Joining method for concrete structures

Abstract

To provide a joining method of a concrete structure capable of integrating a new precast member with an existing support member by fixing a tensile resistance material such as a stirrup of the existing support member.SOLUTION: The top of a support member joined to an RC member by supporting the RC member from below is cut off to expose the top of a tensile resistance member consisting of reinforcement, the tensile resistance member cut by cutting the exposed tensile resistance member in the middle is bent, a precast member with a box-out hole is placed on the support member, the tensile resistance material is housed in the box-out hole to fill a filler and harden, and the filler fixes the tensile resistance material so as not to be shifted in a material axial direction to integrate the precast member with the support member.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a method for joining concrete structures. [Background technology]

[0002] Existing reinforced concrete components, such as road bridge decks, box culvert upper decks, and building decks supported by walls and columns, are being removed and replaced with new components. In these cases, the new components are typically precast. This is because precast components are manufactured in factories with well-maintained environments, allowing for a stable supply of high-quality products and shortening the construction period for the replacement work.

[0003] For example, Patent Document 1 discloses a method for replacing precast deck slabs for PC composite girders, in which the cast-in-place RC deck slabs of a T-shaped composite girder concrete bridge are replaced with precast deck slabs for PC composite girders (see paragraphs

[0034] to

[0041] of the specification of Patent Document 1, Figures 5 to 14 of the drawings, etc.).

[0004] However, in the method of replacing precast deck slabs for PC composite girders described in Patent Document 1, it is necessary to leave the anti-slip rebars 12 and stirrups 13 of the main girder 3 in place at the joints between the integrated composite girder and the RC deck slab, which means that a large amount of concrete must be chipped away using ultra-high pressure water such as a breaker or water jet, which creates the problem of long work times.

[0005] Furthermore, in the method of replacing precast deck slabs for PC composite girders described in Patent Document 1, the anti-slip rebars 12 and stirrups 13 placed on the main girders are left in place, which causes the steel plates embedded in the precast deck slab to interfere with the rebars, making it difficult to install the precast deck slab in the appropriate position or taking a long time to install.

[0006] Furthermore, in the method of replacing precast deck slabs for PC composite girders described in Patent Document 1, a space is required below the precast deck slab for PC composite girders to secure anti-slip reinforcing bars 12 and stirrups 13, and the deck thickness is required above that space to accommodate horizontally fastened PC steel members. This means that the thickness of the deck after renewal is thicker than before renewal, which places a strain on the remaining main girders and substructures.

[0007] To solve this problem, it is possible to cut the anti-slip rebars and stirrups midway. However, stirrups, which are tension resistance materials, have the problem that they do not function effectively unless they are anchored to the compression chord members, and therefore do not function as a load-bearing mechanism. For this reason, there has been a strong demand for a method to solve this problem and effectively anchor the cut stirrups when replacing RC members with precast members, and to replace RC members with precast members. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 2019-132070 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been devised in view of the above-mentioned problems, and its object is to provide a method for joining concrete structures that can fix tension resistance materials such as stirrups of existing support members to integrate new precast members with existing support members. [Means for solving the problem]

[0010] The method for joining concrete structures according to the first invention is characterized in that an RC member is supported from below, the upper part of the support member to be joined to the RC member is chipped off to expose the upper part of the tensile resistance material made of reinforcing bars, the exposed tensile resistance material is cut in the middle and bent, a precast member having a box cutout hole is placed on the support member, the tensile resistance material is placed in the box cutout hole, a filler material is filled in and hardened, and the filler material fixes the tensile resistance material so that it does not shift in the axial direction of the material, thereby integrating the precast member and the support member.

[0011] The method for joining concrete structures according to the second invention is to support an RC member from below, chip off the upper part of the support member to be joined to the RC member, expose the upper part of the tensile resistance member made of reinforcing steel, cut the exposed tensile resistance member midway, and attach the cut tensile resistance member to the tensile resistance member. Made of steel plate The fixing material is pressed or welded, a precast member having a box cutout hole is placed on the support member, the tensile resistance material and the fixing material are placed in the box cutout hole, a filler material is filled and hardened, and the filler material fixes the tensile resistance material so that it does not shift in the material axial direction, thereby integrating the precast member and the support member.

[0013] The method for joining concrete structures according to the fourth invention involves supporting an RC member from below, chipping off the top of the support member to be joined to the RC member, exposing the top of the tensile resistance material made of reinforcing bars, cutting the exposed tensile resistance material midway, and placing a precast member with a box-punched hole on the support member and cutting it. The state was maintained The tensile resistance material is placed in the box-cut hole, and a filler made of high-strength mortar or ultra-high-strength mortar is filled in and hardened, and the filler fixes the tensile resistance material so that it does not shift in the material axial direction, integrating the precast member and the support member. [Effects of the Invention]

[0014] According to the first invention, the tension resistance material is bent and then fixed with filler material so that the bent tension resistance material does not shift in the material axis direction. This ensures that the bent tension resistance material has a sufficient anchorage length relative to the filler material, and allows old and damaged existing RC members to be replaced with new, high-quality precast members. This allows existing concrete structures to be updated inexpensively and in a short period of time, and with appropriate maintenance, the lifespan of the structure can be extended.

[0015] According to the second invention, anchoring materials are pressed or welded to the tensile resistance material, and the filler material fixes the tensile resistance material to prevent it from shifting in the axial direction. This ensures sufficient anchorage between the tensile resistance material and the anchoring materials in the filler, allowing old and damaged existing RC members to be replaced with new, high-quality precast members. This allows existing concrete structures to be updated inexpensively and in a short period of time, and with appropriate maintenance, the structure's lifespan can be extended.

[0016] According to the third invention, anchoring members made of rebar are connected to the tensile resistance members via coupling members, and the tensile resistance members connected to the anchoring members are fixed by filler material so that they do not shift in the material axial direction. This ensures sufficient anchorage length between the tensile resistance members and the anchoring members in the filler material, and allows old and damaged existing RC members to be replaced with new, high-quality precast members. This allows existing concrete structures to be updated cheaply and in a short period of time, and with appropriate maintenance, the structure's lifespan can be extended.

[0017] According to the fourth invention, the filler, which is ultra-high-strength mortar or high-strength mortar, anchors the tensile resistance material so that it does not shift in the material axis direction. This ensures that the tensile resistance material has a sufficient anchorage length relative to the filler, and allows old and damaged existing RC members to be replaced with new, high-quality precast members. This allows existing concrete structures to be updated inexpensively and in a short period of time, and with appropriate maintenance, the lifespan of the structure can be extended. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a vertical cross-sectional view showing a bridge to which a concrete structure joining method according to a first embodiment of the present invention is applied, cut vertically in a direction perpendicular to the bridge axis. [Figure 2] FIG. 2 is an enlarged view of part A in FIG. [Figure 3] FIG. 3 is a process explanatory diagram showing the removal process of the concrete structure joining method according to the first embodiment of the present invention in an overall cross-sectional view cut along the direction Y perpendicular to the bridge axis. [Figure 4] Figure 4 is a process explanatory diagram showing the upper support member chipping process of the concrete structure joining method according to the first embodiment of the present invention in an enlarged cross-sectional view similar to Figure 2, where (a) shows the state before the upper support member chipping process and (b) shows the state after the upper support member chipping process. [Figure 5] FIG. 5 is a process explanatory view showing an unevenness adjusting process of the concrete structure joining method according to the first embodiment of the present invention in an enlarged cross-sectional view of part B in FIG. [Figure 6] FIG. 6 is an enlarged cross-sectional view showing a tensile resistance member bending step in the method for joining concrete structures according to the first embodiment of the present invention. [Figure 7] FIG. 7 is a process explanatory diagram showing the precast deck placement process of the concrete structure joining method according to the first embodiment of the present invention in an overall cross-sectional view cut along the direction Y perpendicular to the bridge axis. [Figure 8] FIG. 8 is a process explanatory diagram showing, in plan view, the precast slab placing step of the method for joining concrete structures according to the first embodiment of the present invention. [Figure 9] FIG. 9 is an enlarged cross-sectional view showing an anchoring material connecting step of the method for joining concrete structures according to the second embodiment of the present invention. [Figure 10] FIG. 10 is an enlarged cross-sectional view showing an anchoring material connecting step of the method for joining concrete structures according to the third embodiment of the present invention. [Figure 11] FIG. 11 is a cross-sectional view taken along line AA in FIG. [Figure 12]FIG. 12 is a process explanatory diagram showing the precast deck slab placing process of the concrete structure joining method according to the fourth embodiment of the present invention in an overall cross-sectional view cut along the direction Y perpendicular to the bridge axis. [Figure 13] FIG. 13 is a process diagram illustrating the application of the present invention to a box girder bridge, where (a) shows the state before renewal, (b) shows the state after the deck slab is removed, and (c) shows the state after renewal. [Figure 14] Figure 14 is a process diagram illustrating the application of this invention to a hollow slab deck bridge, where (a) shows the state before renewal, (b) shows the state after the deck is removed, and (c) shows the state after renewal. [Figure 15] Figure 15 is a process diagram for when columns are used as support members, where (a) shows the state before renewal, (b) shows the state after the deck slab is removed, and (c) shows the state after renewal. [Figure 16] FIG. 16 is an enlarged cross-sectional view showing an example of the bending process of the tensile resistance material of the present invention when a pillar is used as a support member. [Figure 17] FIG. 17 is an enlarged cross-sectional view showing the anchoring material connecting step of the present invention when a pillar is used as the support member. [Figure 18] FIG. 18 is an enlarged cross-sectional view showing the anchoring material connecting step of the present invention when a pillar is used as a support member. [Figure 19] Figure 19 is a process explanatory diagram showing the precast deck placement process of the present invention when columns are used as support members, in an overall cross-sectional view cut along the direction Y perpendicular to the bridge axis. DETAILED DESCRIPTION OF THE INVENTION

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the method for joining concrete structures according to the present invention will be described in detail below with reference to the drawings.

[0020] A method for joining concrete structures according to an embodiment of the present invention will be described using Figures 1 to 19. The method for joining concrete structures according to an embodiment of the present invention is applied to, for example, a concrete bridge, and will be described using a T-girder bridge as an example of the bridge. The method for joining concrete structures according to an embodiment of the present invention replaces the RC slab, which is an RC member of a T-girder bridge, which is an existing concrete structure, with a precast slab, which is a new precast member, and joins it to a support member.

[0021] <Bridges> First, a bridge to which the method for joining concrete structures according to the first embodiment of the present invention is applied will be briefly described with reference to Figures 1 and 2. Figure 1 is a vertical cross-sectional view showing a bridge to which the method for joining concrete structures according to the first embodiment of the present invention is applied, cut vertically in a direction perpendicular to the bridge axis, and Figure 2 is an enlarged view of part A in Figure 1.

[0022] The bridge B1 to which this invention is applied is a reinforced concrete (RC) bridge used as a road bridge, and as shown in Figures 1 and 2, it is composed of four T-girders G1-G4, which are main girders made of reinforced concrete (including main girders made of prestressed concrete; the same applies below), and a cast-in-place RC deck F1, which is a composite deck joined to the top of these T-girders G1-G4. Also, along the edges of both sides of the RC deck F1, a wall parapet W1 and a ground guard W2 serving as a vehicle stop are formed. However, facilities and asphalt pavement installed above the wall parapet W1 and ground guard W2 are omitted because they are not necessarily installed.

[0023] In the figure, the X direction indicates the bridge axis direction along the axis of the T-girders G1 to G4 of bridge B1, the Y direction indicates the direction perpendicular to the bridge axis, which is the horizontal direction perpendicular to the bridge axis direction X of bridge B1, and the Z direction indicates the vertical direction, which is the up-down direction.

[0024] As shown in Figure 2, the stirrups Sr, which are tension resistance members of the T-girders G2 (G1, G3, G4), extend at their tops to the RC deck slab F1, securing the anchorage length with hooks and anchoring them within the upper part F1a of the main girder of the RC deck slab F1. Furthermore, the upper part F1a of the main girder where it joins with the T-girder G2 of bridge B1 is reinforced with U-shaped shear stop rebars S1. Furthermore, the haunch portion of the RC deck slab F1 is reinforced with diagonal rebars S2 that continue up to the T-girder G2. In this way, bridge B1 is a site-fabricated composite girder bridge in which the T-girder G2 and the RC deck slab F1 work together as a single unit to resist external forces.

[0025] Next, specific steps of the method for joining concrete structures according to the first embodiment of the present invention will be described with reference to FIGS.

[0026] (Removal process) 3 is a process explanatory diagram showing the removal process of the joining method for concrete structures according to the first embodiment of the present invention in an overall cross-sectional view cut along the direction perpendicular to the bridge axis Y. First, in the joining method for concrete structures according to this embodiment, as shown in FIG. 3, a removal process is carried out in which the RC deck slab F1 is cut and removed.

[0027] Specifically, using a large rotary cutting device such as a wall saw or diamond cutter, the RC deck F1 beside the T-girders G1 to G4, indicated by the ▽ in the diagram, is cut along the bridge axis direction X, and the RC deck F1 is cut along the direction perpendicular to the bridge axis Y, dividing the RC deck F1 into smaller pieces. The divided RC deck F1 is then lifted using a lifting machine such as a crane and carried out, and the concrete is broken up using a breaker or similar device at another location for dismantling and removal.

[0028] (Support member upper part chipping process) 4 is a process explanatory diagram showing the support member upper part chipping step of the concrete structure joining method according to the first embodiment of the present invention in an enlarged cross-sectional view similar to that of FIG. 2, where (a) shows the support member upper part chipping step before the step, and (b) shows the support member upper part chipping step after the step. Next, in the concrete structure joining method according to this embodiment, as shown in FIG. 4, the girder upper part chipping step is carried out to chip off the main girder upper part F1a of the RC deck F1 of the bridge B1.

[0029] Specifically, a chipping device such as a water jet is used to chip away the concrete from the upper part of the main girder F1a, which is the remaining part of the RC deck F1 removed in the previous removal process other than the T-girders G1 to G4, and the internal reinforcing bars are also cut and removed. However, as shown in Figure 4, the top of the stirrup Sr is left exposed, leaving only a predetermined length (approximately 50 mm to 100 mm in this embodiment), and the rest is removed together with other internal reinforcing bars that would interfere with the replacement work.

[0030] In addition, the end faces of the anti-slip bars S1 and the diagonal bars S2 that are exposed to the outside after cutting are treated to prevent rust, such as by applying anti-rust resin.

[0031] Also, at this point, the tension resistance material in truss theory is not continuous, so shear and torsion are checked using the cross section of the T-girder G2 (G1, G3, G4) shown in Figure 4, rather than the composite cross section including the precast deck 5 described below. After the shear stopper means connection process described below and integration with the precast deck 5, the tension resistance material in truss theory becomes continuous, so the composite cross section is checked. If the calculated strength is insufficient, this can be addressed by gluing carbon fiber to the outer surface of the web of the T-girder G2, for example. Prestress may also be introduced as appropriate.

[0032] (Unevenness adjustment process) Figure 5 is a process explanatory diagram showing the unevenness adjustment step of the method for joining concrete structures according to the first embodiment of the present invention in an enlarged cross-sectional view of part B in Figure 4. Next, in the method for joining concrete structures according to this embodiment, as shown in Figure 5, an unevenness adjustment step is carried out in which the upper surfaces of the T-girders G1 to G4 are adjusted to be smooth using an unevenness adjustment material P.

[0033] Specifically, the top surface of the T-girders G2, which was chipped off in the front support member upper chipping process to form unevenness, is cleaned, a concrete primer is applied, and then a putty-like unevenness adjustment material P is applied to the top surfaces of the T-girders G1 to G4 around at least the exposed stirrup Sr to adjust the unevenness so that it is smooth.

[0034] Examples of primers include epoxy primers, acrylic primers, and urethane primers. Examples of the unevenness control material P include inorganic and organic materials (e.g., epoxy, acrylic, urea, and urethane), and resin mortar. However, the unevenness control material used in the present invention can be any putty-like material that has a predetermined viscosity and can be adhered to concrete via a primer.

[0035] Furthermore, in this process, it is acceptable to smooth not only the periphery of the stirrup Sr but also the entire top surface of the T-girders G1 to G4. This is because it makes it easier to carry out the subsequent process of installing the precast deck slab. However, it is also possible to skip this process and go straight to the next process. This is because the stirrup Sr can be fixed by carrying out the next process without performing any leveling adjustment.

[0036] (Tension resistance material bending process) 6 is an enlarged cross-sectional view showing the tensile resistance member bending step in the method for joining concrete structures according to the first embodiment of the present invention. Next, in the method for joining concrete structures according to this embodiment, the tensile resistance member bending step is carried out, in which the stirrups Sr, which are tensile resistance members, are bent.

[0037] Specifically, as shown in FIG. 6, the exposed portion of the stirrup Sr left behind in the front support member upper part chipping process on the main girder of the T-girders G1 to G4 is bent 180° to form a hook portion on the stirrup Sr.

[0038] (Precast deck placement process) Fig. 7 is a process explanatory diagram showing the precast slab placing step of the method for joining concrete structures according to the first embodiment of the present invention in an overall cross-sectional view cut along the direction Y perpendicular to the bridge axis, and Fig. 8 is a process explanatory diagram showing the precast slab placing step of the method for joining concrete structures according to the embodiment of the present invention in a plan view. Next, in the method for joining concrete structures according to this embodiment, a precast slab placing step is carried out in which the precast slab is placed on top of the main girder.

[0039] The precast deck 5 used in this process is provided with a box-punched hole 50 for integration with the stirrups Sr described above. As shown in Figure 7, this box-punched hole 50 is a through-hole that passes through the precast deck 5 from top to bottom, and is tapered upward to prevent the shear stopper from being pulled out by bending stress acting on the precast deck 5. However, in some cases, this box-punched hole 50 can also be a hole with a closed top.

[0040] Specifically, in this step, a lifting machine such as a crane is used to place the stirrups Sr, which are formed by bending the precast floor slab 5, on the T-girders G1 to G4 so that they are accommodated in the box punching holes 50.

[0041] In this process, filler M such as non-shrinkage mortar is filled between the precast deck 5 and the T-girders G1 to G4 and into the box cutout holes 50, and is then hardened, and the filler M fixes the stirrups Sr so that they do not shift in the material axis direction, integrating the precast deck 5 and the main girders G1 to G4. With the completion of this process, the work of updating to a precast deck using the concrete structure joining method according to this embodiment is complete.

[0042] According to the method for joining concrete structures according to the embodiment of the present invention described above, the stirrups Sr of the T-girders G1 to G4, which are the main girders of the bridge B1, are bent and fixed with filler material so that the bent stirrups Sr do not shift in the axial direction of the material. This ensures that the bent stirrups Sr have a sufficient fixed length relative to the filler material M, and then the old and damaged existing RC deck F1 can be replaced with a new, high-quality precast deck 5. This makes it possible to renew the deck of the existing concrete bridge B1 inexpensively and in a short period of time, and to achieve a longer lifespan for the bridge B1 through appropriate maintenance.

[0043] Furthermore, according to the method for joining concrete structures of this embodiment, the newly constructed precast deck 5 and the existing main girders, the T-girders G1 to G4, can be integrated, and the composite cross section including the precast deck 5 can withstand external forces, thereby reducing the thickness of the newly constructed precast deck 5 and improving the lifespan and durability of the existing T-girders G1 to G4.

[0044] Next, a description will be given of a method for joining concrete structures according to the second embodiment. In the method for joining concrete structures according to the second embodiment, a removal step, a chipping step of the upper part of the support member, and a leveling step are performed, similarly to the first embodiment.

[0045] (Fixing material connection process) 9 is an enlarged cross-sectional view showing the anchor connecting step of the method for joining concrete structures according to the second embodiment of the present invention. Next, in the method for joining concrete structures according to this embodiment, the anchor connecting step is performed in which the anchor Z1 is pressure-welded or welded to the stirrup Sr, which is the cut tensile resistance material.

[0046] The fixing material Z1 is made of, for example, a steel plate, and is friction-welded or welded to the upper end of the cut stirrup Sr.

[0047] In this way, a predetermined anchoring length can be secured by the stirrup Sr and anchor Z1, and by the stirrup Sr and anchor Z2. This makes it possible to integrate the existing main girders G1 to G4 with the new precast deck slab 5, further improving safety and reliability.

[0048] (Precast deck placement process) Next, in the method for joining concrete structures according to this embodiment, a precast slab placing step is carried out in which a precast slab is placed on the main girder, as in the first embodiment.

[0049] Specifically, in this step, a lifting machine such as a crane is used to place the precast deck 5 on the T-girders G1 to G4 so that the stirrups Sr and the anchoring materials Z1 are housed in the box punching holes 50.

[0050] In this process, filler M such as non-shrinkage mortar is filled between the precast deck 5 and the T-girders G1 to G4 and into the box cutout holes 50, and is then hardened, and the filler M fixes the stirrups Sr so that they do not shift in the material axis direction, integrating the precast deck 5 and the main girders G1 to G4. With the completion of this process, the work of updating to a precast deck using the concrete structure joining method according to this embodiment is complete.

[0051] According to the joining method for concrete structures according to the embodiment of the present invention described above, the anchoring materials Z1 are pressure-welded or welded to the stirrups Sr of the T-girders G1 to G4, which are the main girders of the bridge B1, and the filler material M is used to fix the stirrups Sr to which the anchoring materials Z1 are pressure-welded or welded so that they do not shift in the material axial direction. This ensures that the stirrups Sr and the anchoring materials Z1 have a sufficient anchorage length relative to the filler material M, and then the old and damaged existing RC deck slab F1 can be replaced with a new, high-quality precast deck slab 5. This makes it possible to renew the deck of the existing concrete bridge B1 at low cost and in a short period of time, and to achieve a longer lifespan for the bridge B1 through appropriate maintenance.

[0052] Next, a description will be given of a method for joining concrete structures according to the third embodiment. In the method for joining concrete structures according to the third embodiment, a removal step, a chipping step of the upper part of the support member, and a leveling step are performed, as in the first embodiment.

[0053] (Fixing material connection process) Fig. 10 is an enlarged cross-sectional view showing the anchoring member connecting step of the method for joining concrete structures according to the third embodiment of the present invention. Fig. 11 is a cross-sectional view taken along line AA in Fig. 10. Next, in the method for joining concrete structures according to this embodiment, an anchoring member connecting step is carried out in which the anchoring member Z2 is connected to the stirrup Sr, which is the cut tensile resistance member, via the joint member J.

[0054] The anchoring material Z2 is made of rebar. The anchoring material Z2 is formed by bending the rebar 180° to form a hook portion. As shown in FIG. 11 , the joint member J has a cylindrical sleeve J1 and a wedge portion J2 that is inserted into a through hole provided in the side of the sleeve J1. The joint member J accommodates the stirrup Sr and the anchoring material Z2 inside the sleeve J1, and can connect the stirrup Sr and the anchoring material Z2 by inserting the wedge portion J2 into the through hole of the sleeve J1.

[0055] In this way, the stirrups Sr and anchoring materials Z2 can ensure a predetermined anchoring length, which allows the existing main girders G1 to G4 to be integrated with the new precast deck slab 5, further improving safety and reliability.

[0056] (Precast deck placement process) Next, in the method for joining concrete structures according to this embodiment, a precast slab placing step is carried out in which a precast slab is placed on the main girder, as in the first embodiment.

[0057] Specifically, in this step, a lifting machine such as a crane is used to place the precast deck 5 on the T-girders G1 to G4 so that the stirrups Sr and the anchoring materials Z2 are housed in the box punching holes 50.

[0058] In this process, filler M such as non-shrinkage mortar is filled between the precast deck 5 and the T-girders G1 to G4 and into the box cutout holes 50, and is then hardened, and the filler M fixes the stirrups Sr so that they do not shift in the material axis direction, integrating the precast deck 5 and the main girders G1 to G4. With the completion of this process, the work of updating to a precast deck using the concrete structure joining method according to this embodiment is complete.

[0059] According to the joining method for concrete structures according to the embodiment of the present invention described above, anchoring materials Z2 made of rebar are connected to the stirrups Sr of the T-girders G1 to G4, which are the main girders of the bridge B1, via joint members J, and the stirrups Sr connected to the anchoring materials Z2 are fixed by filler material M so as not to shift in the material axial direction. This ensures that the stirrups Sr and anchoring materials Z2 have a sufficient anchorage length relative to the filler material M, and then the old and damaged existing RC deck slab F1 can be replaced with a new, high-quality precast deck slab 5. This makes it possible to renew the deck of the existing concrete bridge B1 at low cost and in a short period of time, and to achieve a longer lifespan for the bridge B1 through appropriate maintenance.

[0060] Next, a description will be given of a method for joining concrete structures according to the fourth embodiment. In the method for joining concrete structures according to the fourth embodiment, similarly to the first embodiment, a removal step, a chipping step of the upper part of the support member, and a leveling step are performed.

[0061] (Precast deck placement process) 12 is a process explanatory diagram showing the precast slab placing step of the method for joining concrete structures according to the fourth embodiment of the present invention in an overall cross-sectional view cut along the direction perpendicular to the bridge axis Y. Next, in the method for joining concrete structures according to this embodiment, a precast slab placing step is carried out in which the precast slab is placed on the main girder, as in the first embodiment.

[0062] Specifically, in this step, a lifting machine such as a crane is used to place the precast floor slab 5 on the T-girders G1 to G4 so that the stirrups Sr are accommodated in the box punching holes 50.

[0063] In this process, filler M, which is a non-shrinkage ultra-high strength mortar or high strength mortar, is filled between the precast deck 5 and the T-girders G1 to G4 and into the box cutout holes 50 and allowed to harden, and the filler M fixes the stirrups Sr so that they do not shift in the material axis direction, integrating the precast deck 5 and the main girders G1 to G4. With the completion of this process, the work of updating to a precast deck using the concrete structure joining method according to this embodiment is complete.

[0064] Here, ultra-high strength mortar has a compressive strength of 80N / mm 2 High-strength mortar refers to mortar with a compressive strength of 60N / mm 2 This refers to the above mortar.

[0065] According to the joining method for concrete structures according to the embodiment of the present invention described above, the filler material M, which is ultra-high strength mortar or high strength mortar, fixes the stirrups Sr so that they do not shift in the material axis direction. This ensures a sufficient fixing length for the stirrups Sr relative to the filler material M, and then makes it possible to replace the old and damaged existing RC deck slab F1 with a new high-quality precast deck slab 5. Therefore, the deck of the existing concrete bridge B1 can be updated cheaply and in a short period of time, and proper maintenance can be carried out to extend the life of the bridge B1.

[0066] Although the joining method for concrete structures according to the embodiment of the present invention has been described in detail above, the above-described and illustrated embodiments are merely specific embodiments for carrying out the present invention, and therefore the technical scope of the present invention should not be construed as being limited by them.

[0067] In particular, although a T-girder bridge has been described as an example of a bridge to which the present invention is applicable, the present invention is not limited to T-girder bridges. For example, as shown in Fig. 13, the present invention can also be applied to replacing the concrete deck slab of a box girder bridge with a precast deck slab. Also, as shown in Fig. 14, the present invention can also be applied to replacing the concrete deck slab of a deck bridge with a hollow slab with a precast deck slab. In short, the present invention can be applied when replacing the RC deck slab of a concrete bridge with a precast deck slab.

[0068] In particular, although the present invention has been described using girders as an example of a support member to which the present invention can be applied, the present invention is not limited to girders. For example, as shown in Figure 15, the present invention can also be applied to replacing concrete members supported by columns K as support members with precast members. The present invention can also be applied to replacing reinforced concrete members supported by walls as support members with precast members.

[0069] When upgrading to a precast member, for example, as shown in Figure 16, the exposed portion of the stirrup Sr left behind in the support member upper part chipping step on the column K may be bent 180° to form a hook portion on the stirrup Sr. When upgrading to a precast member, as shown in Figure 17, fixing material Z1 may be pressure welded or welded to the stirrup Sr left behind in the support member upper part chipping step. When upgrading to a precast member, fixing material Z2 may be connected to the stirrup Sr left behind in the support member upper part chipping step via a joint member J, as shown in Figure 18. When upgrading to a precast member, as shown in Figure 19, the stirrups Sr left behind in the process of chipping off the upper part of the support member are placed so that they are accommodated in the box-punched holes 50, and a filler M, which is a non-shrinkage ultra-high strength mortar or high strength mortar, is filled between the precast member and the column K and in the box-punched holes 50 and allowed to harden, and the filler M fixes the stirrups Sr so that they do not shift in the material axial direction, thereby integrating the precast member 5 and the column K. [Explanation of symbols]

[0070] 5: Precast members 50: Box cutout hole B1: Bridge F1 :RC floor slab F1a: Upper part of main girder G1: Column G2: Column G3 :digit G4: Column J: Joint member J1: Sleeve J2: Wedge K: Pillar M:Filling material P: Unevenness adjustment material S1: Shear stop bar S2: Oblique muscles Sr: Stirrup W1: Wall parapet W2: Earth cover Department Z 1: Fixing agent Z2: Fixing material X: Bridge axis direction Y: Perpendicular direction to the bridge axis Z: Vertical direction

Claims

1. The RC member is supported from below, the upper part of the support member that is joined to the RC member is chipped off to expose the upper part of the tensile resistance material made of reinforcing bars, the exposed tensile resistance material is cut in the middle and the cut tensile resistance material is bent, a precast member with a box-cut hole is placed on the support member, the tensile resistance material is placed in the box-cut hole, a filler material is filled and hardened, and the filler material fixes the tensile resistance material so that it does not shift in the material axial direction, integrating the precast member and the support member. A method for joining concrete structures, characterized by:

2. The RC member is supported from below, the upper part of the support member that is joined to the RC member is chipped off to expose the upper part of the tensile resistance material made of rebar, the exposed tensile resistance material is cut halfway, and an anchor material made of steel plate is pressed or welded to the cut tensile resistance material, a precast member with a box-cut hole is placed on the support member, the tensile resistance material and the anchor material are placed in the box-cut hole, a filler material is filled in and hardened, and the filler material fixes the tensile resistance material so that it does not shift in the material axis direction, integrating the precast member and the support member. A method for joining concrete structures, characterized by:

3. The RC member is supported from below, the upper part of the support member that is joined to the RC member is chipped off to expose the upper part of the tensile resistance material made of reinforcing bars, the exposed tensile resistance material is cut in the middle, a precast member with a box-cut hole is placed on the support member, the tensile resistance material that remains cut is placed in the box-cut hole, a filler material made of high-strength mortar or ultra-high-strength mortar is filled and hardened, and the filler fixes the tensile resistance material so that it does not shift in the material axis direction, integrating the precast member and the support member. A method for joining concrete structures, characterized by:

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