is divided into an inner tube side sleeve piece having an outer thread and an outer tube side sleeve piece having an inner thread that is screwed into the outer thread of the inner tube side sleeve piece, and the inner thread and the outer thread of the inner tube side sleeve piece and the outer tube side sleeve piece are screwed together. The present invention is not limited to a sleeve that is integrated with the sleeve piece on the inner tube by a tapping member for a set screw. For example, the sleeve piece on the inner tube side and the sleeve piece on the outer tube side may be integrated with the sleeve by a set screw passed through a set screw mounting hole and screwed into a set screw tap. In Fig. 11 and Fig. 12, in order to facilitate understanding of these modified examples, some cross sections are not hatched and new or existing prestressing steel B is shown only in some of the drawings. Fig. 11(G) shows a cross section taken along line AA in Fig. 11(F), and Fig. 12(G) shows a cross section taken along line AA in Fig. 12(F).

[0060] <<First Modification>> As shown in Figure 11, the intermediate fixing device of this modified example is a pressure plate type, and the presence of the wedge itself can be confirmed by providing a protrusion at the rear end of the wedge that protrudes from the rear end of the sleeve to make it visible, and the set position of the wedge is maintained (to prevent it from falling off) by providing a pressure plate that can be bolted to the sleeve and pressing this pressure plate to a specified position with a bolt.

[0061] More specifically, as shown in Figure 11(E) and Figure 11(A) showing the AA cross section of Figure 11(E), the pressure plate 300 is a flat plate, for example made of a metal, having a cutout portion 324 into which the new or existing PC steel B can be inserted when viewed from a plane perpendicular to the longitudinal direction of the new or existing PC steel B, and has a bolt hole 302 for connecting this pressure plate 300 to the sleeve 2100 described later with a bolt 310 (more specifically, by screwing the bolt 310 into a female threaded hole 2222 provided in the sleeve piece 2220 on the outer tube side).

[0062] As shown in FIG. 11B, the wedge 340 is the above-mentioned three-piece type wedge 140, and is provided with a protrusion 342 at the rear end of the wedge 340 which protrudes from the rear end of the sleeve 2100. As shown in Fig. 11(C), the sleeve piece 2220 on the outer tube side is provided with a female threaded hole 2222 having a female thread for screwing with the bolt 310 in the sleeve piece 220 on the outer tube side described above. As shown in Fig. 11(D), the sleeve piece 210 on the inner tube side is the same as the sleeve piece 210 on the inner tube side described above, and is therefore given the same reference numeral. The sleeve piece 2220 on the outer tube side shown in Fig. 11(C) and the sleeve piece 210 on the inner tube side shown in Fig. 11(D) constitute the sleeve 2100 in the intermediate fixing device according to this modification.

[0063] In the intermediate fixing device of this modified example having such a structure, the method of confirming the presence of the wedge itself and the maintenance of the set position of the wedge (preventing it from falling off) will be described below with reference to Figures 11(E) to 11(G). When everything other than the pressure plate 300 and the bolt 310 shown in Figure 11(A) is assembled to the newly installed or existing PC steel B as shown in Figure 11(F), the pressure plate 300 is set in the direction of the black arrow shown in Figure 11(E) to the intermediate fixing device to which everything other than the pressure plate 300 and the bolt 310 has been assembled to the newly installed or existing PC steel B so that the positions of the bolt hole 302 and the female thread hole 2222 match.

[0064] Bolt 310 is passed through bolt hole 302 of pressing plate 300, and bolt 310 is screwed (here fully at two places, top and bottom) into female threaded hole 2222. In this work process, the presence of wedge 340 itself can be easily confirmed by visually checking protrusion 342 protruding from the rear end of sleeve 2100 at the rear end of wedge 340. In addition, since pressing plate 300 can be securely connected by screwing with sleeve 2100 and bolt 310, pressing plate 300 to a predetermined position (a position where bolt 310 is fully screwed into female threaded hole 2222) by bolt 310 can easily be achieved by securing the set position and preventing it from falling off.

[0065] <<Second Modification>> As shown in Figure 12, the intermediate fixing device of this modified example is a wire clip type, and the presence of the wedge itself is confirmed by visually checking that the wire clip is in a predetermined position because the position of the wire clip would not be determined without the wedge being present, and the set position of the wedge is maintained (to prevent it from falling off) by restraining the end of the wedge with the wire clip and fixing the end of the wire clip to the sleeve to determine the positional relationship between the wedge and the sleeve.

[0066] More specifically, as shown in Fig. 12(A), the wire clip 400 is a metal wire having a predetermined shape that is symmetrical in the vertical direction of the paper surface of Fig. 12(A). The wire clip 400 comprises an insertion piece 402 that is inserted into an insertion hole 2212 provided in an end face of a sleeve 2200 (more specifically, of the sleeve piece 2210 on the inner tube side) described later in the direction in which the taper of the sleeve narrows, an end face piece 404 that is bent at a substantially right angle from the insertion piece 402 (in the plan view shown in Fig. 12(A)) and positioned at the end face in the direction in which the taper of the sleeve 2200 narrows, and an end face piece 404 that is bent at a substantially right angle from the end face piece 404 (in the plan view shown in Fig. 12(A)) and positioned around the outer periphery of the sleeve 2200. 12(F) 。 Constraining end face piece 408 is bent at a right angle from outer peripheral surface piece 406 (when viewed in a plane as shown in FIG. 12(A)) to be positioned at the end face in the direction in which the taper of sleeve 2200 widens, and an arc-shaped restraining arc piece 410 (when viewed from the direction as shown in FIG. 12(F)) that is continuous with the restraining end face piece 408 and is fitted into a restraining groove 148 provided on the end face of wedge 140 in the direction in which the taper of wedge 140 widens.

[0067] The characteristic structure of this wire clip 400 is that it comprises an insertion piece 402 that is inserted into an insertion hole 2212 provided on the end face of the sleeve 2200 in the direction in which the taper narrows, and an arc-shaped restraining arc piece 410 that is inserted into the restraining groove 148 of the wedge 140. Note that the dimension L in Fig. 12(A) corresponds to the longitudinal length of the new or existing PC steel material B in the sleeve 2200. As shown in Fig. 12(B), the wedge 140 is the same as the three-piece wedge 140 described above, and is therefore given the same reference numerals. Note that in Fig. 4(B), the reference numerals of the restraining grooves 148 are not given to the wedge 140.

[0068] As shown in Fig. 12(C), the sleeve piece 2210 on the inner tube side is provided with a fitting hole 2212 into which the fitting piece 402 of the wire clip 400 is fitted in the sleeve piece 210 on the inner tube side described above. As shown in Fig. 12(C), the sleeve piece 220 on the outer tube side is the same as the sleeve piece 220 on the outer tube side described above, and is therefore given the same reference numeral. The sleeve piece 220 on the outer tube side shown in Fig. 12(C) and the sleeve piece 2210 on the inner tube side shown in Fig. 12(D) constitute the sleeve 2200 in the intermediate fixing device according to this modification. In the intermediate fixing device of this modified example having such a structure, the method of confirming the presence of the wedge itself and the maintenance of the set position of the wedge (preventing it from falling off) will be described below with reference to Figures 12(F) to 12(G).

[0069] When a wire clip other than the wire clip 400 shown in FIG. 12(A) is assembled to a new or existing PC steel material B, as shown in FIG. 12(E) and FIG. 12(G), the wire clip 400 is set by fitting the insertion piece 402 of the wire clip 400 into the fitting hole 2212 provided on the end face of the sleeve 2200 in the direction in which the taper narrows, and fitting the restraining arc piece 410 of the wire clip 400 into the restraining groove 148 of the wedge 140. In such a work process, the presence of the wedge 140 itself can be easily confirmed by visually confirming that the wire clip 400 is present at a predetermined position. In addition, the wire clip 400 restrains the restraining groove 148 at the end of the wedge 140 and fixes the end of the wire clip 400 (the insertion piece 402) to the sleeve (the fitting hole 2212), thereby determining the positional relationship between the wedge and the sleeve, and thus the set position can be easily guaranteed and the prevention of falling off can be easily realized.

[0070] It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. For example, the following changes are included: The intermediate fixing device for existing PC steel bars (intermediate fixing device 30) is composed of a wedge that grips the newly installed or existing PC steel bar B and a sleeve that stores the wedge, and it is preferable that the wedge and sleeve are made of metal or resin. The wedge and sleeve may have any structure as long as they can be attached to the existing PC steel rod, and the structure described above is merely one example. The wedge may be divided into two or more parts, and the sleeve may be one in which the halves can be fastened with a bolt, or it may have a slit (cutout) through which the PC steel rod can pass, and its shape may be cylindrical, hollow cylindrical, solid cylindrical, rectangular prism, or polygonal prism.

[0071] The sleeve may have a taper in one direction (intermediate fastener 30) or in two opposing directions (intermediate fastener 32) relative to the longitudinal direction (material axis) of the PC steel bar. The taper angle of the sleeve and wedge is optional, but is preferably about 5 to 15 degrees. The longitudinal length of the sleeve and wedge PC steel bars is optional, but is preferably about 20mm to 200mm. The material used for the sleeve and wedge may be metal, resin, or synthetic fiber. [Industrial Applicability]

[0072] The present invention is preferable for an intermediate fixing device that can be suitably used for newly installed or existing prestressed PC steel members in a tensioned state, and an intermediate fixing construction method using the same, and is particularly preferable in terms of its excellent workability. [Explanation of symbols]

[0073] 100 sleeve 110, 120 Sleeve pieces 140 Wedge 142, 144, 146 Wedge pieces 200 sleeve 210, 220 Sleeve piece 240 Wedge 242, 244 Wedge pieces S Sleeve W Wedge B New or existing prestressing steel

Claims

1. An intermediate fastener that is suitably used for tensioned PC steel members in the middle of a new or existing concrete structure, A wedge divided into two or more wedge pieces when viewed from a plane perpendicular to the longitudinal direction of the PC steel material; a sleeve divided into an inner sleeve piece having a taper that is combined with the wedge and an outer sleeve piece that is provided on the outside of the inner sleeve piece; With respect to the inner tube side sleeve piece and the outer tube side sleeve piece, at least the inner tube side sleeve piece is provided with a notch portion into which the PC steel material can be inserted as viewed from a plane perpendicular to the longitudinal direction of the PC steel material, The sleeve piece on the inner cylinder side and the sleeve piece on the outer cylinder side are joined together to form an integrated sleeve that functions as a sleeve to be combined with the wedge, This intermediate fixing device for PC steel is characterized in that a key is provided across a key groove provided on the outer peripheral surface of the sleeve piece on the inner tube side and a key groove provided on the inner peripheral surface of the sleeve piece on the outer tube side, and the sleeve piece on the inner tube side and the sleeve piece on the outer tube side are joined to form an integrated sleeve.

2. An intermediate fixing device suitable for use with tensioned PC steel members in the intermediate portion of a new or existing concrete structure, comprising: A wedge divided into two or more wedge pieces when viewed from a plane perpendicular to the longitudinal direction of the PC steel material; a sleeve divided into an inner sleeve piece having a taper that is combined with the wedge and an outer sleeve piece that is provided on the outside of the inner sleeve piece; With respect to the inner tube side sleeve piece and the outer tube side sleeve piece, at least the inner tube side sleeve piece is provided with a notch portion into which the PC steel material can be inserted as viewed from a plane perpendicular to the longitudinal direction of the PC steel material, The sleeve piece on the inner cylinder side and the sleeve piece on the outer cylinder side are joined together to form an integrated sleeve that functions as a sleeve to be combined with the wedge, a male thread provided on an outer peripheral surface of the sleeve piece on the inner tube side and a female thread provided on an inner peripheral surface of the sleeve piece on the outer tube side are screwed together to join the sleeve piece on the inner tube side and the sleeve piece on the outer tube side, thereby forming an integrated sleeve; The sleeve further includes a flat plate joined to the sleeve at an end surface in a direction in which the taper widens and perpendicular to the longitudinal direction of the PC steel material, the plate has a notch portion into which the PC steel can be inserted as viewed from a plane perpendicular to the longitudinal direction of the PC steel and into which a wedge protrusion provided at an end of the wedge in a direction in which the taper widens can protrude; An intermediate fixing device for PC steel, characterized in that the plate is joined to the end face of the sleeve, thereby positioning the wedge at a predetermined position on the sleeve and the wedge protrusion portion protruding from the cutout portion of the plate.

3. An intermediate fixing device suitable for use with tensioned PC steel members in the intermediate portion of a new or existing concrete structure, comprising: A wedge divided into two or more wedge pieces when viewed from a plane perpendicular to the longitudinal direction of the PC steel material; a sleeve divided into an inner sleeve piece having a taper that is combined with the wedge and an outer sleeve piece that is provided on the outside of the inner sleeve piece; With respect to the inner tube side sleeve piece and the outer tube side sleeve piece, at least the inner tube side sleeve piece is provided with a notch portion into which the PC steel material can be inserted as viewed from a plane perpendicular to the longitudinal direction of the PC steel material, The sleeve piece on the inner tube side and the sleeve piece on the outer tube side are joined together to form an integrated sleeve that functions as a sleeve to be combined with the wedge, a male thread provided on an outer peripheral surface of the sleeve piece on the inner tube side and a female thread provided on an inner peripheral surface of the sleeve piece on the outer tube side are screwed together to join the sleeve piece on the inner tube side and the sleeve piece on the outer tube side, thereby forming an integrated sleeve; Further comprising a three-dimensional shaped wire clip; The wire clip is A straight portion of the sleeve corresponding to a length of the PC steel in a longitudinal direction; a wedge groove provided on an outer periphery of an end of the wedge in a direction in which the taper of the wedge widens, the wedge being fitted into the wedge groove on a side of the sleeve where the taper of the wedge widens from the straight portion; and an insertion piece that is inserted into a sleeve hole provided on an end face of the sleeve in the direction in which the taper narrows, the end face being perpendicular to the longitudinal direction of the PC steel material, on the side of the sleeve where the taper narrows from the straight portion, This intermediate fixing device for PC steel is characterized in that the arc portion of the wire clip is fitted into the wedge groove portion and the fitting piece of the wire clip is fitted into the sleeve hole portion, thereby positioning the wedge at a predetermined position on the sleeve and positioning the straight portion of the wire clip along the outer periphery of the sleeve.

4. An intermediate fixing method using the intermediate fixing tool according to any one of claims 1 to 3, an exposure step of chipping the concrete when the PC steel member fixed by the intermediate fixing device is embedded in concrete to expose the PC steel member in a tensioned state; a wedge installation step of installing two or more divided wedge pieces to the tensioned PC steel member so that the taper of the wedge narrows in the direction of the concrete to which the compressive force is applied; a sleeve attachment step of attaching a sleeve having a structure that can be attached to the PC steel member to the PC steel member in a tensioned state so that the direction in which the taper of the sleeve narrows corresponds to the direction of the concrete into which the compressive force is introduced; a sleeve functionalization step of making the sleeve function as a sleeve that can be combined with the wedge; and an insertion step of inserting two or more wedge pieces attached to the tensioned PC steel material in the divided state into the sleeve functioning as a sleeve by aligning the taper direction of the wedge with the taper direction of the sleeve.

5. The PC steel intermediate anchoring method according to claim 4, wherein the inserting step includes a step of manually inserting the wedge into the sleeve by an operator without using a jack.

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