Joint structure for precast concrete members and joint method for precast concrete members

Abstract

To install an economical and rational joint structure between adjacent precast concrete members.SOLUTION: In a joint structure for precast concrete members, a convex side end face provided on one precast concrete member and a concave side end face provided on the other precast concrete member face each other and are joined. A shear reinforcement member is provided protruding near the center of the convex side end face, and a storage space that can store the shear reinforcement member is provided on the concave side end face. A protruding part of the shear reinforcement member protruding from the convex side end face is inserted into the storage space in a state of being isolated in the storage space.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a joint structure for precast concrete members that constitute a concrete structure and a method for joining precast concrete members. [Background technology]

[0002] A method has been widely known in the past in which precast concrete members manufactured to a transportable size are brought to a construction site and then joined together to construct a concrete structure. In general, the end of a reinforcing bar protruding from one adjacent precast concrete member is inserted into a sleeve embedded in the other precast concrete member, and the joint surfaces of the two members are brought together, and then the sleeve is filled with mortar to form a mortar-filled joint.

[0003] Adjacent precast concrete members are joined in this way, but this type of joint structure lacks shear transfer, so measures are often taken such as roughening the joint surfaces to create friction, or providing uneven surfaces (shear keys) or steel members that provide shear resistance.

[0004] However, when rebars undergo repeated loads during a large earthquake and become plastic, residual plastic deformation can easily cause gaps in the joints, which can lead to problems such as loss of contact between the joint surfaces, loss of friction, and damage and shear deformation in uneven areas and steel materials, which can reduce the shear transmission performance.

[0005] In this situation, for example, in Patent Document 1, in addition to mortar-filled joints and shear keys for reinforcing bars, PC steel members are used to prevent gaps in the joints. Specifically, PC steel members are inserted through all of the multiple precast concrete members connected in series, and tension is applied to press the precast concrete members together. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2020-94391 A Summary of the Invention [Problem to be solved by the invention]

[0007] It is expected that the shear transfer performance will be improved by taking measures such as increasing the amount of reinforcing bars in the precast concrete members, in addition to the method of using PC steel members as in Patent Document 1. However, this is not necessarily a rational structure, as it is less economical due to the increased manufacturing and material costs of the precast concrete members, and construction is also time-consuming.

[0008] The present invention has been made in consideration of the above problems, and its main object is to provide an economical and rational connection structure for adjacent precast concrete members. [Means for solving the problem]

[0009] In order to achieve this objective, the joint structure for precast concrete members of the present invention is a joint structure for precast concrete members in which a convex end face of one precast concrete member is joined opposite a concave end face of the other precast concrete member, characterized in that a shear reinforcement member is provided protruding near the centroid of the convex end face, a storage space capable of storing the shear reinforcement member is provided in the concave end face, and the protruding portion of the shear reinforcement member protruding from the convex end face is inserted into the storage space with its edges cut off.

[0010] The joint structure of precast concrete members of the present invention is characterized in that an edge separation layer is provided on the outer surface of the shear reinforcement member, the storage space is the inner hollow portion of a cylinder embedded in the other precast concrete member, and the cylinder with the protruding portion of the shear reinforcement member inserted is filled with filler material.

[0011] The joint structure of precast concrete members of the present invention is characterized in that a reinforcing bar surrounding the cylindrical body is embedded in the other precast concrete member.

[0012] The joint structure of the precast concrete member of the present invention is characterized in that a reticulated steel bar is provided in the joint formed by the opposing convex side end face and concave side end face, and a filler material that fills the cylindrical body is continuously filled in.

[0013] The method of joining precast concrete members of the present invention is a method of joining precast concrete members in which a convex end face on one precast concrete member is opposed to a concave end face on the other precast concrete member, and is characterized in that it comprises an insertion step of inserting a protruding portion of a shear reinforcement member which has an edge-cutting layer on its outer peripheral surface and protrudes near the centroid of the convex end face into a storage space consisting of a cylindrical body embedded in the concave end face, and a filling step of continuously filling a filler material into the joint portion formed by the convex end face and the concave end face and into the cylindrical body.

[0014] The method of joining precast concrete members of the present invention is characterized in that the main reinforcement of one precast concrete member and the main reinforcement of the other precast concrete member are inserted into a sleeve embedded in the one precast concrete member or the other precast concrete member, and in the filling process, the filler is filled into the sleeve continuously from the joint portion.

[0015] According to the joint structure and the joint method of the present invention, the shear reinforcement member is provided protruding near the centroid of the convex end face where the contribution of bending compression and bending tension is small. Also, this protruding portion is inserted into the storage space of the concave end face with the edge cut off, so that the shear reinforcement member bears shear stress but bears almost no tensile stress.

[0016] This allows the joint structure of precast concrete members to be able to control shear transmission capacity and bending deformation capacity separately, making it possible to design rational joints with the required bending deformation capacity and shear transmission capacity for areas that are allowed to undergo plastic deformation during an earthquake. Excessive performance improvements, such as increasing the amount of rebar in precast concrete members, are no longer necessary in order to ensure the desired shear transmission capacity, making it possible to realize an economically advantageous structure.

[0017] In addition, the cylinder is embedded in the other precast concrete member starting from the concave end face that is most affected by shear, and the protruding part of the shear reinforcement is inserted via a filler into the storage space inside the cylinder. The shear reinforcement member wrapped around the cylinder in this way has greater rigidity than the shear reinforcement member alone, making it possible to ensure greater shear resistance.

[0018] Furthermore, when shear force is generated in the joint, the bearing pressure is applied from the shear reinforcement member through the filler and the cylinder to the surrounding concrete, so the pressure-bearing area of ​​the concrete is increased compared to when only the shear reinforcement member is used. Therefore, even if a large bearing pressure is applied, the concrete part of the other precast concrete member is not damaged. If the reinforcement is arranged so as to surround the cylinder, the pressure-bearing area is further increased, so the impact of the bearing pressure acting on the concrete part can be further reduced.

[0019] In addition, the joints formed by the opposing convex and concave end faces are filled with filler with reticulated reinforcing bars in place, which makes it possible to prevent the filler filling the joints from being crushed or peeled off even when repeated loads are applied during earthquakes, etc. Effect of the Invention

[0020] According to the present invention, it is possible to provide an economical and rational connection structure between adjacent precast concrete members. [Brief description of the drawings]

[0021] [Figure 1] 1 is a diagram showing an outline of a joint structure of a precast concrete member according to the present embodiment. [Diagram 2] 4A and 4B are diagrams showing a convex end face and its vicinity in the present embodiment; [Diagram 3] 4A and 4B are diagrams showing a concave side end face and its vicinity in the present embodiment. [Figure 4] 1 is a diagram showing a method of joining precast concrete members according to the present embodiment. FIG. [Diagram 5] 11A and 11B are diagrams showing other examples of joint structures of precast concrete members in this embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The joint structure for precast concrete members and the joint method for precast concrete members of the present invention will be described below with reference to Figures 1 to 5. Hereinafter, the precast concrete members will be referred to as precast members.

[0023] <<<<Precast material joint structure>>>> As shown in Figures 1(a) and (b), the joint structure 100 for precast members is provided at a joint portion where the end faces of one precast member 10 and another precast member 20 are joined facing each other.

[0024] As shown in Fig. 1(b), multiple main reinforcements 12 are embedded in one precast member 10, and multiple main reinforcements 22 and sleeves 23 are embedded in the other precast member 20. In addition, one precast member 10 has a convex end face 11, and the other precast member 20 has a concave end face 21. A joint is formed between the two, and is filled with non-shrink mortar 50.

[0025] <<<<One of the precast members>>>> 2(a) and (b), one precast member 10 has the above-mentioned main reinforcements 12 and ties, as well as shear reinforcement members 13 and first reinforcement bars 15 embedded in the concrete portion. A convex end face 11 is formed on the end face of the concrete portion facing the other precast member 20.

[0026] ≪≪Convex end surface≫≫ The convex end face 11 is made of a smooth concrete surface, and has protruding ends of a plurality of main reinforcements 12. In addition, a shear reinforcement member 13 is provided protruding from the centroid (center of cross section) of the convex end face 11.

[0027] <Shear reinforcement member> One end of the shear reinforcement member 13 is embedded in one of the precast members 10 to form an embedded portion 131, and the other end forms a protruding portion 132 that protrudes from the convex end face 11. Any material may be used for the shear reinforcement member 13, but a rod-shaped member that is more rigid than the main reinforcement bars 12 and has a smooth outer circumferential surface is preferred. In this embodiment, a steel bar (round steel) that can tenaciously resist repeated loads is used. The outer circumferential surface of the shear reinforcement member 13 with this structure is covered with an edge isolation layer 14.

[0028] <The severing of ties layer> Any material may be used for the edge isolation layer 14 as long as it has the function of suppressing adhesion of the non-shrink mortar 50 to the shear reinforcement member 13. For example, it may be formed by applying a lubricant such as grease, or may be processed using a material with a low friction coefficient, such as by wrapping a wrap film or applying Teflon (registered trademark) processing.

[0029] 2(b), both the embedded portion 131 and the protruding portion 132 are covered with the edge isolation layer 14. However, it is sufficient that the edge isolation layer 14 is formed on at least the outer peripheral surface of the protruding portion 132, and it is not necessary for the edge isolation layer 14 to cover the entire outer peripheral surface of the shear reinforcement member 13.

[0030] <First Reinforcement Bar> The first reinforcing bar 15 is arranged so as to surround the embedded portion 131 of the shear reinforcement member 13, and is embedded in one of the precast members 10. Although a spiral reinforcing bar is used in Fig. 2(b), for example, a reticulated reinforcing bar may be used as long as it can reinforce the concrete around the shear reinforcement member 13.

[0031] <<<<The other precast material>>>> 3(a) and (b), the other precast member 20 has a plurality of sleeves 23 and sheath pipes 24 embedded in the concrete portion together with the above-mentioned plurality of main reinforcements 22 and hoops. A concave end face 21 is formed on the end face of the concrete portion facing the one precast member 10.

[0032] ≪≪Concave end surface≫≫ The concave end surface 21, like the convex end surface 11, is made of a smooth concrete surface, and has openings for a plurality of sleeves 23 and one sheath tube 24 provided therein.

[0033] The sleeves 23 are arranged coaxially with the main reinforcements 22, and one end of each of the main reinforcements 22 is inserted into the sleeves 23. The length of the sleeves 23 is set to a length that can accommodate the end of the main reinforcements 12 on one precast member 10 side protruding from the convex end face 11, and as shown in Fig. 1(b), a so-called mortar-filled joint is formed by filling the sleeves with non-shrink mortar 50.

[0034] Such a sleeve 23 is filled with non-shrink mortar 50 from an opening on one end side facing the concave end surface 21. For this reason, a mortar drain hole 231 having a diameter capable of discharging the non-shrink mortar 50 is provided in the vicinity of the other end side where the main reinforcement 22 is inserted, so as to penetrate the other precast member 20.

[0035] <Sheath tube> The inner hollow portion of the sheath tube 24 functions as a storage space 242 that stores the protruding portion 132 of the shear reinforcement member 13. This storage space 242 is disposed so as to be located at the centroid (center of cross section) of the concave side end face 21. As shown in Fig. 1(b) , the storage space 242 has an inner diameter and length that are substantially larger than those of the protruding portion 132 so that non-shrink mortar 50 can be filled with the protruding portion 132 inserted.

[0036] The non-shrink mortar 50 is filled from the opening on one end side facing the concave end surface 21. For this reason, as shown in Fig. 3(a), a mortar drain hole 241 having a diameter capable of discharging the non-shrink mortar 50 is provided near the closed bottom of the sheath tube 24 so as to penetrate the other precast member 20.

[0037] In this way, by filling the space between the protruding portion 132 of the shear reinforcement member 13 and the sheath tube 24 with non-shrink mortar 50, when the protruding portion 132 moves radially, the supporting pressure can be smoothly transmitted to the concrete portion of the other precast member 20 via the non-shrink mortar 50 and the sheath tube 24.

[0038] <Second Reinforcement Bar> The second reinforcing bar 25 is arranged to surround the sheath pipe 24 and is embedded in the other precast member 20. In Fig. 3(a), a spiral reinforcing bar is used, but for example, a reticulated reinforcing bar may be used as long as it can reinforce the concrete around the sheath pipe 24.

[0039] <<Precast material joining method>> The method for joining one precast member 10 and the other precast member 20 having the above-mentioned configuration is as follows.

[0040] <Insertion process> As shown in Figure 4(a), the convex end face 11 of one precast member 10 is opposed to the concave end face 21 of the other precast member 20. Next, the multiple main reinforcements 12 protruding from the convex end face 11 are inserted into the multiple sleeves 23 provided on the concave end face 21, with the reticulated reinforcing bars 30 sandwiched between them.

[0041] Furthermore, the protruding portion 132 of the shear reinforcement member 13 protruding from the convex end face 11 is inserted into the storage space 242, which is the inner hollow portion of the sheath tube 24 provided on the concave end face 21. In this state, as shown in Fig. 4(b), a predetermined space is formed between the convex end face 11 and the concave end face 21 to provide a joint portion.

[0042] ≪Filling process≫ 4(c), a sealing portion 40 such as a formwork or a sealant is provided so as to surround the joint, and then the filling operation of non-shrink mortar 50 is started using one of the mortar removal holes 231 or the mortar filling pipe 60. The joint communicates with the openings of the multiple sleeves 23 and the opening of the sheath tube 24.

[0043] Therefore, the non-shrink mortar 50 is continuously filled from the joint portion toward the sleeve 23 and the sheath tube 24. When the non-shrink mortar 50 is discharged from the mortar drain hole 231 of the sleeve 23 and the mortar drain hole 241 of the sheath tube 24, the filling operation is completed.

[0044] The joint structure 100 for precast members constructed by the above method is, as shown in Figure 1(b), in which the main reinforcement 12 constituting one precast member 10 and the main reinforcement 22 constituting the other precast member 20 are connected by a mortar-filled joint using a sleeve 23 and non-shrink mortar 50.

[0045] 2(a) and 2(b), the shear reinforcement member 13 protruding from one of the precast members 10 is provided near the centroid of the convex end face 11 where the contribution of bending compression and bending tension is small. The protruding portion 132 of the shear reinforcement member 13 is constrained in radial movement, but is free to slide in the axial direction and rotate about the axis via the edge separation layer 14. In other words, the shear reinforcement member 13 bears shear stress but bears almost no tensile stress.

[0046] This allows the joint structure 100 of precast members to have separate control over shear transmission performance and bending deformation performance, making it possible to design rational joints with predetermined bending deformation performance and shear transmission performance for areas that allow plastic deformation during an earthquake. Excessive performance improvements, such as increasing the amount of rebar in one precast member 10 and the other precast member 20, to ensure the desired shear transmission performance are no longer necessary, making it possible to realize an economically advantageous structure.

[0047] Also, the sheath tube 24 is embedded in the other precast component 20 starting from the concave end surface 21 which is most affected by shear, and the protruding portion 132 of the shear reinforcement member 13 is inserted into the storage space 242, which is the internal space of the sheath tube 24, via the non-shrink mortar 50. By adopting an embodiment in which the sheath tube 24 and the non-shrink mortar 50 are wrapped around the shear reinforcement member 13 in this manner, the rigidity becomes greater than that of the shear reinforcement member 13 alone, and therefore it becomes possible to ensure greater shear resistance.

[0048] Furthermore, when a shear force is generated in the joint, the bearing pressure acts on the surrounding concrete part (the concrete part of the other precast member 20) from the shear reinforcement member 13 through the non-shrink mortar 50 and the sheath pipe 24, but the pressure-receiving area is larger than when the sheath pipe 24 is not provided. Therefore, even if a large bearing pressure acts, the concrete part is not damaged, which can be suppressed.

[0049] In addition, by providing the second reinforcing bar 25 around the sheath pipe 24, the pressure-receiving area of ​​the concrete can be increased, and the effect of the bearing pressure acting on the concrete can be reduced. This is also true for the embedded part 131 of the shear reinforcement member 13 in one precast member 10.

[0050] Therefore, as explained with reference to Figure 2(b), by arranging the first reinforcing bar 15 so as to surround the embedded portion 131, even if a large bearing pressure is applied from the embedded portion 131 of the shear reinforcement member 13 to the concrete portion of one of the precast members 10, it is possible to suppress the phenomenon in which the concrete portion is damaged.

[0051] In addition, in Fig. 1(b), non-shrink mortar 50 is filled in the joints with reticulated reinforcing bars 30 arranged in them. This makes it possible to prevent the non-shrink mortar 50 from being crushed or peeled off from the joints even if repeated loads are applied to the joint structure of the precast concrete members during an earthquake or other such event.

[0052] The precast member joining structure and precast member joining method of the present invention are not limited to the above-described embodiments, and it goes without saying that various modifications are possible without departing from the spirit of the present invention.

[0053] For example, in this embodiment, the first and second reinforcing bars 15, 25 are provided to surround the embedded portion 131 of the shear reinforcement member 13 and the sheath tube 24. However, these are not necessarily required, and a configuration in which they are provided on only one of the two may be used.

[0054] In this embodiment, the sheath tube 24 is used to form the storage space 242 for storing the protruding portion 132 of the shear reinforcement member 13. However, the sheath tube 24 may be omitted, and the concave storage space 242 may be formed directly in the concrete portion of the other precast member 20.

[0055] 2(a) and (b) show an example in which one shear reinforcement member 13 is provided at the centroid of the convex end face 11. For example, as shown in Fig. 5, when the precast member 10 is a flat beam, multiple shear reinforcement members 13 may be provided along an axis passing through the centroid.

[0056] In this case, a storage space 242 for storing each of the multiple shear reinforcement members 13 may be provided on the concave side end face 21 of the precast member 20, or a single storage space 242 may be configured to store multiple shear reinforcement members 13. [Explanation of symbols]

[0057] 100 Joint structure of precast members 10 Precast member (one precast concrete member) 11 Convex end face 12 Main reinforcement 13 Shear reinforcement members 131 Buried part 132 Protruding part 14 Edge cutting layer 15 First reinforcement bar 20 Precast member (other precast concrete member) 21 Concave end face 22 Main reinforcement 23 Sleeve 231 Mortar hole 24 Sheath tube (cylinder) 241 Mortar hole 242 Storage space 30 Reticulated steel bars 40 Sealing part 50 Non-shrink mortar (filler) 60 Mortar-filled pipe

Claims

1. A joint structure for precast concrete members in which a convex end surface of one precast concrete member and a concave end surface of the other precast concrete member are joined together, A shear reinforcement member is provided protruding from the vicinity of the centroid of the convex end surface, A storage space capable of storing the shear reinforcement member is provided on the concave end surface, A joint structure for precast concrete members, characterized in that the protruding portion of the shear reinforcement member protruding from the convex end face is inserted into the storage space with its edges cut off.

2. In the joint structure of the precast concrete member according to claim 1, An edge isolation layer is provided on the outer peripheral surface of the shear reinforcement member, The storage space is an inner hollow portion of a cylinder embedded in the other precast concrete member, A joint structure for precast concrete members, characterized in that the cylinder with the protruding portion of the shear reinforcement member inserted therein is filled with filler.

3. In the joint structure of the precast concrete member according to claim 2, A joint structure for precast concrete members, characterized in that a reinforcing bar surrounding the cylindrical body is embedded in the other precast concrete member.

4. In the joint structure of the precast concrete member according to claim 2, A joint structure for precast concrete members, characterized in that a reticulated steel bar is provided in the joint formed by the opposing convex side end face and concave side end face, and a filler material for filling the cylindrical body is continuously filled in the joint.

5. A method for joining precast concrete members, comprising: joining a convex end surface of one precast concrete member to a concave end surface of another precast concrete member by opposing each other, comprising: an insertion step of inserting a protruding portion of a shear reinforcement member having an edge isolation layer on an outer peripheral surface protruding in the vicinity of the centroid of the convex end surface into a storage space formed by a cylindrical body embedded in the concave end surface; a filling step of continuously filling a filler into a joint portion formed by the convex end surface and the concave end surface and the cylindrical body; A method for joining precast concrete members, comprising:

6. 6. The method for joining precast concrete members according to claim 5, The main reinforcement of the one precast concrete member and the main reinforcement of the other precast concrete member are inserted into a sleeve embedded in the one precast concrete member or the other precast concrete member, A method for joining precast concrete members, characterized in that in the filling step, the filler is filled into the sleeve continuously from the joint portion.

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