Method for constructing concrete structure

Abstract

To provide a method for constructing a concrete structure capable of minimizing the number of reinforcing bars ad an increase in diameter of the reinforcing bars necessary for joining an existing first concrete structure and a new second concrete structure.SOLUTION: A method for constructing a concrete structure joins an existing floor slab 22 being one example of an existing first concrete structure and a widened floor slab 33 being one example of a new second concrete structure. The method for joining the concrete structure comprises a step for forming a concave-shaped first shear key 24 on a first end surface 22S2 in the existing floor slab 22, a step for protruding first main reinforcement 23 from the first end surface 22S2, and a step for joining the widened floor slab 33 to the first end surface 22S2.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a method for constructing a concrete structure formed by joining a newly constructed second concrete structure to an existing first concrete structure. [Background technology]

[0002] One example of a concrete structure construction method for joining a new second concrete structure to an existing first concrete structure is the widening of a road bridge. For example, in road bridge widening, a new deck is joined to the end face of an existing deck that is configured so that rebar protrudes. This allows the tensile and shear forces that occur at the joint between the existing and new decks to be transmitted to the existing deck via the rebar protruding from the end face of the existing deck.

[0003] One example of a method for protruding rebars from the end face of an existing deck is to chip off the rebars arranged inside the existing deck using a water jet (see, for example, Patent Document 1). In addition, in cases where the rebars arranged inside the existing deck cannot be used, a method is used in which new anchor rebars are driven into the end face of the existing deck. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-061071 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the joint between the existing deck and the new deck, where the shear force is large, the number and diameter of rebars required to transmit the shear force to the existing deck increases. In this case, in the joint between the existing deck and the new deck where the shear force is large, the work of removing the rebars using a water jet and the work of driving the anchor rebars tend to become complicated.

[0006] For example, when using a water jet to chip out rebar, the amount of work required to chip out (cutting depth) increases. For example, when driving anchor rebar into the end face of an existing deck slab, it is necessary to drill the anchor hole so as to avoid the rebar placed in the existing deck slab. If the anchor hole interferes with the rebar placed in the existing deck slab when it is drilled, it will be necessary to re-drill the hole. [Means for solving the problem]

[0007] A concrete structure construction method that solves the above-mentioned problems is a concrete structure construction method for joining an existing first concrete structure and a newly constructed second concrete structure, and includes a shear key formation process for forming a concave-shaped first shear key in a first end face of the first concrete structure, a joint reinforcing bar formation process for protruding a first joint reinforcing bar from the first end face, and a joining process for joining the second concrete structure to the first end face. Effect of the Invention

[0008] According to the present invention, it is possible to suppress an increase in the number and diameter of reinforcing bars required for joining an existing first concrete structure and a newly constructed second concrete structure. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing the cross-sectional structure of a road bridge. [Diagram 2] FIG. 2 is an explanatory diagram showing the procedure of the first construction method for widening construction. [Diagram 3] FIG. 3 is a schematic diagram of the existing deck after the cutting process of the first construction method has been carried out. [Figure 4] FIG. 4 is a schematic diagram of an existing deck after the chipping-off process of the first construction method. [Diagram 5] FIG. 5 is a schematic diagram of an existing deck after the shear key formation process of the first construction method has been carried out. [Figure 6] FIG. 6 is a schematic diagram showing a joint between an existing deck and an widening deck where the joining step of the first construction method has been carried out. [Figure 7] FIG. 7 is an explanatory diagram showing the procedure of the second construction method for widening construction. [Figure 8] FIG. 8 is a schematic diagram of the existing deck after the cutting process of the second construction method has been carried out. [Figure 9] FIG. 9 is a schematic diagram of an existing deck after the shear key formation process of the second construction method has been carried out. [Figure 10] FIG. 10 is a schematic diagram of an existing deck after the anchor rebar installation process of the second installation method has been carried out. [Figure 11] FIG. 11 is a schematic diagram showing a joint between an existing deck and an widening deck after the joining step of the second construction method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] An embodiment of a construction method for a concrete structure will be described with reference to Figures 1 to 11. In this embodiment, a case will be described in which the construction method for a concrete structure is applied to widening work for a road bridge.

[0011] [Structure of road bridges] As shown in Fig. 1, a road bridge 10 that has undergone widening work comprises an existing section 20 that is part of an existing road bridge, a widening section 30 that is newly constructed relative to the existing section 20, and a joint section 40 that joins the existing section 20 and the widening section 30. In the road bridge 10, the existing section 20 and the widening section 30 are aligned along a width direction D1 that intersects with the bridge axis direction. As an example, the width direction D1 is a direction perpendicular to the bridge axis that is perpendicular to the bridge axis direction. In Fig. 1, the direction into the paper corresponds to the bridge axis direction.

[0012] The existing portion 20 includes an existing substructure 21 and an existing deck 22. The existing substructure 21 includes an existing pier 21A that supports the existing deck 22. The existing deck 22 is, for example, a hollow deck including an existing girder 22A. The existing deck 22 has, for example, a reinforced concrete structure or a prestressed concrete structure. The existing deck 22 may be made of precast concrete or cast-in-place concrete. The existing deck 22 is an example of an existing first concrete structure.

[0013] The widening section 30 includes a widening substructure 31, a widening girder 32, and a widening deck 33. The widening substructure 31 includes a widening pier 31A that supports the widening girder 32. The widening girder 32 is a concrete girder having a U-shaped cross-sectional shape. The widening deck 33 is a flat concrete member placed on the upper surface of the widening girder 32.

[0014] The widening girder portion 32 and the widening deck 33 have, for example, a reinforced concrete structure or a prestressed concrete structure. The widening girder portion 32 and the widening deck 33 may be made of precast concrete or cast-in-place concrete. As an example, the widening girder portion 32 and the widening deck 33 in this embodiment are made of precast concrete. The widening deck 33 is an example of a newly constructed second concrete structure.

[0015] The joint 40 is constructed by pouring a filler. One example of the filler is ultra-high strength fiber reinforced concrete (UFC). At the joint 40, the existing deck 22 of the existing section 20 and the widening deck 33 of the widening section 30 are joined by hardened filler. That is, the road bridge 10 on which widening work has been carried out includes a deck 11 in which the existing deck 22 and the widening deck 33 are joined via the joint 40. The deck 11 is an example of a concrete structure in which a newly constructed second concrete structure is joined to an existing first concrete structure.

[0016] [First construction method] 2 to 6, a first construction method for widening work to form a road bridge 10 will be described as an example of a construction method for a concrete structure. As shown in Fig. 2, the first construction method for widening work includes steps S11 to S15.

[0017] As shown in Fig. 3, in the first construction method for the widening work, a cutting process is performed in step S11, in which one end of the width direction D1 of the existing deck 22 of the existing portion 20 is cut along the bridge axis direction (depth direction of the paper in Fig. 3). As a result, a cut surface 22S1 is formed along the bridge axis direction in the existing deck 22. In Fig. 3, the part of the existing deck 22 cut in the cutting process is indicated by a two-dot chain line.

[0018] In the cutting process, for example, the existing deck 22 is cut so that a part of the first main reinforcement 23 arranged inside the existing deck 22 is cut. An end of the cut first main reinforcement 23 is located on the cut surface 22S1. The first main reinforcement 23 is a reinforcing bar that bears the tensile force applied to the existing deck 22.

[0019] 4, next, in step S12, a chipping-out process is performed in which the concrete constituting the existing floor slab 22 is cut from the cut surface 22S1 side to chip out the first main reinforcement 23. At this time, a first end surface 22S2 is formed in the existing floor slab 22 by cutting the concrete.

[0020] The first main bar 23 is an example of a first joint reinforcing bar protruding from the first end surface 22S2. The chipping-out process of step S12 is an example of a joint reinforcing bar forming process in which the first joint reinforcing bar is caused to protrude from the first end surface 22S2.

[0021] As shown in Fig. 5, next, in step S13, a shear key forming process is performed to form a first shear key 24 on the first end face 22S2. The first shear key 24 has a concave shape extending along the bridge axis direction. The first shear key 24 is a concave stripe that extends continuously or intermittently along the bridge axis direction.

[0022] In the shear key forming process, it is preferable to form a plurality of first shear keys 24 aligned in the vertical direction. For example, in the shear key forming process, the first shear keys 24 are formed at three locations, namely, the upper end, the lower end, and the middle between them, of the first end face 22S2. In the shear key forming process, the first shear keys 24 are formed while avoiding the first main reinforcement 23 protruding from the first end face 22S2.

[0023] The first shear key 24 has a trapezoidal cross-sectional shape that is larger on the first end face 22S2 side, for example. The width W1 (depth) of the first shear key 24 is, for example, 10 mm or more and 200 mm or less, preferably 30 mm or more and 100 mm or less.

[0024] The first shear key 24 may be formed by a cutter capable of cutting reinforced concrete, or may be formed by a water jet. As an example, the first shear key 24 is preferably formed by a cutter from the viewpoint of processing accuracy.

[0025] Next, in step S14, a roughening process is performed to form a fine uneven shape on the surface of the first end face 22S2 on which the plurality of first shear keys 24 are formed. The roughening is performed by, for example, a water jet.

[0026] As shown in Figure 6, next, in step S15, a joining process is performed in which the existing deck 22 of the existing section 20, constructed in the sequence of steps S11 to S14, and the widening deck 33 of the widening section 30, which is constructed as precast concrete, are joined via a filler material.

[0027] Here, the configuration of the widening deck 33 will be described in detail. The widening deck 33 includes second main reinforcements 34 disposed therein. The second main reinforcements 34 are reinforcing bars that bear the tensile force applied to the widening deck 33.

[0028] The widening deck 33 has a second end surface 33S. In the joining process of step S15, the first end surface 22S2 and the second end surface 33S are disposed to face each other. The second main reinforcement 34 is configured to protrude from the second end surface 33S. The second main reinforcement 34 is an example of a second joint reinforcement protruding from the second end surface 33S.

[0029] The widening deck 33 has a second shear key 35 formed on the second end face 33S. The second shear key 35 has a concave shape extending along the bridge axis direction. That is, the second shear key 35 is a concave stripe extending continuously or intermittently along the bridge axis direction.

[0030] The widening deck 33 preferably has a plurality of second shear keys 35 arranged in the vertical direction at the second end surface 33S. The widening deck 33 has the second shear keys 35 at three locations, namely, the upper end, the lower end, and an intermediate portion between the upper end and the lower end, of the second end surface 33S.

[0031] In the joining process of step S15, in a state where the widening deck 33 is arranged so that the first end face 22S2 and the second end face 33S face each other, a formwork or the like is used to pour filler between the first end face 22S2 and the second end face 33S. At this time, in the width direction D1, the tip of the first main reinforcement 23 is located closer to the second end face 33S than the tip of the second main reinforcement 34, and the tip of the second main reinforcement 34 is located closer to the first end face 22S2 than the tip of the first main reinforcement 23. In other words, the first main reinforcement 23 and the second main reinforcement 34 are configured as a lap joint structure via the filler.

[0032] The poured filler is filled inside the first shear key 24 and the second shear key 35. Then, as the filler hardens, a joint 40 is formed that integrally joins the first end face 22S2 and the second end face 33S via the first main reinforcement 23 and the second main reinforcement 34.

[0033] In the joint 40 constructed by the above-mentioned first construction method, the shear force applied to the joint 40 is transmitted to the existing deck 22 via the first shear key 24, and is also transmitted to the widening deck 33 via the second shear key 35. In addition, the tensile force applied to the joint 40 is transmitted to the existing deck 22 via the first main reinforcement 23, and is also transmitted to the widening deck 33 via the second main reinforcement 34.

[0034] In addition, in Fig. 6, two first main reinforcements 23 and two second main reinforcements 34 are illustrated in one cross section, but the number of the first main reinforcements 23 and the second main reinforcements 34 is not limited, and may be any number that can bear the tensile force applied to the joint 40. In addition, the first main reinforcements 23 and the second main reinforcements 34 do not need to be arranged in the same cross section perpendicular to the bridge axis direction, and for example, the first main reinforcements 23 and the second main reinforcements 34 may be arranged alternately along the bridge axis direction. The first main reinforcements 23 and the second main reinforcements 34 may have a lap joint structure in which they contact each other, or may have an open lap joint structure in which they do not contact each other.

[0035] [Second construction method] In the joint 40 constructed by the first construction method, the first main reinforcement 23 provided in the existing deck 22 is used to transmit the tensile force applied to the joint 40. For example, in cases where the first main reinforcement 23 cannot be used to transmit the tensile force applied to the joint 40, or where there are insufficient first main reinforcement 23 for transmitting the tensile force, the second construction method described below can be adopted as a construction method for the widening work to form the road bridge 10.

[0036] Hereinafter, a second construction method for widening work to form a road bridge 10 will be described as an example of a construction method for a concrete structure with reference to Figures 7 to 11. As shown in Figure 7, the second construction method for widening work includes steps S21 to S25.

[0037] As shown in Fig. 8, in the second construction method for widening work, a cutting process is performed in step S21 to cut one end of the width direction D1 of the existing deck 22 of the existing portion 20 along the bridge axis direction (depth direction of the paper in Fig. 8). As a result, a first end face 22S2 is formed in the existing deck 22 along the bridge axis direction. Note that the first end face 22S2 in the second construction method is also the cut surface. In Fig. 8, the part of the existing deck 22 cut in the cutting process is indicated by a two-dot chain line.

[0038] 9, next, in step S22, a shear key forming step is performed to form first shear keys 24 on the first end surface 22S2. In the shear key forming step of step S22, a plurality of first shear keys 24 arranged in the vertical direction are formed by the same method as in step S13.

[0039] Next, in step S23, a roughening step is performed in which a fine uneven shape is formed on the surface of the first end face 22S2 on which the plurality of first shear keys 24 are formed, by a method similar to that in step S14.

[0040] As shown in FIG. 10, next, in step S24, an anchor rebar installation process is performed in which an anchor rebar 25 is driven into the first end face 22S2 on which a plurality of first shear keys 24 are formed. In the anchor rebar installation process, as an example, the anchor rebar 25 is inserted into a hole formed by drilling holes in the first end face 22S2, and the anchor rebar 25 is fixed to the hole with a resin or cement adhesive. Alternatively, the anchor rebar 25 as a metal expansion anchor is driven into a hole formed by drilling holes in the first end face 22S2. Note that the drilling is performed while avoiding the first main reinforcement 23 and other reinforcing bars arranged inside the existing deck 22.

[0041] In the anchor rebar installation process, a plurality of anchor rebars 25 are installed to the first end face 22S2 so that the anchor rebars 25 protrude from the first end face 22S2. The anchor rebars 25 are arranged so as to protrude from a protruding portion of the first end face 22S2 where the first shear key 24 is not formed.

[0042] Anchor reinforcing bar 25 is an example of a first joint reinforcing bar protruding from first end surface 22S2. Also, the anchor reinforcing bar installation process of step S24 is an example of a joint reinforcing bar forming process in which the first joint reinforcing bar is caused to protrude from first end surface 22S2.

[0043] As shown in Fig. 11, next, in step S25, a joining process is performed in which the existing deck 22 of the existing portion 20 constructed in the procedure of steps S21 to S24 is joined to the widening deck 33 of the widening portion 30 made of precast concrete via a filler. The widening deck 33 has a configuration similar to that described in step S15.

[0044] In the joining process of step S25, a filler is placed between the first end face 22S2 and the second end face 33S by the same procedure as in step S15. At this time, in the width direction D1, the tip of the anchor reinforcing bar 25 is located closer to the second end face 33S than the tip of the second main bar 34, and the tip of the second main bar 34 is located closer to the first end face 22S2 than the tip of the anchor reinforcing bar 25. In other words, the anchor reinforcing bar 25 and the second main bar 34 are configured as a lap joint structure via the filler. Then, as the filler hardens, a joint 40 is formed that joins the first end face 22S2 and the second end face 33S together via the anchor reinforcing bar 25 and the second main bar 34.

[0045] In the joint 40 constructed by the above-mentioned second construction method, the shear force applied to the joint 40 is transmitted to the existing deck 22 via the first shear key 24, and is also transmitted to the widening deck 33 via the second shear key 35. In addition, the tensile force applied to the joint 40 is transmitted to the existing deck 22 via the anchor reinforcing bar 25, and is also transmitted to the widening deck 33 via the second main reinforcement 34.

[0046] 11 shows two anchor rebars 25 and two second main reinforcements 34 in one cross section, but the number of anchor rebars 25 and second main reinforcements 34 is not limited as long as they are sufficient to bear the tensile force applied to the joint 40. Furthermore, the anchor rebars 25 and second main reinforcements 34 do not need to be arranged in the same cross section perpendicular to the bridge axis direction, and for example, the anchor rebars 25 and the second main reinforcements 34 may be arranged alternately along the bridge axis direction. The anchor rebars 25 and second main reinforcements 34 may have a lap joint structure in which they come into contact with each other, or a gap lap joint structure in which they do not come into contact with each other.

[0047] [Effects of the embodiment] (1) According to the first construction method including steps S11 to S15, a concave first shear key 24 is formed on the first end face 22S2, and the first main reinforcement 23 protrudes from the first end face 22S2. According to the second construction method including steps S21 to S25, a concave first shear key 24 is formed on the first end face 22S2, and the anchor reinforcement 25 protrudes from the first end face 22S2.

[0048] This allows the shear force applied to the joint 40 to be transmitted to the existing deck 22 via the first shear key 24. Therefore, the first main reinforcements 23 and anchor reinforcements 25 protruding from the first end face 22S2 can be configured with a number and diameter sufficient to transmit the tensile force applied to the joint 40 to the existing deck 22. In other words, by providing the first shear key 24, it is possible to reduce the number of first main reinforcements 23 and anchor reinforcements 25 that have conventionally been used as a configuration for transmitting the shear force applied to the joint 40 to the existing deck 22. As a result, it is possible to suppress an increase in the number and diameter of the first main reinforcements 23 and anchor reinforcements 25 required for connecting the existing deck 22 and the widening deck 33.

[0049] (2) By providing the second shear key 35 on the second end face 33S of the widening deck 33, the shear force applied to the joint 40 can be transmitted to the widening deck 33 via the second shear key 35. As a result, it is sufficient to provide the second main reinforcement 34 on the second end face 33S to the extent that the tensile force applied to the joint 40 can be transmitted to the widening deck 33, and the second main reinforcement 34 for transmitting the shear force applied to the joint 40 to the widening deck 33 is not required. As a result, the increase in the number and diameter of the second main reinforcement 34 required for connecting the existing deck 22 and the widening deck 33 can be suppressed.

[0050] (3) In the first construction method, in step S12, the existing deck 22 is cut so that the first main reinforcement 23 located inside the existing deck 22 protrudes from the first end face 22S2. This allows the tensile force applied to the joint 40 to be transmitted to the existing deck 22 by the first main reinforcement 23 cut out from inside the existing deck 22. By using the first main reinforcement 23 inside the existing deck 22 to bear the tensile force applied to the joint 40, the durability of the joint 40 can be increased compared to, for example, the case in which an anchor rebar 25 driven into the first end face 22S2 is used as in the second construction method.

[0051] (4) In the second construction method, in step S24, the anchor rebar 25 is driven into the first end face 22S2. This allows the anchor rebar 25 constructed on the first end face 22S2 to transmit the tensile force applied to the joint 40 to the existing deck 22. According to this construction method, for example, even when the first main reinforcement bars 23 cannot be used to transmit the tensile force or the number of first main reinforcement bars 23 is insufficient, the first joint reinforcement bars for transmitting the tensile force applied to the joint 40 to the existing deck 22 can be disposed on the first end face 22S2.

[0052] (5) The first end surface 22S2 is formed with a plurality of first shear keys 24 aligned in the vertical direction. This allows the shear force applied to the joint 40 to be suitably transmitted to the existing deck 22 by the plurality of first shear keys 24. In addition, by having the plurality of first shear keys 24 bear the shear force applied to the joint 40, the width W1 of each first shear key 24 can also be reduced.

[0053] (6) By configuring the first shear key 24 to have a trapezoidal shape in cross section so that the opening side of the concave shape is larger, it is possible to make it easier to fill the inside of the first shear key 24 with filler material. (7) The first end surface 22S2 is subjected to a roughening process to form a fine uneven shape on its surface, which can improve the adhesion between the first end surface 22S2 and the filler that constitutes the joint 40.

[0054] [Example of change] This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.

[0055] The roughening process may be omitted. For example, in the first construction method, when a water jet is used in the chipping-out process of step S12 and the shear key forming process of step S13, a fine uneven shape is formed on the first end face 22S2 and the surface of the first shear key 24 without going through the roughening process.

[0056] The first shear key 24 is not limited to a trapezoid shape in cross section and may be any shape. For example, the first shear key 24 may be a rectangular parallelepiped shape in cross section. In addition, when forming the first shear key 24, other main bars and reinforcing bars arranged inside the existing deck slab 22 may be cut as long as they are reinforcing bars other than the first main bars 23 that function as the first joint reinforcing bars.

[0057] The number of first shear keys 24 formed on the first end surface 22S2 is not limited, as long as at least one first shear key 24 is formed on the first end surface 22S2. The first construction method and the second construction method may be combined as appropriate. For example, after the first main reinforcement 23 is caused to protrude from the first end face 22S2 by the chipping-out process in step S12, an anchor reinforcement construction process in step S24 may be performed in which the anchor reinforcement 25 is driven into the first end face 22S2. That is, both the first main reinforcement 23 and the anchor reinforcement 25 protruding from the first end face 22S2 may be provided on the first end face 22S2 of the existing floor slab 22. In this case, as an example, the process in steps S11 to S14 of the first construction method may be performed, and then the process in step S24 of the second construction method may be performed.

[0058] The second end face 33S of the widening deck 33 does not have to be provided with the second shear key 35. In this case, in addition to the second main reinforcement 34 for transmitting the tensile force applied to the joint 40 to the widening deck 33, other rebars for transmitting the shear force applied to the joint 40 to the widening deck 33 may be provided on the second end face 33S of the widening deck 33. Since the widening deck 33 is a newly installed member, the number and diameter of the rebars protruding from the second end face 33S can be appropriately adjusted as necessary.

[0059] There are no limitations on the configuration of the existing portion 20. For example, the existing deck 22 is not limited to a hollow deck having an existing girder portion 22A, and the girder and the deck may be configured separately. The configuration of the widening portion 30 is not limited. For example, the widening portion 30 is not limited to a configuration in which the widening girder portion 32, which is a concrete girder, and the widening deck slab 33, which is a concrete deck, are configured as precast concrete, and these members may be configured from cast-in-place concrete. In addition, the widening deck slab 33 is not limited to a configuration in which the second main reinforcement 34 protrudes from the second end face 33S, and a reinforcing bar similar to the anchor reinforcing bar 25 may be driven into the second end face 33S.

[0060] The joint 40 is not limited to a structure formed by UFC as a filler, and may be made of any material. For example, the widening portion 30 and the joint 40 may be constructed simultaneously by cast-in-place concrete. In other words, the existing deck 22 and the widening deck 33 may be joined without a filler by constructing the widening deck 33 and the portion corresponding to the joint 40 by cast-in-place concrete. In this case, it is preferable that the first main reinforcement 23 or the anchor reinforcement 25 of the existing deck 22 and the second main reinforcement 34 of the widening deck 33 are configured as a lap joint structure via the (cast-in-place) concrete material constituting the widening deck 33. In this case, a part of the widening deck 33 functions as the joint 40 that bundles the first main reinforcement 23 or the anchor reinforcement 25 of the existing deck 22 and the second main reinforcement 34 of the widening portion 30.

[0061] Although the construction method for widening the road bridge 10 has been exemplified as a construction method for a concrete structure, this construction method can be applied to other than the deck of the road bridge 10, such as railroad facilities, port facilities, decks installed in tunnels, precast concrete decks in buildings, etc. In addition, this construction method is not limited to joining decks together, but can also be applied to joining any existing first concrete structure to any newly constructed second concrete structure, such as joining concrete girders together or joining substructures together. [Explanation of symbols]

[0062] D1...width direction, S11~S15, S21~S25...step, W1...width, 10...road bridge, 11...deck slab, 20...existing section, 21...existing substructure, 21A...existing pier, 22...existing deck slab, 22A...existing girder section, 22S1...cut surface, 22S2...first end face, 23...first main bar, 24...first shear key, 25...anchor bar, 30...widening section, 31...widening substructure, 31A...widening pier, 32...widening girder section, 33...widening deck slab, 33S...second end face, 34...second main bar, 35...second shear key, 40...joint.

Claims

1. A method for constructing a concrete structure for joining an existing first concrete structure and a newly constructed second concrete structure, comprising the steps of: a shear key forming step of forming a concave first shear key in a first end surface of the first concrete structure; A joint reinforcing bar forming process of protruding a first joint reinforcing bar from the first end surface; and a joining step of joining the second concrete structure to the first end surface. Construction methods for concrete structures.

2. The second concrete structure has a second end surface from which a second joint reinforcing bar protrudes, In the joining step, the first end surface and the second end surface are joined via a filler. A method for constructing a concrete structure according to claim 1.

3. The second end surface is formed with a second concave shear key. A method for constructing a concrete structure according to claim 2.

4. The first joint reinforcing bar is a main bar disposed inside the first concrete structure, In the joint reinforcing bar forming step, the first concrete structure is cut so that the main reinforcement bar protrudes from the first end surface. A method for constructing a concrete structure according to any one of claims 1 to 3.

5. The first joint reinforcing bar is an anchor reinforcing bar driven into the first end surface, In the joint reinforcing bar forming step, the anchor reinforcing bar is installed to the first end surface so that the anchor reinforcing bar protrudes from the first end surface. A method for constructing a concrete structure according to any one of claims 1 to 3.

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