Precast members, joint structures for precast members, and methods for manufacturing them.

Abstract

To provide: a precast member enabling producing joint structures of the precast member at low cost in a short construction period; a joint structure of the precast member; and a construction method thereof.SOLUTION: A precast member 1 (2) has joint surfaces 11 (21) at both ends in the extension direction, and formed with a vertical joint 4 in the joint surface 11 (21) through filling of a grout 3. The precast member includes: a protrusion 12 (22) continuously formed on at least a lower edge and left and right edges of each joint surface 11 (21); and a regular sealing material 5 affixed to the protrusion 12 (22) of the at least one joint surface 11 (21).SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This invention relates to a precast member in which a reinforced concrete member is precast, a joint structure using this precast member, and a manufacturing method thereof.

Background Art

[0002] A construction method of assembling precast members in which reinforced concrete members are precast at a construction site is known. In this construction method, in order to absorb manufacturing errors of the precast members and construction errors at the construction site, a vertical joint is formed by leaving a gap between joint surfaces of the precast members. Further, in the case of a reinforced concrete structure, in order to transmit member cross-sectional stress, the reinforcing bars (main bars) of the precast members are joint-connected at the vertical joints. As this joint connection, when using a mechanical joint embedded on the joint surface side of one precast member, grout is filled into the joint member of this mechanical joint and at the same time grout is also filled between the joint surfaces.

[0003] In this grout filling, it is necessary to install a stop frame for preventing the outflow of liquid grout around the vertical joint. As the stop frame, a frame member having a structure for connection with the precast member and capable of withstanding the filling pressure is used. Alternatively, there is also a method of filling solidified mortar from the outside of the vertical joint and curing it to form a stop frame.

[0004] Note that Patent Document 1 discloses a joint sealing method in which a tube body is inserted without a gap along the outer peripheral edge of the joint portion of a precast concrete member.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the method using mortar as the retaining frame has the disadvantage of a longer construction period because the grout filling work cannot begin until the mortar hardens. In addition, the method using the frame members as the retaining frame has the disadvantage of higher construction costs due to the effort required to manufacture the frame members.

[0007] The purpose of this invention is to provide a precast member, a precast member joint structure, and a method for constructing the same, which enable the production of precast member joint structures in a short period of time and at low cost. [Means for solving the problem]

[0008] The precast member of this invention has joint surfaces at both ends in the extension direction, and a vertical joint is formed on the joint surface by grout filling, and is characterized by comprising: a protruding portion that extends vertically continuously from the joint surface at least on the left and right edges of each joint surface, and a pre-formed sealing material attached to the protruding portion of at least one of the joint surfaces.

[0009] With the above configuration, by butting the joint surfaces of adjacent precast members together, a sealing portion is formed between the joint surfaces to seal the grout, using the protrusions on the precast members themselves and the pre-formed sealing material attached to the protrusions. Therefore, there is no need to wait for the mortar to harden as in the conventional method, which shortens the construction period and reduces costs compared to using conventional frame members.

[0010] In the precast member described above, at least the central part of the pre-formed sealing material attached to the protruding left and right edges, on the side where the grout is filled, may be concave horizontally when not pressed. This reduces the amount of bulging at the central part when the pre-formed sealing material bulges out toward the grout filling side upon being pressed, compared to a structure that is not concave, thereby suppressing the occurrence of grout defects between the joint surfaces.

[0011] Alternatively, in the precast member described above, the material of the central part of the pre-formed sealing material in the direction of the pressing may be made of a material that is less prone to deformation than the material of the non-central part. This allows the amount of bulging at the central part when the pre-formed sealing material bulges in a direction perpendicular to the direction of the pressing upon receiving the pressing to be reduced compared to a pre-formed sealing material where the degree of bulging is the same throughout, thereby suppressing the occurrence of grout defects between the joint surfaces.

[0012] The above-mentioned precast member comprises at least a foundation beam section and a footing section extending laterally from the lower part of the foundation beam section, with reinforcing bars protruding from one joint surface of the foundation beam section, and a mechanical joint may be embedded on the other joint surface side of the foundation beam section to connect reinforcing bars protruding from the joint surface of an adjacent precast member.

[0013] Furthermore, the joint structure for precast members of this invention is a joint structure for precast members in which a vertical joint is formed by filling the mutually opposing joint surfaces of one adjacent precast member and the other precast member with grout, using any of the above-mentioned precast members, and is characterized in that the standard sealing material is pressed by the protruding portion.

[0014] With the above configuration, the grout is sealed at the point where the precast sealant is pressed by the protrusions on the precast member itself, thus reducing costs compared to using the above-mentioned frame member. In addition, since there is no need to wait for the mortar to harden, the construction period can also be shortened.

[0015] Furthermore, the method for creating a joint structure for precast members according to this invention is a method for creating a joint structure by joining any of the above-mentioned precast members together, The process involves butting the joint surfaces of adjacent precast members together with the above-mentioned standard sealant interposed, and pressing the standard sealant with the above-mentioned protrusion, The step of filling grout between the joint surfaces, characterized by including the above.

[0016] According to the above manufacturing method, since the grout is sealed at the location where the molded sealing material is pressed by the protruding part of the precast member itself, cost reduction can be achieved compared to the case of using the above frame member. In addition, since there is no need to wait for the mortar to harden, the construction period can be shortened.

[0017] In the above manufacturing method, a precast member with the molded sealing material already attached may be transported to the construction site where the precast member is installed. According to this, the operation of attaching the molded sealing material at the construction site becomes unnecessary, and the construction can be accelerated.

Effect of the Invention

[0018] According to the present invention, it is possible to manufacture the joint structure of the precast member at a low cost, and the effect of shortening the construction period can be achieved.

Brief Description of the Drawings

[0019] [Figure 1] FIG. (A) is a perspective explanatory view showing the joint structure of the precast member of the embodiment, and FIG. (B) is a cross-sectional explanatory view showing the vertical joint portion. [Figure 2] It is a perspective explanatory view showing the precast member of the embodiment. [Figure 3] It is a perspective explanatory view showing the precast member and the mechanical joint of the embodiment. [Figure 4] It is a perspective explanatory view showing the manufacturing method of the joint structure of the precast member of the embodiment. [Figure 5] It is a perspective explanatory view showing the manufacturing method of the joint structure of the precast member of the embodiment. [Figure 6] [[ID= forty]]FIG. (A) is an explanatory view showing the cross-sectional shape of another molded sealing material used in the joint structure of the precast member of the embodiment, and FIG. (B) is an explanatory view showing the bulging due to the compression of the molded sealing material. [Figure 7] FIG. (A) is an explanatory view showing a cross-sectional shape of another standard sealing material used in the joint structure of the precast member of the embodiment, and FIG. (B) is an explanatory view showing the bulging due to compression of the standard sealing material.

Mode for Carrying Out the Invention

[0020] Hereinafter, an embodiment according to an aspect of this invention will be described based on the accompanying drawings. As shown in FIGS. 1(A) and 1(B), the joint structure 100 of the precast members of this embodiment is a structure in which grout 3 is filled between the opposing joint surfaces 11 and 21 of one adjacent precast member 1 and the other precast member 2 to form a vertical joint 4.

[0021] The above precast member 1 and precast member 2 have the same structure and have joint surfaces 11 and 21 at both ends in their respective extending directions. Further, for example, as shown in FIG. 2, the precast member 1 has a foundation beam portion 15, a footing portion 16 that projects laterally from the lower part of the foundation beam portion 15, and a waist wall portion 17 that rises from the upper surface of the foundation beam portion 15. Similarly, the precast member 2 also has a foundation beam portion 25, a footing portion 26 that projects laterally from the lower part of the foundation beam portion 25, and a waist wall portion 27 that rises from the upper surface of the foundation beam portion 25.

[0022] In the foundation beam portions 15 and 25 of the precast members 1 and 2, for example, four main reinforcement bars 15a and 25a are embedded in a predetermined arrangement, and from one joint surface 11 and 21, the four main reinforcement bars 15a and 25a project by a predetermined length in the extending direction of the precast members 1 and 2.

[0023] Also, mechanical joints 18 and 28 are embedded on the other joint surface 11 and 21 sides of the foundation beam portions 15 and 25 of the precast members 1 and 2.

[0024] As shown in Figure 3, the mechanical joint 18 in the precast member 1 has four joint members 18a into which the four main reinforcing bars 25a protruding from one joint surface 21 of the precast member 2 are inserted. The ends of the main reinforcing bars 15a in the foundation beam section 15 are located in each joint member 18a, and the space between the main reinforcing bars 15a and the end opening of the joint member 18a is sealed with a rubber plug. In addition, two resin pipes 18c are connected to each joint member 18a and extend vertically, and the upper ends of each resin pipe 18c are exposed on the upper end surface of the foundation beam section 15.

[0025] One of the eight resin pipes 18c is used for introducing liquid grout 3, and the other seven are used for discharging the liquid grout 3. The liquid grout 3 introduced through the resin pipe 18c for introducing liquid grout is filled between the joint surfaces 11 and 21 and within the joint member 18a. That is, the main reinforcement bars 25a protruding from one joint surface 21 of the foundation beam section 25 of the precast member 2 are joined with the main reinforcement bars 15a of the other foundation beam section 15 within the resin pipe 18c of the mechanical joint 18.

[0026] On the lower and left and right edges of the joint surfaces 11 and 21 of the precast members 1 and 2 described above, protruding portions 12 and 22 are formed, respectively, continuously in the lateral and vertical directions and projecting from the joint surfaces 11 and 21. The cross-sectional shape of these protruding portions 12 and 22 is, for example, a trapezoidal shape with a narrower width at the tip side in the direction of projection, and the corners are pre-chamfered to avoid chipping. The width at the tip side of this trapezoidal shape is, for example, about 17 mm, and the width at the base is, for example, about 30 mm. The difference between the inner end at the tip and the inner end at the base is, for example, about 3 mm, and the difference between the outer end at the tip and the outer end at the base is, for example, about 10 mm. The projection height of the protruding portions 12 and 22 is, for example, about 6 mm. The design separation distance between the tips of the protruding parts 12 and 22 in the joint structure 100 of the precast members 1 and 2 is, for example, about 8 mm, and the design separation distance between the joint surfaces 11 and 21 is, for example, about 20 mm. The design separation distance between the end faces of the footing parts 16 and 26 is, for example, about 8 mm. The design separation distance between the end faces of the parapet parts 17 and 27 is, for example, about 20 mm.

[0027] A pre-formed sealant 5 is attached to the tip of each of the protruding portions 12 and 22 on one side of each of the precast members 1 and 2 (for example, the side on which the mechanical joint 18 is placed). In the joint structure 100 of the precast members, the pre-formed sealant 5 is compressed between the opposing surfaces of the protruding portions 12 and 22 by being pressed by them. In this compressed state, the pre-formed sealant 5 is crushed in the direction of the pressing (the extension direction of the precast members 1 and 2) and bulges out in a direction perpendicular to this pressing direction. On the side of the protruding portions 12 and 22 perpendicular to the direction of pressing, the trapezoidal shape of the protruding portions 12 and 22 expands the edge space of the joint surfaces 11 and 21, allowing the bulging portion of the pre-formed sealant 5 to spread out within this expanded edge space. The portions where the above-mentioned protrusions 12 and 22 are formed are furring areas with a width of approximately 30 mm and are not considered structural elements of the foundation beams 15 and 25. In other words, the joint surfaces 11 and 21 consist of a grout-filled area where grout is filled and a furring area located outside this grout-filled area.

[0028] The vertical cross-sectional shape of the pre-formed sealant 5 in its unpressed state is, for example, rectangular, and the protruding height and width in the direction of pressing are, for example, about 20 mm each. The pre-formed sealant 5 is made of, for example, EPDM (ethylene propylene diene rubber) foam. The grout 3 introduced between the joint surfaces 11 and 21 is sealed by the protruding parts 12 and 22 and the pre-formed sealant 5. In actual construction of the joint structure 100 of the precast members, the distance between the protruding parts 12 and 22 may exceed the design value of 8 mm. In such cases, the size of the pre-formed sealant 5 is set so that leakage of grout 3 can be prevented.

[0029] Next, a method for manufacturing the joint structure 100 of the precast members in this embodiment will be described. As shown in Figure 4, the joint surface 21 of the other precast member 2 is brought into contact with the joint surface 11 of one precast member 1 that has already been installed. Then, these joint surfaces 11 and 21 are brought together and the standard sealing material 5 is pressed with the protruding parts 12 and 22. In this butt joint operation, for example, the four main reinforcing bars 25a of the precast member 2, which has been lifted by a hoisting machine, are inserted into the joint members 18a of the mechanical joint 18 of the precast member 1 that has already been installed.

[0030] Then, as shown in Figure 5, plate members B1 and B2 are placed against the sides and top surfaces (the parts that are separated from the parapet sections 17 and 27) of the foundation beam sections 15 and 25, and these plate members B1 and B2 are fixed to the foundation beam sections 15 and 25 with bolts or the like.

[0031] Furthermore, in the portion of the upper surface of the foundation beams 15 and 25 that is separated from the parapet walls 17 and 27, the plate member B2 functions as a stopper for the liquid grout 3. On the other hand, since the plate member B2 that serves as a stopper cannot be placed at the lower edge of the parapet walls 17 and 27, in this embodiment, the protruding portion and the standard sealing material are placed on the lower edge side of the parapet walls 17 and 27 (the portion that does not overlap with the foundation beams 15 and 25). However, if a furring area is also provided on the upper side of the foundation beams 15 and 25, and the protruding portions 12 and 22 and the standard sealing material 5 are extended into this furring area, the plate member B2 is unnecessary.

[0032] Next, liquid grout 3 is introduced between the joint surfaces 11 and 21. In introducing the liquid grout 3, a pipe is inserted into one of the eight resin pipes 18c designated for introducing the liquid grout 3, and the liquid grout 3 is sent out at a predetermined pressure from a hose connected to this pipe. When the joint surfaces 11 and 21 and the mechanical joint 18 are filled with liquid grout 3, the liquid grout 3 will overflow from the seven resin pipes 18c, and the injection of liquid grout 3 is completed. The plate member B2 may be removed at the beginning of the filling of the liquid grout 3 so that the filling status of the grout 3 can be checked, and the plate member B2 may be attached to the foundation beams 15 and 25 when the liquid grout 3 begins to overflow.

[0033] With the precast members 1 and 2 described above, by butting the joint surfaces 11 and 21 of adjacent precast members 1 and 2 together, a sealing portion is formed between the joint surfaces 11 and 21 that seals the grout 3, by the protrusions 12 and 22 provided by the precast members 1 and 2 themselves and the pre-formed sealing material 5 attached to the protrusions 12 (or 22). Therefore, there is no need to wait for the mortar to harden as in the conventional method, which shortens the construction period and reduces costs compared to using conventional frame members. It is also possible to attach the pre-formed sealing material 5 to the opposing protrusions 12 and 22, respectively.

[0034] Furthermore, in the joint structure 100 of the precast members and its manufacturing method, the liquid grout 3 is sealed between the joint surfaces 11 and 21 at the points where the precast sealing material 5 is pressed by the protrusions 12 and 22 provided by the precast members 1 and 2 themselves, thus reducing costs compared to using conventional frame members. In addition, since there is no need to wait for the mortar to harden, the construction period can also be shortened.

[0035] Furthermore, if the precast members 1 and 2, with the standard sealant 5 already attached to the protruding parts 12 and 22, are transported to the construction site where the precast members 1 and 2 are to be installed, the work of attaching the standard sealant 5 at the construction site becomes unnecessary, thus speeding up the construction process.

[0036] Instead of the above-mentioned standard sealant 5, the standard sealant 5A shown in Figure 6(A) can be used. In the cross-sectional shape of this standard sealant 5A perpendicular to the longitudinal direction, the pressure surfaces (upper and lower surfaces) are flat, while both sides are concave. When this standard sealant 5A is attached to the protruding parts 12 and 22 on the left and right edges of the foundation beams 15 and 25, the central part of the standard sealant 5 in the direction of pressure is concave horizontally when unpressed, and when it is attached to the protruding parts 12 and 22 on the lower edges, the central part of the standard sealant 5 in the direction of pressure is concave vertically when unpressed.

[0037] By using the above-mentioned pre-formed sealant 5A, the amount of bulging in the central part when the pre-formed sealant 5A bulges in a direction perpendicular to the direction of pressure is reduced compared to the non-concave structure. As shown in Figure 6(B), this suppresses the occurrence of defects in the grout 3 between the joint surfaces 11 and 21. In other words, it is possible to prevent the pre-formed sealant 5A from penetrating beyond the furring area into the grout-filled area between the joint surfaces 11 and 21.

[0038] The above-mentioned standard sealant 5A can be obtained, for example, by cutting a plate-shaped standard sealant with a thickness of 20 mm and dimensions of 1000 mm in length and width into 20 mm widths using a cutting blade. Here, the pressure applied by the cutting blade causes distortion at the cut point of the plate-shaped standard sealant, so the concave portion is naturally formed in the standard sealant 5A. The standard sealant 5A does not need to have concave portions on both sides; if it has a concave portion on only one side, it should be attached to the protrusions 12 and 22 so that the concave portion faces inward (towards the grout-filled area). It is also possible to obtain the standard sealant 5A by bonding the narrow surfaces of two standard sealants with a trapezoidal cross-section together.

[0039] A standard sealant 5B shown in Figure 7(A) may be used. The cross-sectional structure of this standard sealant 5B perpendicular to the longitudinal direction is, for example, a three-layer structure, in which the middle layer is less prone to deformation than the upper and lower layers.

[0040] When using the pre-formed sealant 5B, the amount of bulging in the central part when the pre-formed sealant 5B bulges in a direction perpendicular to the direction of pressure is reduced compared to a pre-formed sealant where the degree of deformation is the same throughout. As a result, as shown in Figure 7(B), the occurrence of defects in the grout 3 between the joint surfaces 11 and 21 can be suppressed. In other words, it is possible to prevent the pre-formed sealant 5B from entering the grout-filled area between the joint surfaces 11 and 21 beyond the furring area.

[0041] The resistance of each layer of the standard sealant 5B to deformation under compression can be changed, for example, by adjusting the foaming ratio of the EPDM foam. That is, by making the foaming ratio of the central part of the standard sealant lower than that of the non-central parts, the amount of deformation due to compression in the central part can be made smaller compared to the non-central parts.

[0042] Alternatively, if the foam in the central part of the standard sealant 5 is made into closed cells, and the foam in the non-central parts is made into open cells or semi-closed cells, the amount of deformation due to pressure in the central part can be made smaller compared to the non-central parts.

[0043] Alternatively, in the standard sealing material 5, the materials of the central portion and the non-central portion may be made different. Let the Poisson's ratio of the material of the central portion be P1 and the Poisson's ratio of the material of the non-central portion be P2, and by setting P1 < P2, the amount of deformation due to the pressing of the central portion can be made smaller than that of the non-central portion.

[0044] Further, the precast members 1 and 2 may have a structure that does not have the footing portions 16 and 26 described above.

[0045] As described above, the embodiments of the present invention have been described with reference to the drawings, but the present invention is not limited to those of the illustrated embodiments. Various modifications and variations can be made within the same scope or equivalent scope as the present invention with respect to the illustrated embodiments.

Explanation of Reference Numerals

[0046] 1: Precast member 2: Precast member 3: Grout 4: Vertical joint 5: Standard sealing material 5A: Standard sealing material 5B: Standard sealing material 11: Joint surface 12: Protrusion 15: Foundation beam portion 15a: Main reinforcement [[ID=Z39]]16: Footing portion 17: Wall waist portion 18: Mechanical joint 18a: Joint member 18c: Resin pipe 21: Joint surface 22: Protrusion 25: Foundation beam portion 25a: Main reinforcement 26: Footing portion 27: Wall waist portion 100: Joint structure B1: Plate member B2: Plate member

Claims

1. A precast member having joint surfaces at both ends in the extension direction, wherein a vertical joint is formed on the joint surface by grout filling, and comprising: a protruding portion that continuously protrudes from the joint surface in the vertical direction on at least the left and right edges of each joint surface; and a pre-shaped sealing material attached to the protruding portion of at least one of the joint surfaces, wherein at least the grout-filled side of the central part in the direction receiving pressure from the protruding portion is horizontally concave when not pressed.

2. A precast member having joint surfaces at both ends in the extension direction, wherein a vertical joint is formed on the joint surface by grout filling, and comprising: a protruding portion that continuously protrudes from the joint surface in the vertical direction on at least the left and right edges of each joint surface; and a pre-formed sealing material attached to the protruding portion of at least one of the joint surfaces, wherein the material in the central part in the direction receiving pressure from the protruding portion is made of a material that is less prone to deformation than the material in the non-central part.

3. A precast member according to claim 1 or claim 2, comprising at least a foundation beam portion and a footing portion extending laterally from the lower part of the foundation beam portion, wherein reinforcing bars protrude from one joint surface of the foundation beam portion, and a mechanical joint is embedded on the other joint surface side of the foundation beam portion to connect reinforcing bars protruding from the joint surface of an adjacent precast member.

4. A joint structure for precast members, wherein a vertical joint is formed by filling the joint surfaces of adjacent precast members with grout, using a precast member according to any one of claims 1 to 3, A joint structure for a precast member, characterized in that the above-mentioned standard sealant is pressed by the above-mentioned protruding portion.

5. A method for creating a joint structure by joining precast members according to any one of claims 1 to 3, The process involves butting the joint surfaces of adjacent precast members together with the above-mentioned standard sealant interposed, and pressing the standard sealant with the above-mentioned protrusion, The step of filling the gap between the above-mentioned joint surfaces with grout, A method for manufacturing a joint structure for precast members, characterized by including [a specific element].

6. A method for manufacturing a joint structure for a precast member according to claim 5, characterized in that the precast member with the standard sealant already attached is transported to the construction site where the precast member is to be installed.

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