JP2004211514A - Method for repairing circular structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for repairing a circular structure made of prestressed or reinforced concrete. <P>SOLUTION: This work method repairs a circular structure by means of a pair of anchors moveable in the circumferential direction installed on the external wall surface of the circular structure at opposite points across the center of the structure, and four anchoring PC steel materials inserted vertically, two PC steel materials arranged along the half-circle external wall surface of the structure between the pair of anchors, and fixed by these anchors at both ends, other two PC steel materials arranged along the other half-circle external wall surface between the pair of anchors, and fixed by these anchors at both ends, and spacers for arranging external cables installed in the circumferential direction along the external wall surface of the structure and holding the PC steel materials at a predetermined level. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for repairing circular structures such as prestressed concrete and reinforced concrete tanks.
[0002]
[Prior art]
As a tank that stores liquids such as tap water, the load acting on the wall is an even internal pressure.Therefore, by using a circular structure, only the tensile force acting in the circumferential direction is applied to the wall. Therefore, circular tanks have been adopted for many structures. As a material constituting the structure, in order to use a concrete material having excellent durability, in order to compensate for the weakness of the concrete having a low tensile force, a material having a reinforced concrete structure combining steel is often used. Has been adopted. In addition, since the reinforced concrete structure has cracks due to drying shrinkage and low tensile strength of the concrete, in order to cancel the tensile stress generated in the concrete, the outside of the concrete must be removed in advance. In recent years, many tanks having a prestressed concrete structure in which a PC steel wire is wound around a wall surface to apply a compressive stress have been constructed. As a method for preventing rust on the PC steel wire, a method of spraying mortar or the like with a sprayer to prevent the surface of the PC steel wire from coming into contact with the atmosphere and protecting it is adopted.
[0003]
[Problems to be solved by the invention]
The prestressed concrete structure tank described above is sound even after the service life of the concrete has passed without causing troubles such as cracks due to the previously introduced compressive force, but protects the PC steel wire. There is a problem that the mortar is deteriorated by being exposed to wind and rain, and the PC steel wire rusts and cannot maintain a predetermined stress. In addition, the tank of the reinforced concrete structure has a problem that even if the wall itself is sound, the structure does not conform to the current design standard due to the change of the seismic design standard and the like.
[0004]
For this reason, although there is no technical document for solving the above-mentioned problem, usually, concrete is newly added to the outer peripheral wall surface of the existing concrete tank with a predetermined thickness, and the outer peripheral surface of the wall body is formed. Alternatively, a method of applying a prestress to a wall by a PC steel material installed in the wall to satisfy a design standard has been implemented.
[0005]
However, the above-mentioned technology is a work process of newly assembling the outer formwork and the shoring, laying concrete and curing, and then introducing prestress, which causes a problem that the construction period becomes extremely long and construction costs. Is also large. In addition, the concrete wall of the existing tank is hardly deteriorated, and there is a problem that even if the concrete wall can be sufficiently used, it is not effectively used.
[0006]
The present invention provides a method for efficiently repairing a concrete tank or the like manufactured in a cylindrical shape at low cost.
[0007]
[Means for Solving the Problems]
That is, the present invention relates to a method for repairing a circular structure of a prestressed concrete tank or a reinforced concrete tank manufactured in a cylindrical shape,
A pair of fixing metal fittings, which can be fixed by inserting four PC steel members in a vertical direction, which are installed on the outer wall facing each other so as to be movable in the circumferential direction with respect to a center point on the plane of the cylindrical structure; Two PC steel members are arranged along the outer peripheral wall by a half circumference between the fixing brackets and both ends are fixed to a pair of fixing brackets, and are disposed along the outer peripheral wall by a half circumference on the opposite side between the pair of fixing brackets. Then, two PC steel members, both ends of which are fixed to a tension jack through a pair of fixing brackets, are installed at predetermined intervals in the circumferential direction of the outer wall surface of the circular structure, and the PC steel materials are adjusted to a predetermined height. And a spacer for arranging an outer cable for holding the outer wall of the circular structure, which tensions the two PC steel members by extending the tension jack to thereby tension the opposite two PC steel members. It is a repair method.
[0008]
The fixing bracket is configured such that a support plate having four holes through which four PC steel materials are inserted in the vertical direction at both ends is fixed by a fixing plate. A support plate is provided in two upper and lower through holes of the support plate at one end, and a support plate is provided in two intermediate through holes of the support plate at the other end. The fixing bracket is made of a relatively strong steel material to support a large load due to the tension of the PC steel material. The distance between the fixing members arranged in the vertical direction is determined by the diameter and the number of the PC steel materials so that a tensile force is not generated by the internal pressure in the circumferential direction of the tank wall, and the arrangement of the fixing members is also determined. The fixing bracket is supported by a suspension facility or the like from above so as to be movable in the circumferential direction.
[0009]
For PC steel, it is necessary to spray mortar to protect the PC steel after tensioning by covering the circumference with a coating material such as resin and using the PC steel filled with a filler material such as resin. The construction period can be shortened and construction costs can be reduced. When using a PC steel material in a normal bare wire state, it is necessary to perform surface protection work by spraying mortar or the like after the tension of the PC steel material.
[0010]
As for the PC steel material arranged on the outer peripheral wall, a pair of fixing brackets is installed at a half-periphery portion of the outer peripheral wall of the tank. For the PC steel material arranged on the outer peripheral wall, the PC steel material is inserted through the two insertion holes of the support plate at one end of each fixing bracket for half a circumference, and is passed to the insertion hole of the support plate at the other end, and the support plate of the support plate is inserted. Fix it with a fixture at the part. The other half circumference of the PC steel material is inserted through a through hole different from the above described through hole of the support plate at one end of each fixing bracket, and is passed through the through hole of the support plate at the other end. A tension jack is installed in the insertion hole of the support plate, and the PC steel material is fixed by the head through the PC steel material in the tension jack.
[0011]
As for the tension of the PC steel material, a half circumference of the PC steel material is tensioned by simultaneously extending the tension jacks installed on the pair of fixing brackets. When the PC steel material for one half circumference is tensioned, the movable fixing bracket is moved, so that the PC steel material for the other half circumference is also tensioned, so that the tensioning work can be performed very efficiently. Become.
[0012]
The outer cable arrangement spacer is provided with a key-type shelf fitting in accordance with the arrangement of the PC steel material on the steel plate corresponding to the height of the wall body, and at a predetermined interval in the circumferential direction of the outer peripheral wall of the tank. Installed. The outer cable arrangement spacer is fixed to a wall surface by a hole anchor or the like.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view illustrating a method for repairing a circular structure according to the present invention. A pair of fixing metal fittings 1 are installed on a semi-circumferential portion of an outer wall surface of a concrete tank which is a circular structure so as to be movable in a circumferential direction. The fixing plate 1 is fixed to a support plate 4 having insertion holes through which four PC steel wires 2 of PC steel can be inserted vertically at both ends. The arrangement of the PC steel wires 2 is set by two strips and is arranged by half a circumference along the outer peripheral wall. One of the PC steel wires 2 is inserted through the two insertion holes 6 in the middle of the support plate 4 of the pair of fixing brackets 1. The PC steel wire 2 is fixed by the fixture 14 at the end of the support plate 4 through the insertion hole 6 of the support plate 4 at the other end. On the other side, the tension of the PC steel wire 2 is inserted through the upper and lower insertion holes 6 of the support plate 4 of the pair of fixing brackets 1, and the tension is set on the support plate 4 through the insertion hole 6 of the support plate 4 at the other end. Fix to jack 3.
[0014]
Next, a method for tensioning the PC steel wire 2 will be described with reference to FIG. When the attachment of the PC steel wire 2 to the fixing bracket 1 is completed, the tension jacks 3 set on the pair of fixing brackets 1 are extended to tension the PC steel wire 2 for a half circumference. Due to the tension of the PC steel wire 2, the fixing fitting 1 moves to the opposite side to the tension jack 3, and accordingly, the PC steel wire 2 for the half circumference on the opposite side is also tensioned. In this manner, the tensioning of the PC steel wire 2 over the entire circumference can be performed by one tensioning operation, and the shortening of the construction period is facilitated, since the tensioning operation for the half circumference is not required twice as in the prior art.
[0015]
FIG. 2 is a plan view illustrating the fixing fitting of the present invention. A support plate 4 having insertion holes 6 at both ends is fixed by a fixing plate 5. The size of the insertion hole 6 is such that the PC steel wire 2 arranged on the outer peripheral wall can be inserted. A support plate 14 is fixed on the side of the support plate 4 where the end of the PC steel wire 2 is fixed, in order to distribute the tension to the support plate 4 widely.
[0016]
FIG. 3 is a front view illustrating the fixing fitting of the present invention. The fixing metal fitting 1 adopts a method of arranging the PC steel wires 2 in sets of two so that the tension by the PC steel wire 2 acts evenly on the fixing metal fitting 1. In the present embodiment, the end portion of the PC steel wire 2 is inserted into the insertion hole 6 from the left side, and the intermediate portion is fixed to the support plate 7 installed on the right support plate 4 by the fixture 14. On the other hand, the upper and lower portions are inserted from the right end of the PC steel wire 2 into the insertion hole 6 and are fixed to the supporting plate 7 installed on the left support plate 4 by the fixing device 14. Power is working.
[0017]
FIG. 4 is an explanatory diagram of a spacer for arranging outer cables according to the present invention. The configuration of the outer cable arranging spacer includes a steel plate 8 corresponding to the height of a wall such as a tank, and a key-shaped shelf metal fitting 9 corresponding to the height of the PC steel wire 2 disposed on the outer peripheral wall. Is fixed. The outer cable arrangement spacers are arranged in the circumferential direction at intervals such that the PC steel wire 2 does not hang down by its own weight.
[0018]
FIG. 5 is a detailed diagram illustrating a method of installing the steel plate of the outer cable arrangement spacer. The outer cable arranging spacer is fixed to the outer peripheral wall by passing the hole anchor 11 driven into the outer peripheral wall through a hole provided in the upper part of the steel plate 8 and tightening it with a nut. A rubber mat 10 is inserted between the steel plate 8 and the outer peripheral wall so as to make uniform contact. The installation conditions of the outer cable arrangement spacer are set at predetermined intervals in the circumferential direction of the circular structure, but depending on the condition of the concrete surface which is the outer wall surface of the circular structure. The method of transmitting the force of the PC steel wire 2 directly to the outer wall surface by changing the interval or transmitting the force from the steel plate 8 of the outer cable arrangement spacer is selected.
[0019]
FIG. 6 is a detailed diagram illustrating the shelf fitting. On the surface of the steel plate 8, a key-shaped shelf metal fitting 9 is fixedly provided in accordance with the planned height of the PC steel wire 2. By installing the outer cable arrangement spacer on the outer wall surface, accurate arrangement can be performed only by placing a PC steel wire on the shelf metal fitting 9.
[0020]
FIG. 7 is a detailed view illustrating a cap for protecting the fixing device. When the tension of the PC steel wire 2 is completed in the fixing fitting 1, the PC steel wire 2 is fixed to the supporting plate 7 by the fixing tool 14. Then, the cap 12 is fixed to the support plate 7 so as to cover the fixture 14, and the resin material 15 is filled through the filling hole 13 provided in the cap 12 to prevent the end of the PC steel wire 2 from being rusted.
[0021]
In the present embodiment, the filling of the resin material 15 in the cap 12 is disclosed by an injection method. However, it is also possible to use a method in which the resin material 15 is filled in the cap 12 in advance and fitted to the fixture 14. .
[0022]
【The invention's effect】
As described above, according to the method for repairing a circular structure of the present invention, a predetermined concrete is newly added to the outer peripheral wall surface of an existing concrete tank or the like as in the prior art, and the outer peripheral surface of the wall body or The work of applying prestress with the PC steel material installed in the wall is eliminated, and the tension work of the PC steel material directly on the existing circular structure can be efficiently performed by the fixing bracket of the present invention. For this reason, it was possible to shorten the construction period and reduce construction costs by utilizing the existing structures.
[0023]
[Brief description of the drawings]
FIG. 1 is a schematic view illustrating a method for repairing a circular structure according to the present invention.
FIG. 2 is a plan view illustrating a fixing fitting of the present invention.
FIG. 3 is a front view illustrating a fixing fitting of the present invention.
FIG. 4 is an explanatory diagram of a spacer for arranging outer cables according to the present invention.
FIG. 5 is a detailed view for explaining a method of installing a steel plate of the outer cable arrangement spacer.
FIG. 6 is a detailed diagram illustrating a shelf bracket.
FIG. 7 is a detailed view illustrating a cap for protecting the fixture.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fixing bracket 2 PC steel wire 3 Tension jack 4 Support plate 5 Fixing plate 6 Insertion hole 7 Support plate 8 Steel plate 9 Shelf bracket 10 Rubber mat 11 Hall-in anchor
12 Cap 13 Filling hole 14 Fixture 15 Resin material

Claims (1)

In the repair method of circular structure of cylindrical prestressed concrete tank and reinforced concrete tank,
A pair of fixing brackets, which can be fixed by inserting four PC steel members in a vertical direction, which are movably mounted in a circumferential direction on outer wall surfaces facing each other with respect to a center point on the plane of the circular structure, and Two PC steel members, which are arranged along the outer peripheral wall by a half circumference between the fixing brackets, and both ends are fixed by a pair of fixing brackets, and are disposed along the outer peripheral wall by the opposite half circumference between the pair of fixing brackets. Then, two PC steel members, both ends of which are fixed to a tension jack through a pair of fixing brackets, are installed at predetermined intervals in the circumferential direction of the outer wall surface of the circular structure, and the PC steel materials are held at predetermined positions. And an outer cable arranging spacer for tensioning the two PC steel materials by extending the tension jack to thereby tension the two PC steel materials on the opposite side. How to repair the structure.

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