JP2018111952A - Junction structure and junction metal fitting for precast concrete staircase, and method of manufacturing wall pillar - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem in which a conventional junction structure for a precast concrete staircase cannot follow up deformation of a building in a case of an earthquake since a connector for coupling a wall pillar and a tread sticks on cast concrete and a tightening-up length which freely extends is not secured, according to the present invention.SOLUTION: The present invention relates to a junction structure for a precast concrete staircase such that junction metal fittings 1 are embedded in a precast concrete wall pillar 21a; and a connector 23 inserted into the junction metal fittings 1 does not have a part sticking on cast concrete from a bearing flat plate 1b of the junction metal fittings in the wall pillar to an end face of a junction part of a precast concrete tread 24 joined to a through concrete form 6 and the wall pillar and a space capable of freely extending in a longer direction is thereby maintained so as to construct a system staircase 3.SELECTED DRAWING: Figure 1-A

Description

  The present invention mainly relates to a method for manufacturing an outdoor staircase in a reinforced concrete apartment house, a precast concrete staircase joint structure, a joint fitting, and a wall column.

  Conventionally, construction of stairs using cast-in-place concrete requires a skilled worker, and is a construction method that is difficult to select due to the lack of skilled workers. Therefore, a method is known in which a part of a staircase made of reinforced concrete is manufactured in advance at a factory to make it an outdoor staircase of a building (see Patent Document 1).

  The method of constructing the precast concrete (hereinafter referred to as PCa) staircase is, for example, Conventional Example 1: Precasting the middle wall (wall pillar) and the step board into one piece, dividing one floor into two parts, and then dividing it on site Assembling method, conventional example 2: There are methods such as a method in which only a corrugated board is precast, and a one-floor two-piece corrugated board is integrated with an inner wall of the cast-in-place concrete. Among these, the said patent document 1 is a construction method which assembles 1 piece of inner walls and a corrugated board on-site, and the schematic structure is demonstrated with reference to drawings.

  As shown in FIGS. 6 and 7, for example, there is a reinforcing joint 2 as a joint for joining the PCa wall column 21 a and the PCa step plate 24 in the field. When the PCa step plate 24 and the PCa wall column 21a constituting the precast concrete staircase 3 are connected to each other, the joint fitting 2 is horizontally inserted into the PCa step plate 24 from the connection side wall surface 24b. In order to connect a “screw joint rebar” (also referred to as a screw rebar), which is a connector 23, from the PCa wall column 21a side to a joint for a threaded rebar joint (long nut 25b), it is embedded in the PCa wall column 21a. It is what is done.

  The connection fitting 2 includes a cylindrical body 2a through which the threaded reinforcing bar as the connection tool 23 is inserted in the front-rear direction (longitudinal direction) from the PCa wall column 21a toward the PCa step plate 24. The cylindrical body 2a is a cylindrical body made entirely of metal.

  There are a metal support flat plate 2b and a frame flat plate 2c which are fixedly provided on the outer periphery of both ends in the front-rear direction of the cylindrical body 2a along the left-right direction orthogonal to the front-rear direction.

  Furthermore, as shown in FIG. 7, the reinforcement provided along the front-rear direction is constructed by being fixed by welding means between the end portions of the bearing plate 2b and the frame flat plate 2c in the left-right direction. There are flat plate bodies 2d, 2d, and U-shaped reinforcing bars 2f fixed to the outer surfaces of the reinforcing flat plates 2d, 2d by welding means.

  The U-shaped reinforcing bar 2f is fixed to the reinforcing flat plate 2d by welding means at both ends 2g and 2g on the U-shaped opening side, and is embedded in the wall column 21a as shown in FIG. In the used state, it is installed in the upward or downward direction along the vertical direction orthogonal to the front-rear direction.

  As shown in FIG. 7 (A), the reinforcing flat plate 2d is a rectangular flat plate, and a through-hole for allowing concrete to enter the inside and ensuring the integrity with the wall column 21a. 2e is provided in the center.

  As shown in FIG. 8, in the formwork for the said PCa wall column 21a, it arranges with the said connector 2, the vertical reinforcement 21b, and the horizontal reinforcement 21c, concrete is laid, and it precasts into concrete at a factory. Further, the anchor 25a and the long nut 25b are embedded, and concrete is placed in the mold, so that the PCa corrugated board 24 is precast concrete.

  As shown in FIGS. 6 and 8, a PCa step plate 24 is arranged at a predetermined position on the PCa wall column 21a, and a connector 23 is connected to the cylinder 2a of the connection fitting 2 of the PCa wall column 21a from the outside. The threaded portion 23a is screwed into the long nut 25b.

  The washer 4 is fitted into the head 23b of the connector 23, and further, the fixing nut 5 is tightened with a required torque to fasten. By repeating this, the PCa staircase 3 according to the conventional example is completed as a system staircase, which is an external staircase of the building.

JP 2000-64551 A

  However, the joint structure of PCa stairs 3 is affected by the interlayer deformation of the building that occurs at the time of the earthquake, and a large forced deformation occurs in the stairs itself depending on the joint position of the building and the stairs. It is difficult to predict deformation with wall columns.

  In addition, when the connection between the PCa wall column 21a and the PCa corrugated plate 24 is made by friction bonding with a normal bolt, the degree of freedom and the length of the connection tool 23 cannot be sufficiently obtained, and it cannot follow the deformation of the building at the time of the earthquake. In some cases, the stairs are damaged. In addition, when an unexpected deformation acts on the stairs during an earthquake, it is a big problem that the stairs serving as an evacuation route are damaged in order to ensure the safety of human lives. The joint structure of a precast concrete staircase, a joint metal fitting, and a method for manufacturing a wall column according to the present invention have been proposed in order to solve such problems.

  The gist for solving the above-mentioned problems of the joint fittings for PCa staircases according to the present invention is to achieve the purpose by connecting the stepboards constituting the precast concrete staircase and the wall columns to the connection side of the stepboards. In order to connect a connector from the side of the wall column to a joint for a threaded rebar joint inserted horizontally from the side wall surface to the inside thereof, the connector is embedded in the wall column. A cylindrical body that is inserted in the front-rear direction from the front to the corrugated plate, and concrete that is respectively placed along the left-right direction perpendicular to the front-rear direction on the outer periphery of both ends in the front-rear direction of the cylindrical body. In addition to preventing intrusion, the head of the connecting tool is fixed on one side and a supporting plate that becomes a fixing portion for joining, and a sealing plate that the fitting is loosely fitted in the through hole. Precast that can follow the deformation of the building A metal fitting capable of forming a space portion not filled with concrete between the inner wall of the cylindrical body and the outer peripheral surface of the connection tool so that the connection tool extends in the longitudinal direction by a tensile force to be a concrete staircase It is to be.

  The gist for solving the above-mentioned problems of the method for manufacturing a wall column in the precast concrete staircase according to the present invention is to provide a cast concrete from one side along the thickness direction inside the precast concrete formwork. A fixing part forming frame for forming a fixing part, a joining metal fitting according to the present invention arranged to be connected to the fixing part mold, and a connection to the joining metal fitting. And at least a penetrating mold that prevents penetration of the cast concrete into the inside of the cast concrete to place the concrete into the mold and prevent the cast concrete from entering the cylindrical body of the joint fitting. .

  The dimension between the outer end face of the flat plate for supporting pressure of the joint fitting and the outer end face of the through-type frame is set to a dimension 5 to 9 times the diameter of the connection tool inserted through the tubular body of the joint fitting. It includes that.

  The gist for solving the above-mentioned problems of the joint structure of precast concrete staircases according to the present invention and achieving the object is that the joint fitting according to the present invention is embedded in a precast concrete wall column, and From the plate for bearing to the end face of the joint part of the precast concrete corrugated plate joined to the penetration mold and the wall column, the connecting tool inserted through the joint metal has no adhesion part with the placed concrete. The system staircase is constructed by maintaining a space that can freely extend in the longitudinal direction.

  The dimension between the outer end face of the flat plate for supporting pressure of the joint fitting and the outer end face of the through-type frame is set to a dimension 5 to 9 times the diameter of the connection tool inserted through the tubular body of the joint fitting. It includes that.

  According to the method of manufacturing a PCa staircase joint structure, joint metal fitting, and wall column according to the present invention, the length of the connection column and the cast concrete can be freely moved while being prevented from adhering. When the tightening length L of the connector connecting the step board is sufficiently secured, and the building is deformed during an earthquake, the PCa staircase is also flexibly deformed and the deformation energy is absorbed efficiently, and the building is deformed. It has an excellent effect of being able to follow up sufficiently.

It is the partially expanded longitudinal cross-sectional view which shows the use condition of the joining metal fitting 1 of the PCa staircase of the same invention. They are the sectional side view (A), the front view (B), and the rear view (C) of the joint fitting 1. It is sectional drawing of the state which set concrete in the formwork, after setting the joining metal fitting 1 to the formwork for PCa wall pillar 21a. They are the side view (A) and the top view (B) which show the whole structure of PCa staircase 3 concerning the present invention. It is explanatory drawing of the experiment mode which shows the performance experiment of the joining metal fitting 1 which concerns on this invention, The partial side view (A) of PCa step board, The top view (B) of the PCa step 3, The front view (C), the same It is a side view (D) figure. It is a characteristic curve figure which shows the load-deformation amount of the front-end | tip part of PCa corrugated board 24. FIG. It is a characteristic curve figure which shows the relationship of the load-strain amount of the screw reinforcement which is the connector 23 in the position of each a, b, c, and d shown in FIG.3 (D). It is the partially expanded plane sectional view which shows the use condition of the joining metal fitting 2 of the PCa staircase which concerns on a prior art example. They are a front view (A), a left side view (B), a right side view (C), and a plan view (D) of the joint fitting 2. It is a front view of the PCa wall column 21a which shows the state which arranged the joining metal fitting 2, the vertical reinforcement 21b, the horizontal reinforcement 21c, etc. in the PCa staircase concerning a prior art example.

  As shown in FIGS. 1A and 1B, the precast concrete staircase joint structure according to the present invention secures the deformation follow-up performance of the connector 23 using the joint metal 1, and the deformation of the building during an earthquake. In addition, the joint structure is such that the PCa staircase (system staircase) 3 can follow the deformation caused by leaning of the building.

  The joining metal fitting 1 used for joining PCa steps according to the present invention will be described. The same members as those in the conventional example are denoted by the same reference numerals as those in the conventional example.

  First, as shown in FIGS. 1-A and 1-B, when the joining metal fitting 1 connects the PCa step plate 24 constituting the precast concrete staircase 3 and the PCa wall column 21a, In order to connect the screw reinforcement which is the connection tool 23 from the side of the PCa wall column 21a to the joint (long nut 25b) for the screw reinforcement joint inserted horizontally from the side wall surface on the connection side to the inside thereof, the PCa wall It is embedded in the pillar 21a.

As shown in FIG. 1-B, the joining metal fitting 1 has a screw rebar (or a threaded rebar) that is a connecting tool 23 extending from the PCa wall column 21a toward the step floor 24a of the PCa step plate 24. A cylindrical body 1a that is inserted in a direction, and the concrete that is placed on the outer periphery of both ends in the front-rear direction of the cylindrical body 1a along the left-right direction perpendicular to the front-rear direction is prevented from entering the inside of the cylindrical body 1a. At the same time, a head plate 23b of the connection tool 23 is fixed on one side and a supporting plate 1b serving as a fixing part for joining and a sealing plate 1d in which the connection tool 23 is loosely fitted in the through hole. Become.
The load plate 1b and the contact plate 1d are provided with through holes 1c and 1e, respectively.

  A method for manufacturing the PC wall column 21a will be described. As shown in FIG. 1-C, the joint fitting 1 is arranged in a wall column mold as follows. A fixing part mold 8 for preventing intrusion of the cast concrete from one side of the precast concrete mold along the thickness direction and forming a space for the fixing part, and the fixing part mold 8 is provided with a joint metal 1 connected to 8, a through-mold frame 6 connected to the joint metal 1 to prevent intrusion of cast concrete, and a counterbored plate 7 for connecting step plates. To do. The fixing unit mold 8, the penetrating mold 6, and the counterbore plate 7 are removed together with the concrete hardening of the wall column 21a. Also, even if the cast-in-concrete intrudes into the inside of the cylinder 1a, the hole for installing the connection tool 23 penetrates the PC wall column 21a, so that it can be easily removed by demolding after the concrete is hardened. Can be removed.

  The dimension (tightening length L) between the outer end face of the pressure-bearing flat plate 1b of the joint fitting 1 and the outer end face of the through-type frame 6 (also the end face of the joint portion of the step plate 24) is the joint fitting 1. 5 to 9 times the diameter D of the connection tool 23 inserted through the cylindrical body 1a, and the dimension is set to 5D ≦ L ≦ 9D. This is due to the following reasons. For example, the state without the tightening length L is a state in which the grout is filled in the cylindrical body 1a, and the connector 23 is distorted in accordance with the deformation of the member. With respect to an unexpected large deformation that occurs during a large earthquake or the like, there is no room for deformation and there is no room for it, and the corrugated plate 24 is easily damaged, and the connector is also easily broken.

  Therefore, in the connector 23, if the free tightening length (L) extending in the longitudinal direction is even a little, there is an allowance for a deformation escape space for a large deformation that occurs during a large earthquake, etc. The plate is hard to be damaged. The length of the tightening length (L) is determined by the total thickness of the washer and the plate, and is generally 2 times or less and at most 5 times or less (according to “Structural Design Standards” of the Architectural Institute of Japan). However, if the tightening length (L) is less than 5 times the diameter of the connector 23, the wall wall thickness is 200 to 300 mm and the tightening length (L) is 150 to 250 mm. The tool 23 becomes D32 and D35, workability is not good, and the diameter of the connecting tool 23 is large and excessive design, which is uneconomical. On the other hand, when it is 9 times or more, for example, when the connection tool 23 is D29, the tightening length (L) is 261 mm or more, and the required wall pillar thickness is 311 mm or more, which is too economical. In this way, the fastening length (L) is determined.

  In addition, as another embodiment, as shown in FIG. 1-C, the penetrating mold 6 and the counterbore plate 7 are integrally formed by a fixing means such as a screw or an adhesive, and are taken together at the time of demolding. You may make it remove. Furthermore, the fixing unit mold 8 and the through mold 6 may be provided with a through hole and a screw part, and attached integrally with a long bolt, and set in the mold.

  Thus, even if the said joining metal fitting 1 is arrange | positioned in a formwork and concrete is laid in the said formwork, it is made for a placement concrete not to penetrate | invade inside the cylinder 1a in the said joining metal fitting 1. FIG. Then, after arranging the joint fitting 1 and the vertical and horizontal bars for the wall column, concrete is placed in the mold to construct the PCa wall column 21a shown in FIG. 1-A.

  The joint structure of the system staircase 3 will be described. The PCa wall column 21a and the PCa step plate 24 are inserted through the tubular body 1a as shown in FIG. 1-A. Further, it is screwed onto the long nut 25 b, the washer 4 is fitted into the head 23 b of the long nut 23, and the fixing nut 5 is fastened and fixed.

  In this way, the joining metal fitting 1 is embedded in the PCa wall column 21a, and the joint portion of the PCa corrugated plate 24 joined to the penetration frame 6 and the wall pillar 21a from the supporting plate 1b of the joining metal fitting in the wall pillar. There is no space where the connecting tool 23 inserted through the joint fitting 1 is attached to the placed concrete and can be freely extended in the longitudinal direction (tightening length L) until reaching the end face, and the system Stair 3 is constructed. The tightening length (L) is set to a size 5 to 9 times the diameter of the connection tool 23 inserted through the tubular body 1a of the joint fitting 1. The reason is as described above.

  Thus, the system staircase 3 efficiently follows the deformation of the building at the time of the earthquake by using the joint metal fitting 1, the method for manufacturing the wall column using the joint metal fitting 1, and the PCa stair joint structure. Absorb.

  About the deformation | transformation property etc. of the system staircase 3 which uses such a joining metal fitting 1, as shown to FIG. 3 (A)-(D), when the predetermined load P is applied to the PCa step board 24, the said The structural performance and fracture characteristics of the system staircase 3 were confirmed, and the amount of deformation was tested.

  Considering the deformation of the system staircase 3, as shown in FIG. 4, the applied force P was repeatedly performed in the vertical direction. However, even when the required proof stress is greatly exceeded, the connecting member is sufficiently stretched to There were no cracks in the vicinity.

  Further, as shown in FIG. 5, in the connection tool 23, the stress bias decreases as the yield load is approached, and since the difference in strain amount at the four locations of the connection tool 23 is small, chain breakage of the connection tool occurs. Hateful. This is because the connection tool 23 is freely movable around the fixing portion of the joint fitting 1 and the tightening length (L) is utilized. In this way, the deformation amount of the PCa staircase 3 with respect to the deformation amount of the building increases, and it can be seen that the PCa step board 24 is deformed following the deformation of the building.

  This is a result of the connector 23 exhibiting sufficient elongation, and this elongation and the tightening length (L) are in a directly proportional relationship. If the tightening length (L) of the conventional example (FIG. 7) is 20 mm, and L in FIG. 1-A of this embodiment is 200 mm, the amount of deformation at the time of breakage of the connection tool (step collapse) compared to the conventional example is 10 times. In addition, as shown in FIG. 4, the collapse of the entire staircase is determined by the yielding of the connection tool 23 based on the observation of the destruction status of the experiment, and a structure such as a concrete portion that is difficult to proceed with destruction other than the connection tool is formed.

  In addition, when the stairs are deformed more than expected due to large deformation of the building and the connecting device yields, the frictional force acting on the contact surface between the PCa plate 24 and the PCa wall column 21a is reduced, and the PCa wall column 21a Free movement of the PCa corrugated plate 24 is promoted. In this way, the connection tool yields and continues to grow without breaking while maintaining the tensile strength, so that the collapse safety of the present embodiment at the time of large deformation of the building is ensured. Thus, the system staircase has a structure that is easy to assume such as destructive properties and limit load, is safe and easy to design, and has high collapse safety.

  In addition, in the case of a staircase having such a collapse mechanism, destruction occurs mainly in this connecting device, so it is highly possible that disaster recovery can be performed quickly by replacing only this connecting device.

  According to the PCa staircase joint structure and joint metal fitting according to the present invention, the present invention can be widely applied to the joining of precast concrete concrete system staircases.

1 bearing joint, 1a cylinder,
1b flat plate for supporting pressure, 1c through hole,
1d contact plate, 1e through hole,
1f Expanded cylindrical body,
2 Reinforced joint fitting, 2a cylinder,
2b flat plate for bearing, 2c flat plate for housing,
2d reinforcing flat plate, 2e through hole,
2f reinforcing bar, 2g end,
2h U-shaped curved part, 2i through hole,
3 PCa stairs (system stairs),
4 Washers,
5 fixing nut,
6 Penetration formwork,
7 Counterbore board,
8 Fixing part formwork,
21a PCa wall column, 21b longitudinal bar,
21c transverse muscle, 21d opening,
22 through hole,
23 connector, 23a screw part,
23b head,
24 PCa corrugated board, 24a corrugated floor (tread),
24b landing,
25 insert hardware, 25a anchor,
25b Long nut.

Claims (5)

From the side of the wall column to the joint for the threaded rebar joint inserted horizontally from the side wall surface on the connection side of the step plate when connecting the step plate and the wall column constituting the precast concrete staircase It is embedded in the wall pillar to connect the connection tool,
A cylindrical body that allows the connection tool to be inserted in the front-rear direction from the wall pillar toward the step board;
In addition to preventing the concrete placed in the outer periphery of both ends in the front-rear direction of the cylinder along the left-right direction perpendicular to the front-rear direction from entering the inside of the cylinder, the head of the connector is on one side. It is composed of a supporting plate that is fixed and serves as a fixing portion for joining, and a sealing plate that is loosely fitted into the through hole,
Space that is not filled with concrete between the inner wall of the cylinder and the outer peripheral surface of the connector so that the connector extends in the longitudinal direction by a tensile force so as to be a precast concrete staircase that can follow the deformation of the building A metal part that can be formed
Precast concrete staircase fittings characterized by From one side along the thickness direction inside the precast concrete formwork,
A fixing part mold for preventing intrusion of cast concrete and forming a fixing part;
The joint fitting according to claim 1, wherein the joint fitting is disposed so as to be connected to the fixing unit mold.
A penetrating mold that is arranged in connection with the joint metal fitting and prevents entry into the cast concrete;
A concrete is placed in the mold by disposing at least, and the cast concrete is not allowed to enter the cylindrical body in the joint fitting,
A method of manufacturing a wall column in a precast concrete staircase characterized by The dimension between the outer end face of the pressure-bearing flat plate of the joint fitting and the outer end face of the through-type frame is set to a dimension 5 to 9 times the diameter of the connection tool inserted through the tubular body of the joint fitting. about,
The manufacturing method of the wall pillar in the precast concrete stairway of Claim 2 characterized by these. The joint metal fitting according to claim 1 is embedded in a precast concrete wall column, and the end face of the joint part of the precast concrete corrugated plate joined to the penetration mold and the wall column from the supporting plate of the joint metal in the wall column. Until the connection tool inserted through the joint fitting has no adhesion part with the placed concrete, a space capable of freely extending in the longitudinal direction is maintained and a system staircase is constructed,
Precast concrete staircase joint structure characterized by The dimension between the outer end face of the pressure-bearing flat plate of the joint fitting and the outer end face of the through-type frame is set to a dimension 5 to 9 times the diameter of the connection tool inserted through the tubular body of the joint fitting. about,
The joint structure of the precast concrete staircase according to claim 4.

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