JPH0347381B2 - - Google Patents

Description

[Detailed Description of the Invention] When peeling and dismantling the surface layer of a reinforced concrete structure, a cut groove is provided that reaches the reinforcing bars to a required depth, and an electrode terminal made of a metal plate is pressed against the end face of the reinforcing bars exposed in the cut groove. Then, electricity is applied and the heat generated by the electrical resistance of the reinforcing bars is used to deteriorate the concrete around the reinforcing bars and reduce their adhesion, and the thermal expansion of the reinforcing bars generates cracks in the concrete, thereby preventing the peeling and demolition of the surface concrete. The present inventors have previously developed a construction method that is easy to carry out, but the present invention allows the reinforcing bars in concrete to rise to a required temperature when energized, and expand to a temperature higher than that which causes cracks in the surrounding concrete. This relates to a method and device for injecting cooling gas to electrode terminals in order to prevent adverse effects such as heating and softening of the terminals. In Fig. 2, reference numeral 1 denotes an electrode terminal made of, for example, a copper alloy with high temperature characteristics and molded into an appropriate shape, and a contact point 2 of, for example, a spherical surface suitable for contact is formed at the tip of the electrode terminal, and this spherical portion If necessary, special materials suitable for contact and contact resistance may be used. Further, this electrode terminal is provided with a cord attachment terminal 3.

When using the electrode terminal configured as described above, it is inserted into the opposing notches B and B' provided in the surface layer of the reinforced concrete structure A, as shown in Fig. 3, and the contact point 2 at the tip is inserted into the notch. Both ends of the reinforcing bar C exposed on the surface are brought into contact with each other, and for this purpose, a holder 6 made of an electrical insulator is provided on the plunger 5, 5' inserted into the hydraulic cylinder 4, 4'.
It is used by attaching it to the clamping pieces 7, 7' of 6'. In order to appropriately adjust the direction of the electrode terminal 1, a bearing 8 is provided at the bottom of the hydraulic cylinder 4.
This is supported by a pin 10 at the tip of a support body 9, and its direction can be changed appropriately by rotating this support frame body 9 in the direction of the arrow. A bearing 11 is provided, and is attached to the tip of a plunger 14' of a hydraulic cylinder 14 supported by a pin 13 to a bearing 12 provided on a support frame 9 by a pin 15. It is made to be inclined.

In the present invention, in order to energize the electrode terminal 1, the cords 16, 1 are connected to the terminal 3 provided with the electrode terminal 1.
6', and the electrode terminal holding pieces 7,
7' is provided with holding pieces 17, 17', to which gas injection nozzles 18, 18' are attached.

When the electrode terminal and its holding device constructed as described above are used, as shown in FIG. 7' and operate the hydraulic cylinder 4 to insert the contact point 2 at the tip into the grooves B and B', which are set in the surface layer of the reinforced concrete structure A.
When the cords 16 and 16' are crimped on both end faces of the reinforcing bar C exposed at B', the reinforcing bar C will be heated and expanded due to electrical resistance, expanding as shown in Figure 4, and the surrounding concrete will As it deteriorates and its adhesion strength decreases, the expansion of the reinforcing bars causes cracks in the concrete, resulting in peeling of the surface concrete.
It can be easily dismantled. In this way, when electricity is applied to the electrode terminals to heat the reinforcing bars and raise the temperature necessary for concrete peeling and demolition, the electrode terminals may become excessively heated and soften or deform, making it impossible to work properly. In order to prevent this, in the present invention, cooling gas is particularly injected onto the surface of the electrode terminal 1, and for this purpose, injection nozzles 18, 18' are set in the holding device.
By pressurizing this through hoses 19, 19' connected to an appropriate cylinder or air compressor, it is possible to prevent an excessive rise in temperature of the electrode terminals and perform work at an appropriate temperature.

As described above, according to the construction method of the present invention, when peeling off the surface layer of a reinforced concrete structure or dismantling it, excessive temperatures can be prevented by spraying cooling gas from a nozzle onto the surface of the current-carrying electrical terminal attached to the reinforcing steel. Since rising can be prevented, electrical processing work on reinforcing bars can be performed safely and properly. Further, according to the device of the present invention, the holding portion of the electrode terminal can be easily set to match the cut groove of the structure, or can be set to match the cut groove in the vertical and horizontal directions, and can also be cooled. Since the jetting nozzle of the gas is set, it has an exceptional effect and feature of being able to always correctly inject the gas to the electrode terminal.

[Brief explanation of drawings]

Fig. 1 is a side view of the electrode terminal, Fig. 2 is a plan view of the same, Fig. 3 is a side view of the mode of use in which the electrode terminal is set as a holding device, and Fig. 4 shows the relationship between the expansion reinforcing bar and the electrode terminal. It is an explanatory diagram. 1... Electrode terminal, 2... Contact, 3... Wire attachment terminal, 4, 4'... Cylinder, 5, 5'... Plunger, 6, 6'... Holder, 7, 7'... Clipping piece , 8... Bearing, 9... Support frame, 10... Pin, 11, 12... Bearing, 13... Pin, 14...
...Hydraulic cylinder, 15...Pin, 16, 16'
...Cord, 17,17'...Holding piece, 18,1
8'... Gas injection nozzle, A... Reinforced concrete structure, B, B'... Cut groove, C... Reinforced bar.

Claims (1)

[Claims] 1. A cut groove is provided that reaches the reinforcing bars in the concrete of a reinforced concrete structure, and an electrode terminal is inserted into the opposing cut groove and brought into contact with the end face of the reinforcing bar exposed in the cut groove, and the electrode terminal is Electric heating of reinforcing bars in reinforced concrete structures characterized by injecting cooling gas to electrode terminals to suppress excessive temperature rise when heating and expanding reinforcing bars interposed between them by applying electricity. Surface layer peeling method. 2. A hydraulic cylinder is equipped so that it can be rotated and adjusted vertically with respect to the support frame, and a clamping piece for the electrode terminal is provided on each plunger on both sides of the hydraulic cylinder via an electrical insulator, and A surface layer peeling device for electrically heating reinforcing bars of a reinforced concrete structure, characterized in that a holding part for a cooling gas injection nozzle is provided.