Bag body for repairing hollow concrete structure body, structure for fixing the bag body, and repair method for the hollow concrete structure body

Abstract

To provide an easier, less-cost and steadier repair method for hollow concrete structure bodies.SOLUTION: A bag body 20, being made of a material with flexibility, is used for repairing concrete around a form 10 in a hollow concrete structure body in which the cylindrical form 10 is buried in the concrete. The form 10 has an opening 13 in an area where the concrete around the form 10 has been removed. The bag body is inserted into the form 10 via the opening 13 and inflated with a fluid 23 filled in it, enabling casting of concrete in the part covering the opening 13 around the form 10. The bag body 20 is arranged in such a way that a non-contact part of the bag body 20 and the inner surface 12 of the form 10 is positioned lower than the cylinder axis of the form 10 forming a void 22 in the view of a cross section perpendicular to the cylinder axis.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a bag body used in repairing a hollow concrete structure, a fixing structure for the bag body, and a method for repairing a hollow concrete structure. [Background technology]

[0002] Among bridges and viaducts for roads and railways, concrete slabs in buildings, and various other concrete structures, there are some that have a hollow space inside. This type of structure with a hollow space is called a hollow concrete structure.

[0003] For example, in the case of an elevated bridge deck as shown in Fig. 16, when concrete is poured, a hollow pipe (hereinafter referred to as a hollow formwork) and necessary rebars are placed inside a concrete pouring formwork in advance, and unhardened concrete is poured in and hardened in this state. For example, a steel cylindrical pipe is used as the hollow formwork. The hollow formwork is placed on a support member placed inside the formwork and is fixed so as not to move laterally, and appropriate measures are taken to prevent it from floating up (for example, see Patent Document 1).

[0004] Furthermore, in hollow concrete structures, when the concrete around the hollow portion deteriorates, there is a repair method that uses a bag made of a flexible material. The concrete in the deteriorated portion is removed, a bag is inserted into the hollow portion, the bag is filled with urethane foam, and then the concrete in the removed portion is poured. The presence of the bag filled with urethane foam prevents concrete from entering the space that corresponds to the original hollow portion (for example, see Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2002-138665 A [Patent Document 2] JP 2005-146569 A Summary of the Invention [Problem to be solved by the invention]

[0006] When repairing a hollow concrete structure, if an opening (hole) occurs in a part of the formwork due to corrosion or the like, or if an opening (hole) occurs when removing the surface layer of concrete, it is necessary to prevent the newly poured repair concrete from flowing into the formwork. For this reason, the use of a bag body as in Patent Document 2 is effective. However, Patent Document 2 does not disclose the specific configuration of the bag body. In addition, when using a bag body in repairing a hollow concrete structure, it is desired to facilitate the work of handling the bag body and reduce costs. However, Patent Document 2 does not specifically disclose how to facilitate these operations or reduce costs. In addition, when repairing the concrete around the formwork using a bag body, there is a problem of how to stabilize the position of the bag body in the formwork until the poured concrete hardens. However, Patent Documents 1 and 2 do not disclose these problems or their solutions.

[0007] Therefore, an object of the present invention is to repair hollow concrete structures more easily, inexpensively and stably. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides, as a first means, A bag made of a flexible material is used when repairing concrete around a form in a hollow concrete structure in which a cylindrical form is embedded in concrete, The form has an opening in the area around the form from which the concrete has been removed, and the bag is inserted into the form through the opening. When the bag is expanded by filling it with fluid, concrete can be poured into the area around the form facing the opening. The uppermost contact portion between the bag and the inner surface of the form in a cross section perpendicular to the cylindrical axis is located below the edge of the opening (configuration 1).

[0009] In an embodiment having this configuration 1, the movement of the bag body toward the opening side is restricted by the abutment portion, and a configuration can be adopted in which the abutment portions are arranged intermittently around the cylindrical axis in a cross section perpendicular to the cylindrical axis (configuration 2).

[0010] In an embodiment having configuration 1, or in an embodiment having configurations 1 and 2, a configuration can be adopted in which the bag body has an inner bag and an outer bag that contains the inner bag, and the fluid is filled in the inner bag (configuration 3).

[0011] A bag body having the configuration 1, or a bag body having the configuration 2 or the configuration 3 added to the configuration 1, or both, can be used to adopt a bag body fixing structure in which the bag body is pulled up toward the opening side by an anchor portion connected to the bag body (configuration 4).

[0012] In order to solve the above problems, the present invention provides, as a second means, A bag made of a flexible material is used when repairing concrete around a form in a hollow concrete structure in which a cylindrical form is embedded in concrete, The form has an opening in the area around the form from which the concrete has been removed, and the bag is inserted into the form through the opening. When the bag expands due to the filling of a fluid into its interior, concrete can be poured into the area around the form facing the opening. In a cross section perpendicular to the cylindrical axis, the non-contact portion between the bag and the inner surface of the form exists below the cylindrical axis of the form, forming a gap (configuration 5).

[0013] In an embodiment having this configuration 5, the bag body is prevented from falling within the formwork by the abutment portion between the bag body and the inner surface of the formwork, and a configuration can be adopted in which the abutment portions are arranged intermittently around the cylindrical axis in a cross section perpendicular to the cylindrical axis (configuration 6).

[0014] In addition, in an embodiment having configuration 5, or an embodiment having configurations 5 and 6, a configuration can be adopted in which the lowest one of the abutment portions in a cross section perpendicular to the cylindrical axis is located above the bottom of the formwork (configuration 7).

[0015] In a configuration having configuration 5, or in a configuration in which configuration 6 or configuration 7 or both are added to configuration 5, a configuration can be adopted in which the bag body has an inner bag and an outer bag that contains the inner bag, and the fluid is filled in the inner bag (configuration 8).

[0016] By using the bag body having the above-mentioned configuration 5, or a configuration in which a single or multiple elements selected from configuration 6, configuration 7, and configuration 8 are added to configuration 5, a bag body fixing structure can be adopted in which the bag body is pulled up toward the opening side by an anchor portion connected to the bag body (configuration 9).

[0017] In order to solve the above problems, the present invention provides, as a third means, A method for repairing a hollow concrete structure in which a cylindrical form is embedded in concrete, comprising: The method includes the steps of inserting a bag made of a flexible material into the form through an opening in the form, filling the inside of the bag with a fluid, and forming a new concrete layer in the portion from which the concrete has been removed, A method for repairing a hollow concrete structure is adopted in which the pressure of the fluid within the bag is set to be equal to or greater than the pouring pressure of the concrete at the minimum temperature within the set hardening time of the concrete poured to form the new concrete layer (Configuration 10).

[0018] In an embodiment having the configuration 10, a configuration can be adopted in which the minimum temperature is determined based on a predicted minimum air temperature within the set curing time (configuration 11).

[0019] As a third means, a method for repairing a hollow concrete structure in which a cylindrical form is embedded in concrete, comprising the steps of: The method includes the steps of inserting a bag made of a flexible material into the form through an opening in the form, filling the inside of the bag with a fluid, and forming a new concrete layer in the portion from which the concrete has been removed, A method for repairing a hollow concrete structure can be adopted in which the pressure of the fluid within the bag is set to be lower than the pressure resistance of the bag when the concrete is poured to form the new concrete layer at its highest temperature within the set hardening time of the concrete (Configuration 12).

[0020] In an embodiment having configuration 12, a configuration can be adopted in which the maximum temperature is determined based on the predicted maximum temperature of the concrete taking into account the heat of hydration within the set hardening time, or is determined based on the predicted maximum road surface temperature around the opening within the set hardening time (configuration 13).

[0021] In an embodiment having these configurations 10, or in an embodiment in which a single or multiple configurations selected from configurations 11, 12, and 13 are added to configuration 10, the bag body (20) can have an inner bag and an outer bag that contains the inner bag, and the fluid can be filled in the inner bag (configuration 14).

[0022] In order to solve the above problems, the present invention provides, as a fourth means, A bag made of a flexible material is used when repairing concrete around a form in a hollow concrete structure in which a cylindrical form is embedded in concrete, A bag can be employed which has an opening in the formwork at the portion around the formwork from which the concrete has been removed, is inserted into the formwork through the opening, and in a state in which the bag is expanded by filling the interior with a fluid, concrete can be poured into the portion around the formwork facing the opening, and an anchor portion connected to the bag can be embedded and fixed in the concrete poured for repair (configuration 15).

[0023] In the embodiment having feature 15, the anchor portion may include a member protruding from the outer surface of the bag body (feature 16).

[0024] In addition, in an embodiment having configuration 15, the anchor portion can adopt a configuration including a handle connected to the bag body and an auxiliary tool connected to the handle (configuration 17).

[0025] Furthermore, in an embodiment having the configuration 15, the anchor portion may have a configuration including a valve provided for injecting or discharging the fluid into the bag body (configuration 18).

[0026] In a configuration having configuration 15, or in a configuration in which a single or multiple elements selected from configuration 16, configuration 17, and configuration 18 are added to configuration 15, the bag body can have an inner bag and an outer bag that contains the inner bag, and the fluid can be filled in the inner bag (configuration 19).

[0027] A bag body having the above-mentioned configuration 15, or a bag body having a single or multiple configurations selected from configuration 16, configuration 17, configuration 18, and configuration 19 added to configuration 15, can be used, and a fixing structure for the bag body in which the anchor portion is fastened to a reinforcing bar facing the opening can be adopted (configuration 20).

[0028] In an embodiment having configuration 20, the bag body can adopt a configuration adapted to come into contact with the edge of the opening of the formwork (configuration 21). Effect of the Invention

[0029] According to the present invention, repairs to hollow concrete structures can be carried out more easily, cheaply and stably. [Brief description of the drawings]

[0030] [Figure 1] FIG. 1 is a cross-sectional view showing an embodiment of the present invention, illustrating a state in which a bag body is inserted into a mold. [Diagram 2] FIG. 2 is a cross-sectional view showing the state in which the bag of FIG. 1 is filled with a fluid. [Diagram 3] A cross-sectional view showing the state in which concrete has been poured onto the top of the formwork in Figure 2. [Figure 4] FIG. 13 is a perspective view showing the operation of inserting the bag into the formwork; [Diagram 5] FIG. 13 is a perspective view showing a state in which the bag body is inserted into the mold; [Figure 6] A perspective view showing the state in which concrete is poured on top of the formwork. [Figure 7] FIG. 1A is a cross-sectional view showing a state in which a bag body according to a first embodiment of the present invention is used, and FIGS. 1B to 1I are cross-sectional views showing modified examples thereof. [Figure 8] FIG. 1A is a cross-sectional view showing a state in which a bag body according to a second embodiment of the present invention is used, and FIGS. 1B to 1H are cross-sectional views showing modified examples thereof. [Figure 9] FIG. 13 is a perspective view of a bag body (inner bag) according to a third embodiment of the present invention; [Figure 10] FIG. 13 is a perspective view of a bag body (outer bag) according to a third embodiment of the present invention; [Figure 11] FIG. 13 is a perspective view of a bag body (inner bag) showing a modified example of the third embodiment. [Figure 12] FIG. 13 is a perspective view of a bag body (outer bag) showing a modified example of the third embodiment. [Figure 13] FIG. 11 is a cross-sectional view showing a state in which the bag body according to the fourth embodiment of the present invention is used. [Figure 14] FIG. 13 is a vertical cross-sectional view showing a state in which the bag body of the fourth embodiment is used; [Figure 15] 1A to 1F are cross-sectional views showing modified examples of the anchor part. [Figure 16] Cross-section of a concrete structure DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] An embodiment of the present invention will be described with reference to the drawings. Here, the configuration of the present invention will be described using a deck of an elevated bridge used for a road as an example of a hollow concrete structure 1 (hereinafter referred to as structure 1) in which a hollow formwork 10 is embedded in concrete.

[0032] As shown in FIG. 16, in the structure 1 of this embodiment, a hollow formwork 10 (hereinafter, simply referred to as formwork 10) made of a hollow tube is embedded inside the deck concrete constituting the roadbed 2. Necessary reinforcing bars 4 are arranged around the formwork 10. The type, location, number, etc. of the reinforcing bars 4 are appropriately set according to the specifications of the structure 1. In addition, in this embodiment, a steel cylindrical tube is adopted as the formwork 10, and a plurality of formworks 10 are arranged in parallel along the bridge axis direction of the viaduct. Note that the formwork 10 is held by various fixing devices (not shown / see, for example, FIG. 1 and FIG. 2 of Patent Document 1) so that a predetermined covering thickness is secured for the reinforcing bars 4 and for the upper and lower surfaces of the deck, and further so that lateral movement is restricted, and is embedded in the concrete in this state.

[0033] When the concrete of the structure 1 becomes corroded or damaged due to deterioration over time, repairs are performed. Corroded or damaged areas can be identified by visual inspection of abnormalities that appear on the surface or by well-known non-destructive testing methods.

[0034] When the area requiring repair is around the formwork 10, the repair begins with the first step of removing the concrete around the formwork 10 to expose the formwork 10. Reference numeral 3 in FIG. 16 indicates a portion where the pavement constituting the surface layer of the roadbed 2 has been removed (hereinafter referred to as the surface layer removed portion 3). Reference numeral 5 indicates a portion below the surface layer where the concrete constituting the deck structure has been removed (hereinafter referred to as the deep layer removed portion 5). In the deep layer removed portion 5, the reinforcing bars 4 located above the formwork 10 are exposed. The reinforcing bars 4 are arranged in a lattice pattern in which the reinforcing bars in the bridge axis direction and the reinforcing bars in the direction perpendicular to the bridge axis intersect at right angles in a plan view. Concrete is removed below the reinforcing bars 4 until the top surface of the formwork 10 is exposed. In the prior art, the reinforcing bars 4 were cut in order to repair the formwork 10, but according to the present invention, which uses the bag body 20 described below, repairs can be carried out without cutting the reinforcing bars 4, except in cases where the reinforcing bars 4 are corroded.

[0035] As shown in Figs. 1 and 4, an opening 13 formed in the formwork 10 is exposed below the deep layer removal portion 5 from which the concrete has been removed. The opening 13 may be a hole formed by corrosion of the members constituting the formwork 10, or may be a hole formed when removing the surface layer of concrete. Furthermore, it may be a (enlarged) hole formed by removing the surrounding corroded portion including the hole caused by the corrosion or the like. Reference numeral 11 in the figure indicates the formwork removal portion. In this embodiment, the opening 13 is formed in the upper surface (cylindrical surface) of the formwork 10 curved in a saddle shape, as shown in Fig. 4, within a range of length L0 along the cylindrical axis direction. The shape of the opening 13 varies, but in Fig. 4, the opening 13 is rectangular in plan view.

[0036] Next, a longitudinal bag body 20 made of a flexible material is inserted into the formwork 10 through the opening 13. The bag body 20 is inserted so that its longitudinal direction is aligned with the cylindrical axis direction of the formwork 10. FIG. 1 illustrates the state of the bag body 20 according to the first embodiment of the present invention. The process of inserting the bag body 20 is referred to as the second process. The bag body 20 is made of a flexible material and can be flexibly deformed. Therefore, it is easy to insert the bag body 20 into the formwork 10 through the gaps in the lattice-shaped reinforcing bars 4 (see FIG. 4). The material of the bag body 20 may be any material that has a predetermined strength that can withstand pressure from inside and outside and is resistant to external damage (resistant to holes), for example, polyvinyl chloride, polyester, polyurethane, etc., and may be a non-stretchable material or a material that has a certain degree of stretchability (shape-following ability).

[0037] The length (length in the longitudinal direction) of the bag body 20 is set to be longer than the axial length L0 (see FIG. 4) of the opening 13. Therefore, the bag body 20 has a length that allows it to protrude outward beyond the edges of the opening 13 on both sides in the axial direction.

[0038] Next, the inside of the bag body 20 is filled with the fluid 23 as a filler (see Figs. 2 and 5). This process of filling the fluid 23 is called the third process. In this embodiment, air is used as the fluid 23. The filling of the fluid 23 can be performed by pumping the fluid 23 from an external fluid supply source through a supply pipe 29 connected to a valve (inlet) 21 provided in the bag body 20. At this time, if the valve 21 is provided in the center of the cylindrical bag body 20 in the axial direction, the bag body 20 can expand smoothly. At this time, it is preferable that the valve 21 is located at a position facing the opening 13 when the bag body 20 is installed in the formwork 10. This is because the connection and disconnection of the supply pipe 29 to the valve 21 can be easily performed. When the opening 13 is at the end of the bridge axis direction of the deck slab, the valve 21 may be provided at the end of the cylindrical bag body 20 in the axial direction. As a result, the bag body 20 expands in one direction along the cylindrical axial direction, so that the expansion of the bag body 20 at the end portion of the form 10 is smooth.

[0039] Next, a new concrete layer 41 is poured above the opening 13, i.e., in the area where the concrete has been removed (see Figs. 3 and 6). This step of pouring concrete is referred to as the fourth step. In the fourth step, the new concrete layer 41 is poured, and a new surface layer 42 is also poured on top of it as a pavement for road surface finishing. Reference H1 in Fig. 2 is the covering dimension from the lower edge of the reinforcing bar 4 at the top of the formwork 10 (the edge of the opening 13). Reference H2 is the covering thickness dimension from the lower edge of the reinforcing bar 4 at the top of the bag body 20 (the top of the top surface 26). H1 ≦ H2 is ensured. However, the covering thickness H0 (not shown) of the formwork 10 before repair is H0 ≦ H1 ≦ H2. This is common to each embodiment described later. In general, the minimum allowable covering thickness is determined based on various regulations set forth for each structure 1. In the structure 1 shown in the embodiment, the predetermined distance can be, for example, 35 mm or more, 50 mm or more, or the like.

[0040] (First embodiment / first means) Hereinafter, a bag body 20 according to a first embodiment of the present invention (including its modified examples) will be described. 2 and 7(a), the bag body 20 of the first embodiment is configured such that, when filled with the fluid 23 and inflated, the multiple contact portions 24, 25a, 25b of the bag body 20 press the inner surface 12 of the formwork 10 by the internal pressure, thereby maintaining the position of the bag body 20 within the formwork 10 and restricting it from floating up toward the opening 13. This more reliably ensures that the covering thickness is in the range H0≦H1≦H2.

[0041] Here, the bag body 20 has a configuration in which a plurality of abutment parts 24, 25a, 25b against the inner surface 12 of the formwork 10 are intermittently provided along the cylindrical axis of the formwork 10. In the example of Fig. 7(a), in the cross section of the bag body 20 (called the cross section perpendicular to the cylindrical axis), the abutment parts 24, 25a, 25b have a large curvature (small curve radius) and the other parts have a small curvature (large curve radius), forming a triangular cross section. Therefore, the internal pressure is easily transmitted as a pressing force to the inner surface of the formwork 10 through the abutment parts 24, 25a, 25b. In particular, of the three abutment portions 24, 25a, 25b, the abutment portion 24 closest to the bottom presses against the bottom of the formwork 10, and the reaction force pushes the bag body 20 upward, but the abutment portions 25a, 25b at both ends in the width direction on the upper top surface 26 are pushed out in the width direction within the formwork 10, thereby stabilizing the position of the bag body 20.

[0042] Here, it is important that the inner surface 12 of the formwork 10 has a portion (above the abutting portions 25a, 25b) that is not in contact with the bag body 20 at a position facing the opening 13 of the bag body 20. This allows the repair concrete to be filled up to the abutting portions through the opening 13, so that the required repair thickness (strength) can be obtained while suppressing the rise in the road surface height.

[0043] Here, it is desirable for stabilizing the bag body 20 that the uppermost one of the multiple abutting parts 24, 25a, 25b in the cross section perpendicular to the cylindrical axis of the bag body 20 is located below the edge of the opening 13. At this time, the uppermost one of the multiple abutting parts 24, 25a, 25b in the cross section perpendicular to the cylindrical axis of the bag body 20 may be configured to press the formwork 10 via a buffer material (not shown) that is a separate member from the bag body 20. That is, the abutment between the inner surface 12 of the formwork 10 and the bag body 20 here is a concept that includes both a case where the bag body 20 and the formwork 10 are in direct contact with each other and a case where the bag body 20 and the formwork 10 are in indirect contact with each other by sandwiching a separate member such as a buffer material between them. This makes it possible to prevent the poured unhardened concrete from entering the formwork 10. For example, an elastic body such as sponge, urethane, or rubber, or urethane foam can be used as the buffer material. The urethane foam can be sprayed. The timing for filling the buffer material may be any time, but filling the fluid 23 after the buffer material is installed makes construction easier. Furthermore, adhesion and gap covering between the bag body 20 and the formwork 10, between the buffer material and the bag body 20, and between the buffer material and the formwork 10 can be appropriately performed by using silicon caulking, adhesive coating, double-sided tape, or the like.

[0044] By pressing and fixing the bag body 20 toward the upper side within the formwork 10, a gap 22 can be secured in the lower part within the formwork 10. The gap 22 can function as a space for discharging water and foreign matter. The gap 22 is formed between a lower surface 27 of the surface 28 of the bag body 20 and the inner surface 12 of the formwork 10.

[0045] In some cases, a corrugated pipe or the like having an uneven inner surface 12 is used as the cylindrical form 10. When the inner surface 12 is uneven, the abutment of the bag body 20 with the inner surface 12 of the form 10 includes a state in which at least a part of the bag body 20 and the inner surface 12 of the form 10 (i.e., a part of the form 10 with a small inner diameter) are in contact with each other in a cross section perpendicular to the pipe axis, and the bag body 20 is not in contact with the groove of the form 10 (i.e., a part of the form 10 with a large inner diameter) in another cross section perpendicular to the pipe axis. Furthermore, it also includes a state in which the bag body 20 is in contact (tightly packed) with both a part of the form 10 (i.e., a part of the form 10 with a small inner diameter) and the groove of the form 10 (i.e., a part of the form 10 with a large inner diameter).

[0046] 7(b) to 7(i) show modified examples of the bag body 20 of the first embodiment.

[0047] In the example of FIG. 7(b), the bag body 20 has a rectangular cross section in a cross section perpendicular to the cylinder axis, and is provided with four contact parts 24a, 24b, 25a, and 25b around the cylinder axis. That is, the cross section is rectangular, with a large curvature (small curve radius) at the four contact parts 24a, 24b, 25a, and 25b, and a small curvature (large curve radius) at the other parts. Therefore, the internal pressure is easily transmitted as a pressing force to the inner surface of the formwork 10 through the contact parts 24a, 24b, 25a, and 25b. In particular, the lower contact parts 24a and 24b among the four contact parts 24a, 24b, 25a, and 25b press the bottom of the formwork 10, and the bag body 20 is pushed upward by the reaction force, but the upper contact parts 25a and 25b are pushed in the width direction within the formwork 10, so that the position of the bag body 20 can be stabilized. The rest of the configuration is the same as that in FIG. 7(a) (the same is true for other modified examples).

[0048] In the example of Fig. 7(c), the bag body 20 has a pentagonal cross section in a cross section perpendicular to the cylinder axis, and is provided with five contact parts 24a, 24b, 24c, 25a, and 25b around the cylinder axis. That is, the five contact parts 24a, 24b, 24c, 25a, and 25b have a large curvature (small curve radius) and the other parts have a small curvature (large curve radius), forming a pentagonal cross section. Of the five contact parts 24a, 24b, 24c, and 25a, and 25b, the lower contact parts 24a, 24b, and 24c press the bottom of the formwork 10, and the bag body 20 is pushed upward by the reaction force, but the upper contact parts 25a and 25b are pushed in the width direction within the formwork 10, so that the position of the bag body 20 can be stabilized in the same way.

[0049] In the drawings, the contact portion is shown as a sharp apex with the remaining portion being linear, but the concept of a pentagonal cross-section (polygonal cross-section) also includes a case in which the contact portion is shown as a smooth arc and the remaining portion is shown as a gentle arc. This also applies to the bag body 20 having a polygonal cross-section in other modified examples and other embodiments.

[0050] In the example of Fig. 7(d), the bag body 20 has a hexagonal cross section in a cross section perpendicular to the cylindrical axis, and is provided with six contact parts 24a, 24b, 24c, 24d, 25a, and 25b around the cylindrical axis. That is, the six contact parts 24a, 24b, 24c, 24d, 25a, and 25b have a large curvature (small curve radius), and the other parts have a small curvature (large curve radius), forming a hexagonal cross section. Among the six contact parts 24a, 24b, 24c, 24d, and 25a, and 25b, the lower contact parts 24a, 24b, 24c, and 24d press against the bottom of the formwork 10, and the bag body 20 is pushed upward by the reaction force, but the upper contact parts 25a and 25b are pushed in the width direction within the formwork 10, so that the position of the bag body 20 can be stabilized. Here, the side abutment portions 24a, 24d also exert a function of pushing the bag body 20 in the width direction into the mold 10 to hold the position of the bag body 20.

[0051] In the example of Fig. 7(e), the bag body 20 has a D-shaped cross section in a cross section perpendicular to the cylindrical axis, and the entire area around the cylindrical axis except for the top surface 26 serves as an abutment portion with the inner surface 12 of the formwork 10. The entire area except for the flat top surface 26 is a cylindrical surface, and the entire cylindrical surface serves as an abutment portion with the inner surface 12 of the formwork 10. Of the abutment portions consisting of the entire cylindrical surface except for the top surface 26, the abutment portions closer to the lower side press against the bottom of the formwork 10, and the bag body 20 is pushed upward by the reaction force, but the abutment portions 25a, 25b on both sides in the width direction of the top surface 26 are pushed in the width direction within the formwork 10, so that the position of the bag body 20 can be stabilized.

[0052] In the example of FIG. 7(f), the bag body 20 has a D-shaped cross section in a cross section perpendicular to the cylinder axis, and both ends of the flat top surface 26 in the width direction are abutment parts 25a, 25b with the inner surface 12 of the formwork 10. The entire area except the flat top surface 26 is a cylindrical surface or a circular arc surface, and a gap is interposed between the entire area of ​​the cylindrical surface or the circular arc surface other than the abutment parts 25a, 25b and the inner surface 12 of the formwork 10, thereby securing the gap 22. Here, the bag body 20 is pulled upward by the anchor part 30. This allows the abutment parts 25a, 25b to be in close contact with the inner surface 12 of the formwork 10 around the opening 13. The anchor part 30 may be engaged with the reinforcing bar 4 in a state in which the bag body 20 is pulled up. Here, it is preferable to first inflate the bag body 20, pull up the bag body 20 to adjust the position in the vertical direction, and then engage the anchor part 30 with the reinforcing bar 4.

[0053] The anchor portion 30 may be embedded and fixed in poured concrete so that the bag body 20 can be maintained in that position. The installation of the anchor portion 30 is optional, and the installation of the anchor portion 30 may be omitted if the function of the anchor portion 30 is not required. The anchor portion 30 may also be used in other modified examples and other embodiments.

[0054] By providing the anchor portion 30 as described above, the following effects can be expected regardless of the cross-sectional shape of the bag body 20. (1) When pouring concrete, the bag body 20 can be prevented from falling due to the pouring pressure (the position of the bag body 20 can be fixed). (2) The bag body 20 can be easily attached to the formwork 10, and the inflow of concrete into the formwork 10 can be suppressed. (3) The bag body 20 is prevented from falling into the formwork 10 after the concrete has been poured, thereby preventing blockage of the drainage channel within the formwork 10.

[0055] 7(g), the bag body 20 has a two-sided cross section (a part around the cylindrical axis and a part on the opposite side of the cylindrical axis are flat surfaces) in a cross section perpendicular to the cylindrical axis, and both ends in the width direction of the flat top surface 26 form abutment portions 25a, 25b with the inner surface 12 of the formwork 10. The entire area except for the flat top surface 26 and the lower surface 27 is a cylindrical or arcuate surface, and a gap is provided between the entire cylindrical or arcuate surface except for the abutment portions 25a, 25b and the inner surface 12 of the formwork 10, ensuring the gap 22.

[0056] Here, the pressing force of the uppermost contact parts 25a, 25b of the bag body 20 in the cross section perpendicular to the cylindrical axis against the inner surface of the formwork 10 is increased by the reaction force from the spacer 50 arranged below the bag body 20. That is, although the bag body 20 is pushed upward by the reaction force from the spacer 50, the upper contact parts 25a, 25b are pushed in the width direction within the formwork 10, so that the position of the bag body 20 can be stabilized.

[0057] In the example of Fig. 7(h), the upper part of the bag body 20 in the cross section perpendicular to the cylinder axis is a cylindrical surface or a circular arc surface, and the lower part is composed of two inclined surfaces that form a V-shaped cross section with each other. Both ends of the top surface 26 in the width direction that forms a circular arc shape are abutment parts 24a, 24c with the inner surface 12 of the formwork 10, and the connection part of the two inclined surfaces is also abutment part 24b with the inner surface 12 of the formwork 10. The abutment parts 24a, 24c on both sides of the top surface 26 in the width direction are pushed in the width direction within the formwork 10, so that the position of the bag body 20 can be stabilized. A gap is interposed between the top surface 26 and the entire lower surface 27 (two inclined surfaces) other than the three abutment parts 24a, 24b, 24c and the inner surface 12 of the formwork 10, and a gap 22 is secured.

[0058] In the example of Fig. 7(i), the entire periphery of the bag body 20 in the cross section perpendicular to the cylindrical axis is a cylindrical surface or a circular arc surface, and the entire periphery of the bag body 20 forms the abutment portion, except for the portion facing the opening 13 and the portion close to the edge of the opening 13. As in Figs. 7(a) to (h), the uppermost abutment portions 25a, 25b between the bag body 20 and the inner surface 12 of the formwork 10 in the cross section perpendicular to the cylindrical axis are located below the edge of the opening 13, so that the repair concrete can slightly enter the formwork 10 through the opening 13.

[0059] (Second embodiment / second means) A second embodiment of the present invention (including its modified example) will be described below. As shown in Fig. 8(a), when the bag body 20 of the second embodiment is filled with a fluid 23 and inflated, a plurality of contact portions 24, 25a, 25b of the bag body 20 press the inner surface 12 of the mold 10 by the internal pressure, so that the position of the bag body 20 within the mold 10 is maintained, the descent of the bag body 20 within the mold 10 is restricted, and a gap 22 is secured below the cylindrical axis within the mold 10.

[0060] Here, it is important that there are areas on the inner surface 12 of the bottom of the formwork 10 that are not in contact with the bag body 20 (areas below the abutment portions 24a, 24b), thereby ensuring a drainage path, i.e., a waterway, during and after construction.

[0061] As in the above embodiment, when the inner surface 12 of the mold 10 is uneven, the presence of the gap 22 between the bag body 20 and the inner surface 12 of the mold 10 includes a state in which, even if at least a part of the bag body 20 and the inner surface 12 of the mold 10 (i.e., a part with a small inner diameter of the mold 10) are in contact with each other in a cross section perpendicular to the tube axis, the bag body 20 is not in contact with the groove of the mold 10 (i.e., a part with a large inner diameter of the mold 10) in another cross section perpendicular to the tube axis. However, by ensuring as continuous a gap as possible along the longitudinal direction, the effect of securing a water channel is more certain. Furthermore, since the bag body 20 expands most in the longitudinal center, it is desirable that the gap 22 is present in the longitudinal center of the bag body 20, but if there is a gap 22 at least at the longitudinal end of the bag body 20, the effect of securing at least a part of the water channel can be expected.

[0062] Here, the bag body 20 also has a configuration in which a plurality of abutment parts 24, 25a, 25b against the inner surface 12 of the formwork 10 are intermittently arranged around the cylindrical axis of the formwork 10. In the example of Fig. 8(a), in the cross section (called the cross section perpendicular to the cylindrical axis) of the bag body 20, the curvature is large (the curve radius is small) at the abutment parts 24, 25a, 25b, and the curvature is small (the curve radius is large) in the other parts, forming a triangular cross section. Therefore, the internal pressure is easily transmitted as a pressing force to the inner surface of the formwork 10 through the abutment parts 24, 25a, 25b. In particular, of the three abutment portions 24, 25a, 25b, the abutment portion 24 closest to the bottom presses against the bottom of the formwork 10, and the reaction force pushes the bag body 20 upward, but the abutment portions 25a, 25b at both ends in the width direction on the upper top surface 26 are pushed out in the width direction within the formwork 10, thereby stabilizing the position of the bag body 20.

[0063] By pressing and fixing the bag body 20 toward the upper side within the formwork 10, a void 22 can be secured in the lower part within the formwork 10. The void 22 can function as a space for discharging water and foreign matter. The void 22 is formed between a lower surface 27 of a surface 28 of the bag body 20 and the inner surface 12 of the formwork 10. In Fig. 8(a), the portion indicated by diagonal lines below a line c in the width direction passing through the cylindrical axis is a region where the void 22 is preferably provided.

[0064] The bag body 20 in Fig. 8(b) has the same cross section as the bag body 20 in Fig. 7(b), and below, Fig. 8(c) has the same cross section as the bag body 20 in Fig. 7(c), Fig. 8(d) has the same cross section as the bag body 20 in Fig. 7(d), Fig. 8(e) has the same cross section as the bag body 20 in Fig. 7(f), and Fig. 8(f) has the same cross section as the bag body 20 in Fig. 7(g). Therefore, detailed explanations will be omitted, and the following explanation will focus on the action in securing the gap 22.

[0065] 8(b), it is desirable for the lowermost one of the multiple contact portions 24, 25a, 25b in the cross section perpendicular to the cylindrical axis of the bag body 20 to be located above the bottommost part in the formwork 10 in order to ensure the gap 22. This is because it is desirable to ensure that the bottommost part in the formwork 10 is wide and free of obstacles in order to drain water, etc. Note that, similarly to the first embodiment, the uppermost contact portions 25a, 25b in the cross section perpendicular to the cylindrical axis of the bag body 20 may be configured to press the formwork 10 via a cushioning material (not shown) that is a separate member from the bag body 20.

[0066] In the example of Fig. 8(c), the bag body 20 has a pentagonal cross section in a cross section perpendicular to the cylindrical axis, and is configured to have five contact parts 24a, 24b, 24c, 25a, and 25b around the cylindrical axis. Of the five contact parts 24a, 24b, 24c, 25a, and 25b, the lower contact parts 24a, 24b, and 24c press against the bottom of the formwork 10, and the bag body 20 is pushed upward by the reaction force, but the upper contact parts 25a and 25b are pushed in the width direction within the formwork 10, so that the gap 22 can be stably secured.

[0067] In the example of Fig. 8(d), the bag body 20 has a hexagonal cross section in a cross section perpendicular to the cylindrical axis, and is configured to have six contact parts 24a, 24b, 24c, 24d, 25a, and 25b around the cylindrical axis. Of the six contact parts 24a, 24b, 24c, 24d, and 25a, and 25b, the lower contact parts 24a, 24b, 24c, and 24d press against the bottom of the formwork 10, and the bag body 20 is pushed upward by the reaction force, but the upper contact parts 25a and 25b are pushed in the width direction within the formwork 10, so that the gap 22 can be stably secured.

[0068] In the example of Fig. 8(e), the bag body 20 has a D-shaped cross section in a cross section perpendicular to the cylindrical axis, and the entire area except for the flat top surface 26 is a cylindrical surface or a circular arc surface. Both ends in the width direction of the top surface 26 form abutment portions 25a, 25b with the inner surface 12 of the formwork 10, and a gap is provided between the entire lower surface 27 except for the abutment portions 25a, 25b and the inner surface 12 of the formwork 10, thereby ensuring the gap 22. The configuration of the anchor portion 30 is the same as in the first embodiment.

[0069] In the example of FIG. 8(f), the bag body 20 has a two-sided cross section (a part around the cylindrical axis and a part on the opposite side of the cylindrical axis are flat surfaces) in a cross section perpendicular to the cylindrical axis, and both ends in the width direction of the flat bottom surface of the lower surface 27 serve as abutment parts 24a, 24b against the inner surface 12 of the formwork 10. Reference numeral 40 in the figure denotes a pressing means 40. The pressing means 40 presses the upper surface of the bag body 20, thereby preventing the upper end of the bag body 20 from approaching the reinforcing bar 4 and increasing the pressing force of the abutment parts 24a, 24b against the inner surface 12 of the formwork 10. Furthermore, the bag body 20 can be prevented from floating up when concrete is poured.

[0070] Of the surface 28 of the bag body 20, a gap is provided between the entire lower surface 27, excluding the contact portions 24a and 24b, and the inner surface 12 of the formwork 10 to ensure the gap 22. Here, a buffer material may be placed in the gap between the edge of the opening 13 and the bag body 20 to close the gap, so that unhardened concrete does not flow into the gap 22 above the contact portions 24a and 24b.

[0071] In the example of Fig. 8(g), the bag body 20 has a D-shaped cross section in a cross section perpendicular to the cylindrical axis, and the entire area except for the flat top surface 26 is a cylindrical surface or a circular arc surface. Both ends of the top surface 26 in the width direction form abutment portions 25a, 25b with the inner surface 12 of the formwork 10, i.e., the uppermost abutment portions 25a, 25b. Although the bag body 20 is pushed upward by a reaction force from a spacer 50 (receiving means 50) for raising the bag body 20, the upper abutment portions 25a, 25b are pushed in the width direction within the formwork 10, so that the position of the bag body 20 can be stabilized.

[0072] Here, the downward movement of the bag body 20 is restricted by the spacer 50, so that it is easy to ensure the gap 22 below the spacer 50. As the spacer 50, a wooden slat, various mesh members, various plate-like members, etc. can be used. The spacer 50 is preferably made of a material with good drainage that allows liquids such as water to pass downward.

[0073] In the example of Fig. 8(h), the entire periphery of the bag body 20 is a cylindrical surface or a circular arc surface in a cross section perpendicular to the cylindrical axis. The bag body 20 abuts against the edge of the opening 13 so that repair concrete does not get into the formwork 10. Also, similar to Figs. 8(a) to (g), in the cross section perpendicular to the cylindrical axis, the non-abutting portion between the bag body 20 and the inner surface 12 of the formwork 10 exists below the cylindrical axis of the formwork 10, forming a gap 22.

[0074] (Third embodiment / third means) A third embodiment of the present invention will now be described. As shown in Figures 9 and 10, a bag body 20 of this embodiment includes an inner bag 20A and an outer bag 20B that houses the inner bag 20A therein.

[0075] As described above, the repair method for hollow concrete structures of the present invention comprises a first step of removing the concrete around the formwork 10 to expose the formwork 10, a second step of inserting a bag body 20 into the formwork 10 through the opening 13 of the formwork 10, a third step of filling the inside of the bag body 20 with a fluid 23, and a fourth step of forming a new concrete layer 41 in the area from which the concrete was removed.

[0076] Here, in the third step, the pressure of the fluid 23 in the bag body 20 is set to be equal to or higher than the pouring pressure of the concrete at the lowest temperature within the set hardening time (the time until the concrete hardens and exerts a predetermined strength) of the concrete poured when forming the new concrete layer 41. The lowest temperature can be determined, for example, based on the expected lowest temperature within the set hardening time. As a specific example, a safety factor can be estimated for the expected lowest temperature forecasted by the Meteorological Agency or the like for the relevant day and time period, and a predetermined temperature can be subtracted from the expected lowest temperature to determine the lowest temperature as -3°C, -5°C, -10°C, -20°C, etc. Note that the predetermined temperature estimated for the expected lowest temperature may be set to ±0°C, and the expected lowest temperature itself may be used as the minimum temperature. If the pressure of the bag body 20 is set in consideration of the lowest temperature during the set hardening time of the concrete, it is easy to maintain the bag body 20 in an appropriate state for the concrete to be poured. Note that the set hardening time can be set, for example, to one day or less, three days, seven days or more, etc., when ordinary general concrete is used.

[0077] In addition, at the maximum temperature within the set hardening time, the pressure of the fluid 23 in the bag body 20 is desirably set to the withstand pressure of the bag body 20 or less. The maximum temperature can be determined based on the expected maximum temperature of the concrete taking into account the heat of hydration within the set hardening time, or based on the expected maximum road surface temperature around the opening 13 within the set hardening time. As a specific example, the maximum temperature can be determined as +3°C, +5°C, +10°C, +20°C, etc. by taking into account the expected maximum temperature of the concrete taking into account the heat of hydration, or the expected maximum road surface temperature assumed for the corresponding day and time period, and adding a predetermined temperature to the expected maximum temperature. Note that the predetermined temperature expected for the expected maximum temperature may be ±0°C, and the expected maximum temperature itself may be used as the maximum temperature. If the pressure of the bag body 20 is set in consideration of the maximum temperature during the set hardening time of the concrete, it is easy to maintain the bag body 20 in an appropriate state for the concrete to be poured. That is, the temperature of the concrete rises due to heat of hydration until the concrete is completely hardened, and there is a possibility that the internal pressure will rise due to temperature changes caused by air temperature, sunlight, etc. until the concrete is completely hardened. However, by making the bag body 20 strong enough to withstand such conditions, it can reliably function as a formwork until the poured concrete hardens.

[0078] In addition, the bag body 20 may be provided with a pressure gauge that detects the pressure inside the bag body 20, and the pump may be feedback-controlled while monitoring the pressure, thereby controlling the pressure inside the bag body 20 to an appropriate range. Furthermore, in order to prevent an excessive pressure rise in the bag body 20, a relief valve that releases the internal fluid 23 to the outside when the internal fluid 23 reaches a predetermined pressure so as not to increase the pressure any further may be provided somewhere in the bag body 20. This simplifies the complicated pressure monitoring work. In addition, in order to prevent an excessive temperature rise, a heat insulating layer may be provided around the bag body 20 (outer bag 20B) or between the inner bag 20A and the outer bag 20B. Alternatively, the material of the inner bag 20A and the outer bag 20B may be made to have high heat insulating properties. It is desirable that these parts for which heat insulation is to be achieved are at least located at positions facing the opening 13 of the formwork 10, and this is expected to have the effect of effectively blocking the heat of hydration of the poured concrete while reducing the amount of heat insulating layer and heat insulating material used.

[0079] Here, the concrete pouring pressure refers to the pressure acting on the bottom of the flowing unhardened concrete when the concrete is poured. Here, it corresponds to the pressure from the unhardened concrete near the top surface 26 of the bag body 20. For example, if the concrete pouring pressure is 10 kPa, then the pressure inside the bag body 20 can be set to 20 kPa (safety factor 2) after taking into account a safety factor. By making the bag body 20 strong enough to withstand this pressure, it can reliably function as a formwork until the poured concrete hardens.

[0080] Furthermore, it is desirable for the material of the bag body 20 to be such that when the pressure of the fluid 23 inside the bag body 20 is brought to a predetermined pressure, the bag body 20 does not protrude outward from the opening 13, or a material that can maintain a specified covering thickness (including selection of the type of material and thickness of the material, etc.) is used.

[0081] In this embodiment, the bag body 20 has a double structure consisting of an inner bag 20A and an outer bag 20B, so that it is easy to maintain both the functions of stretchability and strength. However, it is not essential to use the inner bag 20A and the outer bag 20B, and a bag body 20 having a single structure as in the above-mentioned embodiment may be used. Conversely, the bag body 20 having a double structure of this embodiment may be used in other embodiments.

[0082] When a double-structured bag body 20 is used, the material of the inner bag 20A is preferably a fabric that is easy to stretch, and a synthetic resin or rubber sheet or film (e.g., polyethylene, polyurethane, polyvinyl chloride, chloroprene rubber, EPDM, Hypalon rubber, etc.) can be used. Of these, polyethylene or polyurethane is particularly preferred. As the material of the outer bag 20B, a synthetic resin or rubber sheet (e.g., polyethylene, polyurethane, polyvinyl chloride, polypropylene, polyethylene, chloroprene rubber, EPDM, Hypalon rubber, etc.) can be used as a fabric that is somewhat stretchable and durable, and it is preferable that both sides of a synthetic fiber fabric are coated with these resins or rubbers. Of these, vinyl chloride, polypropylene, polyethylene, etc. can be used as a synthetic resin that is difficult to stretch and durable. Of these, polypropylene is particularly preferred.

[0083] When combining the inner bag 20A and the outer bag 20B, it is preferable that the outer bag 20B is made of a material that is less likely to stretch than the inner bag 20A. In other words, within a range in which the material returns to its original state (recovers) when the tensile force is released after being stretched (stretched) by a tensile force, it is preferable that the elongation rate (%) of the material of the inner bag 20A for a certain tensile force is smaller than the elongation rate (%) of the material of the outer bag 20B for the same tensile force. This allows the cross section (outer diameter) of the inner bag 20A to be larger (taking into account expansion and elongation) than the cross section (outer diameter) of the outer bag 20B when an assumed pressure is applied by filling the fluid 23. Note that, in the state before filling the fluid 23, the cross section (outer diameter) of the inner bag 20A may be smaller than the cross section (outer diameter) of the outer bag 20B. In other words, it is preferable that the inner bag 20A is larger than the outer bag 20B so that the inner bag 20A does not move around in the outer bag 20B when pouring concrete. In this way, by making the bag body 20 have a double structure, the bag body 20 can easily expand even from a deflated state due to the expansion of the inner bag 20A, and the strong outer bag 20B can restrain excessive expansion and deformation of the entire bag body 20, so that the bag body installation shape as designed can be easily realized and can be easily adapted to the shape of the inner surface of the cylindrical form 10. Furthermore, by using a high-strength material for the outer bag 20B, damage to the bag body 20 can be suppressed even if the bag body 20 comes into contact with obstacles such as the edge of the opening 13 of the cylindrical form 10 or burrs around the installation site.

[0084] As shown in FIG. 9, the inner bag 20A is formed by winding a strip-shaped material into a cylindrical shape and processing the ends so as to squeeze both ends in the axial direction to form a sealed bag. The inner bag 20A has a double structure using two overlapping sheets, taking into consideration pinholes and breaks during construction. In addition, two valves 21 are installed in one bag body 20 so that a supply pipe 29 can be connected to another bag body 20 adjacent in the axial direction so that the fluid 23 can flow between them and the other bag body 20 connected thereto, and pressure control can be performed including the other bag body 20 connected thereto. That is, one valve 21 can be used for injection from a pump, and the other valve 21 can be used as a bypass to the other bag body 20. The reference numeral 31 in the figure denotes a handle 31 prepared for holding the inner bag 20A.

[0085] As shown in Fig. 10, the outer bag 20B may be formed by winding a strip-shaped material into a cylindrical shape and processing the ends to squeeze both ends in the axial direction to form a sealed bag. After winding the strip-shaped material into a cylindrical shape, end members made to match the expected cross-sectional shape of the bag may be sewn to both ends in the axial direction of the cylindrical member. Here, the end processed parts 34 of the inner bag 20A may be held by the outer bag 20B at both ends in the axial direction of the outer bag 20B. In Fig. 10, the end processed parts 34 protrude from the outer bag 20B and are held to prevent them from coming off.

[0086] The valve 21 of the bag body 20 protrudes to the outside from a hole provided in the top surface 26 of the outer bag 20B. Reference numeral 35 in the figure denotes a stopper 35 for preventing the injection port 2 from dropping into the outer bag 20B. Reference numeral 32 denotes a handle 32 provided for grasping the inner bag 20A. Reference numeral 62 in the figure will be described later in the fourth embodiment.

[0087] 11 and 12 show inner bag 20A and outer bag 20B having a square (rectangular) cross section. In this way, even in the double-structured bag body 20, the cross-sectional shape is free, and various cross-sectional shapes shown in Fig. 7 and Fig. 8 can be adopted.

[0088] The installation position of the valve 21 can be set freely, but providing the valve 21 at the center in the longitudinal direction makes it easier for the bag body 20 to expand evenly as a whole. However, there are cases where it is desired for the bag body 20 to expand toward one side in the longitudinal direction, such as the bag body 20 used at the end of a deck slab. In such a case, the valve 21 may be installed close to one end in the longitudinal direction. The valve 21 may be of a type that does not protrude from the bag body 20 (such as a removable valve or a valve that bends along the surface of the bag body 20), or if it is of a type that protrudes from the bag body 20, the valve 21 may be installed on the side of the bag body 20 so that the concrete to be poured does not cover the valve, or the protruding valve 21 may be embedded in the concrete poured for repair to serve as an anchor part 30. These matters are similar to other embodiments.

[0089] (Fourth embodiment / fourth means) A fourth embodiment of the present invention will be described below. As shown in Fig. 13, the bag body 20 of the fourth embodiment is filled with the fluid 23 and inflated, and the anchor parts 30 connected to the bag body 20 are embedded and fixed in concrete poured for repair. The anchor parts 30 are held in the hardened concrete, making it easy to maintain the position of the bag body 20 in the formwork 10.

[0090] In the embodiment, the anchor part 30 is composed of a handle 32 installed to grip the bag body 20 and an auxiliary tool 33 connected to the handle 32, but for example, only the handle 32 may be the anchor part 30. Here, the handle 32 and the reinforcing bar 4 may be fastened with a band (auxiliary tool 33), or the handle 32 may be fastened directly to the reinforcing bar 4. The valve 21 may be the anchor part 30. A protrusion may be provided other than the handle 32 or the valve 21, and the protrusion may be the anchor part 30. That is, the anchor part 30 may be a protrusion protruding from the outer surface of the bag body 20, and the protrusion may be only the handle 32, the handle 32 and the auxiliary tool 33, only the valve 21, the valve 21 and the auxiliary tool 33, or other protrusions or combinations thereof. The handle 32 is convenient for adjusting the position, so it is preferable that the handle 32 also functions as an anchor. In addition, since the valve 21 is a necessary component of the bag body 20, it is also preferable that the valve 21 has an anchor function.

[0091] The handle 32 is preferably located on the upper surface side of the bag body 20 (at a position facing the opening), and also functions as a mark for checking the orientation of the bag body 20 around the cylindrical axis and the position in the cylindrical axis direction. The handle 32 can also be used when rotating or moving the bag body 20 in the cylindrical axis direction to shift the position of the valve 21 in the formwork 10. This makes it possible to adjust the position of the valve 21 according to the reinforcing bar 4 and its surrounding structure, and to adjust the position of the bag body 20 and the opening 13 of the formwork 10. In particular, by moving the bag body 20 along the longitudinal direction, the overlapping allowance between the bag body 20 and the formwork 10 (the overlapping range in the longitudinal direction between the bag body 20 and the inner surface 12 of the formwork 10 except for the opening 13) can be adjusted.

[0092] Here, if the bag body 20 does not fall downward within the formwork 10 due to the effect of the anchor portion 30 and is pulled upward, the bag body 20 is likely to come into contact with the edge of the opening 13 of the formwork 10. This makes it possible to prevent concrete from flowing into the formwork 10. Also, by using the reinforcing bars 4 to pull the bag body 20 upward before pouring the concrete, the vertical position of the bag body 20 can be fixed at any position. This makes it difficult for the bag body 20 to move downward even when the pouring pressure of the repair concrete is applied, and a drainage channel can be secured during and after construction.

[0093] In each of the above-described embodiments, a connecting means 60 as shown in Fig. 14 may be employed. The connecting means 60 connects adjacent bag bodies 20, 20 in the cylindrical axial direction, and includes a first member 61 and a second member 62.

[0094] In this embodiment, a hook-and-loop fastener is used as the connecting means 60. A first member 61 constituting the hook-and-loop fastener is a belt-like member (sheet-like member) separate from the bag body 20, and a second member 62 is fixed to the longitudinal end of the bag body 20 by adhesion, sewing, or the like. Here, one of the first member 61 and the second member 62 is a member with a hook-like raised side, and the other is a member with a loop-like raised side, and the two are attached by pressing them together, and separated by pulling them together. This allows a plurality of bag bodies 20 to be connected and used within the mold 10 along the tubular axial direction (longitudinal direction).

[0095] In addition to the hook-and-loop fastener, for example, a line fastener or a point fastener (such as a button or a snap button) can be used as the connecting means 60. In order to prevent the longitudinal center of the first member 61 from bending due to the pouring pressure of the concrete, a core material may be added along the longitudinal direction of the first member 61. Alternatively, the expansion pressure of the bag body 20 can be used to generate tension in the first member 61 to resist the pouring pressure of the concrete for repair. This is because the bag bodies 20 expand while the end faces of the adjacent bag bodies 20 are in contact with each other, and a force is generated that tries to separate the bag bodies 20 from each other. This utilizes the fact that the first member 61 attached to those bag bodies 20 generates a tension that pulls them in the pipe axial direction. The bag bodies 20 may be joined together at any time, but if the opening 13 into which the bag body 20 is inserted is narrow, it is easier to join them before the opening 13 is inserted.

[0096] 15(a) to (f) each show a modified example of the anchor portion 30. As described above, the anchor portion 30 may be any shape as long as it protrudes from the outer surface of the bag body 20 so as to be embedded and fixed in concrete poured for repair.

[0097] FIG. 15(a) shows an anchor part 30 with a T-shaped cross section. The anchor part 30 has a base part 37 rising from the bag body 20 and an expanded part 36 located above the base part 37, and has a T-shaped cross section. Providing the expanded part 36 is expected to have a high effect of preventing the anchor part 30 from coming off the concrete. Note that the left-right direction in the figure is the longitudinal direction of the bag body 20, but the anchor part 30 may be fixed to the bag body 20 by rotating the direction of the anchor part 30 by 90 degrees in a plan view (the same applies to the following FIGS. 15(b) to (f)). FIG. 15(b) is an improvement over FIG. 15(a), and the anchor part 30 has a two-stage T-shaped cross section with a base part 37, an expanded part 36, a base part 37, and an expanded part 36, in that order from bottom to top.

[0098] Fig. 15(c) shows an arc-shaped anchor part 30. A semicircular arc part 38 rising from the bag body 20 has a gap 38a on the inside. Concrete fills the gap 38a, enhancing the retention effect. Fig. 15(d) shows a further improvement of Fig. 15(c), in which the arc part 38 is made annular and the annular arc part 38 is supported by a base part 37.

[0099] Figure 15(e) shows a wedge-shaped anchor part 30. The wedge part 39 rising from the bag body 20 has a shape that gradually widens from bottom to top in cross section. The wedge effect enhances the retention effect. Figure 15(f) is a further improvement of Figure 15(e) in that the wedge part 39 is provided in two stages.

[0100] In each of the above embodiments, a spacer (pressing means 40 / see FIG. 8(f)) may be provided at the opening 13 of the formwork 10 to prevent a part of the bag body 20 from protruding from the opening 13 to the outside of the formwork 10. The pressing means 40 presses the upper surface of the bag body 20, thereby preventing the upper end of the bag body 20 from approaching the reinforcing bar 4 and ensuring the covering thickness.

[0101] The holding means 40 may have a hook (such as a recess) for the reinforcing bar 4. The holding means 40 may be a member for holding the bag body 20 at a point, a member for holding the bag body 20 on a surface, or a combination of these. For example, a plate-shaped member made of concrete, wood, resin, metal, or the like, an axis-shaped member made of a similar material, a block-shaped member, or the like may be adopted, and these holding means 40 may be fixed between the reinforcing bar 4 and the formwork 10 so as to be tensioned. As another example of the holding means 40, the part of the bag body 20 facing the opening 13 may be wrapped around the cylindrical axis with a shape-constraining band, or the material of the bag body 20 may be made of a material that is less likely to stretch at that part than the surrounding area. That is, since the bag body 20 is prone to bulge at the center in the longitudinal direction, it is preferable to prevent the bulge at that part with a shape-constraining band, or to make that part of a material that is less likely to stretch than other parts.

[0102] In each of the above embodiments, air is used as the fluid 23 filled in the bag body 20, but the fluid 23 may be a gas other than air or a liquid such as water. Water has little volume change due to temperature change and is easy to work with. When a liquid such as water is used as the fluid 23, it is desirable to discharge the liquid to the outside of the bag body 20 after the new concrete layer 41 has hardened in the above-mentioned fourth step. Also, when a gas is used as the fluid 23, the internal gas can be discharged to the outside of the bag body 20 after the new concrete layer 41 has hardened. Discharge can be performed from a discharge port (not shown) provided in the bag body 20. In this case, the valve 21 connecting the supply pipe 29 may also be used as the discharge port. When the internal fluid 23 has been discharged, the bag body 20 may be taken out to the outside of the formwork 10. This removal can be performed from an opening at the end of the formwork 10 in the axial direction of the cylinder, or from an inspection port or the like provided at any point of the formwork 10. At this time, if a string is attached to an end of the bag body 20, the bag body 20 can be easily removed by pulling the string. At this time, if a release agent is applied to the surface of the bag body 20 in advance, the bag body 20 will not stick to the formwork 10 and the removal work will be easier.

[0103] In conventional repair methods using urethane foam, it was necessary to prepare special equipment and specific workers to handle urethane foam. This resulted in longer construction time and increased construction costs. However, in this embodiment, the fluid 23 filled in the bag body 20 is made of materials that are easy to handle, such as air and water, so there is an advantage in that it has less impact on construction time and costs.

[0104] In the above embodiment, a steel cylindrical tube is used as the form 10, but the form 10 can have various shapes. For example, in addition to a cylindrical tube with a perfectly circular cross section, tubular bodies with various cross sections are also conceivable. The bag body 20 of the present invention can be applied to the form 10 having these shapes. In addition, the cross-sectional shape of the bag body 20 can also be set to an appropriate shape.

[0105] It is advisable to prepare a plurality of types of bag body 20 having different lengths in the axial direction (length in the longitudinal direction) when filled with fluid 23, such as 0.5 m, 1.0 m, 1.5 m, . . . 5.0 m. This allows bag body 20 to be installed in a required range within formwork 10 according to the on-site conditions.

[0106] In the above embodiment, it is assumed that the opening 13 of the formwork 10 is located above (on the top surface) of the formwork 10, and a method of inserting the bag body 20 into the formwork 10 from above, i.e., top surface construction, is adopted. In the case of top surface construction, it is necessary to block the traffic provided by the structure 1, so it can be said that there is a great merit in shortening the construction period by adopting the construction method using the bag body 20 of this invention. Furthermore, with top surface construction, gravity can be used when inserting the bag body 20 into the formwork 10, so the work can be easily performed by dropping the bag body 20 into the formwork 10 from the opening 13 without using a large force.

[0107] In the above embodiment, the configuration of the present invention has been described using the deck of an viaduct used for a road as the structure 1 as an example, but in addition to the aspects shown in this embodiment, the present invention can be applied to, for example, viaducts other than roads, various bridges used for roads and railways, concrete slabs in buildings, and various other concrete structures. Furthermore, the present invention can be applied not only to applications during large-scale repairs that are carried out in a planned manner on the structure 1, but also to applications for daily repairs and emergency repairs for partial deformations that have occurred in the structure 1 (such as partial collapses in the road surface). [Explanation of symbols]

[0108] 1. Hollow concrete structure (structure) 2 Roadbed 3 Surface layer removal part 4. Steel Bars 5 Concrete removal section (deep layer removal section) 10 Formwork 11 Formwork removal section 12 Inner surface of formwork 13 Opening 20 Bag body 20A Inner Bag 20B outer bag 21 Valve 22 void 23 Fluid 24,24a,24b,24c,24d Lower contact point 25a,25b Upper contact point 26 Top 27 Lower Surface 28 Surface 29 Supply pipe 30 Anchor section 31 Inner bag handle 32 Outer bag handle 33 Assistive devices 34 End processing section 35 Stopper 40 Holding means 50 Receiving means (spacer) 60 Connection means 61 First member 62 Second member

Claims

1. A bag (20) made of a flexible material is used when repairing concrete around a cylindrical form (10) in a hollow concrete structure in which the form (10) is embedded in concrete, The bag has an opening (13) in the formwork (10) in the area around the formwork (10) from which the concrete has been removed, is inserted into the formwork (10) through the opening (13), and when it expands due to the filling of a fluid (23) into its interior, concrete can be poured into the area around the formwork (10) facing the opening (13), and the non-contact portion between the bag (20) and the inner surface (12) of the formwork (10) in a cross section perpendicular to the cylindrical axis exists below the cylindrical axis of the formwork (10) to form a gap (22).

2. The bag body (20) is prevented from falling within the formwork (10) by the abutment portion between the bag body (20) and the inner surface (12) of the formwork (10), and the bag body has a plurality of abutment portions intermittently arranged around the cylindrical axis in a cross section perpendicular to the cylindrical axis.

3. 3. The bag body according to claim 2, wherein the lowermost one of the abutting portions is located above the bottom of the mold (10) in a cross section perpendicular to the cylindrical axis.

4. The bag (20) according to claim 1, wherein the bag (20) has an inner bag (20A) and an outer bag (20B) that houses the inner bag (20A), and the fluid (23) is filled in the inner bag (20A).

5. A bag fixing structure in which the bag body (20) according to any one of claims 1 to 4 is used, and the bag body (20) is pulled up toward the opening (13) by an anchor portion (30) connected to the bag body (20).

Images