PCa joint material

Abstract

To provide a PCa joint member which has PCa members joined to each other via tendons in an unbonded state, capable of inhibiting or suppressing a failure in the integration of the PCa joint member resulting from the breakage of all tendons due to the rust development or the collision with sheath pipes, or a shift between the joined PCa members.SOLUTION: A PCa joint member 100 in which PCa members 10, 20 made of precast concrete and including a plurality of sheath pipes 16, 26 are joined to each other while allowing the communication of the corresponding sheath pipes 16, 26 therewith to form a communication sheath pipe 30. Tendons 17, 27 are inserted into all the communication sheath pipes 30, and the tendons 17, 27 are strained in an unbonded state. A protruded part 15 is provided on an end face 12 of one PCa member 10 joined to the other, and a recessed part 25 is provided in an end face 22 of the other PCa member 20, through which the protruded part 15 is inserted.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a PCa joint member. [Background technology]

[0002] For example, when using on-site concrete pouring to construct joints between columns on upper and lower floors in reinforced concrete (RC) structures, joints between RC columns and beams, or joints in hybrid structures between RC columns and steel beams, construction time can be lengthy. This issue is particularly pronounced in high-rise buildings. Therefore, a construction method is sometimes used in which the columns or columns and joints on both floors are made of precast concrete (hereinafter referred to as "PCa"), and the PCa columns and joints (both included in PCa components) are transported to the site and assembled to form PCa joint components, thereby integrating them with minimal grouting. This construction method for PCa joint components significantly shortens construction time, including for high-rise buildings, and enables the construction of buildings with high structural reliability, since continuous column and column-beam joints are formed using PCa components. Among the methods for constructing PCa joint members, construction time can be further shortened by constructing precast prestressed concrete (hereinafter referred to as "PCaPC") joint members by tensioning the PCa members with tendons such as PC (Prestressed Concrete) steel bars or PC steel wires and fastening them together.In this specification, PCaPC joint members are considered to be included in PCa joint members, and their constituent PCaPC members are considered to be included in PCa members.

[0003] The PCa components typically have multiple sheath tubes inside. When connecting PCa components, the corresponding sheath tubes are connected to form a continuous sheath tube. Tendons are inserted into the continuous sheath tubes and tensioned. Then, grout is filled into the continuous sheath tubes to bond the tendons. This connects the PCa components together. However, filling the continuous sheath tubes with grout is time-consuming, and this issue becomes even more pronounced as the number of continuous sheath tubes increases and the number of grout-filled areas increases with the rise of taller buildings. Furthermore, the curing period required for the grout filled in the continuous sheath tubes to develop a predetermined strength can significantly extend the construction period.

[0004] Patent Document 1 proposes a high-rise building equipped with precast prestressed concrete columns. This high-rise building is equipped with a plurality of precast prestressed concrete columns, each having a tension member inserted vertically into a concrete column body, and a plurality of vibration control devices that suppress the swaying of the building. The precast prestressed concrete columns have tension members disposed in the concrete column body in an unbonded state, and the vibration control devices suppress the swaying of the high-rise building by keeping deformation of the tension members due to the swaying of the high-rise building within the elastic range of the tension members. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-19664 Summary of the Invention [Problem to be solved by the invention]

[0006] The high-rise building described in Patent Document 1 uses unbonded tendons, which can solve the above-mentioned problems associated with grout filling. However, when tendons are tensioned in an unbonded state inside sheath tubes, the tendons are not protected by grout, which can lead to rusting of the tendons, for example, in the joint area of ​​the PCa members. Furthermore, during earthquake deformation of the building, there is a risk that the tendons may collide with the sheath tube, for example, in the joint area. Rust and collision in the joint area can lead to breakage of the tendons, and all tendons may break in the joint area, resulting in a loss of integrity of the PCa joint members. Furthermore, during earthquake deformation of the building, there is a risk that the PCa members may shift relative to each other, for example, in the joint area.

[0007] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a PCa joint member in which PCa members are joined together using unbonded tendons, which can prevent all tendons from being damaged by rust or collision with the sheath pipe, resulting in the loss of integrity of the PCa joint member, and can suppress or prevent the joined PCa members from shifting relative to each other. [Means for solving the problem]

[0008] In order to achieve the above object, one aspect of the PCa joint member according to the present invention is: A PCa joint member in which PCa members made of precast concrete and having a plurality of sheath pipes are joined to each other while communicating the corresponding sheath pipes to form a communicating sheath pipe, Tendons are inserted into all of the communicating sheath tubes, and the tendons are tensioned in an unbonded state; A convex portion is provided on the end surface of one of the PCa members to be joined together, and a concave portion is provided on the end surface of the other PCa member through which the convex portion is inserted.

[0009] According to this aspect, a convex portion is provided on the end face of one of the PCa members to be joined, and a concave portion is provided on the end face of the other PCa member through which the convex portion is inserted.Therefore, even if all of the tension members are damaged, for example, by rusting in the joining area or by collision with the sheath tube, the loss of integrity of the PCa joined members can be prevented, and shifting between the joined PCa members can be suppressed or prevented.

[0010] For example, if the PCa members to be joined are both PCa columns, the lower PCa column may have a convex portion and the upper PCa column may have a concave portion, or vice versa. The convex and concave portions that engage with each other may have various complementary shapes, such as a rectangular parallelepiped, cube, polygonal prism, cylinder, or hemisphere, with a concave portion of a complementary shape. The PCa member may have a single convex and concave portion at the center of its end face, or multiple convex and concave portions at its end faces. Furthermore, the gap between the convex and concave portions may be filled with grout, or typically, a joint material that forms a joint between the PCa members is used to fill the gap. As described above, the PCa joint member of this embodiment includes a PCaPC joint member, the PCa member includes a PCaPC member, the PCa joint includes a PCaPC joint, the PCa column includes a PCaPC column, and the PCa beam includes a PCaPC beam.

[0011] Another aspect of the PCa joint member according to the present invention is The area including the recess is characterized in that it is made of concrete having a relatively high strength compared to other general areas.

[0012] According to this aspect, since the area including the recess is formed from concrete that is relatively strong compared to other general areas, it is possible to reinforce narrow areas that may be formed around the recess, for example, and to prevent chipping or breakage of the narrow areas around the recess.

[0013] Another aspect of the PCa joint member according to the present invention is The convex portion is characterized in that it is formed of concrete having a relatively high strength compared to other general areas.

[0014] According to this aspect, since the convex portion is formed from concrete that is relatively high in strength compared to other general areas, the convex portion, which is narrower than the general areas, can be reinforced, and chipping or breakage of the convex portion can be prevented.

[0015] Another aspect of the PCa joint member according to the present invention is The area including the recess and the protrusion are formed of high-strength concrete.

[0016] According to this aspect, since the area including the recess and the protrusion are both formed of high-strength concrete, chipping or breakage of the narrow area around the recess and the protrusion can be effectively prevented. 2 Although concrete has the above design standard strength, in high-rise buildings, even in the general area of ​​PCa members, 2 ~120N / mm 2 In some cases, concrete with a design standard strength of approximately 100% is applied, and in such cases, the entire PCa member is made of high-strength concrete.

[0017] Another aspect of the PCa joint member according to the present invention is It is characterized in that it further comprises a stiffener that straddles the joint interface between the two PCa members and surrounds their outer peripheries.

[0018] According to this aspect, by further providing a stiffener that straddles the joint interface and surrounds the outer periphery thereof, it is possible to stiffen the joint area, which is an area of ​​reduced rigidity due to cross-sectional loss of both PCa members, and the stiffener can prevent peeling of the concrete cover in the joint area. Furthermore, by surrounding the outer periphery of the joint area with the stiffener, it is possible to prevent outside air, rainwater, etc. from penetrating into the interface, making it possible to suppress rusting of the tendons.

[0019] In another embodiment of the PCa joint member according to the present invention, The PCa members joined to each other are characterized by being PCa columns.

[0020] According to this embodiment, since all of the PCa members that are joined to each other are PCa columns, it is possible to prevent the tendons connecting the vertically consecutive PCa columns from being damaged by rust or collision with the sheath tube, which would result in the loss of integrity between the PCa columns, and it is also possible to suppress or prevent misalignment between the joined PCa columns.

[0021] In another embodiment of the PCa joint member according to the present invention, The PCa members that are joined to each other are characterized by being PCa columns and PCa joints.

[0022] According to this embodiment, since the PCa members joined to each other are a PCa column and a PCa joint, it is possible to prevent the tension members provided in the column-beam joint from being damaged by rust or collision with the sheath pipe, which would result in the loss of integrity of the column-beam joint, and it is also possible to suppress or prevent misalignment between the joined PCa column and PCa joint.

[0023] In another embodiment of the PCa joint member according to the present invention, The PCa members joined to each other are characterized by being PCa beams and PCa beams.

[0024] According to this embodiment, since all of the PCa members joined to each other are PCa beams, it is possible to prevent the tension members connecting the horizontally consecutive PCa beams from being damaged by rust or collision with the sheath pipe, which would result in the loss of integrity between the PCa beams, and it is also possible to suppress or prevent misalignment between the joined PCa beams. [Effects of the Invention]

[0025] As can be understood from the above explanation, the PCa joint member of the present invention, in a PCa joint member in which PCa members are joined together by unbonded tendons, can prevent all tendons from being damaged by rust or collision with the sheath tube, resulting in the loss of integrity of the PCa joint member, and can also prevent or suppress misalignment of the joined PCa members relative to each other. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 2 is a longitudinal cross-sectional view of an example of a PCa joint member according to the first embodiment, showing an enlarged view of the periphery of the joint region of PCa columns joined to each other. [Figure 2] FIG. 2 is a view taken along the line II-II in FIG. [Figure 3] FIG. 10 is a longitudinal cross-sectional view of an example of a PCa joint member according to a second embodiment, showing an enlarged view of the periphery of the joint region of PCa columns joined to each other. [Figure 4] FIG. 10 is a longitudinal cross-sectional view of an example of a PCa joint member according to a third embodiment, showing an enlarged view of the periphery of the joint region of PCa columns joined to each other. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, an example of a PCa joint member according to each embodiment will be described with reference to the accompanying drawings. Note that in this specification and drawings, substantially identical components may be designated by the same reference numerals to avoid redundant description.

[0028] [PCa joint member according to the first embodiment] First, an example of a PCa joint member according to the first embodiment will be described with reference to Figures 1 and 2. Here, Figure 1 is a vertical cross-sectional view of an example of a PCa joint member according to the first embodiment, and is an enlarged view of the periphery of the joint region of PCa columns joined to each other, and Figure 2 is a view taken along the arrows II-II in Figure 1.

[0029] A PCa joint member (PCaPC joint member) 100 is formed by joining a PCa column (PCaPC column) 10 (an example of a PCa member (PCaPC member)) of a lower floor to a PCa column (PCaPC column) 20 (an example of a PCa member (PCaPC member)) of an upper floor. Although not shown here, in addition to the illustrated example, PCa joint members also include joint members between PCa columns (PCaPC columns) and PCa joints (PCaPC joints) and joint members between PCa beams (PCaPC beams), and these various PCa joint members form a hybrid frame structure that makes up a multi-story building.

[0030] Here, the "hybrid frame" refers to a structure that includes PCa columns 10, 20, which are precast RC (Reinforced Concrete) columns, PCa joints (not shown), which are also precast RC joints, and steel beams (not shown) that connect the PCa joints. More specifically, the PCa joints can be said to be SRC (Steel Reinforced Concrete) structures, incorporating brackets that form part of the steel beams.

[0031] The PCa column 10 on the lower floor has a rectangular parallelepiped PCa concrete body 11, with multiple (four in the illustrated example) sheath pipes 16 buried inside, and unbonded PC steel members 17 (an example of a tendon) inserted into each sheath pipe 16. Here, the unbonded PC steel members 17 are PC steel bars, but they may also be PC steel wires or the like. Although not shown, the PCa column 10 has multiple column main reinforcements extending in the vertical direction, and multiple rectangular frame-shaped hoops surrounding the outer periphery of each column main reinforcement.

[0032] The unbonded PC steel 17 protrudes upward from the upper end 12 of the PCa concrete body 11, and by tightening the nut 19 while it is in a tensioned state, the anchoring plate 18 is fixed to the upper end 12 of the PCa concrete body 11, and the tensioned state of the unbonded PC steel 17 is maintained.

[0033] The gap G inside the sheath pipe 16 is not filled with grout, and therefore the unbonded PC steel member 17 is literally in an unbonded state inside the sheath pipe 16.

[0034] On the other hand, the PCa column 20 on the upper floor has a rectangular parallelepiped PCa concrete body 21, and a plurality of sheath pipes 26 (four in the illustrated example) are buried inside the PCa concrete body 21 at positions corresponding to each sheath pipe 16, and an unbonded PC steel member 27 (an example of a tendon) is inserted into each sheath pipe 26. Here, the unbonded PC steel member 27 is a PC steel rod.

[0035] The upper end of unbonded PC tendon 17 and the lower end of unbonded PC tendon 27 are connected to each other via a mechanical joint 35 such as a coupler. In addition, the sheath tubes 16 and 26 are connected vertically to form a communicating sheath tube 30, and the connected unbonded PC tendons 17 and 27 are inserted into the communicating sheath tube 30.

[0036] Here, below the upper sheath tube 26 is an expanded sheath tube 26A with an expanded diameter, and a mechanical joint 35 is accommodated inside this expanded sheath tube 26A.

[0037] Although not shown in the figures, the unbonded PC steel 27 protrudes upward from the upper end of the PCa concrete body 21, and by tightening the nuts in a tensioned state, the anchoring plate is fixed to the upper end of the PCa concrete body 21, thereby maintaining the tension of the unbonded PC steel 27. The sheath pipe 26 is also not filled with grout, and therefore the unbonded PC steel 27 is literally in an unbonded state inside the sheath pipe 26.

[0038] In this way, the unbonded PC steel members 17, 27 on each floor are fixed to the upper ends of the corresponding PCa concrete bodies 11, 21 via anchoring plates.

[0039] A curing member 37 is installed around the fixing plate 18 at the upper end 12 of the PCa concrete body 11, surrounding the unbonded PC steel 17 protruding upward, so that the joint material 40 poured into the joint space 41 (joint interface 80) between the upper end 12 of the PCa column 10 and the lower end 22 of the PCa column 20 does not enter the upper and lower sheath pipes 26, 16.

[0040] Here, for example, a bellows joint is used as the curing member 37, and grout such as mortar is used as the joint material.

[0041] 1 and 2, a rectangular parallelepiped convex portion 15 that protrudes upward is provided at the center of the upper end 12 of the PCa column 10 located below, and a concave portion 25 into which the convex portion 15 is inserted is provided at the center of the lower end 22 of the PCa column 20 located above. The joint material 40 is also filled into the gap between the convex portion 15 and the concave portion 25.

[0042] Although not shown in the figures, the PCa column 10 may have a recess, and the PCa column 20 may have a protrusion that is inserted into the recess. Furthermore, the shapes of the protrusion and recess may be polygonal pillars, cylindrical pillars, etc., other than the illustrated examples, and further, multiple protrusions and recesses may be provided on the end faces of the PCa columns 10, 20.

[0043] According to the PCa joint member 100, a convex portion 15 is provided on the end face 12 of the PCa columns 10 that are joined to each other, and a concave portion 25 through which the convex portion 15 is inserted is provided on the end face 22 of the PCa column 20. Therefore, even if the areas near the joint interface 80 of all the unbonded PC steel members 17, 27 are damaged due to rust or collision with the sheath tubes 16, 26, the mutually engaging convex portions 15 and concave portions 25 can prevent the loss of integrity of the PCa joint member 100, and can also suppress or prevent the joined PCa columns 10, 20 from shifting relative to each other.

[0044] [PCa joint member according to the second embodiment] Next, an example of a PCa joint member according to the second embodiment will be described with reference to Fig. 3. Here, Fig. 3 is a longitudinal cross-sectional view of an example of a PCa joint member according to the second embodiment, and is an enlarged view of the periphery of the joint region of PCa columns joined to each other.

[0045] PCa joint member 100A differs from PCa joint member 100 in that convex portion 15 is formed from relatively high-strength concrete compared to other general areas of PCa column 10, and the area including concave portion 25 is formed from relatively high-strength concrete compared to other general areas of PCa column 20.

[0046] For example, the concrete in the general area of ​​PCa columns 10 and 20 is 50N / mm 2 When the convex portion 15 has a design standard strength of less than 50 N / mm 2 The area including the recess 25 is also formed of high-strength concrete 11A having the above design standard strength and has a resistance of 50 N / mm 2 The PCa columns 10 and 20 are made of high-strength concrete 21A having the above design standard strength. 2 ~120N / mm 2 Since concrete with a design standard strength of about 1000 MPa can be applied, in this case the entire PCa columns 10, 20 are made of high-strength concrete.

[0047] In addition to achieving the same effects as PCa joint member 100, PCa joint member 100A has the advantage that the areas including the mutually engaging convex portion 15 and concave portion 25 are both formed of high-strength concrete 11A, 21A, which has higher strength than other general areas, thereby preventing chipping and breakage, particularly around concave portion 25 and convex portion 15.

[0048] [PCa joint member according to the third embodiment] Next, an example of a PCa joint member according to the third embodiment will be described with reference to Fig. 4. Here, Fig. 4 is a longitudinal cross-sectional view of an example of a PCa joint member according to the third embodiment, and is an enlarged view of the periphery of the joint region of PCa columns joined to each other.

[0049] The PCa joint member 100B further includes a stiffener 70 that straddles the joint interface 80 of the PCa columns 10, 20 and surrounds their outer peripheries (side surfaces 13, 23) compared to the PCa joint member 100. Here, instead of the PCa joint member 100, the PCa joint member 100A may also be provided with a stiffener 70.

[0050] The stiffener 70 is arranged across the joint area A spanning the joint interface 80 of the side surfaces 13, 23 of the PCa columns 10, 20, and is fixed to the PCa columns 10, 20 with bolts 75.

[0051] Here, the joint area A is an area within each of the PCa columns 10, 20, spanning a range of, for example, several centimeters to several tens of centimeters across the joint interface 80. This range is set as the largest of the ranges identified by specifying the area from the joint interface 80 where rust may occur and the area where the unbonded PC steel members 17, 27 will collide with the sheath pipes 16, 26 when the building deforms. The range of rust occurrence is also set depending on the location and environment of the building.

[0052] The stiffener 70 shown in the figure is a steel plate or a carbon fiber sheet, but other frame structures made of multiple shaped steel members, steel pipes, square pipes, etc. may also be used.

[0053] According to the PCa joint member 100B, by further comprising a stiffener 70 that straddles the joint interface 80 and surrounds the outer periphery thereof, it is possible to stiffen the joint area A, which is an area of ​​reduced rigidity due to cross-sectional loss in both PCa columns 10, 20, and the stiffener 70 can prevent peeling of the concrete cover in the joint area A. Furthermore, by having the stiffener 70 surround the outer periphery of the joint area A, it is possible to prevent outside air, rainwater, etc. from penetrating into the interface, and it is possible to suppress rusting of the unbonded PC steel members 17, 27.

[0054] The present invention is not limited to the configurations shown here, and other embodiments may be possible in which other components are combined with the configurations described in the above embodiments. In this regard, the present invention can be modified within the scope of the present invention, and can be appropriately determined depending on the application form. [Explanation of symbols]

[0055] 10: PCa columns (lower floor PCa columns, PCa components, PCaPC columns) 11: PCa concrete body 11A: High-strength concrete 12: Upper end (end surface) 13: Side 15: Convex part 16: Sheath tube 17: Unbonded PC steel (tension member) 18: Fixing plate 19: Nut 20: PCa columns (upper floor PCa columns, PCa components, PCaPC columns) 21: PCa concrete body 21A: High-strength concrete 22: Lower end (end surface) 23: Side 25: Recess 26: Sheath tube 26A: Widened sheath tube 27: Unbonded PC steel (tension member) 30: Connecting sheath tube 35: Mechanical coupling 37: Curing material (accordion joint) 40: Joint material 41: Joint space 50:Grout 70: Stiffener (steel plate) 75: Bolt 80: Bonding interface 100, 100A, 100B: PCa joint material (PCaPC joint material) A: Joint area G: Gap

Claims

1. A PCa joint member in which PCa members made of precast concrete and having a plurality of sheath pipes are joined to each other while communicating the corresponding sheath pipes to form a communicating sheath pipe, Tendons are inserted into all of the communicating sheath tubes, and the tendons are tensioned in an unbonded state; A convex portion is provided on an end surface of one of the PCa members to be joined together, and a concave portion through which the convex portion is inserted is provided on an end surface of the other PCa member, A PCa joint member characterized in that the area including the recess is formed of concrete having a relatively high strength compared to other general areas.

2. The PCa joint member according to claim 1, wherein the convex portion is formed of concrete having a relatively high strength compared to other general areas.

3. The PCa joint member according to claim 2, wherein the region including the recess and the protrusion are formed of high-strength concrete.

4. The PCa joint member according to any one of claims 1 to 3, further comprising a stiffener spanning the joint interface between the two PCa members and surrounding their outer peripheries.

5. The PCa joint member according to any one of claims 1 to 4, characterized in that the PCa members to be joined together are PCa columns.

6. The PCa joint member according to any one of claims 1 to 4, characterized in that the PCa members to be joined to each other are a PCa column and a PCa joint.

7. The PCa joint member according to any one of claims 1 to 4, characterized in that the PCa members to be joined together are PCa beams.

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