Patent Application
20240093494
The present invention relates to an anchoring device and a prestressed concrete (PC), and more specifically relates to an anchoring device used to tension a wire in a prestressed concrete and the prestressed concrete.
As an anchoring device used to tension a wire (cable, rod) in PC, there is known a wedge-type anchoring device including a barrel member (sleeve member) which is fixed to a PC concrete block and has a through hole having a tapered shape, and multiple wedge members which each have an outer peripheral surface having a tapered shape and slidably contacting an inner peripheral surface of the through hole and which cooperate with each other to grip the wire (for example, Patent Document 1).
In this wedge-type anchoring device, the barrel member is fixed to the concrete block, and the end of the wire is gripped or anchored by the multiple wedge members according to wedge action of the wedge members being pushed into the tapered side of the through hole.
General wedge-type anchoring devices which are conventionally known may have a barrel member made of steel or a barrel member made of resin. Those with a barrel member made of steel have sufficient strength against diameter expansion deformation of the barrel member due to wedge action, but corrosion (rust) may occur depending on environmental conditions. Those with a barrel member made of resin do not cause corrosion but are difficult to have sufficient strength against the diameter expansion deformation of the barrel member due to wedge action.
A task to be accomplished by the present invention is to provide a wedge-type anchoring device in which the barrel member does not corrode, and which has sufficient strength against the diameter expansion deformation of the barrel member due to wedge action.
An anchoring device according to one embodiment of the present invention is an anchoring device (10) for an end of a wire (110), comprising: a barrel member (12) which is composed of resin or mortar and has a through hole (14) having a tapered shape; multiple wedge members (20) which each have an outer peripheral surface (20A) having a tapered shape and slidably contacting an inner peripheral surface (14A) of the through hole and which cooperate with each other to grip the wire; and a reinforcement member (16, 52, 60, 70) including a part that extends in a circumferential direction of the barrel member to suppress diameter expansion deformation of the barrel member.
According to this configuration, the barrel member does not corrode, and sufficient strength against the diameter expansion deformation of the barrel member due to wedge action is provided.
In the above-mentioned anchoring device, preferably, each wedge member is composed of resin or fiber reinforced resin.
According to this configuration, the wedge members do not corrode.
In the above-mentioned anchoring device, preferably, the reinforcement member comprises fibers (16, 52) embedded in the barrel member.
According to this configuration, the barrel member and the reinforcement member can be integrally molded, which allows excellent productivity of the anchoring device.
In the above-mentioned anchoring device, preferably, the barrel member is composed of a prepreg (42, 44, 46, 48) wound cylindrically so as to have an outer peripheral surface (42A, 44A, 46A, 48A) tapered in steps in a direction same as that of the tapered shape of the through hole, the prepreg comprises a base material (50) made of resin and fibers (52) impregnated in the base material, and the reinforcement member is composed of fibers comprised in the prepreg.
According to this configuration, the barrel member including the reinforcement member is manufactured efficiently by using the prepreg, whereby the productivity is excellent. Further, the wall thickness of the barrel member can be made close to a uniform thickness over the entire length in the axial direction, and the barrel member can be made compact and lightweight.
In the above-mentioned anchoring device, preferably, the prepreg is composed of multiple strip-shaped bodies disposed to overlap with each other in a radial direction at parts in an axial direction of the through hole.
According to this configuration, the required shape of the barrel member is reliably formed by the prepreg.
In the above-mentioned anchoring device, preferably, the reinforcement member comprises an annular body (30) provided on an outer circumference of the barrel member to surround the barrel member.
According to this configuration, the diameter expansion of the barrel member is effectively suppressed by the annular body, whereby the diameter expansion deformation of the barrel member due to wedge action is effectively suppressed.
In the above-mentioned anchoring device, preferably, the barrel member is composed of fiber reinforced resin, and the annular body is composed of fiber reinforced resin having a higher Young's modulus than the fiber reinforced resin composing the barrel member.
According to this configuration, the diameter expansion deformation of the barrel member is reliably suppressed by the annular body, and in addition, the material cost is reduced compared to a case where the barrel member also is composed of fiber reinforced resin having a high Young's modulus.
In the above-mentioned anchoring device, preferably, the annular body is provided partially in an axial direction of the through hole.
According to this configuration, the material cost is reduced compared to a case where the annular body is provided over the entirety in the axial direction of the through hole.
In the above-mentioned anchoring device, preferably, the annular body is provided continuously over an entirety in an axial direction of the through hole.
According to this configuration, the diameter expansion deformation of the barrel member is reliably suppressed.
In the above-mentioned anchoring device, preferably, the barrel member has an outer peripheral surface (12C) having a cylindrical shape, and the reinforcement member comprises a spiral restraint body (60) wound on the outer peripheral surface of the barrel member.
According to this configuration, the diameter expansion of the barrel member is effectively suppressed by the spiral restraint body, whereby the diameter expansion deformation of the barrel member due to wedge action is effectively suppressed.
In the above-mentioned anchoring device, preferably, the barrel member is composed of fiber reinforced resin, and the spiral restraint body is composed of fiber reinforced resin having a higher Young's modulus than the fiber reinforced resin composing the barrel member.
According to this configuration, the diameter expansion deformation of the barrel member is reliably suppressed, and in addition, the material cost is reduced compared to a case where the barrel member also is composed of fiber reinforced resin having a high Young's modulus.
In the above-mentioned anchoring device, preferably, the barrel member has a spiral groove (12D) on the outer peripheral surface, and the spiral restraint body is fitted in the spiral groove.
According to this configuration, axial movement of the spiral restraint body relative to the barrel member is suppressed, and the effect of the spiral restraint body of suppressing the diameter expansion deformation of the barrel member becomes stable.
In the above-mentioned anchoring device, preferably, the barrel member has an outer peripheral surface (12E) having a conical shape, and the reinforcement member comprises an annular restraint body (70) fitted on the outer peripheral surface of the barrel member.
According to this configuration, the annular restraint body acts to suppress the diameter expansion of the barrel member, whereby the diameter expansion deformation of the barrel member due to wedge action is suppressed.
In the above-mentioned anchoring device, preferably, the barrel member is composed of fiber reinforced resin, and the annular restraint body is composed of fiber reinforced resin having a higher Young's modulus than the fiber reinforced resin composing the barrel member.
According to this configuration, the diameter expansion deformation of the barrel member is reliably suppressed, and in addition, the material cost is reduced compared to a case where the barrel member also is composed of fiber reinforced resin having a high Young's modulus.
In the above-mentioned anchoring device, preferably, an end surface (70B) of the annular restraint body on a tapered side of the conical shape of the barrel member includes a surface perpendicular to an axial direction of the barrel member.
According to this configuration, in a state in which the barrel member is embedded in a concrete block of prestressed concrete, axial movement of the barrel member relative to the concrete block is suppressed, and operation of the anchoring device in the prestressed concrete becomes stable.
A prestressed concrete according to one embodiment of the present invention comprises: a concrete block having a rectangular parallelepiped shape; a wire penetrating in a longitudinal direction of the concrete block; and the anchoring device according to the above-described embodiment which is provided at each of two end portions of the concrete block in the longitudinal direction and to which an end portion of the wire is locked.
According to this configuration, a stable prestressed state is maintained over an extended period of time and excellent durability is obtained.
In the above-mentioned prestressed concrete, the anchoring device may either be embedded in the concrete block or be mounted to the concrete block such that one end surface (12B) of the barrel member contacts an end surface of the concrete block and an outer peripheral surface (12C, 12E) of the barrel member is exposed to outside.
In the anchoring device according to the present invention, corrosion of the barrel member does not occur, and sufficient strength against the diameter expansion deformation of the barrel member due to wedge action is provided.
As shown in
The prestressed concrete 100 further includes left and right anchoring devices 10 which are provided at both longitudinal end portions of the concrete block 102 (left and right end portions as seen in
The left and right anchoring devices 10 are of a wedge type and each include a cylindrical barrel member 12 and a pair of upper and lower wedge members 20 as seen in
As shown in
Thereby, the barrel member 12 is fixed to the concrete block 102 so as not to be displaceable both in the axial direction (the left-right direction as seen in
The barrel member 12 has a through hole 14 extending through a central part thereof in the axial direction. The through hole 14 is a hole having a tapered shape extending from the outer end 12A to the inner end 12B of the barrel member 12, with both ends open. In other words, the through hole 14 is a tapered hole having an inner diameter gradually decreasing from the outer end 12A to the inner end 12B of the barrel member 12.
The barrel member 12 is a molded product made of resin such as epoxy resin, polyester resin, or the like. As shown in
Note that, as shown in
In either case, the fibers 16 increases an apparent tensile strength and Young's modulus (longitudinal elastic modulus) of the barrel member 12 in the diameter expansion direction and thereby suppresses the diameter expansion deformation of the barrel member 12. To effectively suppress the diameter expansion deformation of the barrel member 12, it is preferred that the fibers 16 include a part continuously extending around the central axis of the through hole 14, but may be discontinuous depending on the required tensile strength and Young's modulus of the barrel member 12 in the radial direction.
Each wedge member 20 is a molded product made of resin or fiber reinforced resin, has a shape formed by dividing a tapered rod in half, and has an outer peripheral surface 20A having a tapered shape and slidably contacting the inner peripheral surface 14A of the through hole 14 and a cable groove 20B having a substantially semicircular cross-sectional shape and opened in a halved surface 20C.
The two wedge members 20 cooperate with each other to grip an end of the cable 106 engaged with the cable groove 20B and in the state of tension, and are pressed toward the tapered side of the through hole 14, in other words, are driven into the tapered side of the through hole 14, to increase the friction resistance against the cable 106 due to wedge action with respect to the barrel member 12 and to lock (anchor) the end of the cable 106 to the concrete block 102 via the barrel member 12.
As a result of the wedge action mentioned above, a load urging the barrel member 12 to undergo diameter expansion deformation acts on the barrel member 12. In this state, the fibers 16 act as a reinforcement member to suppress the diameter expansion deformation of the barrel member 12.
Accordingly, even though the barrel member 12 is composed of resin instead of steel to prevent rust, the barrel member 12 is provided with sufficient strength against the diameter expansion deformation due to wedge action, and thus, reduction of wedge action is prevented.
As described above, with the anchoring device 10 of Embodiment 1, the barrel member 12 does not corrode even when used over an extended period of time, and sufficient strength against the diameter expansion deformation of the barrel member 12 due to wedge action is provided, whereby lowering of the anchoring strength of the cable 106 due to the diameter expansion deformation of the barrel member 12 is prevented. Since the wedge member 20 also is a molded product made of resin or fiber reinforced resin, the wedge member 20 does not corrode in use over an extended period of time.
In the anchoring device 10 of Embodiment 1, as a result of molding of the barrel member 12 containing the fibers 16, the fibers 16 and the barrel member 12 (base material) are integrally molded, which allows excellent productivity of the anchoring device 10.
An anchoring device 10 of Embodiment 2 will now be described with reference to
In Embodiment 2, multiple annular bodies 30 are provided on the outer circumference of the cylindrical barrel member 12 at a predetermined interval in the extension direction (axial direction) of the through hole 14. As seen in the axial direction of the through hole 14, the multiple annular bodies 30 are partially provided on the barrel member 12. Each annular body 30 has an annular shape continuously extends around the outer circumference of the barrel member 12, namely, is provided to completely surround the outer circumference of the barrel member 12. Each annular body 30 is integrally molded with the barrel member 12 or retrofitted on the barrel member 12.
The annular body 30 is composed of fiber reinforced resin. The fibers (not shown in the drawings) contained in the fiber reinforced resin may be glass fibers, carbon fibers, boron fibers, aramid fibers, basalt fibers, or the like. These fibers may be mesh-like or sheet-like fibers wound cylindrically around the central axis of the through hole 14 to form multiple layers, and include a part continuously extending in the circumferential direction of the barrel member 12.
The fibers (not shown in the drawings) contained in each annular body 30 may be a bundle of fibers wound multiple times around the central axis of the through hole 14 in form of helices with different diameters. In this case also, the fibers contained in the annular body 30 include a part continuously extending in the circumferential direction of the barrel member 12.
In addition to the fibers 16 embedded in the barrel member 12, each annular body 30 acts as a reinforcement member that suppresses the diameter expansion deformation of the barrel member 12, and this makes the barrel member 12 difficult to undergo diameter expansion deformation even further.
Each annular body 30 may be composed of fiber reinforced resin containing high-tensile fibers having a Young's modulus and a tensile strength higher than those of the fibers 16 embedded in the barrel member 12, such as carbon fiber reinforced resin and the like. In other words, each annular body 30 is composed of fiber reinforced resin having a higher Young's modulus than the fiber reinforced resin composing the barrel member 12. With the high-tensile fibers contained in the fiber reinforced resin, each annular body 30 exerts a reinforcing effect to suppress diameter expansion deformation of the barrel member 12.
Therefore, even when the anchoring device 10 of Embodiment 2 is used over an extended period of time, the barrel member 12 does not corrode. In addition, the barrel member 12 is provided with sufficient strength against the diameter expansion deformation due to wedge action, whereby lowering of the anchoring strength of the cable 106 due to the diameter expansion deformation of the barrel member 12 is prevented.
Even though the fibers 16 embedded in the barrel member 12 and the fibers in the fiber reinforced resin composing the annular bodies 30 are composed of different materials and the fibers 16 are composed of glass fibers cheaper than carbon fibers or the like contained in the annular bodies 30, strength similar to when the barrel member 12 is composed of expensive carbon fiber reinforced resin or the like (strength that suppresses the diameter expansion deformation of the barrel member 12) is obtained due to the high reinforcing effect of each annular body 30. Therefore, the material cost of the barrel member 12 is saved (reduced), and in addition, the diameter expansion deformation of the barrel member 12 is effectively suppressed.
Also, since each annular body 30 is partially provided in the axial direction of the barrel member 12, the material cost of the annular bodies 30 is reduced compared to a case where an annular body 30 is provided continuously over the entire length of the barrel member 12.
When embedded in the concrete block 102 with the barrel member 12, an annular end surface 30A of each annular body 30 is joined to the concrete block 102. This enhances the bonding strength between the barrel member 12 and the concrete block 102. In other words, the end surface 30A of each annular body 30 functions as a barrier surface that prevents the barrel member 12 from moving in the axial direction relative to the concrete block 102.
Due to this function, axial movement of the barrel member 12 relative to the concrete block 102 is effectively suppressed. As a result of this, the high-quality prestressed concrete 100 to which stable prestress is applied over an extended period of time is manufactured with excellent productivity without requiring additional components and steps.
An anchoring device 10 of Embodiment 3 will now be described with reference to
In Embodiment 3, the annular body 30 is composed of a cylindrical body having a substantially same axial length as the axial length of the barrel member 12 and provided on the outer circumference of the barrel member 12.
To effectively suppress the diameter expansion deformation of the barrel member 12, the fibers contained in the annular body 30 preferably include a part continuously extending around the central axis of the through hole 14. These fibers may be mesh-like or sheet-like fibers wound in the circumferential direction, may be wound in two directions of the circumferential direction and the axial direction and pasted together, or may be woven in two directions and wound.
In this embodiment also, the annular body 30 may be composed of fiber reinforced resin containing high-tensile fibers having a Young's modulus and a tensile strength higher than those of the fibers 16 embedded in the barrel member 12, such as carbon fiber reinforced resin and the like. In other words, in this embodiment also, the annular body 30 is composed of fiber reinforced resin having a higher Young's modulus than the fiber reinforced resin composing the barrel member 12.
In this embodiment also, even though the fibers 16 embedded in the barrel member 12 and the fibers in the fiber reinforced resin composing the annular bodies 30 are composed of different materials and the fibers 16 are composed of glass fibers cheaper than carbon fibers or the like contained in the annular bodies 30, strength similar to when the barrel member 12 is composed of expensive carbon fiber reinforced resin or the like (strength that suppresses the diameter expansion deformation of the barrel member 12) is obtained due to the high reinforcing effect of each annular body 30. Therefore, the material cost of the barrel member 12 is reduced, and in addition, the diameter expansion deformation of the barrel member 12 is effectively suppressed.
In Embodiment 3, the effect of suppressing the diameter expansion deformation of the barrel member 12 by the annular body 30 is obtained substantially uniformly over the entirety of the axial length of the barrel member 12.
Thus, with the anchoring device 10 of Embodiment 3, the barrel member 12 does not corrode even when used over an extended period of time, and sufficient strength against the diameter expansion deformation of the barrel member 12 due to wedge action is provided, whereby lowering of the anchoring strength of the cable 106 due to the diameter expansion deformation of the barrel member 12 is prevented.
An anchoring device 10 of Embodiment 4 will now be described with reference to
As shown in
In other words, the outer winding diameters of the prepregs 42, 44, 46, 48 become smaller in steps from the prepreg 48 which is positioned on the side of the outer end 12A of the barrel member 12 to the prepreg 42 which is positioned on the side of the inner end 12B.
As shown in
As shown in
The fibers 52 are mesh-like or sheet-like fibers and are present in the matrix 50 in a form wound cylindrical around the central axis of the through hole 14 to form multiple layers. Thereby, the fibers 52 constitute a reinforcement member including a part continuously extending in the circumferential direction of the barrel member 12 composed of the matrix 50.
Note that, as shown in
In Embodiment 4 also, similarly to Embodiment 1, a load urging the barrel member 12 to undergo diameter expansion deformation acts on the barrel member 12 due to wedge action resulting from the driving of the wedge members 20. In this state, the fibers 52 act as a reinforcement member to suppress the diameter expansion deformation of the barrel member 12.
Accordingly, even though the barrel member 12 is composed of matrix resin instead of steel to prevent rust, the barrel member 12 is provided with sufficient strength against the diameter expansion deformation due to wedge action, and thus, reduction of wedge action is prevented.
As described above, with the anchoring device 10 of Embodiment 4, the barrel member 12 does not corrode even when used over an extended period of time, and sufficient strength against the diameter expansion deformation of the barrel member 12 due to wedge action is provided, whereby lowering of the anchoring strength of the cable 106 due to the diameter expansion deformation of the barrel member 12 is prevented.
In Embodiment 4, the barrel member 12 including the reinforcement member is manufactured efficiently by using the prepregs 42, 44, 46, 48, whereby the productivity is excellent. Since the prepregs 42, 44, 46, 48 are composed of multiple strip-shaped bodies arranged to overlap with each other in the radial direction at parts in the axial direction of the through hole 14, the barrel member 12 having a predetermined shape is reliably formed by the prepregs 42, 44, 46, 48.
Also, in the anchoring device 10 of Embodiment 4, the barrel member 12 has a shape tapered in steps in the same direction as the through hole 14 due to the outer peripheral surfaces 42A, 44A, 46A, 48A of the respective prepregs 42, 44, 46, 48, a change in the wall thickness in the axial direction of the barrel member 12 is smaller than in Embodiment 1.
Thus, the barrel member 12 is manufactured efficiently by using the prepregs 42, 44, 46, 48, whereby the productivity is excellent and, in addition, the wall thickness of the barrel member 12 can be made close to a uniform thickness over the entire length in the axial direction. Further, the wall thickness of the barrel member 12 can be made close to the minimum required thickness over the entire axial length, and the barrel member 12 can be made compact and lightweight.
Also, in the state embedded in the concrete block 102, end surfaces 42B, 44B, 46B, 48B of the cured prepregs 42, 44, 46, 48 on the side of the inner end 12B function as barrier surfaces that enhance the bonding strength between the barrel member 12 and the concrete block 102 and prevent the barrel member 12 from moving in the axial direction (rightward) relative to the concrete block 102.
Therefore, movement of the barrel member 12 in the axial direction (right direction) relative to the concrete block 102 is effectively suppressed. As a result of this, the high-quality prestressed concrete 100 to which stable prestress is applied over an extended period of time is manufactured with excellent productivity without requiring additional components and steps.
An anchoring device 10 of Embodiment 5 will now be described with reference to
The barrel member 12 is a cylindrical molded product made of fiber reinforced resin composed of matrix resin such as epoxy resin, polyester resin, or the like and fibers such as glass fibers, carbon fibers, boron fibers, aramid fibers, basalt fibers, or the like, and is molded in a cylindrical shape having a through hole 14. The barrel member 12 may be a product similar to the barrel member 12 of Embodiment 1.
The outer peripheral surface 12C of the barrel member 12 is formed with a spiral groove 12D having a semi-circular cross section with a predetermined pitch substantially over the entire length of the axial direction of the barrel member 12. In the spiral groove 12D, a spiral restraint body 60 having a circular cross section is fitted. The spiral restraint body 60 is a molded product made of fiber reinforced resin composed of matrix resin such as epoxy resin, polyester resin, or the like and fibers such as glass fibers, carbon fibers, boron fibers, aramid fibers, basalt fibers, steel fibers, or the like.
Therefore, the spiral restraint body 60 is wound on the outer peripheral surface 12C of the barrel member 12 and constitutes a reinforcement member including a part extending in the circumferential direction of the barrel member 12. Since the spiral restraint body 60 is fitted in the spiral groove 12D, the spiral restraint body 60 does not shift relative to the barrel member 12 at such time as when manufacturing the concrete block 102, and the placement position of the spiral restraint body 60 with respect to the barrel member 12 does not fluctuate. This stabilizes the effect of suppression of the diameter expansion deformation of the barrel member 12 by the spiral restraint body 60.
The fitting of the spiral restraint body 60 to the spiral groove 12D may be achieved by moving the spiral restraint body 60 in the axial direction relative to the barrel member 12 from the side of one end of the barrel member 12, with the spiral restraint body 60 deformed to have an expanded diameter such that the inner diameter of the spiral restraint body 60 is larger than the outer diameter of the barrel member 12, and releasing the diameter expansion deformation at a position where the spiral restraint body 60 aligns with the spiral groove 12D in the axial direction, or by making the spiral groove 12D threadedly engaged with the spiral restraint body 60 from the side of one end of the barrel member 12 while rotating the spiral restraint body 60 relative to the barrel member 12.
In Embodiment 5 also, similarly to Embodiment 1, a load urging the barrel member 12 to undergo diameter expansion deformation acts on the barrel member 12 due to wedge action resulting from the driving of the wedge members 20. In this state, the spiral restraint body 60 acts as a reinforcement member to suppress the diameter expansion deformation of the barrel member 12. To properly obtain this effect, preferably, the spiral restraint body 60 is fitted in the spiral groove 12D in a preloaded state.
Accordingly, even though the barrel member 12 is composed of matrix resin instead of steel to prevent rust, the barrel member 12 is provided with sufficient strength against the diameter expansion deformation due to wedge action, and thus, reduction of wedge action is prevented.
As described above, with the anchoring device 10 of Embodiment 5, the diameter expansion deformation of the barrel member 12 is effectively suppressed by the spiral restraint body 60. Accordingly, the barrel member 12 does not corrode even when used over an extended period of time, while the barrel member 12 is provided with sufficient strength against the diameter expansion deformation due to wedge action, whereby lowering of the anchoring strength of the cable 106 due to the diameter expansion deformation of the barrel member 12 is effectively prevented.
The spiral restraint body 60 may be composed of high-tensile fiber reinforced resin having a Young's modulus and a tensile strength higher than those of the barrel member 12. In other words, the spiral restraint body 60 is composed of fiber reinforced resin having a higher Young's modulus than the fiber reinforced resin composing the barrel member 12.
In this case, even though the barrel member 12 is composed of reinforced resin containing glass fibers cheaper than carbon fibers or the like, strength similar to when the barrel member 12 is composed of carbon fiber reinforced resin or the like (strength that suppresses the diameter expansion deformation of the barrel member 12) is obtained due to the reinforcing effect of the spiral restraint body 60. Therefore, the diameter expansion deformation of the barrel member 12 is effectively suppressed, and the material cost of the barrel member 12 is saved.
An anchoring device 10 of Embodiment 6 will now be described with reference to
The barrel member 12 is a molded product made of fiber reinforced resin composed of matrix resin such as epoxy resin, polyester resin, or the like and fibers such as glass fibers, carbon fibers, boron fibers, aramid fibers, basalt fibers, or the like, and is molded in a truncated conical shape having a through hole 14. An outer peripheral surface 12E of the barrel member 12 consists of a conical surface (tapered surface) having an outer diameter gradually diminishing from the outer end 12A to the inner end 12B. In other words, the barrel member 12 has a conical shape tapered in the same direction as the through hole 14.
On the outer peripheral surface 12E of the barrel member 12, multiple annular restraint bodies 70 are mounted at intervals in the axial direction. Each annular restraint body 70 is a molded product made of fiber reinforced resin composed of matrix resin such as epoxy resin, polyester resin, or the like and fibers such as glass fibers, carbon fibers, boron fibers, aramid fibers, basalt fibers, steel fibers, or the like.
Each annular restraint body 70 has an inner peripheral surface 70A in a tapered shape matching the outer peripheral surface 12E of the barrel member 12, and the inner peripheral surface 70A is fitted on the outer peripheral surface 12E of the barrel member 12 so as not to be displaceable in the axial direction of the barrel member 12.
An end surface 70B of each annular restraint body 70 on the tapered side of the conical shape of the barrel member 12 (right side in the drawing) consists of a surface perpendicular to the axial direction of the barrel member 12.
In Embodiment 5 also, similarly to Embodiment 1, a load urging the barrel member 12 to undergo diameter expansion deformation acts on the barrel member 12 due to wedge action resulting from the driving of the wedge members 20. In this state, each annular restraint body 70 acts as a reinforcement member to suppress the diameter expansion deformation of the barrel member 12.
Accordingly, even though the barrel member 12 is composed matrix resin instead of steel to prevent rust, the barrel member 12 is provided with sufficient strength against the diameter expansion deformation due to wedge action, and thus, reduction of wedge action is prevented.
As described above, with the anchoring device 10 of Embodiment 5, the diameter expansion deformation of the barrel member 12 is effectively suppressed by the annular restraint bodies 70. Accordingly, the barrel member 12 does not corrode even when used over an extended period of time, while barrel member 12 is provided with sufficient strength against the diameter expansion deformation due to wedge action, whereby lowering of the anchoring strength of the cable 106 due to the diameter expansion deformation of the barrel member 12 is effectively prevented.
Each annular restraint body 70 may be composed of high-tensile fiber reinforced resin having a Young's modulus and a tensile strength higher than those of the barrel member 12. In other words, each annular restraint body 70 is composed of fiber reinforced resin having a higher Young's modulus than the fiber reinforced resin composing the barrel member 12.
In this case, even though the barrel member 12 is composed of reinforced resin containing glass fibers cheaper than carbon fibers or the like, strength similar to when the barrel member 12 is composed of carbon fiber reinforced resin or the like (strength that suppresses the diameter expansion deformation of the barrel member 12) is obtained due to the reinforcing effect of each annular restraint body 70. Therefore, the diameter expansion deformation of the barrel member 12 is effectively suppressed, and the material cost of the barrel member 12 is saved.
Since the barrel member 12 has a conical shape tapered in the same direction as the through hole 14, movement of the barrel member 12 in the axial direction (rightward) relative to the concrete block 102 is suppressed, and the high-quality concrete block 102 to which stable prestress is applied over an extended period of time is obtained.
Further, in the state embedded in the concrete block 102, each annular restraint body 70 enhances the bonding strength between the barrel member 12 and the concrete block 102, and the end surface 70B of each annular restraint body 70 functions as a barrier surface that prevents movement of the barrel member 12 in the axial direction (rightward) relative to the concrete block 102.
Due to this function, axial movement of the barrel member 12 relative to the concrete block 102 is effectively suppressed. As a result of this, the high-quality prestressed concrete 100 to which stable prestress is applied over an extended period of time is manufactured with excellent productivity without requiring additional components and steps.
Embodiment 7 of the prestressed concrete 100 will now be described with reference to
In this embodiment, the anchoring device 10 is mounted to each of the two ends of the concrete block 102 after molding and curing.
More specifically, a recess 112 having a truncated conical shape and opened to outside is molded at each of the two longitudinal end portions of the concrete block 102. Each recess 112 has an axial length greater than that of the anchoring device 10. A bottom surface 112A of each recess 112 forms a part of a substantial outer end surface of the concrete block 102.
The anchoring device 10 is mounted to the concrete block 102 such that the inner end 12B of the barrel member 12 contacts the bottom surface 112A of the recess 112 via a patch plate 80 and the outer peripheral surface 12C of the barrel member 12 is exposed to outside. In this embodiment, the entirety of the barrel member 12 is disposed in the recess 112.
The anchoring devices 10 give a tension to the cable 106, whereby each anchoring device 10 is fixed to the concrete block 102 with the inner end 12B of the barrel member 12 being pressed against the patch plate 80 due to the tension.
The prestressed concrete 100 of this embodiment allows for easy maintenance such as replacement of the anchoring device 10.
Note that the recess 112 may be filled with mortar, asphalt, resin, or the like after arrangement of the anchoring device 10.
The anchoring device 10 applied to the other embodiment shown in
In the foregoing, the present invention has been described in terms of preferred embodiments thereof. However, as will be readily appreciated by a person of ordinary skill in the art, the present invention is not limited to such embodiments and may be modified appropriately within the spirit of the present invention.
For example, the barrel member 12 and the wedge member 20 may be composed of material other than resin, such as mortar, that is resistant to oxidation and corrosion. The barrel member 12 of Embodiments 2, 3, 5 and 6 may be made of resin containing no fibers. The wedge member 20, the spiral restraint body 60, and the annular restraint body 70 may be composed of material other than resin, such as titanium, that is resistant to oxidation and corrosion. The number of the wedge members 20 is not limited to two, and may be three or more. Instead of the cable 106, the wire may be a rod having flexibility. The anchoring device 10 is not limited to the one whose entirety is embedded in the concrete block 102, and may be adapted such that only a part on the side of the inner end 12B of the barrel member 12 is embedded in the concrete block 102 over a predetermined axial length.
Also, not all of the components shown in the above embodiments are necessarily indispensable and they may be selectively adopted as appropriate without departing from the spirit of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-208553 | Dec 2020 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/045668 | 12/10/2021 | WO |
