Method for reinforcing a hollow column

Abstract

Provided is a reinforcement method capable of reliably reinforcing the cylindrical wall of a hollow column from the inside and the outside. 【Solution means】 A first reinforcing material comprising a bag-shaped member having an outer peripheral surface impregnable with an adhesive before curing and a cylindrical member covering the outer peripheral surface of the bag-shaped member, allowing the passage of the adhesive and reinforcing the tensile strength inside the cylindrical wall, and a second reinforcing material comprising a sheet member allowing the passage of the adhesive before curing and reinforcing the tensile strength outside the cylindrical wall are used. The first reinforcing material is inserted into the cylindrical wall of the hollow column, the cylindrical member is embedded in a first adhesive layer formed between the outer peripheral surface of the bag-shaped member and the inner peripheral surface of the cylindrical wall, and the second reinforcing material is wound around the root portion of the ground-exposed portion on the outer peripheral surface of the cylindrical wall of the hollow column. The second reinforcing material is embedded in a second adhesive layer formed by curing the adhesive impregnated in the second reinforcing material, and a paint made of an inorganic material is applied on the second adhesive layer to form a fireproof layer.

Description

Technical Field

[0001] The present invention relates to a reinforcing method for reinforcing the cylindrical walls of hollow columns such as concrete hollow columns used as utility poles or signal poles, steel hollow columns used as guardrail poles, pile bridge piers, or pier columns, from both the inside and outside.

Background Art

[0002] Conventionally, as a method for reinforcing the entire hollow column, as shown in Patent Document 1 below, a bag-shaped reinforcing material is inserted and fixed inside the cylindrical wall of the hollow column, and a filler such as cement mortar is filled into the bag-shaped reinforcing material and cured, thereby making the hollow column solid and reinforcing the cylindrical wall of the hollow column from the inside. This method is known.

[0003] In this conventional inner reinforcement method, it is important that the bag-shaped reinforcing material containing the filler and the hollow column are integrated. For this purpose, it is necessary to strongly adhere the outer peripheral surface of the bag-shaped reinforcing material and the inner peripheral surface of the hollow column, and it is necessary to adhere considering especially the weight of the filler filled in the bag-shaped reinforcing material. This adhesion is performed by an adhesive applied to the outer peripheral surface of the bag-shaped reinforcing material.

[0004] Also, it is known that the outer side of the cylindrical wall of the hollow column deteriorates from the underground buried part to the root part of the above-ground exposed part due to acidic soil, acid rain, excrement of pet animals such as dogs, etc. Therefore, as a method for reinforcing the outside of the hollow column, as shown in Patent Document 2 below, a reinforcing fiber sheet is wound and adhered to the base end part of the hollow column (the outer peripheral surface part of the cylindrical wall extending from the above-ground exposed part to the underground buried part) (Patent Document 2:

[0017] and [Fig. 1]), and a synthetic resin sheet for preventing paper sticking is further pasted on the outside, and a method for reinforcing the cylindrical wall of the hollow column from the outside is known.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the above-described conventional inner reinforcement method, the bag-shaped reinforcing material is formed by sewing together sheet materials woven with synthetic resin fibers so that cement mortar or the like as a filler does not leak and so that it exhibits a desired strength (Patent Document 1: paragraph

[0021] , etc.). The sheet material woven in this way does not have water retention, and it is difficult to appropriately apply an amount of adhesive necessary for reliable adhesion. Therefore, even if adhered, the bag-shaped reinforcing material may slip off due to the weight of the filler or the like.

[0007] Further, in the above-described conventional outer reinforcement method, it is necessary to wind and adhere a reinforcing sheet also to the underground buried portion of the hollow column, which may make the work complicated.

Means for Solving the Problems

[0008] The present invention provides a reinforcement method capable of reliably reinforcing the cylindrical wall of a hollow column from the inside and the outside.

[0009] Specifically, the reinforcement method for a hollow column according to the present invention is a reinforcement method for reinforcing the cylindrical wall of a hollow column from the inside and the outside, and includes a bag-shaped member having a water-retaining outer peripheral surface portion capable of impregnating a liquid adhesive before curing, and a cylindrical member that covers the outer peripheral surface portion of the bag-shaped member, has water permeability that allows the passage of the adhesive, and reinforces the tensile strength inside the cylindrical wall. A first reinforcing material composed of the above, and a second reinforcing material composed of a sheet member having water permeability that allows the passage of a liquid adhesive before curing and reinforcing the tensile strength outside the cylindrical wall are used, and by including the following steps A to J, reliable reinforcement can be achieved with a simple process.

[0010] A: Impregnating the outer peripheral surface portion of the bag-shaped member in the first reinforcing material with an adhesive B: Cover the outer peripheral surface impregnated with the adhesive with the cylindrical member. C: Insert the bag-shaped member covered with the cylindrical member into the cylindrical wall of the hollow column. D: Fill the bag-shaped member existing within the cylindrical wall with a filler. E: Inflate the bag-shaped member to press the cylindrical member against the inner peripheral surface of the cylindrical wall of the hollow column, and at the same time, allow the adhesive impregnated in the outer peripheral surface to ooze out through the cylindrical member. F: Embed the cylindrical member in the first adhesive layer formed between the outer peripheral surface of the bag-shaped member and the inner peripheral surface of the cylindrical wall by the curing of the oozed adhesive. G: Wrap the second reinforcing material around the base of the ground-exposed portion on the outer peripheral surface of the cylindrical wall of the hollow column. H: Apply an adhesive from above the wrapped second reinforcing material to impregnate the second reinforcing material and allow it to reach the outer peripheral surface of the cylindrical wall. I: Embed the second reinforcing material in the second adhesive layer formed by the curing of the impregnated adhesive. J: Apply a paint made of an inorganic material on the second adhesive layer to form a fireproof layer.

[0011] Preferably, the cylindrical member of the first reinforcing material and / or the sheet member of the second reinforcing material is made of a synthetic resin fiber sheet formed by connecting a plurality of warp threads made of synthetic resin fibers at intervals for water passage. While being able to surely guide the adhesive to the inner peripheral surface or the outer peripheral surface of the cylindrical wall of the hollow column, in particular, the warp threads can appropriately respond to the tensile stress applied to the hollow column.

[0012] Also, the bag-shaped member is formed by molding a water-retaining sheet into a bag shape. Or, the bag-shaped member is formed by molding a non-water-permeable sheet into a bag shape and covering its outer peripheral surface with a water-retaining sheet. In any case, water retention is imparted to the outer peripheral surface of the bag-shaped member, and a sufficient amount of adhesive can be impregnated.

[0013] As the water retention sheet, a non-woven fabric sheet is preferably used. As the water-impermeable sheet, a nylon sheet is preferably used. As the airtight sheet, a rubber sheet is preferably used.

[0014] The vertical length of the range where the second reinforcing member is wound is set to a length including at least two pitches of the spiral reinforcement embedded spirally in the concrete column when the hollow column is a concrete column, so that the length can be shortened as much as possible while surely reinforcing the part where tensile stress is applied.

Advantages of the Invention

[0015] According to the reinforcing member and the reinforcing method of the hollow column according to the present invention, the reinforcing member can be surely integrated with the hollow column, and reliable reinforcement can be achieved.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Best Mode for Carrying Out the Invention

[0017] The optimal embodiment of the method for reinforcing a hollow column according to the present invention will be described with reference to FIGS. 1 to 8.

[0018] <Basic Configuration> As shown in FIGS. 6 and 7, the first reinforcing member 1 according to the present invention is a reinforcing member that reinforces the cylindrical wall 12 of the hollow column 11 to be reinforced from the inside. The outer peripheral surface portion 2a is a bag-shaped member 2 having water retention properties that can impregnate a liquid adhesive before curing, and a cylindrical member 3 having water permeability that allows the passage of a liquid adhesive before curing and covers the outer peripheral surface portion 2a of the bag-shaped member 2. By filling the filling material f into the bag-shaped member 2, the cylindrical member 3 is brought into close contact with the inner peripheral surface 12a of the cylindrical wall, and at the same time, the adhesive impregnated in the outer peripheral surface portion 2a of the bag-shaped member 2 is allowed to ooze out, and the cylindrical member 3 and the bag-shaped member 2 are integrated with the cylindrical wall 12 to achieve reinforcement.

[0019] Also, as shown in FIGS. 4, 6, and 7, the second reinforcing member 21 according to the present invention is a reinforcing member that reinforces the cylindrical wall 12 of the hollow column 11 to be reinforced from the outside. It is composed of a sheet member 22 having water permeability that allows the passage of a liquid adhesive before curing. By embedding the sheet member 22 in the adhesive applied on the sheet member 22 (the outer peripheral surface of the sheet member 22), it is integrated with the cylindrical wall 12 to achieve reinforcement.

[0020] The hollow column 11 to be reinforced by the reinforcement method according to the present invention may be made of concrete or steel, and the hollow cylindrical structure is not limited to a cylindrical shape, but may be an elliptical cylindrical shape, a polygonal cylindrical shape, or the like. In addition, GL in FIGS. 3 to 7 is the ground. In FIGS. 6 and 7, the state in which the first reinforcing member 1 is arranged from the upper part (the above-ground exposed part) to the lower part (the underground buried part) of the ground GL for reinforcement is being described. In FIGS. 4, 6, and 7, the state in which the second reinforcing member 21 is arranged only above the ground GL for reinforcement is being described. Also, 11a in FIG. 6 is the inner top surface in the internal space of the cylindrical wall 12, and 11b is the inner bottom surface.

[0021] <First Reinforcing Member 1> <<Bag-shaped member 2>> As shown in FIG. 1, the bag-shaped member 2 that constitutes the first reinforcing member 1 is literally a bag-shaped member, and by filling a filler inside, it has an outer peripheral surface portion 2a that swells to a size that adheres to the inner peripheral surface 12a of the cylindrical wall of the hollow column 11 to be reinforced. Further, the length of the bag-shaped member 2 in the vertical direction (longitudinal direction), that is, for example, the length from the upper end portion S1a to the lower end portion S1b of the water retention sheet S1 described later can be appropriately adjusted according to the reinforcement location. Although not specifically shown, a filling port for filling a filler can be provided at a desired location.

[0022] In the present invention, by imparting water retention to the outer peripheral surface portion 2a of the bag-shaped member 2, the outer peripheral surface portion 2a can be impregnated with as much liquid adhesive as possible, and at the same time as pressing the cylindrical member 3 described later against the inner peripheral surface 12a of the cylindrical wall of the hollow column 11, a necessary amount of adhesive can be reliably supplied.

[0023] In order to impart water retention to the outer peripheral surface portion 2a, as shown in FIG. 1, the water retention sheet S1 can be formed into a bag shape, and the bag-shaped member 2 itself can be formed of the water retention sheet S1. That is, the water retention sheet S1 is formed into a cylindrical shape similar to the internal space of the reinforcement location of the hollow column 11, and the upper end portion S1a and the lower end portion S1b are sewn or adhered and closed to form the bag-shaped member 2.

[0024] Alternatively, as shown in FIG. 7, a bag-forming sheet S3 made of a sheet other than the water retention sheet, for example, a non-water-permeable sheet or a non-breathable sheet, is formed into a cylindrical shape, the upper end portion S3a and the lower end portion S3b are closed to form a bag shape, and the outer peripheral surface thereof is covered with the water retention sheet S1 to form a double structure, whereby water retention can be imparted to the outer peripheral surface portion 2a.

[0025] As the water retention sheet S1, in addition to a non-woven fabric sheet, by using a sheet having a porous structure such as a paper sheet, a wooden sheet, a cloth sheet, a foam sheet, etc., it is possible to impregnate as much as possible the liquid adhesive before curing, and when compressed, the impregnated adhesive can be appropriately exuded. Preferably, if a non-woven fabric sheet is used, not only the water retention property, but also when the bag-shaped member 2 is constituted only by the water retention sheet S1, when a cement-based material such as cement mortar or concrete is used as a filler, the filler can be appropriately held.

[0026] Further, when a non-water-permeable sheet is used as the bag-forming sheet S3, there is no particular limitation as long as it can prevent the passage of liquid. However, a nylon sheet, a polyvinyl chloride sheet, a polyethylene sheet, a polypropylene sheet, and an acrylic urethane sheet are preferable because they are easy to mold and durable. When the bag-shaped member 2 is constituted by using the bag-forming sheet S3 which is a non-water-permeable sheet, a simple liquid such as water which does not harden like a cement-based material can be used as a filler.

[0027] Further, when a non-breathable sheet is used as the bag-forming sheet S3, there is no particular limitation as long as it can prevent the passage of gas, particularly air. However, a rubber sheet, a polyvinyl chloride sheet, a polyethylene sheet, a polypropylene sheet, and an acrylic urethane sheet are preferable because they are easy to mold and durable. When the bag-shaped member 2 is constituted by using the bag-forming sheet S3 which is a non-breathable sheet, a simple gas such as air which does not harden like a cement-based material can be used as a filler.

[0028] In addition, as the adhesive, known liquid adhesives such as epoxy-based adhesives and acrylic urethane-based adhesives can be used. Preferably, if an epoxy-based adhesive is used, for example, even when moisture of the cement-based material leaks out from the bag-shaped member 2, the adhesive strength is not inhibited. Also, it can be appropriately adjusted according to the material of the hollow column to be reinforced.

[0029] ≪Cylindrical member 3≫ In the present invention, the cylindrical member 3 is characterized by having water permeability in order to allow the adhesive impregnated in the outer peripheral surface portion 2a of the bag-shaped member 2 described above to reach the cylindrical wall 12 of the hollow support column 11. Therefore, it is formed by molding a water-permeable sheet S2 into a cylindrical shape. The length from the upper end portion S2a to the lower end portion S2b of the water-permeable sheet S2 can be appropriately adjusted as necessary. However, as shown in FIG. 2, it is desirable that the length be shorter than the length from the upper end portion S1a to the lower end portion S1b of the water-retaining sheet S1 that constitutes the outer peripheral surface portion 2a of the bag-shaped member 2. This is to ensure the embedding of the water-permeable sheet S2 as the cylindrical member 3 into the first adhesive layer 7 described later.

[0030] The water-permeable sheet S2 needs to be a sheet that can allow a liquid, particularly a liquid adhesive, to pass through and can be embedded in the cured first adhesive layer 7 to provide tensile strength from the inside of the cylindrical wall 12. As the water-permeable sheet S2, it is desirable to use a synthetic resin fiber sheet formed by knitting or weaving synthetic resin fibers such as known ultra-high density polyethylene fibers, aramid fibers, carbon fibers, and polyester fibers, with appropriate gaps for water passage provided.

[0031] In particular, as the water-permeable sheet S2, as shown in FIG. 2, it is desirable to use a synthetic resin fiber sheet formed by joining a plurality of warp threads 4 made of synthetic resin fibers with weft threads 5 while leaving intervals 6 for water passage. In other words, it is desirable to use a “yoshi-zu-shaped sheet” mainly composed of warp threads 4 extending in the vertical direction during use and having appropriate gaps 6. As shown in FIG. 8(A), since the warp threads 4 extend straight in the vertical direction from the beginning, it is easier to exhibit tensile strength. On the other hand, as shown in FIG. 8(B), in a synthetic resin sheet formed by weaving synthetic resin fibers, which has also been conventionally used, the warp threads 8 meander due to being woven with the weft threads 9, and it was not possible to expect the effective exhibition of tensile strength. It should be noted that it is desirable to use a fiber bundle in which a large number of synthetic resin fibers are bundled as the warp threads 4 to ensure strength.

[0032] <Second reinforcing material 21> The sheet member 22 constituting the second reinforcing member 21 can use the water-permeable sheet S2 in the same manner as the cylindrical member 3 of the first reinforcing member 1. As described above, the water-permeable sheet S2 can allow a liquid adhesive to pass through and can be embedded in the adhesive layer formed by curing the adhesive to reinforce the tensile strength of the cylindrical wall. A specific example of the water-permeable sheet S2 will not be described here.

[0033] The length from the upper end S2a to S2b of the water-permeable sheet S2 as the sheet member 22 can be adjusted as appropriate, but as shown in FIG. 4, it is desirable to match the vertical width of the reinforcement portion. This is because the winding operation becomes easier. Further, it is also optional depending on the implementation to shorten the length from the upper end S2a to S2b of the water-permeable sheet S2 as the sheet member 22 to be shorter than the vertical width of the reinforcement portion and wind the sheet member 22 spirally around the outer peripheral surface 12b of the cylindrical wall.

[0034] In addition, as the adhesive used for the second reinforcing member 21, known liquid adhesives such as epoxy adhesives and acrylic urethane adhesives can be used in the same manner as the adhesive used for the first reinforcing member 1. Further, it can be appropriately adjusted according to the material of the hollow support column to be reinforced.

[0035] <Reinforcement method> The reinforcement method performed using the first reinforcing member 1 and the second reinforcing member 21 described above will be described. The reinforcement method according to the present invention is characterized by comprising the following steps.

[0036] ≪Step of impregnating the bag-shaped member of the first reinforcing member with the adhesive≫ In this project, first, the outer peripheral surface portion 2a of the bag-shaped member 2 that constitutes the first reinforcing member 1 is impregnated with an adhesive. As a method of impregnation, it can be carried out by applying the adhesive to the outer peripheral surface portion 2a using known coating methods such as brush coating, roller coating, spray coating, etc. In particular, when applying with a roller called a defoaming roller that can remove the bubbles of the coating material, the outer peripheral surface portion 2a of the bag-shaped member 2 can be effectively impregnated with the adhesive. Considering the weights of the first reinforcing member 1 and the filling material f, the material of the cylindrical wall 12, etc., the coating amount can be adjusted appropriately.

[0037] ≪First Reinforcing Member Setting Step≫ This step is a step of covering the outer peripheral surface portion 2a of the bag-shaped member 2 impregnated with the adhesive with the cylindrical member 3 as shown in FIG. 1 after the above adhesive impregnation step. In this step, it will be set as the first reinforcing member 1 composed of the bag-shaped member 2 and the cylindrical member 3.

[0038] ≪First Reinforcing Member Insertion Step≫ This step is a step of inserting the first reinforcing member 1 set in the above cylindrical member covering step, that is, the bag-shaped member 2 covered with the cylindrical member 3 into the cylindrical wall 12 of the hollow support column 11. It is inserted through the working long hole H provided in the cylindrical wall 12, and the fixing balloon 13 for temporary fixing is inflated and engaged with the cylindrical wall 12 for temporary fixing. The fixing balloon 13 is deflated as shown in FIGS. 6 and 7 after the adhesive hardens. In the present invention, if the first reinforcing member 1 can be appropriately inserted into the inside of the cylindrical wall 12, there is no particular limitation on the insertion method.

[0039] ≪Filling Material Filling Step for First Reinforcing Member≫ This step is to fill the filler f into the bag-shaped member 2 existing inside the cylinder wall 12 by the above-mentioned reinforcing material insertion step. As described above, through the filling port provided in the bag-shaped member 2, fillers such as cementitious materials, water, and air can be filled. As will be described later, according to the reinforcing method of the present invention, the cylinder wall 12 and the first reinforcing member 1 (the bag-shaped member 2 and the cylindrical member 3) can be integrated. In particular, since the cylindrical member 3 can reinforce the tensile strength inside the cylinder wall 12, even if the filler does not harden like a cementitious material, that is, even if the hollow support 11 is not made solid, appropriate reinforcement can be achieved.

[0040] <<Adhesive Infiltration Step>> This step is to squeeze out the adhesive impregnated in the outer peripheral surface portion 2a of the bag-shaped member 2 through the cylindrical member 3 while pressing the cylindrical member 3 against the inner peripheral surface 12a side of the cylinder wall by the bag-shaped member 2 swollen by the above-mentioned filler filling step. By this step, a sufficient amount of adhesive for reliable adhesion can be supplied.

[0041] <<First Embedding Step>> This step is to cure the adhesive oozed out by the above-mentioned adhesive infiltration step. By this step, as shown in FIGS. 6 and 7, the cylindrical member 3 can be embedded in the first adhesive layer 7 formed between the outer peripheral surface portion 2a of the bag-shaped member 2 and the inner peripheral surface 12a of the cylinder wall.

[0042] <<Second Reinforcing Material Wrapping Step>> This step is to wrap the second reinforcing material 21 made of the sheet member 22 around the outer peripheral surface 12b of the cylinder wall of the hollow support 11. Specifically, the sheet member 22 is wrapped only around the root portion of the above-ground exposed portion on the outer peripheral surface 12b of the cylinder wall of the hollow support 11, and the underground buried portion on the outer peripheral surface 12b of the hollow support 11 is not targeted. Thereby, the second reinforcing material 21 can be easily arranged without digging up the underground buried portion of the hollow support 11.

[0043] When the hollow column 11 to be reinforced is a concrete column, as shown in Fig. 3, a large number of vertical reinforcing bars 14a extending in the vertical direction are embedded along the circumference of the cylindrical wall 12, and a spiral reinforcing bar 14b is embedded spirally along the outer circumference of the vertically arranged reinforcing bars 14a. In the present invention, it is desirable that the length in the vertical direction of the range where the second reinforcing member 21 (sheet member 22) is wound is at least twice the pitch P of the spiral reinforcing bar 14b. This range is the part where the tensile stress is most applied, and extending the winding range upward by a longer length will not change the reinforcing effect.

[0044] <<Adhesive application process to the second reinforcing member>> This process is a process of applying an adhesive from the outer surface side to the sheet member 22 arranged at the reinforcing portion in the above-described second reinforcing member winding process to impregnate the second reinforcing member 21 and reach the outer peripheral surface 12b of the cylindrical wall. As the application method, known application methods such as brush coating, roller coating, and spray coating can be used. In particular, when applying with a roller called a defoaming roller that can remove the bubbles of the coating material, the sheet member 22 can be effectively impregnated with the adhesive, and the adhesive can reach the outer peripheral surface 12b of the cylindrical wall. Considering the weight of the second reinforcing member 21 (sheet member 22) and the weight of the fireproof layer described later, etc., the application amount can be adjusted as appropriate.

[0045] <<Second embedding process>> This process is a process of curing the adhesive that has impregnated into the sheet member 22 and reached the outer peripheral surface 12b of the cylindrical wall by the above-described adhesive application process. By this process, as shown in Figs. 6 and 7, the sheet member 22 can be embedded in the second adhesive layer 23 formed on the outer peripheral surface 12b of the cylindrical wall.

[0046] <<Fireproof layer forming process>> This process is a process of forming a fireproof layer 24 by applying a paint made of an inorganic material on the second adhesive layer 23 (the outer peripheral surface of the second adhesive layer 23) formed in the above-described second embedding process, as shown in Figs. 5 to 7. The fireproof layer 24 can appropriately prevent the combustion of the second adhesive layer 23.

[0047] As the inorganic material for constructing the fireproof layer 24, there is no particular limitation as long as it can cover and cure the second adhesive layer 23, but cement-based materials such as mortar, cement, or concrete are easy to construct and are preferable.

[0048] <Reinforcement structure> According to the reinforcement method of the present invention, as shown in FIGS. 6 and 7, inside the cylindrical wall 12, the cylindrical wall 12 and the first reinforcing member 1 (the bag-shaped member 2 and the cylindrical member 3) can be surely integrated, and outside the cylindrical wall 12, the cylindrical wall 12 and the second reinforcing member 21 (the sheet member 22) can be surely integrated. Thereby, in particular, the cylindrical member 3 is integrated with the cylindrical wall 12 via the first adhesive layer 7, and the warp 4 constituting the water-permeable sheet S2 of the cylindrical member 3 can appropriately reinforce the tensile strength on the inner peripheral surface 12a side of the cylindrical wall. In addition, the sheet member 22 is integrated with the cylindrical wall 12 via the second adhesive layer 23, and the warp 4 constituting the water-permeable sheet S2 of the sheet member 22 can appropriately reinforce the tensile strength on the outer peripheral surface 12b side of the cylindrical wall. Therefore, the first reinforcing member 1 and the second reinforcing member 21 can cooperate to surely reinforce the hollow column 11.

Explanation of reference numerals

[0049] 1... First reinforcing member, 2... Bag-shaped member, 2a... Outer peripheral surface portion, 3... Cylindrical member, 4... Warp, 5... Weft, 6... Water passage gap, 7... First adhesive layer, 8... Warp of the conventional fiber sheet, 9... Weft of the conventional fiber sheet, S1... Water retention sheet, S1a... Upper end portion, S1b... Lower end portion, S2... Water-permeable sheet, S2a... Upper end portion, S2b... Lower end portion, S3... Sheet for bag formation, S3a... Upper end portion, S3b... Lower end portion, 11... Hollow column, 11a... Inner top surface, 11b... Inner bottom surface, 12... Cylindrical wall, 12a... Inner peripheral surface of the cylindrical wall, 12b... Outer peripheral surface of the cylindrical wall, 13... Fixing balloon, 14a... Vertical reinforcing bar, 14b... Spiral reinforcing bar, 21... Second reinforcing member, 22... Sheet member, 23... Second adhesive layer, 24... Fireproof layer, P... Pitch of the spiral reinforcing bar, f... Filling material, GL... Ground, H... Working long hole.

Claims

1. A method for reinforcing the cylindrical wall of a hollow column from the inside and outside, comprising: a bag-shaped member having an outer peripheral surface with water retention properties that can be impregnated with a liquid adhesive before curing; and a cylindrical member that covers the outer peripheral surface of the bag-shaped member, has water permeability that allows the passage of the adhesive, and reinforces the tensile strength inside the cylindrical wall. The method uses a first reinforcing material composed of a cylindrical member and a second reinforcing material composed of a sheet member that has water permeability that allows the passage of a liquid adhesive before curing and reinforces the tensile strength outside the cylindrical wall, and is characterized by comprising the following steps A to J. A: Impregnating the outer peripheral surface of the bag-shaped member in the first reinforcing material with an adhesive. B: Covering the outer peripheral surface impregnated with the adhesive with the cylindrical member. C: Inserting the bag-shaped member covered with the cylindrical member into the cylindrical wall of the hollow column. D: Filling the bag-shaped member existing inside the cylindrical wall with a filler. E: Inflating the bag-shaped member to press the cylindrical member against the inner peripheral surface of the cylindrical wall of the hollow column, and causing the adhesive impregnated in the outer peripheral surface to ooze out through the cylindrical member. F: Embedding the cylindrical member in a first adhesive layer formed between the outer peripheral surface of the bag-shaped member and the inner peripheral surface of the cylindrical wall by curing the oozed adhesive. G: Wrapping the second reinforcing material around the root portion of the ground-exposed portion on the outer peripheral surface of the cylindrical wall of the hollow column. H: Applying an adhesive from above the wrapped second reinforcing material to impregnate the second reinforcing material and cause it to reach the outer peripheral surface of the cylindrical wall. I: Embedding the second reinforcing material in a second adhesive layer formed by curing the impregnated adhesive. J: Applying a paint made of an inorganic material on the second adhesive layer to form a fireproof layer.

2. The method for reinforcing a hollow column according to claim 1, wherein the cylindrical member of the first reinforcing material is made of a synthetic resin fiber sheet formed by connecting a plurality of warp threads made of synthetic resin fibers at intervals for water passage.

3. The method for reinforcing a hollow column according to claim 1, wherein the bag-shaped member of the first reinforcing material is formed by shaping a water retention sheet into a bag shape.

4. The method for reinforcing a hollow column according to claim 1, wherein the bag-shaped member of the first reinforcing material is formed by shaping a non-water-permeable sheet or a non-breathable sheet into a bag shape and covering its outer peripheral surface with a water retention sheet.

5. The method for reinforcing a hollow column according to claim 3 or claim 4, wherein the water retention sheet is a non-woven fabric sheet.

6. The method for reinforcing a hollow column according to claim 4, wherein the non-water-permeable sheet is a nylon sheet. **Claim 7** The method for reinforcing a hollow column according to claim 4, wherein the airtight sheet is a rubber sheet. **Claim 8** The method for reinforcing a hollow column according to claim 1, wherein the vertical length of the range where the second reinforcing material is wound is at least a length including two pitches of the spiral reinforcing bars spirally embedded in the concrete column when the hollow column is a concrete column.

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