JP4063525B2 - Tensile wire fixing structure and tension measuring sensor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tension wire fixing structure and a tension measuring sensor for fixing an end portion of a tension wire to which a tension force is applied to a given fixing target portion.
[0002]
[Prior art]
Conventionally, by inserting a tension wire such as a PC steel wire into a concrete structure, introducing a tension force into the tension wire, and pre-stressing the concrete structure in advance, the concrete structure A structure called a prestressed concrete structure (PC structure) that increases the strength of the body is known. This prestressed concrete structure is suitably implemented in a structure that requires a higher level of safety than in the past, such as a reactor containment vessel of a nuclear power generation facility.
[0003]
[Problems to be solved by the invention]
By the way, in a reactor containment vessel constructed with a prestressed concrete structure, a high level of safety is always required, so when a predetermined period, for example, 1 year, 3 years, or 10 years has passed since construction. It is obliged to regularly check whether or not sufficient tension is applied to the tension wire applied to the prestressed concrete structure. Conventionally, in this inspection work, a tension jack is attached to the end of the tension wire, the tension wire is pulled, and the residual tension is measured. It was a difficult task. This has led to a significant increase in maintenance costs.
[0004]
The present invention has been made in view of such circumstances, and an object thereof is to easily measure the tension of a tension wire whose end is fixed to a given fixing target portion even after fixing. It is characterized by providing a tension wire fixing structure and a tension measuring sensor.
[0005]
[Means for Solving the Problems]
In order to achieve such an object, the tension wire fixing structure according to the present invention is a structure for fixing an end portion of a tension wire to which a tension force is applied to a given fixing target portion. In addition, a locking member is provided at an end of the tension wire, and the tension force of the tension wire is transmitted to the fixing target portion between the locking member and the fixing target portion, and according to the tension force. The present invention is characterized in that a strain member configured to generate shear strain is interposed, and a strain sensor for detecting the amount of shear strain is provided on the strain member.
[0006]
In such a fixing structure, the tension force from the tension wire is transmitted to the fixing target portion between the locking member provided at the end portion of the tension wire and the fixing target portion, and the tension force is transmitted to the fixing target portion. By providing a strain member configured to generate a corresponding shear strain and providing the strain member with a strain sensor that detects the amount of shear strain, the tension of the tension wire can be measured at any time. Thereby, in the case of a nuclear reactor containment vessel, the periodic tension measuring work of the tension wire can be completed very easily. In addition, since the measurement is performed using shear strain, the strain member can be formed into a thin shape that can be easily attached to the measurement location, and measurement can be performed with very high accuracy.
[0007]
In this fixing structure, the strain member is in contact with the locking member and receives the tension force of the tension wire, and is in contact with the fixing target portion side and the tension member. An outer peripheral portion for transmitting a force to the fixing target portion side, an inner peripheral portion connected between the outer peripheral portion and a beam portion where the shear distortion occurs, and the tension provided on the inner peripheral portion. And an insertion hole portion through which the wire is inserted, and the strain sensor is provided in the beam portion (claim 2). By forming the strain member in this manner, a shear strain corresponding to the tension force of the tension wire can be generated in the beam portion and can be easily detected through the strain sensor. Thereby, the tension | tensile_strength of a tension | tensile_strength wire can be detected accurately.
[0008]
The tension wire tension measuring sensor according to the present invention is a sensor for measuring the tension of a tension wire whose end is fixed to a given fixing target portion, and is applied to the locking member. An inner peripheral part that contacts and receives the tension of the tension wire, an outer peripheral part that contacts the fixing target part side and transmits the tension force to the fixing target part side, and these inner peripheral part and outer peripheral part And a beam portion that generates shear strain in accordance with the tension force of the tension wire, an insertion hole portion that is provided in the inner peripheral portion and through which the tension wire is inserted, and the beam portion And a strain sensor for detecting the amount of shear strain. In such a sensor, a shear strain corresponding to the tension of the tension wire can be easily generated, and the tension of the tension wire can be detected with high accuracy.
[0009]
Further, the strain member is constituted by a plurality of divided pieces (claims 3 and 5). As described above, since the strain member is configured to be divided by the plurality of divided pieces, it is possible to easily perform the detachment work between the locking member and the fixing target portion and the attachment work between them.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a tension wire fixing structure according to the present invention will be described below with reference to the accompanying drawings. FIGS. 1-5 shows one Embodiment at the time of applying the fixing structure of the tension wire which concerns on this invention to the reactor containment vessel (PCCV) made from a prestressed concrete. FIG. 1 is an external view showing the entire reactor containment vessel, FIG. 2 is a partial sectional perspective view showing a sectional structure of an outer wall portion of the reactor containment vessel, and FIG. It is sectional drawing which showed the fixation structure of the PC steel wire inserted in the inside of a containment vessel. 4 and 5 are a plan view and a longitudinal sectional view of a tension measuring sensor used in the fixing structure of the PC steel wire.
[0011]
As shown in FIG. 1, the reactor containment vessel 10 applied here is a cylindrical lower concrete structure 12 constructed at the lower part and a dome-shaped upper concrete structure constructed integrally at the upper part. 14. Inside the lower concrete structure 12 and the upper concrete structure 14, as shown in FIG. 2, a number of PC steel wires 18 are inserted as tension wires together with reinforcing materials such as reinforcing bars 16. The PC steel wire 18 is arranged to introduce a prestress into the concrete structures 12 and 14 to improve the strength. The lower concrete structure 12 has a circumferential direction and a height direction. It is arranged along. Moreover, inside the upper concrete structure 14, the PC steel wire 18 is arrange | positioned at mesh | network shape by cross | intersecting vertically and horizontally along a dome shape.
[0012]
Each PC steel wire 18 is inserted through a sheath tube 20 embedded in the concrete structures 12 and 14 in advance. Both ends of each of the PC steel wires 18 protrude from the surface portions of the concrete structures 12 and 14 and are fixed to the surface portions of the concrete structures 12 and 14. The PC steel wire 18 inside the lower concrete structure 12 is fixed to a buttress 22 projecting from the outer wall portion of the lower concrete structure 12 along the height direction. Further, the PC steel wire 18 inside the upper concrete structure 14 passes through the inside of the lower concrete structure 12 and is fixed to a foundation portion 24 provided at the peripheral edge of the lower end thereof.
[0013]
Each PC steel wire 18 is given a tension, and prestress is introduced into each concrete structure 12, 14, and the strength of the reactor containment vessel 10 is enhanced to ensure high safety. It has come to be.
[0014]
The fixing structure of the PC steel wire 18 will be described. FIG. 3 is an enlarged view of the fixing structure at both ends of the PC steel wire 18. A large number of PC steel wires 18 are inserted into one sheath tube 20. An end 18a of each PC steel wire 18 protrudes from an opening 28 provided on the concrete structure 12, 14 side, and an anchor head 26 is integrally attached thereto as a locking member according to the present invention. . The anchor head 26 includes a plurality of holes 26a through which the PC steel wires 18 are individually inserted, and the PC steel wires 18 are inserted into the holes 26a. Are bundled and locked.
[0015]
Between the anchor head 26 and the concrete structures 12 and 14, a tension measuring sensor 30 for measuring the tension force of the PC steel wire 18 is interposed. The tension measuring sensor 30 includes a strain member 31 and a strain sensor 42 as shown in FIGS. 4 and 5.
[0016]
The strain member 31 is an annular member having a predetermined thickness formed so as to surround the outer periphery of the PC steel wire 18, and a plurality of PC steels locked to the anchor head 26 at the center thereof. One insertion hole 32 through which the line 18 is inserted is formed through. Outside the insertion hole 32, an inner peripheral portion 34 that is in contact with the anchor head 26 is provided. The strain member 31 receives the tension of the PC steel wire 18 through the anchor head 26 at the inner peripheral portion 34.
[0017]
Further, an annular groove 35 is formed outside the inner peripheral portion 34. The annular grooves 35 are formed on the upper and lower sides of the strain member 31 so as to be substantially the same size and coaxial. A through-hole 36 is provided in the groove 35 by connecting the upper and lower grooves 35. The through-hole portions 36 are formed at equal intervals along the groove portion 35.
[0018]
Further, an outer peripheral portion 38 that is in contact with the concrete structures 12 and 14 is provided outside the groove portion 35. The outer peripheral portion 38 comes into contact with an annular pressure plate 39 disposed around the opening 28 on the concrete structure 12, 14 side. As a result, the tension force of the PC steel wire 18 is received as a load from the anchor head 26 at the inner peripheral portion 34 and transmitted from the outer peripheral portion 38 to the concrete structures 12 and 14 side.
[0019]
A beam portion 40 is provided between the inner peripheral portion 34 and the outer peripheral portion 38 by forming a through hole portion 36. That is, the beam part 40 has connected the inner peripheral part 34 and the outer peripheral part 38, and transmits the tension | tensile_strength of the PC steel wire 18 from the anchor head 26 to the concrete structures 12 and 14 side. At that time, a shear strain corresponding to the magnitude of the tension force is generated in the beam portion 40. As shown in FIG. 5, the strain sensor 42 is disposed inside the through hole portion 36 and detects the shear strain amount of the beam portion 40. In the present embodiment, two strain sensors 42 are disposed obliquely while intersecting the inner wall portion of the through hole portion 36. Since the strain sensor 42 is disposed obliquely in this way, the amount of shear strain generated in the beam portion 40 can be detected with high sensitivity. Since the shear strain amount obtained by this detection is a value corresponding to the tension of the PC steel wire 18, the tension of the PC steel wire 18 can be measured with high accuracy and efficiency.
[0020]
The groove portion 35 plays a role of reliably cutting the edge between the anchor head 26 that is in contact with the inner peripheral portion 34 and the concrete structure 12 and 14 side (pressure bearing plate 39) that is in contact with the outer peripheral portion 38. . That is, as in this embodiment, the outer diameter of the contact portion 26b with the inner peripheral portion 34 of the anchor head 26 is set to be slightly smaller than the inner diameter of the opening 28 on the concrete structures 12 and 14 side. Thus, there is no problem when the tension force of the PC steel wire 18 is not directly transmitted to the concrete structures 12 and 14, but the outer diameter size of the contact portion 26b of the anchor head 26 and the concrete structure If the inner diameter dimension of the opening 28 on the body 12, 14 side is substantially the same, or if the outer diameter dimension of the contact portion 26 b of the anchor head 26 is larger than the inner diameter dimension of the opening 28, the PC The tension of the steel wire 18 may be transmitted directly to the concrete structures 12 and 14 side. For this reason, by forming such a groove part 35, it is possible to ensure that the tension of the PC steel wire 18 passes through the beam part 40. The width dimension of the groove part 35 is appropriately set according to the outer diameter dimension of the abutting part 26 b of the anchor head 26 and the inner diameter dimension of the opening 28.
[0021]
Further, the surface of the inner peripheral portion 34 on the anchor head 26 side has a shape that slightly protrudes toward the anchor head side than the surface of the outer peripheral portion 38. On the other hand, the surface of the inner peripheral portion 34 on the side of the concrete structures 12 and 14 has a shape slightly outward (upward in FIG. 5) from the surface of the concrete structures 12 and 14 (supporting plate 39). By setting it as such a shape, in addition to the effect by providing the groove part 35, the tension | tensile_strength of the PC steel wire 18 can be made to pass through the beam part 40 more reliably.
[0022]
Further, in the tension measuring sensor 30 formed in this way, the strain member 31 has a half crack structure. This is because the tension measuring sensor 30 is disposed so as to surround the PC steel wire 18 from the outside. Thus, the strain member 31 is composed of two semicircular divided pieces. The tension measuring sensor 30 can be interposed between the anchor head 26 and the concrete structures 12 and 14 in a state where the anchor head 26 is attached to the end portion 18a of the steel wire 18. Thereby, the attaching operation or the removing operation of the tension measuring sensor 30 can be easily performed.
[0023]
A cup-shaped end cap 50 is attached to the outside of the end 18a of the PC steel wire 18, the anchor head 26, and the tension measuring sensor 30, and the inner end of the end cap 50 is further protected. A rust material 52 is filled.
[0024]
As shown in FIG. 3, the detection signal of the strain sensor 42 is output through a signal line 54 that extends from the strain member 31, passes through the rust preventive material 52, and is led out of the end cap 50. These signal lines 54 are all connected to a computer device or the like via a strain measuring device (not shown) so that the detection result of the strain sensor 42, that is, the tension force of the PC steel wire 18 can be monitored at any time. .
[0025]
As described above, in this fixing structure, the anchor head 26 provided integrally with the end portion 18a of the PC steel wire 18 inserted into the concrete structures 12 and 14 in order to give prestress to the concrete structures 12 and 14, the concrete structures 12, 14, since the tension measuring sensor 30 is interposed between the PC steel wire 18 and the tension force of the PC steel wire 18 can be monitored at any time as in the prior art. There is no need to do work that gives tension. For this reason, it is only necessary to apply the tension only when the tension is insufficient, and therefore the periodic inspection can be completed very simply. Moreover, in the tension measuring sensor 30, since the tension of the PC steel wire 18 is detected as a shear strain and measured by the strain sensor 42, the measurement can be performed with very high accuracy. The inspection accuracy can be improved.
[0026]
Next, the construction method of this fixing structure will be described. FIG. 6 shows a procedure for constructing the fixing structure according to the present invention in place of the conventional fixing structure.
[0027]
First, as shown to Fig.6 (a), the lift-off jack 60 is attached to the edge part 18a of the PC steel wire 18 protruded from the anchor head 26, and the edge part of PC steel wire is gripped. The lift-off jack 60 is fixed to the concrete structures 12 and 14 via a jack chair 62. Using this jack chair 62, the end 18a of each PC steel wire 18 is pulled. Next, the shim 64 is removed as shown in FIG. 6B while pulling the end 18a of the PC steel wire 18 with the lift-off jack 60. Then, as shown in FIG. 6C, the above-described tension measuring sensor 30 is mounted instead of the removed shim 64. Here, as described above, the tension measuring sensor 30 has a half-crack structure, and is divided into two semicircular pieces. Thereby, at the time of attachment or removal, it can be attached to the outside of the PC steel wire 18 by being divided into two divided pieces, and can be removed from the portion. Then, as shown in FIG. 6D, the lift-off jack 60 is removed, the end cap 50 is further attached, and the interior thereof is filled with the rust preventive material 52, thereby completing the operation.
[0028]
Next, a construction method for newly installing the fixing structure according to the present invention will be described. FIG. 7 is for explaining the construction method. When a prestressed concrete reactor containment vessel or the like is newly constructed, a fixing structure for the PC steel wire 18 is newly installed. In this case, the tension measuring sensor 30 can be interposed between the anchor head 26 and the concrete structures 12 and 14 when applying tension to the PC steel wire 18. Then, after interposing the tension measuring sensor 30, as shown in FIG. 7, a tension jack 70 is set on the end of the PC steel wire 18 protruding from the anchor head 26, and the end 18a of the PC steel wire 18 is attached. With the tension jack 70 gripped, the tension measuring sensor 30 is sandwiched between the anchor head 26 and the concrete structures 12, 14, and the end 18a of the PC steel wire 18 is gradually pulled with the tension jack 70. Tension is introduced into the PC steel wire 18.
[0029]
In the above-described embodiment, the case where the tension wire fixing structure according to the present invention is applied to a tension wire fixing structure such as a PC steel wire having a prestressed concrete structure has been described. The present invention is not limited to this case, and can be suitably applied to, for example, a fixing structure of a tension wire having a suspension structure of a bridge, and a fixing structure of a ground anchor such as a slope or a retaining wall.
[0030]
Moreover, in this embodiment, although the distortion member 31 has a half-crack structure composed of two divided pieces, the present invention is not limited to such a case, and is constituted by three or more divided pieces. It doesn't matter.
[0031]
【The invention's effect】
In the fixing structure of the tension wire according to the present invention, while transmitting the tension force from the tension wire to the fixing target part between the locking member provided at the end of the tension wire and the fixing target part, Measure the tension of the tension wire at any time by providing a strain sensor that detects the amount of shear strain by installing a strain member configured to generate shear strain according to the tension force. Can do. Thereby, in the case of a nuclear reactor containment vessel, the periodic tension measuring work of the tension wire can be completed very easily. In addition, since the measurement is performed using shear strain, the strain member can be formed into a thin shape that can be easily attached to a measurement location, and measurement can be performed with very high accuracy.
[0032]
The strain member is in contact with the locking member to receive the tension force of the tension wire, and the strain member is in contact with the fixing target part side to transmit the tension force to the fixing target part side. An outer peripheral portion that is connected between the inner peripheral portion and the outer peripheral portion, the beam portion where the shear strain is generated, and an insertion hole portion that is provided in the inner peripheral portion and through which the tension wire is inserted. Since the strain sensor is provided in the beam portion, a shear strain corresponding to the tension force of the tension wire can be generated in the beam portion and can be easily detected through the strain sensor. Thereby, the tension | tensile_strength of a tension | tensile_strength wire can be detected accurately (Claim 2).
[0033]
The tension wire tension measuring sensor according to the present invention is a sensor for measuring the tension of a tension wire whose end is fixed to a given fixing target portion, and is in contact with the locking member. An inner peripheral part that receives the tension force of the tension wire, an outer peripheral part that is in contact with the fixing target part side and transmits the tension force to the fixing target part side, and these inner peripheral part and outer peripheral part. A beam portion that generates a shear strain according to the tension force of the tension wire, an insertion hole portion that is provided in the inner peripheral portion and through which the tension wire is inserted, and By providing a strain sensor for detecting the amount of shear strain, a shear strain corresponding to the tension of the tension wire is generated in the beam portion, and this can be easily detected by the strain sensor. Thereby, the tension | tensile_strength of a tension | tensile_strength wire can be detected accurately (Claim 4).
[0034]
In addition, since the strain member is constituted by a plurality of divided pieces, removal work and attachment work from between the locking member and the fixing target portion can be easily performed. Claim 5).
[Brief description of the drawings]
FIG. 1 is an overall perspective view showing an appearance of a prestressed concrete reactor containment vessel (PCCV) to which a tension wire fixing structure according to the present invention is applied.
2 is a partial cross-sectional perspective view showing a cross-sectional structure of an outer wall portion of the prestressed concrete reactor containment vessel shown in FIG. 1. FIG.
FIG. 3 is a cross-sectional view showing one embodiment of a tension wire fixing structure according to the present invention.
FIG. 4 is a plan view showing an embodiment of a tension measuring sensor in the tension wire fixing structure according to the present invention.
FIG. 5 is a sectional view showing an embodiment of a tension measuring sensor in the tension wire fixing structure according to the present invention.
FIG. 6 is an explanatory diagram showing a construction procedure in the case of construction by replacing the tension wire fixing structure according to the present invention with a conventional existing fixing structure.
FIG. 7 is an explanatory diagram for explaining a construction method in the case of newly installing a tension wire fixing structure according to the present invention.
[Explanation of symbols]
10 Reactor containment vessel 12 Lower concrete structure 14 Upper concrete structure 16 Reinforcement 18 PC steel wire (tensile wire)
20 Sheath tube 26 Anchor head (locking member)
30 Tension sensor 32 Insertion hole 34 Inner circumference 36 Through hole 38 Outer circumference 39 Bearing plate 40 Beam 42 Strain sensor 50 End cap 52 Rust preventive

Claims (5)

A structure for fixing an end portion of a tension wire to which a tension force is applied to a given fixing target portion,
A locking member is provided at an end of the tension wire, and the tension force of the tension wire is transmitted to the fixing target portion between the locking member and the fixing target portion, and shearing is performed according to the tension force. A tension wire fixing structure comprising a strain member configured to generate strain, and a strain sensor for detecting the amount of shear strain provided in the strain member. The strain member is brought into contact with the locking member to receive the tension force of the tension wire, and is brought into contact with the fixing target portion side to transmit the tension force to the fixing target portion side. An outer peripheral portion, a beam portion that is interposed between the inner peripheral portion and the outer peripheral portion and generates the shear strain, and an insertion hole portion that is provided in the inner peripheral portion and through which the tension wire is inserted. The tension wire fixing structure according to claim 1, wherein the strain sensor is provided in the beam portion. The tension wire fixing structure according to claim 1, wherein the strain member includes a plurality of divided pieces. A sensor for measuring the tension of a tension wire whose end is fixed to a given fixing target part,
An inner peripheral part that contacts the locking member and receives the tension force of the tension wire, an outer peripheral part that contacts the fixing target part side and transmits the tension force to the fixing target part side, and these A beam portion that is interposed between the inner peripheral portion and the outer peripheral portion and generates shear strain according to the tension force of the tension wire, and an insertion hole that is provided in the inner periphery and through which the tension wire is inserted. And a strain sensor for detecting the amount of shear strain of the beam portion. The tension measuring material tension sensor according to claim 4, wherein the strain member includes a plurality of divided pieces.

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