JP2000147177A - End retaining structure of pc steel wire in reactor containment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make simply and exactly perfomable a tension measurement of unbonded PC steel wire buried in concrete wall of a reactor containment without using a tension addition device. SOLUTION: In the end retaining structure, an anchor head 20 is fixed to both ends of unbonded PC steel wire 16, a load cell 22 and a shim 24 for measuring reception pressure are arranged inside the anchor head 20, and by way of the load cell 22 and shim 24, to be retaining via the shim and fixes to a bearing plate 19. With the load cell placed between the anchor head 20 and the bearing plate 19, the tension of PC wire 16 is measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for locking an end portion of an unbonded PC steel wire embedded in a concrete wall of a containment vessel, and more particularly to a structure of the PV after constructing a containment vessel.
The present invention relates to an end locking structure of a PC steel wire in a reactor containment vessel that facilitates measurement of tension of a C steel wire.

[0002]

2. Description of the Related Art In order to increase the strength of a containment vessel made of prestressed concrete, there is a method in which an unbonded PC steel wire is buried in a concrete wall body and tension is applied to the steel wire to form a prestressed concrete wall. In this case, the PC steel wire is pulled from both sides by tension applying devices attached to both ends of the PC steel wire, and a predetermined tension is applied thereto. It is locked and fixed.

[0003] The tension application of the PC steel wire is performed, for example, as shown in FIG.
This is performed using a hydraulic jack 1 as a tension applying device shown in FIG. This hydraulic jack 1 is quite heavy,
As shown in (a), the hydraulic jack 1 is used by being suspended from a jib crane 2 and is installed facing the end of the PC steel wire 3 to which tension is to be applied. Then, as shown in (b), with the tension rod 1a of the hydraulic jack 1,
The anchor head 4 fixed to the end of the PC steel wire 3 is gripped and pulled, and a shim 6 is sandwiched between the anchor head 4 and the concrete wall 5 when a predetermined tension is obtained.
The tension state of the PC steel wire 3 is maintained. Thereafter, the hydraulic jack 1 is removed, and the end of the PC steel wire 3 to which the shim 6 is attached is covered with the grease cap 7 as shown in FIG.

[0004]

However, in such a conventional PC steel wire end locking structure, the PC steel wire 3
Also, when tension is applied to the material, the tension is reduced due to elongation or the like over time. In particular, in the reactor containment vessel, a predetermined period after the tension is applied, for example, one year, three years,
When the year has passed, the tension of the unbonded PC steel wire 3 is measured, and if this tension is insufficient, a predetermined tension is applied to the PC steel wire 3 again.

[0005] Incidentally, the tension measurement of the PC steel wire 3 is as follows.
The operation is performed using the hydraulic jack 1 in the same manner as when the tension is first applied. In other words, the PC whose tension is to be measured
After installing the hydraulic jack 1 at the end of the steel wire 3 using the jib crane 2, the tension jack 1 a is used to connect the hydraulic jack 1 to the PC.
The steel wire 3 was pulled to such an extent that the shim 6 did not crimp, and in this state, the tension was read by a hydraulic gauge provided on the hydraulic jack 1.

Therefore, in the measurement of the tension of the PC steel wire 3, an operation of pulling the end of the PC steel wire 3 using the hydraulic jack 1 is performed in the same manner as when the tension is first applied. That is, the hydraulic jack 1 is installed at the end of the PC steel wire 3 by the jib crane 2, the grease cap 7 is removed, and then the PC steel wire 3 is gripped and pulled by the tension rod 1 a. Will be performed every time. For this reason, the operation of measuring the tension of the PC steel wire 3 is significantly complicated, and requires much labor and time. Also,
Since the tension is read in a state where the PC steel wire 3 is pulled by the hydraulic jack 1, there is a problem that the measured value fluctuates due to the degree of pulling, and it is not possible to detect an accurate tension.

Accordingly, the present invention has been made in view of the above-mentioned conventional problems, and it is possible to easily measure the tension of an unbonded PC steel wire buried in a concrete wall of a containment vessel without using a tension applying device. An object of the present invention is to provide an end locking structure of a PC steel wire in a reactor containment vessel which can be performed accurately.

[0008]

According to the present invention, there is provided a nuclear reactor containment vessel according to claim 1 of the present invention.
The end locking structure of the C steel wire is a PC steel wire that inserts an unbonded PC steel wire into a concrete wall of a reactor containment vessel, applies tension to the PC steel wire, and prestresses the concrete wall. In the end locking structure of (1), a locking member is fixed to an end of a PC steel wire projecting from a concrete wall, and tension is applied to the PC steel wire, and the tension is applied to the locking member and the concrete wall. A load cell for measuring the receiving pressure is interposed therebetween.

According to a second aspect of the present invention, there is provided an end locking structure for a PC steel wire in a reactor containment vessel, wherein the load cell is formed into a splittable annular shape surrounding an outer periphery of the PC steel wire. .

Further, according to a third aspect of the present invention, in the structure for locking an end portion of a PC steel wire in a reactor containment vessel, the load cell surrounds an outer periphery of the PC steel wire and is spaced apart in a circumferential direction. A plurality of sensing elements are provided and output the measured detection value to the measurement device.

The operation of the end locking structure of the PC steel wire in the containment vessel of the present invention having the above configuration will be described below. In claim 1, the concrete wall of the containment vessel and the unbonded PC steel wire are connected. Since the load cell for measuring the receiving pressure is interposed between the locking member fixed to the end and the load cell, the tension of the PC steel wire acts on this load cell, and the pressure corresponding to this tension always acts. It is in. Therefore, PC
When measuring the tension of the steel wire, it is possible to make a quick determination from the detected value of the load cell, so that the determination of the tension of the PC steel wire is significantly simplified, and the current state of the PC steel wire can be measured without being pulled. Since the tension can be measured, the measurement of the tension can be performed accurately and quickly.

According to a second aspect of the present invention, the load cell surrounds the outer periphery of the PC steel wire by sandwiching the splittable annular load cell from both sides of the PC steel wire and connecting the divided pieces in this state. It will be attached in. Therefore, the load cell can be attached to the PC steel wire by retrofitting, thereby simplifying the operation of attaching the load cell. In addition, when the tension is applied to the PC steel wire, by attaching the load cell to the space formed by pulling, the thick portion of the load cell functions as a shim, and the thickness of the newly added shim can be reduced.

Further, according to claim 3, the load cell comprises:
The PC steel wire is provided with a plurality of sensing elements that are arranged at intervals in the circumferential direction around the outer circumference of the steel wire and output measured detection values to a measuring device. By inputting the detected values to the measuring device, for example, the entire load and the load distribution in the circumferential direction of the PC steel wire can be detected from the respective detected values. Therefore, it is possible to constantly measure the entire load of the PC steel wire, that is, the tension.
For this reason, for example, it is possible to detect in real time that the tension exceeds the allowable value without giving a periodicity to the measurement time, so that it is possible to perform an operation of appropriately adding the tension, and it is necessary to perform the work on the PC steel wire. Thus, it is possible to minimize the fluctuation of the tension by maintaining a constant tension as much as possible, thereby avoiding a decrease in the strength of the concrete wall in which the PC steel wire is embedded.

Further, the load distribution in the circumferential direction of the PC steel wire can be detected, and the bias of the tension acting on the PC steel wire can be known. That is, even when the tension satisfies the allowable value for the plurality of PC steel wires as a whole, it is possible to detect a case where a part of the PC steel wire is cut due to the bias of the tension.

[0015]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. 1 to 4 show an embodiment of an end locking structure of a PC steel wire in a containment vessel of the present invention, FIG. 1 is a sectional view showing an attached state of a PC steel wire, and FIG. 2 is a front view of a load cell. FIG. 3 is a side view of a load cell, FIG. 4 is a partially cutaway front view showing a prestressed concrete reactor containment vessel to which the present invention is applied, FIG. c) It is a sectional view taken along the line cc.

That is, the end locking structure of the PC steel wire in the containment vessel of the present embodiment is applied to a prestressed concrete containment vessel (PCCV) 10 shown in FIG. As shown in FIG. 1A, the storage container 10 has a cylindrical concrete wall 12 disposed at a lower portion.
And a dome-shaped concrete wall 14 arranged on the upper part of the wall. And unbonded PC steel wire 16
Are arranged along the circumferential direction in the cylindrical concrete wall 12 portion, and are arranged along the arch-shaped cross section in the dome-shaped concrete wall 14 so as to cross each other vertically and horizontally. The end is guided through the cylindrical concrete wall 12 to the lower end thereof. Further, on the outside (or inside) of the cylindrical concrete wall body 12, projections 12a (two or three places) for locking the end of the unbonded PC steel wire 16 are formed along the generatrix. A base 13 for locking an end of an unbonded PC steel wire 16 guided from the dome-shaped concrete wall 14 is formed at the lower peripheral edge of the cylindrical concrete wall 12.

The cylindrical concrete wall 12 and the dome-shaped concrete wall 14 are formed to have a large thickness, and the inside of the cylindrical concrete wall 12 is multistaged in the circumferential direction as shown in FIG. And the PC steel wire 16 is buried inside the dome-shaped concrete wall body 14 in a cross-like manner as shown in FIG. You.

FIG. 1 is an enlarged sectional view showing a state in which the PC steel wire 16 is buried in a straight line, and shows a portion of the cylindrical concrete wall 12 and the dome-shaped concrete wall 14 in which the PC steel wire 16 is buried. In this example, a sheath tube 18 is buried in advance at the time of casting concrete, and thereafter, after the concrete is hardened, a large number of PC steel wires 16 are inserted into the sheath tube 18.

When the PC steel wire 16 is inserted into the sheath tube 18, the cylindrical concrete wall 12 has one end 16b locked to one side of the projection 12a and the other end. The portion 16c is locked on the other side of the projection 12a. One end 16b of the PC steel wire 16 from the dome-shaped concrete wall 14 is connected to the base 13
And the other end 16c is locked to the base 13 on the opposite side of the storage container 10. The protrusion 1
A supporting plate 19 made of a steel plate or the like is embedded in a portion of the base member 13 where the PC steel wire 16 is locked, and the supporting plate 19 receives the tension of the PC steel wire 16. ing.

FIG. 1 shows a case where the PC steel wire 16 is buried by the BBR method. The BBR method is a method of directly fixing the ends of a large number of PC steel wires 16 with anchor heads 20, and the anchor heads 20 are respectively inserted into both ends of the PC steel wires 16 as shown in FIG. In a state where the one-sided projections are gathered, they are swaged and formed so as to be combined as a whole, thereby being integrated with the anchor head 20.

Here, in the present embodiment, the inside of the anchor head 20 at both ends of the PC steel wire 16, that is, the projection 1
A load cell 22 and a shim 24 for measuring a receiving pressure are arranged on the base 2 a and the base 13.
2, is locked to the support plate 19 via a shim 24.

The load cell 22 is formed in an annular shape so as to surround the outer periphery of the PC steel wire 16 as shown in FIG. As shown in FIG. 3, the load cell 22 includes a pair of rings 26, 26 facing each other at appropriate intervals in the length direction of the PC steel wire 16, and a plurality of sensing elements 28, 28 between the rings 26, 26. (In this embodiment, the sensing element 2
8 are provided as 10 even numbers. ) Is the ring 2
6, 26 are arranged along the circumferential direction.

The sensing elements 28, 28... Electrically detect the received pressure, and the detected values are taken out via input / output cables 28b connected to input / output connectors 28a provided respectively. The input / output cable 28b is connected to a computer 30 as a measuring device, and the sensing element 28,
.. Are input to the computer 30, and a load distribution in the circumferential direction of the PC steel wire is detected from each detected value.

The rings 26, 26 are divided into two parts from the center, and the divided semicircular divided pieces 26a, 26b are
It is detachably connected by a screw 32. The sensing elements 28, 28,...
5 are evenly arranged in b.

When tension is applied to the PC steel wire 16, first, an anchor head 20 is fixed to one end 16b of the PC steel wire 16 and inserted into the sheath tube 18, and the load cell 22 and the shim 24 are attached. It is mounted between the anchor head 20 and the support plate 19. And the above-mentioned sheath tube 1
The anchor head 20 is fixed to the other end 16c of the PC steel wire 16 through which the PC steel wire 8 is inserted and protruded, and the anchor head 20 is pulled by using a tension applying device such as a hydraulic jack. Apply tension.

When a predetermined tension is applied to the PC steel wire 16, the load cell 22 is attached to the space between the anchor head 20 and the support plate 19 formed by pulling the PC steel wire 16, Further, an appropriate number of shims 24 are inserted and attached to the remaining space, and then the tensioning device is released from tension and the device is removed. A grease cap 34 is attached to a portion of the PC steel wire 16 where one end 16b side and the other end 16c side protrude from the support plate 19, and the inside is filled with grease. In the above description, the case where the tension is introduced from one end of the PC steel wire 16 has been described.
Needless to say, a tension applying device may be applied to each end of the PC steel wire 16 to introduce tension from both ends.

With the above configuration, the PC steel wire end locking structure in the containment vessel of the present embodiment is the PC steel wire 16
Is inserted into a sheath tube 18 embedded in the cylindrical concrete wall 12 and the dome-shaped concrete wall 14, and anchor heads 20 are fixed to both ends of the PC steel wire 16, and the anchor head 20 is In the concrete wall 12, it is locked on both sides of the projection 12 a, and in the dome-shaped concrete wall 14, it is locked on the base 13. At this time, the protrusion 12a and the base 1
3 is a supporting plate 1 at a portion where the anchor head 20 is locked.
9 is embedded and a load cell 22 and a shim 24 for measuring a receiving pressure between the support plate 19 and the anchor head 20 in a state where a predetermined tension is applied to the PC steel wire 16.
Is to be sandwiched.

Therefore, since the load cell 22 is interposed between the anchor head 20 and the supporting plate 19, the tension of the PC steel wire 16 is applied to the PC steel wire 1 by the load cell 22.
6 is applied, and the pressure corresponding to this tension is always applied. The pressure at this time is determined by the plurality of sensing elements 28.
Is output to the computer 30 so that the current tension of the PC steel wire 16 can be displayed in real time.

Therefore, when measuring the tension of the PC steel wire 16, the tension can be quickly determined from the detected value of the load cell 22, so that the determination of the tension of the PC steel wire 16 is significantly simplified. And the conventional PC steel wire 1
Unlike the method of measuring the tension by pulling the PC 6, the PC
Since the tension in the current state can be measured without pulling the steel wire 16, this tension measurement can be performed accurately and quickly.

Further, since the tension of the PC steel wire 16 can be constantly measured by the load cell 22, it is possible to detect in real time that the tension exceeds the permissible value without giving a periodicity to the measuring time. it can. Therefore, in this case, by performing the work of quickly adding tension,
The tension required for the PC steel wire 16 is constantly maintained to reduce the fluctuation of the tension as much as possible, thereby avoiding a decrease in the strength of the cylindrical concrete wall 12 and the dome-shaped concrete wall 14 in which the PC steel wire 16 is embedded. it can.

Here, the load cell 22 is composed of a pair of rings 26, 26 and a plurality of sensing elements 28 arranged in the circumferential direction between the rings 26, 26. The part is divided into two parts, and the respective divided pieces 26a and 26b are connected by screws 32. For this reason, when the load cell 22 is interposed between the anchor head 20 and the supporting plate 19, the screw 32 is removed and the load cell 22 is divided into two parts. 16 is enclosed so as to be sandwiched from both sides, and is stopped by the screws 32, whereby the mounting is completed.

Therefore, at the other end 16c on the pulling side of the PC steel wire 16, the load cell 22 is retrofitted to a space provided when the PC steel wire 16 is pulled by the tension applying device in order to apply tension. be able to. For this reason, the anchor head 2 is attached to the PC steel wire 16.
There is no need to insert the load cell 22 before fixing 0, and the work of mounting the load cell 22 can be greatly simplified. Also, one end 16b of the PC steel wire 16
Even on the side, the load cell 22 can be retrofitted between the anchor head 20 and the support plate 19 before applying tension.

Since the load cell 22 is attached to the space provided when the PC steel wire 16 is pulled as described above, the thick portion of the load cell 22 functions as a shim.
, That is, the number of shims 24 can be reduced.

Further, the load cell 22 includes the sensing element 2
8 are provided and arranged in a ring, so that the detection value of each sensing element 28 can be input to the computer 30 and the entire load can be measured from each detection value. PC steel wire 1 from individual detected values of
6 to detect the load distribution in the circumferential direction.
The bias of the tension acting on the steel wire 16 can be known. That is, even when the entire tension of the plurality of PC steel wires 16 satisfies the allowable value, it is possible to detect a case where a part of the PC steel wire 16 is cut due to the bias of the tension. In this case, By replacing the PC steel wire 16 and taking other measures, it is possible to quickly avoid the danger when an excessive load is applied due to the occurrence of a large earthquake.

FIGS. 5 and 6 show another embodiment, in which the end locking structure of the PC steel wire in the containment vessel of the present invention is V-shaped.
In the case where the present invention is applied to the SL method, the same components as those in the above-described embodiment are denoted by the same reference numerals, and redundant description is omitted.
That is, the VSL method is a method of fixing the end of the PC steel wire with a wedge. As shown in FIG. 5, a retainer plate 42 is attached to the outer end of the anchor head 40 attached to the ends 16b and 16c of the PC steel wire 16. Is attached, and a tapered hole 42a through which each PC steel wire 16 is individually inserted is formed in the retainer plate 42. Then, a wedge 44 is driven between each tapered hole 42a and the PC steel wire 16 so that each P
The C steel wire 16 is fixed.

Also in this embodiment, the PC steel wire 16 is inserted through the sheath tube 18.
The anchor head 4 fixed to both ends of the PC steel wire 16
Load cells 22 are interposed between the support plate 19 and the support plate 19, respectively. In this case, the shim 24 is provided only on the other end 16c side which is the pulling side of the PC steel wire 16, but it is needless to say that the shim 24 can also be provided on the one end 16b side as in the above embodiment.

Also in this embodiment, since the tension of the PC steel wire 16 can be measured in real time by the load cell 22, the operation of measuring the tension is greatly simplified, and the load cell 22 is divided into two parts. Thereby, retrofitting to the PC steel wire 16 is enabled. By arranging the plurality of sensing elements 28 in the load cell 22 in a ring shape, the load distribution in the circumferential direction of the PC steel wire 16 can be detected.

In each of the above embodiments, the case where the load cell 22 is attached to both ends of the PC steel wire 16 has been disclosed. However, the present invention is not limited to this. When the load cell 22 is provided at one end, the load cell 22 is provided on the side where the tension applying device is installed, that is, on the side where the space is formed by the amount of elongation due to tension (the other end 16c in the present embodiment). Thereby, the extended portion of the PC steel wire 16 can be effectively used as a mounting space for the load cell 22, so that the PC steel wire 16 is formed to be the shortest and the shim 24 is formed.
Can be reduced.

As a plurality of sensing elements 28 provided on the load cell 22, the load is electrically detected, and the detection signal is processed by a computer.
Although the case of measuring the tension and the load distribution thereof has been disclosed, the present invention is not limited to this, and the sensing element is provided with simple means capable of detecting the individually received pressure, for example, as a hydraulic cylinder, each of which is provided with its hydraulic pressure. Alternatively, the measurement may be performed with a hydraulic pressure gauge.

[0040]

As described above, the structure for locking the end portion of the PC steel wire in the containment vessel according to the first aspect of the present invention includes the concrete wall of the containment vessel and the unbonded PC steel wire. Since the load cell for measuring the receiving pressure is interposed between the locking member fixed to the end of the PC steel wire, the tension of the PC steel wire can be quickly measured by the load cell. Therefore, the determination of the tension of the PC steel wire is significantly simplified, and the tension in the current state can be measured without pulling the PC steel wire, so that the tension measurement can be performed accurately and quickly.

Further, in the structure for locking the end portion of the PC steel wire in the containment vessel according to the second aspect of the present invention, a splittable annular load cell is sandwiched from both sides of the PC steel wire. By combining the respective divided pieces, the load cell can be retrofitted to the PC steel wire,
This mounting work of the load cell can be simplified. In addition, when the tension is applied to the PC steel wire, by attaching the load cell to the space formed by pulling, the thick portion of the load cell functions as a shim, and the thickness of the newly added shim can be reduced.

Further, according to claim 3, the load cell is:
The PC steel wire is provided with a plurality of sensing elements that are arranged at intervals in the circumferential direction around the outer circumference of the steel wire and output measured detection values to a measuring device. By inputting the detected values to the measuring device, for example, the entire load and the load distribution in the circumferential direction of the PC steel wire can be detected from the respective detected values. Therefore, the tension of the PC steel wire can be constantly measured. Therefore, for example, it is possible to detect that the tension exceeds an allowable value in real time without making the measurement time regular, and to take appropriate measures. Therefore, the tension required for the PC steel wire is constantly maintained to minimize the fluctuation of the tension, thereby preventing the concrete wall in which the PC steel wire is embedded from being reduced in strength.

Further, the load distribution in the circumferential direction of the PC steel wire can be detected by the plurality of sensing elements.
Since it is possible to know the bias of the tension acting on the steel wire, even if the tension satisfies the allowable value for multiple PC steel wires as a whole,
It is possible to detect a case where a part of the PC steel wire is cut off due to the bias of the tension, and it is possible to reliably maintain the soundness of the prestressed concrete containment vessel.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a mounted state of a PC steel wire according to an embodiment of the present invention.

FIG. 2 is a front view of a load cell used in one embodiment of the present invention.

FIG. 3 is a side view of a load cell used in one embodiment of the present invention.

FIG. 4 is a view showing a prestressed concrete containment vessel showing one embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a mounted state of a PC steel wire according to another embodiment of the present invention.

FIG. 6 is an enlarged sectional view of a portion A in FIG. 5 showing another embodiment of the present invention.

FIG. 7 shows a procedure for applying tension to a conventional PC steel wire.
It is explanatory drawing shown in order by (d).

[Explanation of symbols]

 Reference Signs List 10 Nuclear containment vessel made of prestressed concrete 12 Cylindrical concrete wall 14 Domed concrete wall 16 Unbonded PC steel wire 20 Anchor head 22 Load cell 24 Shim 28 Sensitive element 30 Measurement device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Ikuo Kawai 1-6-1, Otemachi, Chiyoda-ku, Tokyo Japan Nuclear Power Co., Ltd. (72) Inventor Kazuhiko Kiyohara 2-chome Watanabe, Chuo-ku, Fukuoka City, Fukuoka Prefecture 1-82 Kyushu Electric Power Co., Inc. (72) Inventor Toshio Kuno 2-3-3 Kandaji-cho, Chiyoda-ku, Tokyo Tokyo Main Office, Obayashi Corporation Tokyo (72) Inventor Mikio Yamamoto 2-chome, Kandaji-cho, Chiyoda-ku, Tokyo No. 3 Obayashi Corporation Tokyo head office

Claims (3)

[Claims] 1. An unbonded PC steel wire is inserted into a concrete wall of a reactor containment vessel, and tension is applied to the PC steel wire to prestress the concrete wall. In the end locking structure, a locking member is fixed to an end of a PC steel wire protruding from a concrete wall, and a tension is applied to the PC steel wire, and the tension is applied between the locking member and the concrete wall. An end locking structure of a PC steel wire in a reactor containment vessel, wherein a load cell for measuring a receiving pressure is interposed. 2. The end member of a PC steel wire in a reactor containment vessel according to claim 1, wherein the load cell is formed in a ring shape which can be divided and surrounds the outer periphery of the PC steel wire. Stop structure. 3. The load cell includes a plurality of sensing elements that surround the outer circumference of the PC steel wire and are arranged at intervals in a circumferential direction, and output measured detection values to a measuring device. The end locking structure of a PC steel wire in a reactor containment vessel according to claim 1 or 2, characterized in that: