JPH09317203A - Reinforcing method of existing reinforced concrete structure considering cathodic protection and permanent formwork made of precast concrete - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a method for reinforcing an existing reinforced concrete structure in consideration of cathodic protection, which is expected to speed up construction and improve quality, and a permanent formwork made of precast concrete suitable for the method. SOLUTION: A permanent mold 9 made of precast concrete in which an anode material 7 for cathodic protection and a reinforcing bar 8 is embedded is set on the outside of the structure 1, and a permanent mold 9 between the structure 1 and the permanent mold 9 is set. A non-shrinkable concrete 10 is cast in the gap to reinforce the structure 1 by increasing the cross section and adding a reinforcing bar 8 and using the anode material 7 to the internal reinforcing bar 2 and the reinforcing bar 8 of the structure 1. Be able to apply cathodic protection.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reinforcing an existing reinforced concrete structure in consideration of cathodic protection, and a precast concrete permanent form suitable for carrying out the method.

[0002]

2. Description of the Related Art Recently, since the Great Kansai Earthquake, in particular, it has become popular to reinforce existing reinforced concrete structures as seismic resistance measures. Also, conventionally, electric power has been used as a salt damage countermeasure for existing reinforced concrete structures in coastal areas. Although anticorrosion is performed, they are applied separately, and neither electrocorrosion nor reinforcement is applied at the same time.

In the case of applying an electric protection to an existing reinforced concrete structure, it is general that a mesh-like anode material is attached to the outer surface of the structure, and a coating layer of cement mortar is provided on it. However, in this case, there is a problem in that the coating layer is cracked and peeled off, and the cathodic protection system is hindered.

[0004]

In view of the above-mentioned circumstances, the problem to be solved by the present invention is that it is possible to simultaneously perform reinforcement and cathodic protection on an existing reinforced concrete structure in a coastal area, and at the same time, to use the existing structure. The above-mentioned problems in the conventional example in the case of subjecting an object to electrocorrosion are solved, and
To provide a method for reinforcing an existing reinforced concrete structure, which takes into consideration cathodic protection, which can be expected to speed up the construction (shortening the construction period) and improve the quality, and a precast concrete permanent form suitable for carrying out the method. It is in.

[0005]

In order to solve the above-mentioned problems, in the first method of the present invention, reinforcing reinforcing bars are arranged on the outside of an existing reinforced concrete structure, and on the outside thereof, an anode for cathodic protection. A thin, precast concrete permanent mold with embedded material is set, and the non-shrinkable concrete is filled in the bar arrangement between the structure and the permanent mold.

In the second method of the present invention, a permanent formwork made of precast concrete is set outside the existing reinforced concrete structure with a thick wall in which an anode material for cathodic protection and reinforcing reinforcing bars are embedded. , Non-shrinkable concrete is filled in the gap between the structure and the permanent formwork.

Further, the first permanent mold of the present invention is made of precast concrete, has an anode material for cathodic protection attached to the inner surface thereof, and has reinforcing bars embedded therein.

The second permanent mold of the present invention is made of precast concrete and has an anode material for cathodic protection embedded inside and a reinforcing bar embedded outside.

The first and second permanent molds of the present invention are
Although it is suitable for carrying out the second method of the present invention, its use is not limited to this, and it can also be used, for example, when newly constructing a reinforced concrete structure in consideration of cathodic protection.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view of an embodiment of a first method of the present invention, and FIG. 2 is an explanatory view of an embodiment of a second method of the present invention. Reference numeral 1 indicates an existing reinforced concrete structure (hereinafter referred to as structure 1), and 2 indicates an internal reinforcing bar of the structure 1.

In the case of FIG. 1, a reinforcing rebar 3 is laid out on the outside of the structure 1, and a thin precast concrete permanent mold 5 in which an anode material 4 for cathodic protection is buried is set on the outside thereof. Then, non-shrinkable concrete 6 is filled in the bar arrangement portion between the structure 1 and the permanent formwork 5, and the structure 1 is reinforced by expanding the cross section and adding reinforcing reinforcing bars 3, and at the same time, the anode material 4
The internal rebar 2 and the reinforcing rebar 3 can be galvanically protected by utilizing.

In addition, in the case of FIG. 2, outside the structure 1,
Set a permanent formwork 9 made of precast concrete with a thick wall in which the anode material 7 for cathodic protection and the reinforcing bar 8 are embedded,
A non-shrinkable concrete 10 is filled in the gap between the structure 1 and the permanent formwork 9 to reinforce the structure 1 by enlarging the cross section and adding a reinforcing bar 8 and using the anode material 7. The internal reinforcing bar 2 and the reinforcing reinforcing bar 8 can be galvanically protected.

The permanent molds 5 and 9 are manufactured in a factory, but it is common to use a titanium mesh with a special coating for the anode materials 4 and 7 embedded therein.

The permanent mold 9 has an anode material 7 for cathodic protection buried near the inner surface thereof, and a reinforcing bar 8 buried outside thereof, which is one embodiment of the second permanent mold of the present invention. Correspondingly, the permanent mold used in the second method of the present invention is not limited to the second permanent mold of the present invention, such as permanent mold 9.

That is, in the second method of the present invention, as described above, the first permanent mold of the present invention in which the anode material is attached to the inner surface and the reinforcing bar is embedded inside is used. Also, the arrangement of the anode material and the reinforcing bar is opposite to that of the permanent formwork 9, the reinforcing bar is inside and the anode material is outside.
It is also possible to use embedded permanent molds.

However, when the first and second permanent molds of the present invention are used, the anode material is sandwiched between the internal reinforcing bar 2 and the reinforcing reinforcing bar, whereas the permanent mold 9 is used. When using a permanent formwork in which the arrangement of the anode material and the reinforcing bar is opposite,
Although the internal reinforcing bars and the reinforcing reinforcing bars are located inside the anode material, the former has a more even galvanic protection effect on the internal reinforcing bars and the reinforcing reinforcing bars than the latter. Permanent molds are suitable for carrying out the second method of the invention.

In the figure, 11 is a permanent mold 5 for attaching and integrating the permanent molds 5, 9 and the concrete 6, 10.
A cotter 12 formed on the inner surface of 9 is an anchor material for surely integrating the structure 1, the concrete 6, 10 and the permanent formwork 5, 9.

The anchor material 12 is formed by coating an iron rod with an electric insulating material such as an epoxy resin, one end of which is fixed in a hole formed in the surface of the structure 1 by an appropriate adhesive material, and the other end of which is a permanent formwork. The nuts are fixed by penetrating through the holes provided in Nos. 5 and 9.

Reference numerals 13 and 14 denote energizing circuits for cathodic protection. When cathodic protection is performed, in the case of FIG. 1, from the anode material 4 connected to the plus side of the power source 15 to the minus side of the power source 15 in the case of FIG. A current is supplied to the internal reinforcing bar 2 and the reinforcing reinforcing bar 3 which are connected to each other, and in the case of FIG. 2, from the anode material 7 connected to the positive side of the power sources 16 and 17 to the internal side connected to the negative side of the power sources 16 and 17. A current may be supplied to the reinforcing bar 2 and the reinforcing reinforcing bar 8.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of a first method of the present invention.

FIG. 2 is an explanatory diagram of an embodiment of a second method of the present invention.

[Explanation of symbols]

1: Structure, 2: Internal reinforcing bar, 3: Reinforcing bar, 4: Anode material, 5: Permanent formwork, 6: Concrete, 7: Anode material,
8: Reinforcing steel bars, 9: Permanent formwork, 10: Concrete, 1
1: cotter, 12: anchor material, 13: electric circuit, 1
4: electric circuit, 15: power supply 16: power supply, 17: power supply.

Claims (4)

[Claims] 1. A thin precast concrete permanent formwork in which reinforcing reinforcing bars are laid out on the outside of an existing reinforced concrete structure and an anode material for cathodic protection is embedded on the outside of the structure, A method for reinforcing an existing reinforced concrete structure in consideration of cathodic protection, characterized in that a non-shrinkable concrete is filled in a reinforcing bar portion between the permanent formwork. 2. A permanent formwork made of precast concrete having a wall thickness, in which an anode material for cathodic protection and a reinforcing bar are embedded, is set on the outside of an existing reinforced concrete structure, and the space between the structure and the permanent formwork is set. A method for reinforcing existing reinforced concrete structures in consideration of cathodic protection, which is characterized by filling non-shrinkable concrete into the gaps of the concrete. 3. A permanent formwork made of precast concrete, characterized in that an anode material for cathodic protection is attached to the inner side surface thereof, and reinforcing reinforcing bars are embedded therein. 4. A permanent formwork made of precast concrete, in which an anode material for cathodic protection is embedded inside and reinforcing bars are embedded outside thereof.