JP7371368B2 - pipe cooling method - Google Patents

Description

The present invention relates to a pipe cooling method for cooling concrete using cooling pipes laid in a concrete pouring area.

Conventionally, when constructing mass concrete structures such as foundations for dams and bridge piers, pipe cooling methods have generally been adopted as a means of suppressing temperature cracking. The pipe cooling method reduces the heat of hydration that occurs when concrete hardens by laying cooling pipes in the concrete placement area and then flowing a coolant such as water or air through the cooling pipes during or after the concrete is placed. It is something that makes you

For example, in Patent Document 1, when constructing an underground continuous wall, a cooling pipe is laid in a reinforcing cage at a position where concrete is to be placed, and then water is passed through the cooling pipe. For the cooling pipes, multiple vertical pipes are arranged vertically and connected using connecting pipes, and two pipes each connected vertically are arranged at intervals in the width direction of the underground continuous wall. , are assembled by connecting their lower ends together using a U-shaped tube.

Japanese Patent Application Publication No. 11-141128

As disclosed in Patent Document 1, cooling pipes used in pipe cooling methods generally have a structure in which a plurality of vertical pipes are assembled via joint members such as connecting pipes or U-shaped pipes. Further, as the vertical pipe, steel pipes are often used because they are heavy and cannot be easily bent.

For this reason, the work of assembling cooling pipes tends to be complicated at concrete placement target locations where reinforcing bar cages, formwork separators, etc. are intricately arranged. Furthermore, there may be many locations where it is necessary to perform the reinforcement work for the reinforcing bar cage and the work for laying the cooling pipes in parallel, which poses a problem in workability.

Furthermore, since multiple vertical pipes are connected using joint members, there are many connecting parts, which results in poor workability and the need to provide a water-stop structure to prevent water leakage from the connecting parts. It took a lot of effort.

The present invention has been made in view of this problem, and its main purpose is to provide a pipe cooling method that has a simple configuration and can improve workability.

In order to achieve such an object, the pipe cooling method of the present invention involves laying cooling pipes in gaps between reinforcing bars assembled in a concrete placement area, and then pouring concrete and flowing a refrigerant in the cooling pipes to cool the concrete. The pipe cooling method employs a flexible hollow tube as the cooling pipe, and the reinforcing bars are fixed to the bent part of the cooling pipe on both sides sandwiching the bent part. It is characterized by providing a bending direction holding structure fixed at . Further, the pipe cooling method of the present invention includes: laying a cooling pipe that is buried in a concrete placement area and in contact with each of the concrete and the refrigerant, and then placing the concrete and causing the refrigerant to flow down within the cooling pipe. A pipe cooling method in which the concrete is directly cooled by the cooling pipe in contact with the concrete, wherein a flexible hollow pipe is adopted as the cooling pipe, and the bending part of the cooling pipe is The present invention is characterized in that a bending direction holding structure is provided that includes a fixture that is attached to both sides of the bending part and at a position spaced apart from the bending part.

Further, in the pipe cooling method of the present invention, the bending direction holding structure is provided with a direction holding tool to which both sides of the cooling pipe across the bending part are fixed via the fixing tool, The direction retainer is characterized in that a corner portion is formed along the bent portion.

According to the pipe cooling method of the present invention, since a flexible hollow pipe is used for the cooling pipe, the cooling pipe is bent appropriately within the concrete placement area where reinforcing bars are assembled, and the cooling pipe is placed at a desired position. can be laid down. As a result, the number of locations where it is necessary to perform cooling pipe installation work in parallel with reinforcement work can be significantly reduced, making it possible to significantly improve work efficiency.

In addition, since the cooling pipe can form a bent part by utilizing its own flexibility, a cooling pipe with a bent part can be laid simply by fixing it to the bending direction holding structure, and it is possible to install a cooling pipe with a bent part by simply fixing it to the bending direction holding structure. No assembly work is required.

This makes it possible to significantly reduce the number of parts and construction costs, as well as to significantly reduce the number of work steps and contribute to shortening the construction period. Furthermore, since there are no connecting parts that may cause water leakage, it is possible to avoid a situation where the refrigerant leaks during the concrete curing period and adversely affects the concrete structure.

In the pipe cooling method of the present invention, a slip prevention mechanism for the fixture is formed on the circumferential surface of the cooling pipe on both sides of the bending portion fixed to the bending direction holding structure. It is characterized by

Moreover, the pipe cooling method of the present invention is characterized in that the slip prevention mechanism has an uneven shape that continues in the axial direction of the cooling pipe.

According to the pipe cooling method of the present invention, by installing a fixing device that fixes the cooling pipe by inserting it into the uneven recess formed on the circumferential surface of the cooling pipe, concrete is placed on the cooling pipe when concrete is poured. Even if various external forces are applied to the cooling pipe, such as when a concrete vibrator is dropped or vibrations from a concrete vibrator are transmitted to the cooling pipe, the fixing device may slip or loosen on the outer circumferential surface of the cooling pipe, causing its position to change. The phenomenon of movement can be suppressed.

According to the present invention, by adopting a flexible hollow tube as the cooling pipe, the cooling pipe can be bent to form a bent part, and the structure can be fixed using a bending direction holding structure. , a cooling pipe with a bent part can be laid in the concrete placement area, and the workability of the pipe cooling method can be greatly improved.

It is a figure showing the laying state of the cooling pipe used in the pipe cooling method in an embodiment of the present invention. It is a figure which shows the direction holding tool used for the bending direction holding structure formed in the cooling pipe in embodiment of this invention. It is a figure showing a joint part of a cooling pipe in an embodiment of the present invention.

The present invention employs flexible hollow pipes as cooling pipes to perform pipe cooling during construction of concrete structures including mass concrete structures such as foundations for dams and bridge piers. The pipe cooling method will be described below with reference to FIGS. 1 to 3.

As shown in FIG. 1, a cooling pipe 3 used in a pipe cooling method is installed in a reinforced concrete structure 1 using reinforcing bars 2 assembled in a concrete placement area.

The cooling pipe 3 is watertight and has at least the same thermal conductivity as a steel pipe, so that it will not be deformed or deteriorated even if it comes into contact with concrete or a fluid used as a refrigerant. It is a hollow tube that is flexible enough to be bent by itself without using tools.

In addition to the above-mentioned performance, the hollow tube used for the cooling pipe 3 has an external shape that is a seamless long material spanning several tens of meters, is lighter than a steel tube, and can be easily cut with a cutter or the like without using electric tools. It is preferable that the cooling pipe 3 can be cut into a shape, and that it has been subjected to a corrugated process and has a concavo-convex shape continuous in the axial direction of the cooling pipe 3 on the circumferential surface. In this embodiment, a flexible pipe made of synthetic resin, such as polypropylene or polyethylene, is used.

A pipe cooling method for the reinforced concrete structure 1 using the cooling pipe 3 described above is as shown below.

First, reinforcing bars 2 are assembled in a concrete placement area of a reinforced concrete structure 1. Next, cooling pipes 3 are laid using the gaps between the assembled reinforcing bars 2. The cooling pipes 3 may be arranged in any way as long as they uniformly cover the entire concrete casting area, but in this embodiment, the cooling pipes 3 are arranged so that they reciprocate in the height direction. An example of meandering arrangement is shown.

As mentioned above, the cooling pipe 3 is flexible, lightweight, and is a long member, so the worker uses the gap between the assembled reinforcing bars 2 to align the cooling pipe 3 along the reinforcing bars 2. The cooling pipe 3 can be freely deformed and placed at the planned installation location by bending it at necessary locations.

By the way, since the flexible cooling pipe 3 does not stand on its own, the cooling pipe 3 placed in the gap between the assembled reinforcing bars 2 is fixed to the reinforcing bars 2 using a fixture 4. The fixing tool 4 may be the same as the binding wire that is generally used to cross and fix the reinforcing bars 2, and in this embodiment, two binding wires are used as a bundle.

Further, the fixture 4 may be attached by being inserted into a concave and concave portion formed on the circumferential surface of the cooling pipe 3. In this way, the uneven shape of the cooling pipe 3 functions as a non-slip, and the cooling pipe 3 is prevented from slipping when concrete is poured onto the cooling pipe 3 during concrete pouring or the vibration of the concrete vibrator is transmitted to the cooling pipe 3. Even if an external force is applied to the cooling pipe 3, the phenomenon in which the fixture 4 slips or loosens on the outer circumferential surface of the cooling pipe 3 and moves its position can be suppressed.

Furthermore, it is preferable to form a bending direction holding structure A by the reinforcing bars 2 and two fixtures 4 at the position where the bending part 31 of the cooling pipe 3 is arranged. Specifically, the cooling pipe 3 is bent to form a bent portion 31 having a desired angle α. Then, while maintaining this angle α, the cooling pipe 3 is fixed to the reinforcing bars 2 at two locations on both sides of the bent portion 31 via the two fixtures 4.

As a result, the bent portion 31 of the cooling pipe 3 is fixed to the bending direction holding structure A constituted by the two fixtures 4 and the reinforcing bars 2 near the position where the bent portion 31 is arranged. 3 can be stably bent.

In addition, in FIG. 1, the angles α of the bent portions 31 provided in the cooling pipe 3 are all formed at right angles, but if you want to ensure the desired angle α for the bent portions 31, the reinforcing bars 2 may be replaced with It is preferable that the bending direction holding structure A is configured by a direction holding tool 5 and two fixtures 4 as shown in FIG.

As shown in FIG. 2, the direction retainer 5 has a pair of direction retainers 51 and 52 butted against each other to form an inner corner, and a desired shape to be secured at the bent portion 31 of the cooling pipe 3 is placed in the inner corner. It has a shape with an angle α. The direction holding device 5 having such a shape is manufactured in advance, and the direction holding device 5 is applied to the position where the bent portion 31 of the cooling pipe 3 is formed, and the two places on both sides of the bent portion 31 are fixed. It is fixed to a pair of direction holding members 51 and 52 via the tool 4.

In this way, the bent portion 31 of the cooling pipe 3 is fixed to the bending direction holding structure A constituted by the two fixing devices 4 and the direction holding device 5, and the bending portion 31 of the cooling pipe 3 is fixed to the bending direction holding structure A formed by the two fixtures 4 and the direction holding device 5, and the bending portion 31 of the cooling pipe 3 is fixed to the bending direction holding structure A formed by the two fixtures 4 and the direction holding device 5. It becomes possible to form the curved portion 31.

After the cooling pipes 3 are laid in the concrete placement area according to the above procedure, concrete C is placed and the coolant W is made to flow down the cooling pipes 3. Note that the refrigerant W may be any fluid such as water or cold air, and the openings at both ends of the cooling pipe 3 are arranged at positions where they will not be buried in the concrete C.

According to the concrete pipe cooling method described above, since a lightweight and flexible flexible pipe is used as the cooling pipe 3, the cooling pipe 3 is bent as appropriate within the concrete placement area where the reinforcing bars 2 are assembled, and the cooling pipe 3 is bent as desired. A cooling pipe 3 can be laid at the location. As a result, the number of locations where it is necessary to perform the work of laying the cooling pipes 3 in parallel with the work of arranging the reinforcing bars 2 can be significantly reduced, making it possible to significantly improve work efficiency.

In addition, since the flexible pipe used for the cooling pipe 3 is a long member and can form the bent part 31 by utilizing its own flexibility, it is difficult to install the cooling pipe 3 using conventional technology. There is no need to assemble steel pipes using such joint members.

This makes it possible to significantly reduce the number of parts and construction costs, as well as to significantly reduce the number of work steps and contribute to shortening the construction period. Moreover, since there is no connection part that may cause water leakage, it is also possible to avoid a situation where the refrigerant W leaks during the curing period of the concrete C and adversely affects the structure 1.

The pipe cooling method of the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention.

For example, in this embodiment, one cooling pipe 3 is laid in the concrete pouring area, but the invention is not limited to this, and as shown in FIG. It is also possible to extend the portion 32 while forming it.

Specifically, as shown in FIG. 3, both ends of a cylindrical sleeve 6 having an outer diameter approximately equal to the inner diameter of the cooling pipe 3 are inserted into the end openings of the adjacent cooling pipes 3. A tightening band 7 is attached from the outer circumferential surface of the cooling pipe, and the sleeve 6 and the adjacent cooling pipe 3 are tightened and fixed to ensure water-tightness.

At this time, anti-slip uneven surfaces 61 are formed on both ends of the sleeve 6. In this way, even if an external force such as a tensile force is generated between the sleeve 6 and the cooling pipe 3 due to an unexpected situation, it is possible to prevent the sleeve 6 and the cooling pipe 3 from shifting or coming off.

In addition, for the direction holding device 5 of the bending direction holding structure A, for example, a planar or three-dimensional frame made of a plurality of steel rods arranged in a grid shape is adopted, and these frames correspond to the bending part 31 of the cooling pipe 3. An inside corner having an angle α may be formed and placed in the concrete pouring area. In this way, even if the structure 1 is an unreinforced concrete structure, the cooling pipe 3 with the bent portion 31 having the desired angle α can be laid in the concrete placement area.

1 Structure 2 Reinforcement bar 3 Cooling pipe 31 Bend section 32 Joint section 4 Fixture 5 Direction retainer 51 Direction retainer 52 Direction retainer 6 Sleeve 7 Tightening band A Bending direction retaining structure C Concrete W Refrigerant

Claims (5)

A pipe cooling method in which a cooling pipe is laid in a gap between reinforcing bars assembled in a concrete placement area, and then concrete is poured and a refrigerant is allowed to flow down within the cooling pipe to cool the concrete,
Adopting a flexible hollow tube as the cooling pipe,
A pipe cooling method, characterized in that a bending direction holding structure is provided at the bent portion of the cooling pipe, in which both sides of the bent portion are fixed to the reinforcing bars using fixtures . After laying a cooling pipe that is buried in a concrete placement area and comes into contact with each of the concrete and a refrigerant , the concrete is placed and the refrigerant is made to flow down within the cooling pipe, and the concrete is poured into the concrete and the refrigerant that comes into contact with the concrete. A pipe cooling method that cools directly with a cooling pipe ,
Adopting a flexible hollow tube as the cooling pipe,
A pipe cooling method characterized in that a bending direction holding structure is provided at a bent portion of the cooling pipe, and includes a fixing device attached to a position on both sides of the bent portion and spaced apart from the bent portion. . The pipe cooling method according to claim 1 or 2 ,
The bending direction holding structure includes a direction holding tool to which both sides of the cooling pipe across the bending part are fixed via the fixing tool,
A pipe cooling method characterized in that the direction retainer has a corner portion formed along the bent portion. In the pipe cooling method according to claim 3 ,
A pipe cooling method characterized in that a slip prevention mechanism for the fixture is formed on the circumferential surface of the cooling pipe on both sides of the bending portion fixed to the bending direction holding structure . The pipe cooling method according to claim 4,
A pipe cooling method characterized in that the slip prevention mechanism has an uneven shape that is continuous in the axial direction of the cooling pipe.

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