JP7356951B2 - Beam structure and its construction method - Google Patents

Description

The present invention relates to a beam structure formed by joining precast concrete beam members together, and a method for constructing the same.

Conventionally, a structure has been proposed in which a precast concrete (PC) beam member is joined to a precast concrete (PC) joint member (column beam joint) (see Patent Documents 1 to 3).
Patent Document 1 discloses a method for joining a PC joint member and a PC beam member. The PC joint member is formed with a reinforcing bar accommodation hole that passes through the back-to-back sides of the PC joint member, and at the end of this reinforcing bar accommodation hole, there is a cylindrical hole with a female thread formed on the inner circumferential surface. A shaped fixing hardware is buried. On the other hand, a mechanical joint is attached to the tip of the main beam reinforcement of the PC beam member. First, a PC beam member is placed on the side of the PC joint member, and in this state, a reinforcing bar with a male thread formed on the outer circumferential surface is screwed into the fixing hardware, so that the tip of this reinforcing bar is connected to the mechanical joint of the PC beam member. Arrange the reinforcement so that it reaches inside. Then, nuts are tightened from the ends of the reinforcing bars, and grout is filled into the mechanical joints and reinforcing bar accommodation holes of the PC beam member.

Patent Document 2 shows a joint structure between a PC-built column and a PC-built beam. Rising portions that protrude upward are formed at the four corners of the beam-to-column joints of the columns. A beam is placed on the side of a column, and an end member, which is a fixture, is attached to the tip of the main beam reinforcement of this beam. In this state, concrete is poured at the column-beam joint to construct a joint concrete section.
Patent Document 3 shows a joint structure between a PC beam and a PC column. A through hole is formed in the PC column at a position coaxial with the beam main reinforcement of the PC beam. A joining reinforcing bar is inserted into the through hole, and the tip side of this joining reinforcing bar is joined to the PC beam with a mechanical joint. Next, a filler is filled into the through-hole of the PC pillar, and the base end side of the joining reinforcing bar is fixed in the through-hole.

Japanese Patent Application Publication No. 2009-293192 JP2017-89111A JP 2018-12992 Publication

As a method for constructing a T-shaped beam structure with beams extending in three directions in a short construction period, the present inventor manufactured a first beam member made of PC in which a fixing metal fitting having a female threaded part was embedded in the joint part, Next, a reinforcing bar (connecting reinforcing bar) is inserted into the joint part of the first beam member and screwed onto the fixing hardware, so that the reinforcing bar protrudes from the joint part, and the tip side of the reinforcing bar is inserted into the joint part of the second beam member. The present invention was developed based on the fact that a beam structure can be constructed relatively easily and in a short construction period by joining to the main reinforcement.
The present invention relates to a beam structure formed by joining precast concrete beam members to each other, and provides a beam structure that can be constructed in a short construction period by relatively easily joining the beam members at a construction site, and a method for constructing the same. The challenge is to provide.

The beam structure of the first invention (for example, the beam structure 1 described below) is a precast concrete first beam member (for example, the first beam member described below) having a joint part (for example, the joint part 21 described later). 20); and a second beam member made of precast concrete (for example, a second beam member 30 described later) joined to the joint part of the first beam member, the beam structure comprising: A fixing plate (for example, a fixing plate 40 to be described later) having a female threaded portion (for example, a female threaded portion 41 to be described later) is buried inside the fixing plate, and a reinforcing bar accommodation hole (for example, , a reinforcing bar accommodating hole 42 to be described later) is formed, and a reinforcing bar (for example, a reinforcing bar 25 to be described later) having a male thread (for example, a male thread 26 to be described later) formed on one end side is inserted into the reinforcing bar accommodating hole. The male screw is screwed into the female thread of the fixing plate, and the other end of the reinforcing bar is connected to the main beam reinforcement of the second beam member (for example, the main beam reinforcement 33 described later) with a mechanical joint (for example, the main beam reinforcement 33 described later). They are joined by a mechanical joint 32), and the gap between the reinforcing bar and the reinforcing bar accommodation hole is filled with grout material (for example, grout material 43, which will be described later).

According to this invention, a fixing plate having a female thread is embedded inside the joint part (column-beam joint) of the first beam member, and a reinforcing bar accommodation hole is formed extending from the female thread of the fixing plate to the outside. . Therefore, first, insert the reinforcing bar into the reinforcing bar accommodation hole in the joint part of the first beam member, screw the male thread on one end of this reinforcing bar into the female threaded part of the fixing plate, and then connect the reinforcing bar and the reinforcing bar accommodation hole. By filling the gap with grout, the reinforcing bars protrude from the joint portion of the first beam member to construct a part of the beam structure. Next, a second beam member is placed on the side surface of the joint portion of the first beam member, and the reinforcing bars protruding from the first beam member are joined to the main beam reinforcement of the second beam member using a mechanical joint. Therefore, the second beam member can be relatively easily joined to the joint portion of the first beam member at the construction site, and a precast concrete beam structure can be constructed in a short construction period.
Furthermore, since the first beam member can be transported from the PC factory to the construction site without the reinforcing bars protruding, a large number of the first beam members can be loaded on the truck bed, and the beam structure can be constructed at low cost.

In the beam structure of the second invention, the first beam member includes the joint part and a pair of beam parts (for example, beam parts 22 described below) provided on both sides of the joint part. , the beam main reinforcing bars of the beam portion (for example, the beam main reinforcing bars 24 described later) are arranged vertically in multiple stages passing through the joint part, and at least some of the fixing plates are arranged in multiple stages of the beam part. It is characterized by being placed between the main beam reinforcements.

According to this invention, since at least some of the fixing plates are arranged between the beam main reinforcements passing through the joint part, the reinforcing bars with the fixing plates can be reliably arranged within the joint part of the first beam member. .

A method for constructing a beam structure according to a third aspect of the invention includes a first beam member made of precast concrete having a joint part (column-beam joint), and a first beam member made of precast concrete joined to the joint part of the first beam member. A method for constructing a beam structure comprising: a second beam member; a fixing plate having a female threaded portion is buried inside the joint portion; and reinforcing bars extending from the female threaded portion of the fixing plate to the outside are accommodated. A reinforcing bar having a male thread formed at one end is inserted into the reinforcing bar accommodation hole of the first beam member, and the male thread of the reinforcing bar is screwed into the female threaded part of the fixing plate. Filling the gap with the reinforcing bar accommodation hole with grout (for example, steps S1 and S2 described below), arranging the second beam member at the joint part of the first beam member, and placing the second beam member at the other end of the reinforcing bar. The method is characterized by comprising a step of joining the side to the main beam reinforcement of the second beam member using a mechanical joint (for example, steps S3 and S4 described later).

According to this invention, the reinforcing bars are inserted into the reinforcing bar accommodation holes of the first beam member, the male threads of the reinforcing bars are screwed into the female threads of the fixing plate, and the gaps between the reinforcing bars and the reinforcing bar accommodation holes are filled with grout. As a result, the reinforcing bars protrude from the joint portion of the first beam member. Next, the second beam member is arranged at the joint part of the first beam member, and the other end side of the protruding reinforcing bar is joined to the main beam reinforcement of the second beam member by a mechanical joint. Therefore, the second beam member can be relatively easily joined to the joint portion of the first beam member, and a precast concrete beam structure can be constructed in a short construction period.
Further, since the first beam member can be transported from the PC factory to the construction site without the reinforcing bars protruding, a large number of the first beam members can be loaded on the bed of a truck, making transportation easier.

According to the present invention, it is possible to provide a beam structure that can be constructed in a short construction period by joining the beam members relatively easily, and a method for constructing the same, regarding a beam structure formed by joining beam members made of precast concrete.

FIG. 1 is an exploded perspective view of a beam structure according to a first embodiment of the present invention. FIG. 3 is a plan cross-sectional view of the beam structure. 3 is a sectional view taken along line AA of the beam structure in FIG. 2. FIG. It is a top view of the 1st beam member which constitutes a beam structure. FIG. 3 is an explanatory diagram (Part 1, a diagram showing the arrangement of the fixing plate) of the construction procedure of the first beam member. It is an explanatory view (part 1, a figure showing arrangement of an injection hose) of a construction procedure of a 1st beam member. It is a flowchart of the construction procedure of a beam structure. FIG. 2 is an explanatory diagram (Part 1, a diagram showing the installation of reinforcing bars) of the procedure for constructing a beam structure. FIG. 2 is an explanatory diagram (part 2, diagram showing grout injection) of the construction procedure of the beam structure. FIG. 3 is an explanatory diagram (Part 3, a diagram showing attachment of the second beam member) of the procedure for constructing the beam structure. FIG. 3 is an exploded perspective view of a beam structure according to a second embodiment of the present invention. It is a top view of the 1st beam member concerning the modification of the present invention.

The present invention is a T-shaped or L-shaped beam structure constructed by joining a first beam member and a second beam member made of precast concrete, and a method for constructing the same.
Specifically, the present invention embeds a fixing hardware having a female thread in the joint part of a first beam member made of PC, and screws a male thread on one end of the reinforcing bar into the female thread. This is a beam structure in which the other end of the reinforcing bars is connected to the main beam reinforcement of the second beam member made of PC, and the beam members made of PC are joined to each other.
The first embodiment is a T-shaped beam structure in which a first beam member made of PC and a second beam member made of PC are joined via reinforcing bars screwed to the fixing plate of the first beam member. The second embodiment has a T-shaped structure in which a first beam member made of PC and a second beam member made of PC are connected via reinforcing bars screwed to the fixing plate of the first beam member and a concrete part cast on site. It is a beam structure. Moreover, a modified example is a beam structure in which a first beam member made of PC and a second beam member made of PC are joined in an L-shape.
Embodiments of the present invention will be described below based on the drawings. In addition, in the following description of the embodiment, the same constituent elements are given the same reference numerals, and the description thereof will be omitted or simplified.
[First embodiment]
FIG. 1 is an exploded perspective view of a beam structure 1 according to a first embodiment of the present invention.
The beam structure 1 is approximately T-shaped in plan view, and includes a first beam member made of precast concrete and having a column member 10 and a joint portion (column beam joint) 21 joined to the top of the column member 10. 20, and a second beam member 30 made of precast concrete joined to the joint portion 21 of the first beam member 20.

A column main reinforcement 11 is provided on the upper end surface of the column member 10 so as to protrude upward.
The first beam member 20 includes a joint part 21 and a pair of beam parts 22 provided on both sides of the joint part 21. The pair of beam parts 22 are arranged substantially linearly with the joint part 21 in between.

FIG. 2 is a plan cross-sectional view of the beam structure 1. FIG. 3 is a sectional view taken along the line AA of the beam structure 1 shown in FIG.
A column main reinforcement through hole 23 that penetrates vertically is formed in the joint portion 21 of the first beam member 20 , and the column main reinforcement 11 of the column member 10 is inserted through this column main reinforcement through hole 23 .
Furthermore, a plurality of fixing plates 40 each having a female threaded portion 41 are buried inside the joint portion 21 of the first beam member 20, and a reinforcing bar accommodation hole 42 extending from the female threaded portion 41 of the fixing plate 40 to the outside is formed. ing.

The beam main reinforcements 24 of the beam portion 22 penetrate through the joint portion 21 and are arranged in two stages on the upper and lower end sides.
The fixing plate 40 is provided in two stages on the upper and lower end sides. Among these, the lower fixing plate 40 is arranged between the two main beam reinforcements 24 of the beam portion 22.
Further, a reinforcing bar 25 having a male thread 26 formed at one end thereof is inserted into the reinforcing bar accommodation hole 42 , and the male thread 26 of this reinforcing bar 25 is screwed into the female threaded portion 41 of the fixing plate 40 . A grout material 43 is filled in the gap between the reinforcing bar 25 and the reinforcing bar accommodation hole 42 .

A reinforcing bar accommodation hole 31 is formed in the end face of the second beam member 30, and a mechanical joint 32 joined to the main beam reinforcement 33 of the second beam member 30 is provided at the bottom of this reinforcing bar accommodation hole 31. ing.
The other end of the reinforcing bar 25 attached to the first beam member 20 is inserted into a reinforcing bar accommodation hole 31 of the second beam member 30 and joined to a mechanical joint 32 . Thereby, the reinforcing bars 25 are joined to the main beam reinforcements 33 of the second beam member 30 via the mechanical joints 32.
Note that the gap between the reinforcing bar 25 and the reinforcing bar accommodation hole 31 is also filled with grout material 43.

The first beam member 20 described above is manufactured in a factory, and as shown in FIG. 4, is transported from the factory to the site without the reinforcing bars 25 attached. At this time, since the reinforcing bars 25 do not protrude from the first beam member 20, a large number of reinforcing bars 25 can be loaded on the truck bed without occupying a large space.

The first beam member 20 is constructed by the following procedure.
First, in a formwork for constructing the first beam member 20, the main beam reinforcement 24, the stirrups surrounding the main beam reinforcement 24, the sheath pipe for forming the column main reinforcement through hole 23, and the sheath pipe inserted into the column main reinforcement through hole 23 are inserted into the formwork for constructing the first beam member 20. The reinforcement bars surrounding the column main reinforcement 11 are arranged. Further, a fixing plate 40 is arranged within this formwork, and a sheath pipe 44 forming reinforcing bar accommodation holes 42 is attached to this fixing plate 40 (see FIG. 6).
Here, the fixing plates 40 arranged in the horizontal direction are welded and fixed to a bar-shaped positioning member 45 extending in the horizontal direction, as shown in FIG. The fixing plate 40 is positioned by fixing it with a binding wire or the like. Further, as shown in FIG. 6, the internal spaces of the sheath tubes 44 are communicated with each other through an injection hose 46, and both ends of the injection hose 46 are exposed to the external space.
Then, concrete is poured into the formwork to construct the first beam member 20.

Next, the procedure for constructing the beam structure 1 will be described with reference to the flowchart in FIG.
In step S1, as shown in FIG. 8, reinforcing bars 25 are attached to the reinforcing bar accommodation holes 42 of the first beam member 20 to serve as beam main reinforcements. Specifically, the reinforcing bars 25 are inserted into the reinforcing bar accommodation holes 42 of the first beam member 20, and the male threads 26 of the reinforcing bars 25 are screwed into the female threaded portions 41 of the fixing plate 40. At this time, a mark is made between the reinforcing bar 25 and the joint part 21, and tightened with a predetermined torque (for example, 180 N·m or more).
In step S2, as shown in FIG. 9, the reinforcing bar accommodation hole 42 of the first beam member 20 is filled with grout material 43. Specifically, first, the washer 47 is passed through the portion of the reinforcing bar 25 exposed from the reinforcing bar accommodation hole 42 of the first beam member 20, and the lock nut 48 is tightened. This closes the entrance of the reinforcing bar accommodation hole 42. In this state, by injecting the grout material 43 from one end side of the injection hose 46, the gap between the reinforcing bars 25 and the reinforcing bar accommodation hole 42 is filled with the grout material 43.

In step S3, the column member 10 is erected, and the first beam member 20 is attached on top of this column member 10. Specifically, the first beam member 20 is lifted by a lifting machine, and the column member 10 is lifted up so that the column main reinforcement 11 of the column member 10 is inserted into the column main reinforcement through hole 23 of the joint part 21 of the first beam member 20. The first beam member 20 is suspended above (see FIG. 1).
In step S4, as shown in FIG. 10, the second beam member 30 is attached to the first beam member 20. Specifically, the second beam member 30 is lifted by a lifting machine, placed on the side surface of the joint section 21 of the first beam member 20, and the reinforcing bar 25, which is the main beam reinforcement of the first beam member 20, is lifted up by a lifting machine and placed on the side surface of the joint part 21 of the first beam member 20. 30 into the reinforcing bar accommodating hole 31 and connected to the mechanical joint 32. Thereafter, the gap between the reinforcing bars 25 and the reinforcing bar accommodation holes 31 is filled with grout material 43.

According to this embodiment, there are the following effects.
(1) A fixing plate 40 having a female threaded portion 41 was embedded inside the joint portion 21 of the first beam member 20, and a reinforcing bar accommodation hole 42 extending from the female threaded portion 41 of the fixing plate 40 to the outside was formed. Therefore, first, the reinforcing bar 25 is inserted into the reinforcing bar accommodation hole 42 of the joint part 21 of the first beam member 20, and the male thread 26 of this reinforcing bar 25 is screwed into the female threaded part 41 of the fixing plate 40, thereby connecting the reinforcing bar 25 and the reinforcing bar. By filling the gap with the accommodation hole 42 with grout material 43, the reinforcing bar 25 is made to protrude from the joint portion 21 of the first beam member 20. Next, the second beam member 30 is arranged on the side surface of the joint part 21 of the first beam member 20, and the reinforcing bars 25 of the first beam member 20 are inserted into the reinforcing bar accommodation holes 31 of the second beam member 30, and the machine They are joined using a type joint 32. Therefore, the second beam member 30 can be relatively easily joined to the joint part 21 of the first beam member 20 at a construction site, and the precast concrete beam structure 1 can be constructed in a short construction period.
In addition, since the first beam member 20 can be transported from the PC factory to the construction site without the reinforcing bars 25 protruding, a large number of the first beam members 20 can be loaded on the truck bed, and the beam structure 1 can be constructed at low cost. can.

(2) Since some of the fixing plates 40 are placed between the beam main reinforcements 24 passing through the joint section 21, the reinforcing bars 25 with the fixing plates can be reliably inserted into the joint section 21 of the first beam member 20. Reinforcement can be placed.
(3) Since the main beam reinforcement 33 of the second beam member 30 is joined to the reinforcing bar 25 with the fixing plate embedded in the joint part 21 of the first beam member 20, it is fixed in the joint part 21 of the beam main reinforcement 33. Excellent fixing performance can be ensured while reducing the length of reinforcing bars.

[Second embodiment]
FIG. 11 is a plan cross-sectional view of a beam structure 1A according to a second embodiment of the present invention.
In this embodiment, the structure of the second beam member 30A is different from that in the first embodiment. That is, the mechanical joint 32 is exposed to the outside from the end surface of the second beam member 30. Therefore, after joining the reinforcing bars 25, which are the main beam reinforcements of the first beam member 20, to the mechanical joint 32, concrete is poured between the end face of the second beam member 30 and the joint part 21 of the first beam member 20. By forming the on-site cast concrete portion 49, a beam structure 1A in which the first beam member 20 and the second beam member 30 are joined is realized.
According to this embodiment, the same effects as (1) to (3) described above can be obtained.

Note that the present invention is not limited to the above-described embodiments, and any modifications, improvements, etc. that can achieve the purpose of the present invention are included in the present invention.
For example, in each of the above-described embodiments, the first beam member 20 is provided with a pair of beam parts 22, and the beam structure 1 is formed into a substantially T-shape in plan view. However, the present invention is not limited to this, and as shown in FIG. A single beam portion 22 may be provided in the first beam member 20A, and the first beam member 20A and the second beam member 30 may be joined to form the beam structure 1 into a substantially L-shape in plan view.
Further, in each of the above-described embodiments, the reinforcing bars 25 protruding from the joint portion 21 of the first beam member 20 and the main beam reinforcement 33 of the second beam member 30 are joined by the mechanical joint 32, but the joint is a mechanical joint. It is not limited to, but may be a lap joint or a butt weld joint. Further, the joint position is not limited to the inside of the second beam member 30, but may be provided in the on-site cast concrete portion 49 provided in contact with the second beam member 30.
Furthermore, in each of the embodiments described above, the reinforcing bar accommodation hole 42 is formed with the sheath pipe 44, but when injecting the grout material 43 into the reinforcing bar accommodation hole 42, the grout material 43 is injected with the sheath pipe 44 removed. It's okay.

1, 1A...beam structure 10...column member 11...column main reinforcement 20, 20A...first beam member 21...joint part 22...beam part 23...column main reinforcement through hole 24...beam main reinforcement 25...reinforcing bar 26...formed in reinforcing bar Male screws 30, 30A...Second beam member 31...Reinforcement bar accommodation hole 32...Mechanical joint 33...Beam main reinforcement 40...Fixing plate 41...Female threaded portion 42...Reinforcement bar accommodation hole 43...Grout material 44...Sheath pipe 45...Positioning member 46 …Injection hose 47…Washer 48…Lock nut 49…Concrete poured on site

Claims (3)

A substantially T-shaped beam member comprising a first straight beam member made of precast concrete having a joint part and a second straight beam member made of precast concrete joined to the joint part of the first beam member; The beam structure is approximately L-shaped ,
A fixing plate having a female threaded portion is buried inside the joint portion, and a reinforcing bar accommodation hole extending substantially horizontally from the female threaded portion of the fixing plate to the outside is formed;
One end side of the reinforcing bar accommodation hole remains inside the joint part,
A reinforcing bar having a male thread formed at one end thereof is inserted into the reinforcing bar accommodation hole, the male thread of the reinforcing bar is screwed into the female threaded part of the fixing plate, and the other end of the reinforcing bar is connected to the second threaded part of the fixing plate. It is connected to the beam main reinforcement of the beam member with a mechanical joint,
A beam structure characterized in that a gap between the reinforcing bar and the reinforcing bar accommodation hole is filled with grout material. The first beam member includes the joint part and a pair of beam parts provided on both sides of the joint part,
The beam main reinforcing bars of the beam part are arranged in multiple stages vertically through the joint part,
The beam structure according to claim 1, wherein at least some of the fixing plates are arranged between beam main reinforcements in a plurality of stages of the beam section. A substantially T-shaped beam member comprising a first straight beam member made of precast concrete having a joint part and a second straight beam member made of precast concrete joined to the joint part of the first beam member; A method for constructing a substantially L-shaped beam structure, the method comprising:
A fixing plate having a female threaded portion is buried inside the joint portion, and a reinforcing bar accommodation hole extending substantially horizontally from the female threaded portion of the fixing plate to the outside is formed;
One end side of the reinforcing bar accommodation hole remains inside the joint part,
A reinforcing bar having a male thread formed on one end side is inserted into the reinforcing bar accommodation hole of the first beam member, and the male thread of the reinforcing bar is screwed into the female threaded part of the fixing plate, thereby creating a gap between the reinforcing bar and the reinforcing bar accommodation hole. a step of filling the grouting material into the
arranging the second beam member at the joint part of the first beam member, and joining the other end side of the reinforcing bar to the main beam reinforcement of the second beam member with a mechanical joint. How to construct a beam structure.

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