Method for repairing hollow concrete structure

Abstract

To provide a repair method for a hollow concrete structure further easily and inexpensively.SOLUTION: A method for repairing a concrete structure in which a cylindrical form 10 is embedded in concrete comprises a first step of exposing the form 10 by removing the concrete around the form 10, a second step of inserting a longitudinal bag body 20 made of a flexible material into the form 10 through an opening part 13 of the form 10 in the cylindrical axial direction of the form 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 where the concrete has been removed.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to 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. 9, 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. Furthermore, 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.

[0007] Therefore, an object of the present invention is to make it easier and less costly to repair hollow concrete structures. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides a method for repairing a concrete structure in which a cylindrical form is embedded in concrete, the method comprising the steps of: a first step of removing the concrete around the form to expose the form; a second step of inserting a longitudinal bag body made of a flexible material into the form through an opening in the form along the cylindrical axis direction of the form; a third step of filling the bag body with a fluid; and a fourth step of filling the part from which the concrete has been removed with a fluid. A method for repairing concrete structures was adopted, which includes a fourth step of forming a new concrete layer.

[0009] Here, the concrete structure may have a reinforcing bar facing the opening, and a configuration may be adopted in which the thickness of the concrete on the formwork side of the reinforcing bar at the opening is maintained at a predetermined distance or more.

[0010] In addition, when the concrete structure includes a reinforcing bar facing the opening, a configuration can be adopted in which a spacer is installed between the opening and the reinforcing bar to prevent the bag body from approaching the reinforcing bar.

[0011] It is desirable that the pressure of the fluid within the bag be set to be equal to or greater than the pouring pressure of the new concrete layer at the opening.

[0012] Furthermore, the formwork and the bag body are each cylindrical, and a configuration can be adopted in which the outer diameter of the bag body in a cross section perpendicular to the cylindrical axis at the position of the opening when forming the new concrete layer in the fourth step is less than or equal to the inner diameter of the formwork in a cross section perpendicular to the cylindrical axis at that position.

[0013] Furthermore, in order to solve the above problems, the present invention provides a bag body for use in a method for repairing a concrete structure comprising any of the above-mentioned aspects, the bag body being made of a flexible material and having a longitudinal shape, and being inserted into a cylindrical formwork embedded in concrete along the axial direction of the formwork. Effect of the Invention

[0014] According to the present invention, repairs to hollow concrete structures can be carried out more easily and at lower cost. [Brief description of the drawings]

[0015] [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. [Figure 3A] A cross-sectional view showing the state in which concrete has been poured onto the top of the formwork in Figure 2. [Figure 3B] Enlarged view of the main part of Figure 3A [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. 1 is a perspective view of a fluid-filled bag; [Figure 8A] FIG. 11 is a cross-sectional view showing a modified example of the bag body and an example of using a bag body having a D-shaped cross section. [Figure 8B] FIG. 11 is a cross-sectional view showing a modified example of the bag body and an example of using the bag body having a partially elliptical cross section. [Figure 9] Cross-section of a concrete structure DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] An embodiment of the present invention will be described with reference to the drawings. Here, the configuration of the present invention will be described by taking as an example a deck of an elevated bridge used for a road as a hollow concrete structure 1 (hereinafter referred to as structure 1) in which a hollow formwork 10 is embedded in concrete.

[0017] As shown in FIG. 9, in the structure 1 of this embodiment, a hollow formwork 10 (hereinafter simply referred to as formwork 10) made of a hollow pipe is embedded inside the deck concrete that constitutes 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 this embodiment, the formwork 10 is A steel cylindrical tube is used, and multiple formwork 10 are arranged in parallel along the axial direction of the viaduct. The formwork 10 is held by various fixing devices (not shown; see, for example, Figs. 1 and 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.

[0018] When the concrete of the structure 1 becomes corroded or damaged due to deterioration caused by aging, etc., 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.

[0019] When the area to be repaired is around the formwork 10, the repair starts with the first step of removing the concrete around the formwork 10 to expose the formwork 10. Reference numeral 3 in FIG. 9 indicates a portion where the pavement constituting the surface layer of the roadbed 2 has been removed (hereinafter referred to as the surface layer removal portion 3). Reference numeral 5 indicates a portion below the surface layer where the concrete constituting the body of the deck slab has been removed (hereinafter referred to as the deep layer removal portion 5). In the deep layer removal portion 5, the reinforcing bars 4 located above the formwork 10 are exposed. The reinforcing bars 4 are arranged in a lattice shape in which the reinforcing bars in the bridge axis direction and the reinforcing bars in the direction perpendicular to the bridge axis cross at right angles in a plan view. Below the reinforcing bars 4, the concrete is removed until the top surface of the formwork 10 is exposed. In the conventional technology, the reinforcing bars 4 were cut in order to repair the formwork 10, but in this embodiment, the repair can be performed without cutting the reinforcing bars 4, except when the reinforcing bars 4 are corroded.

[0020] As shown in Figs. 1 and 4, an opening 13 formed in the formwork 10 is exposed below the deep removal portion 5 from which the concrete has been removed. The opening 13 may be a hole formed by corrosion of a member 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 a corroded portion around the hole caused by the corrosion or the like. 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 may vary, but in Fig. 4, the opening 13 is rectangular in plan view.

[0021] 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 axial direction of the formwork 10. This 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 it 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 (hard to be punctured), and examples of such materials include polyvinyl chloride, polyester, and polyurethane. The length L1 of the bag body 20 (see FIG. 7) is set longer than the axial length L0 of the opening 13 (see FIG. 4). Therefore, the bag body 20 has a length that allows it to extend outward beyond the edges of the opening 13 on both sides in the axial direction.

[0022] Next, the inside of the bag body 20 is filled with a fluid 23 as a filler (see Figs. 2 and 5). This process of filling the fluid 23 is referred to as 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 25 connected to an injection port 21 provided in the bag body 20 by using a pump or the like. At this time, if the injection port 21 is provided in the center of the cylindrical surface of the cylindrical bag body 20, the bag body 20 can expand smoothly. At this time, it is desirable that the injection port 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 operation of connecting and disconnecting the supply pipe 25 to the injection port 22 is easy. When the opening 13 is at the end of the deck in the bridge axis direction, the injection port 21 is located at the center of the cylindrical surface of the cylindrical bag body 20. In this way, 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 of the form 10 is smooth.

[0023] Next, a new concrete layer 41 is poured above the opening 13, i.e., in the area where the concrete was removed (see Figs. 3A and 6). This process of pouring concrete is referred to as the fourth process. In the fourth process, 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.

[0024] Here, a spacer 30 is placed in 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. As shown in Fig. 3A, the spacer 30 presses the upper surface of the bag body 20 to prevent the upper end of the bag body 20 from approaching the reinforcing bar 4. As the spacer 30, for example, a plate-shaped member made of concrete, wood, resin, metal, etc., a shaft-shaped member made of a similar material, a block-shaped member, etc. can be used.

[0025] In this embodiment, the spacer 30 is a pressing member 31 placed immediately above the opening 13, and a spacer 32 placed between the pressing member 31 and the reinforcing bar 4 (see FIG. 2). The spacer 32 is placed so as to brace the pressing member 31 and the reinforcing bar 4 located immediately above it, i.e., the reinforcing bar 4 facing the opening 13. The presence of the spacer 32 more reliably prevents the bag body 20 and the pressing member 31 from floating up. The symbol H in FIG. 2 indicates the thickness of the concrete below the reinforcing bar 4 at the opening 13 (cover thickness of the reinforcing bar 4). The pressing member 31 may be one that holds the bag body 20 in a plane having a certain area (surface contact), or may be one that holds the bag body 20 in a dispersed manner using several surfaces (surface contact) or points (point contact) that are separated from each other.

[0026] The thickness of the concrete at the opening 13 on the formwork 10 side of the reinforcing bar 4 (cover thickness of the reinforcing bar 4) is the minimum distance H (see FIG. 2) between the reinforcing bar 31 and the reinforcing bar 4 when the reinforcing member 31 is used, and is the minimum distance H between the bag body 20 and the reinforcing bar 4 when the reinforcing member 31 is not used (see FIG. 8A, FIG. 8B, etc. described below). The minimum distance H is ensured to be equal to or greater than a predetermined specified distance. The specified distance is determined based on various regulations established for each structure 1. In the structure 1 shown in the embodiment, the specified distance can be, for example, 35 mm or more, 50 mm or more, etc.

[0027] Furthermore, if a marking is provided on the upper surface of the bag body 20, the position of the bag body 20 in the axial direction and the orientation of the bag body 20 around the axial direction can be confirmed by viewing the marking through the opening 13. The marking is preferably in a conspicuous color, and can be, for example, a straight red line drawn in the axial direction of the bag body 20.

[0028] As shown in FIG. 3B, a release agent layer 24 is provided on the outer surface 22 of the bag body 20 to facilitate separation between the outer surface of the bag body 20 and the inner surface 12 of the mold form 10. Examples of materials for the release agent layer 24 include silicone resin and fluororesin. By providing the release agent layer 24, it is possible to prevent the bag body 20 from adhering to the mold form 10 after the fluid 23 is introduced into the bag body 20. As a means for expecting a similar effect of preventing adhesion, for example, various types of unevenness such as embossing may be provided on the outer surface 22 of the bag body 20. If the outer surface 22 of the bag body 20 has unevenness, the contact area between the bag body 20 and the mold form 10 is reduced, making it possible to prevent the bag body 20 from adhering to the mold form 10.

[0029] Here, the pressure of the fluid 23 in the bag 20 is set to be equal to or greater than the pouring pressure of the new concrete layer 41 at the opening 13. Here, the pouring pressure of the new concrete layer 41 refers to the pressure acting on the bottom of the flowing unhardened concrete when pouring the concrete. Here, this corresponds to the pressure from the unhardened concrete near the top surface of the bag 20 (near the pressing member 31). For example, if the pouring pressure of the concrete is 3 kPa, Then, taking into consideration the safety factor, the pressure inside the bag body 20 can be set to 6 kPa (safety factor 2). Of course, this is premised on the fact that the bag body 20 has the strength to withstand that pressure.

[0030] It is preferable that the material of the bag body 20 is one that does not protrude outward from the opening 13 when the pressure of the fluid 23 in the bag body 20 is set to a predetermined pressure, or one that can maintain the minimum distance H at a predetermined distance or more (including the selection of the type of material and the thickness of the material, etc.). In particular, when the installation of the pressing member 31 is omitted, it is effective to adopt such a material. Here, the predetermined pressure of the fluid 23 is set to a pressure that the bag body 20 can withstand as described above, and is set to a pressure that is equal to or lower than the pressure that can restrict the intrusion of concrete into the formwork 10 against the above-mentioned concrete pouring pressure, and is set to the minimum pressure necessary for safe and efficient operation.

[0031] In this embodiment, the formwork 10 is cylindrical in shape with a cross section perpendicular to the cylinder axis forming a perfect circle. The bag body 20 in a state where it is filled with the fluid 23 is also cylindrical in shape with a cross section perpendicular to the cylinder axis forming a perfect circle. The outer diameter (diameter) R1 of the bag body 20 in a cross section perpendicular to the cylinder axis in a state where it is filled with the fluid 23 in the formwork 10 is set to be equal to or smaller than the inner diameter (diameter) R0 of the cross section perpendicular to the cylinder axis of the formwork 10. Therefore, when the bag body 20 expands due to the pressure of the fluid 23 in the bag body 20, it is possible to prevent the bag body 20 from overhanging the opening 13 of the formwork 10. This makes it possible to appropriately ensure the thickness of the concrete below the reinforcing bar 4 at the opening 13 (the cover thickness of the reinforcing bar 4).

[0032] Examples of the material of the bag body 20 include polyvinyl chloride, polyester, and polyurethane. The material of the bag body 20 may be a non-stretchable material, or a material having a certain degree of stretchability (shape-following ability). In either case of a non-stretchable material or a stretchable material, it is desirable that the outer diameter R1 of the bag body 20 at the position of the opening 13 when a new concrete layer 41 is formed (when unhardened concrete is poured) after the fluid 23 is filled in the inside in the third step, that is, the outer diameter R1 (hereinafter referred to as the filling diameter R1) of the bag body 20 in the cross section in the direction perpendicular to the cylindrical axis when the pressure of the fluid 23 is set to a predetermined pressure is equal to or smaller than the inner diameter R0 (hereinafter referred to as the form diameter R0) of the form 10 in the cross section in the direction perpendicular to the cylindrical axis at the position of the opening 13. It is even more desirable that the filling diameter R1 is less than the form diameter R0. Here, the form diameter R0 of the form 10 having a circular cross section (perfect circle) refers to the diameter of the inner surface 12 having a circular cross section in the case of a cylindrical form 10. In the case of a form 10 having an uneven peripheral surface such as a spiral pipe or a winding pipe, the form diameter R0 of the form 10 refers to the diameter of the maximum diameter part of the inner surface 12.

[0033] Here, it is assumed that the material of the bag body 20 is an expandable material. In this case, when pouring unhardened concrete to form a new concrete layer 41 in the fourth step, Filling diameter R1 < Formwork diameter R0 ≦ Extension diameter The extension diameter is the outer diameter of the bag body 20 when the fluid 23 is introduced into the bag body 20 at a predetermined pressure in a state where the periphery of the bag body 20 is not restrained. The filling diameter R1 being less than the formwork diameter R0 means that the bag body 20 remains inside the position (the assumed inner surface line) where the inner surface of the formwork 10 was located before (before the repair work) near the opening 13. If the material of the bag body 20 is an expandable material, it has shape-following properties, so that the bag body 20 is tightly fixed in contact with the formwork 10 even in the case where the formwork 10 has an uneven cross-sectional shape or the formwork 10 is bent along the longitudinal direction. Therefore, it is expected to have an effect of more reliably preventing the inflow of concrete into the formwork 10.

[0034] In addition, regardless of whether the material of the bag body 20 is a stretchable material or a non-stretchable material, in a state where the filling of the fluid 23 into the bag body 20 is completed in the third step, near the opening 13, Filling diameter R1 ≧ Formwork diameter R0 There is also a method of setting it as follows. The filling diameter R1 being equal to or larger than the form diameter R0 means that the bag body 20 near the opening 13 coincides with the position (the assumed inner surface line) where the inner surface of the form 10 was located before (before the repair work), or bulges outward from that position. By adopting such a method, the bag body 20 becomes more easily fixed inside the form 10, and it is expected to have an effect of more reliably preventing the inflow of concrete into the form 10. However, it is not preferable for the bag body 20 to protrude outward from the opening 13 of the form 10 in order to ensure a sufficient covering thickness of the reinforcing bar 4. For this reason, a method of reducing the protrusion amount of the bag body 20 from the opening 13 (holding the bag body 20 inside the form 10) by using a spacer 30 as necessary can also be adopted. If the spacer 30 is used to reduce the amount of overhang of the bag body 20, when a new concrete layer 41 is formed in the fourth step, the filling diameter R1 can be adjusted to be equal to or smaller than the form diameter R0 even near the opening 13. Furthermore, as shown in Figs. 8A and 8B described later, there is also a method of reducing the amount of overhang of the bag body 20 from the opening 13 by changing the cross-sectional shape of the bag body 20.

[0035] A concrete structure constructed by these concrete repair methods has the following configuration: a repaired concrete structure including a cylindrical form 10 embedded in concrete, a removed concrete portion 5 where the concrete around the form 10 has been removed, an opening 13 formed in the form 10 exposed in the removed concrete portion 5, a longitudinal bag body 20 made of a flexible material inserted into the form 10 through the opening 13 along the cylindrical axis, and a new concrete layer 41 poured in the removed concrete portion 5.

[0036] In this embodiment, 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 change in volume with 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. At this time, the injection port 21 connecting the supply pipe 25 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. Also, a relief valve may be provided somewhere in the bag body 20 to release the internal fluid 23 to the outside when the internal fluid 23 reaches a predetermined pressure so that the pressure does not increase any further. This makes it possible to prevent the inside of the bag body 20 from becoming excessively pressurized, and simplifies the complicated work of monitoring the pressure when the fluid 23 is introduced.

[0037] 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.

[0038] 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.

[0039] A modified example of the bag body 20 is shown in FIGS. 8A and 8B. FIG. 8A shows an example in which a bag body 20 having a D-shaped cross section is adopted. FIG. 8B shows an example in which a bag body 20 having a partially elliptical cross section is adopted. In the bag body 20 having a D-shaped cross section shown in FIG. 8A, the radii from the center of the bag body 20 (which coincides with the center of the mold 10) to the left, right, and downward directions in the figure all form an arc with a single radius of "r", while the exposed surface 26 facing the opening 13 side is a flat surface. The distance between the flat surface and the center of the bag body 20 is "r' (where r' < r)". In this way, by having the exposed surface 26 facing the opening 13 side of the bag body 20 enter inside the perfect circle line with a radius of "r" around the center of the bag body 20, it is easier to ensure the minimum distance H.

[0040] In the bag body 20 having a D-shaped cross section shown in FIG. 8A, the radii from the center of the bag body 20 (which coincides with the center of the mold 10) to the left, right, and downward directions in the figure all form an arc with a single radius of "r", while the exposed surface 26 facing the opening 13 side is a flat surface. The distance between the flat surface and the center of the bag body 20 is "r' (where r' < r)". In this way, by having the exposed surface 26 facing the opening 13 side of the bag body 20 enter inside the perfect circle line with a radius of "r" around the center of the bag body 20, it is easier to ensure the minimum distance H.

[0041] In the bag body 20 having a partially elliptical cross section shown in FIG. 8B, the radii from the center of the bag body 20 (which coincides with the center of the mold 10) to the left, right, and downward directions in the figure all form an arc with a single radius of "r", while the exposed surface 26 facing the opening 13 side is an elliptical shape with a major axis of "r" in the left-right direction and a minor axis of "r' (where r' < r)" in the upward direction from the center. That is, similar to FIG. 8A, by having the exposed surface 26 facing the opening 13 side of the bag body 20 enter inside the perfect circle line with a radius of "r" around the center of the bag body 20, it is easier to ensure the minimum distance H. In other words, by making the bag body 20 have an elliptical cross section and orienting one end of the minor axis direction of the ellipse toward the opening 13 side, it is possible to more reliably prevent the overhang of the opening 13 upward during pressurization.

[0042] It is advisable to prepare a plurality of types of bag bodies 20 with lengths in the axial direction (length in the longitudinal direction) of, for example, 0.5 m, 1.0 m, 1.5 m, . . . 5.0 m when filled with fluid 23. This allows bag bodies 20 to be installed in a required range within formwork 10 according to the on-site conditions. When a plurality of bag bodies 20 are installed in parallel along the axial direction of formwork 10, the gaps between adjacent bag bodies 20 can be filled with a block-shaped member or a fluid material such as urethane that hardens over time.

[0043] 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, that is, 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 the merit of shortening the construction period by adopting the construction method using the bag body 20 of this invention is large. In addition, in the case of 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. Note that this invention is not limited to the case where the opening 13 of the formwork 10 is located above (on the top surface) of the formwork 10, and this invention can also be applied when the opening 13 is located on the side (side surface) or below (bottom surface) of the formwork 10.

[0044] In the above embodiment, the configuration of the present invention has been described using the deck of an viaduct used for a road as an example of the structure 1, 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 systematically on the structure 1, but also to applications for emergency repairs to partial deformations that have occurred in the structure 1 (such as partial collapses in the road surface). [Explanation of symbols]

[0045] 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 21 Inlet 23 Fluid 25 Supply pipe 31 Pressing member 32 Spacing material 41 Concrete layer

Claims

[Claim 1] A method for repairing a concrete structure in which a cylindrical form (10) is embedded in concrete, comprising: A first step of removing the concrete around the formwork (10) to expose the formwork (10); a second step of inserting a longitudinal bag body (20) made of a flexible material into the inside of the form (10) through an opening (13) of the form (10) along a cylindrical axis direction of the form (10); a third step of filling the inside of the bag (20) with a fluid (23); A fourth step of forming a new concrete layer (41) on the part from which the concrete has been removed; A method for repairing a concrete structure comprising:

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