JP2002242299A - Connecting method between precast concrete beams in beam-column joint part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a connecting method requiring only simple sliding work of a beam connecting lower end reinforcement in a narrow beam-column joint part space surrounded and locked by the end face of a concrete part and having multiple column main reinforcements stood densely while allowing use of a non-timbering construction method in connection between precast concrete beams linearly facing each other for improving workability. SOLUTION: In concrete parts 2 in the opposed end parts of both precast concrete beams 1, a sheath pipe 5 with high strength is buried while connected to the beam lower end reinforcement 3, and a grout material injection passage 6 communicated with the sheath pipe is formed. While the beam connecting lower end reinforcement 7 is inserted into the sheath pipe, the end parts of the both precast concrete beams are placed on column concrete, and the beam connecting lower end reinforcement pulled out from one sheath pipe is inserted into the other sheath pipe. In this condition, a grout material 10 is injected into the sheath pipe from the grout material injection passage, and concrete 12 for the beam upper part and the beam-column joint part is placed after a beam upper end reinforcement 11 is arranged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for connecting precast concrete beams at a beam-column joint.

[0002]

2. Description of the Related Art There are roughly the following two methods for connecting precast concrete beams linearly opposed to each other. One of them is, as shown in FIG. 6 (a), a beam bottom streak c is projected from an end face of a concrete portion b of a precast concrete beam a, and both precast concrete beams a, After placing the ends of a linearly opposite to each other, at the beam-column joint,
This is a method of connecting beam lower end muscles c, c on both sides facing each other via a connecting lower end muscle e. The other one is (b) in FIG.
As shown in FIG. 2, a precast concrete beam a having a shape in which two concrete portions b, b arranged opposite to each other on both sides of a column concrete d are connected by a lower end bar c is produced. After the center portion is placed on the column concrete d, the lower end beams c, c projecting from the end faces of the opposing concrete portions b, b at the center of the span are connected via the lower end line e for connection. This is a method in which connection work of the beam bottom stitch c is not required at the beam-column connection. Although not shown, in any of the methods, the beam top reinforcement is usually temporarily placed on the precast concrete beam a, and after placing the precast concrete a beam on the column concrete d, And are laid over the concrete portions b, b on both sides.

In the method shown in FIG. 6B, since the precast concrete beams a are joined at the center of the span, the joining operation is easy, but the precast concrete beam a is placed on the column concrete d. When it is placed, the precast concrete beam a cannot be kept horizontal only by the beam lower end c connecting the concrete portions b on both sides, so that the support f supporting the center of the span is indispensable.

[0004] In this respect, the method shown in Fig. 6 (a) requires no support at the center of the span since the precast concrete beam a is erected over the column concretes d, d on both sides, and the unsupported construction method is used. It has the advantage that it can be done. However, on the other hand, it is necessary to connect the lower ends of the beams c, c in the space of the narrow beam-to-column connection where the periphery is constrained by the end face of the concrete portion b and a large number of column main bars are erected. There is a problem that it does not.

[0005] Therefore, in order to simplify the work of connecting the beam bottom streaks c, c at the beam-to-column connection, conventionally, for example, the beam bottom streaks and the connection bottom streaks on opposite sides are screwed. It can be connected with a coupler,
As can be seen in Japanese Patent Publication No. 50, connection is made with a joint member in which a nut and grout are used in combination.
As shown in Japanese Patent No. 506403, nuts are screwed into the ends of the opposite beam lower streaks on both sides, respectively, while the lower ends of both sides are fitted to the lower edges of the rectangular longitudinal end plates at both ends in the longitudinal direction. Using a box-shaped connecting hardware formed with a notch, and with this connecting hardware fitted to the lower ends of the beams on both sides, the nut is rotated inside the connecting hardware to remove the lower ends of the beams on both sides. Various joints of the lower end of the beam, such as a pulling method, have been proposed.

However, in each of these methods, the periphery is restricted at the end face of the concrete portion, and
Nuts must be operated in the space of the narrow beam-to-column connection where a large number of column main bars stand, and although the work is simplified compared to the connection work by welding, the workability is extremely high. bad. In addition, since the lower ends of the beams protrude from the end faces of the opposing concrete portions, the projecting lower ends of the beams hinder the work, and the work of suspending the precast concrete beams on the column concrete is troublesome. In addition, in the method using the box-shaped connecting hardware, since the vertical width of the connecting hardware is wider than the outer diameter of the nut, in the beam-to-column connection part where the precast concrete beams cross in a cross shape, the direction in which the connecting hardware is orthogonal. It is an obstacle to the lower end of the beam, making it difficult to apply.

As shown in Japanese Utility Model Laid-Open Publication No. 5-58704, a lower end of a beam protruding from an end face of a concrete portion of a precast concrete beam is bent upward.
There is also a method in which precast concrete beams on both sides are placed on the column concrete in such a way that the lower ends of the beams bent upward are wrapped with each other, and horizontal bars are dropped into the wrapped portion, but from the end face of the concrete portion Since the projecting length of the projecting beam lower end is long and the tip is bent upward, the work of hanging the precast concrete beam on the column concrete is even more troublesome.

[0008]

SUMMARY OF THE INVENTION In view of the above situation, the present invention relates to a method of connecting precast concrete beams that are linearly opposed to each other, in spite of a connection method that can adopt an unsupported construction method. In the space of the narrow beam-to-column connection where the periphery is constrained by the end face of the concrete part and many column main bars are standing, only the simple work of sliding the beam connecting lower bar is performed. Therefore, the present invention provides a connection method with very good workability.

[0009]

The technical measures taken by the present invention to solve the above-mentioned problems are as follows. That is, in the present invention, in connecting the precast concrete beams linearly opposed to each other, in advance, the concrete portions at the opposed ends of the two precast concrete beams have a plurality of strengths that are opened at the end surfaces of the concrete portions. In a state where the high sheath tube is buried in a state connected to the lower end beam of the beam, and a grout material injection path communicating with those sheath tubes is formed, and the lower end line for beam connection is inserted into the sheath tube, On the column concrete, the ends of both precast concrete beams are placed so as to face each other linearly, and then the lower beam for connecting the beams is connected to the column beam connection from the sheath pipe of one of the precast concrete beams. It is pulled out to penetrate and inserted into the opposite sheath tube of the other precast concrete beam. After injecting grout material into the sheath pipe of the recast concrete beam, and arranging the upper end bar of the beam on the upper part of both precast concrete beams, cast concrete at the upper part of the beam and the beam-column connection. I have.

The precast concrete beam may be any of a general RC precast concrete beam and a precast concrete beam into which prestress is introduced. Further, the grout material injection path may be opened at the side surface or the bottom surface of the concrete portion, but is desirably opened at the upper surface of the concrete portion for the reason described later.

According to the above construction, since the precast concrete beams that are linearly opposed to each other are connected at the beam-column connection, the unsupported construction method in which the precast concrete beams erected on the column concrete are not supported at the center of the span. It can be adopted, but there is no joint of the lower end of the beam in the beam-to-column connection, the periphery is constrained at the end face of the concrete part,
In addition, in the space of the narrow beam-to-column connection where many column main reinforcements stand, the lower end reinforcement for beam connection inserted into the sheath pipe of one precast concrete beam is slid horizontally to draw out the required amount. Since only simple work of inserting into the sheath pipe of the other precast concrete beam is necessary, grouting is also performed from outside the space of the beam-column joint with the grouting material injection path formed in the concrete part. Very good sex.

In a state where the grout material is hardened, the lower end reinforcements of the precast concrete beams on both sides are connected to each other through the lower end reinforcements for beam connection and the high-strength sheath pipe, and a stress transmission mechanism is provided. Is clear.

When the ends of both precast concrete beams are linearly opposed to each other on the columnar concrete, the beam connecting lower reinforcement is inserted only into the sheath pipe of one of the precast concrete beams. Accordingly, the other precast concrete beam has no reinforcing bar protruding from the end face of the concrete portion, and the precast concrete beam can be suspended relatively easily. In particular, if the sheath tube into which the lower connecting bar for beam connection is previously set is set to be as long as the lower connecting bar for beam connection, the protruding length of the reinforcing bar for this precast concrete beam is also shortened, and both precast concrete beams are reduced. The suspension of the concrete beam can be easily performed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 1 denotes an RC precast concrete beam. The precast concrete beam 1 is integrated with cast-in-place concrete cast on the upper part thereof to form a beam, and a plurality of beam lower reinforcements 3 are buried in the concrete portion 2 except for both end sides. In addition, the stirrup 4 is buried in a state where its upper end side protrudes from the upper surface of the concrete portion 2. In addition, a plurality of high-strength sheath tubes 5 are embedded at both ends of the concrete portion 2 in a state of being connected to the beam bottom reinforcement 3 by means such as crimping, bonding, welding, and screw fitting. In addition, a grout material injection passage 6 communicating with the sheath pipes 5 is formed in a state where its end is opened to the upper surface of the concrete portion 2.

It is desirable that the communicating portion between the sheath tube 5 and the grout material injection path 6 is near the inner end of the sheath tube 5 in order to improve the filling property of the grout material. Grout material injection path 6
In forming the mold, a rod-shaped die frame, a melted die frame made of styrene foam or the like may be used, or a small-diameter pipe may be embedded. Reference numeral 7 denotes a beam connecting lower end bar inserted into the sheath tube 5, which is longer than the inner dimension of the beam-column connection (distance between opposing end faces of the concrete portion 2), and It is set shorter than the sum of the inner dimension of the mouth and the depth of one of the sheath tubes 5.
In addition, the sheath tube 5 located on the beam lower end muscle 3 and its extension is
It is arranged at a position facing the gap of the column main bar 9 standing on the upper surface of the column concrete 8.

Next, a method of connecting the precast concrete beams 1 which are linearly opposed to each other at the beam-column connection will be described.

First, as shown in FIG. 2, a precast concrete beam 1 is inserted into the sheath pipe 5 of one of the precast concrete beams 1 linearly opposed to each other, and the beam connecting lower reinforcement 7 is inserted into the sheath tube 5. The beam 1 is suspended by a lifting machine and erected on the column concrete 8. As shown in FIG. 1, at the beam-to-column connection, the ends of the precast concrete beams 1 on both sides are placed on the column concrete 8 so as to face each other linearly, and the sheath pipes 5 also face each other. Is located.

In this state, as shown in FIG. 1, the lower connecting streaks 7 are pulled out from the sheath pipe 5 of one precast concrete beam 1 so as to penetrate through the beam-column connection, and the other precast concrete beam is used. The beam 1 is inserted into the opposing sheath tubes 5. In the illustrated example, in order to reduce the grout material injection amount, the sheath tube 5 on one side is shorter than the sheath tube 5 into which the beam connecting lower reinforcement 7 is inserted in advance, but both are longer. It may be formed. At the beam-to-column connection where the precast concrete beam 1 crosses in a cross shape, as shown in FIGS. 1, 3, and 4, the precast concrete beam 1 was inserted between the opposed sheath tubes 5 of the unidirectional precast concrete beam 1. After the lower beam 7 for connecting the beam is slid to the state, the lower beam 7 for connecting the beam is slid in advance in the opposite sheath tube 5 of the precast concrete beam 1 at right angles. Slide it on top of it and insert it.

In this state, the grout material 10 is injected into the sheath pipes 5 of both the precast concrete beams 1 from the grout material injection path 6, and a beam upper end bar 11 is provided above the both precast concrete beams 1, for example. Straddling the precast concrete beams 1 on both sides by a conventional construction method such as pulling out the upper reinforcing bar 11 temporarily placed on one of the beams or setting the upper reinforcing bar 11 temporarily placed on the floor form on the beam. After arranging the reinforcement in the state and performing floor reinforcement not shown in the figure, concrete 12 in the upper part of the beam and the beam-column joint is poured.

The grout material 10 is injected and the upper end of the beam 11
The grouting may be preceded, but it is preferable to inject the grout material 10 after the formwork because a scaffold at the time of work can be secured. Further, the grout material injection path 6 may be opened on the side surface or the bottom surface of the concrete portion 2, but in the illustrated example, the grout material is opened by the grout operator by himself. The grout material 10 can be injected while visually confirming the state of injection of the material 10, that is, while visually checking until the grout material 10 leaks out of the open end of the sheath tube 5 onto the column concrete. It can be done easily and reliably.

Although not shown, at the beam-to-column connection where the three precast concrete beams 1 intersect in a T-shape in plan view, the precast concrete beams 1 linearly opposed to each other.
The above-described method is adopted for the connection between the members. For the remaining precast concrete beam 1, for example, a bent beam main bar at the tip is projected from the end face of the concrete portion, and this is connected to the concrete 12 at the beam-column connection. Will be established.

According to the above configuration, since the precast concrete beams 1 that are linearly opposed to each other are connected at the beam-column connection, the precast concrete beam 1 installed on the column concrete 8 is not supported at the center of the span. It is possible to adopt the construction method, and yet there is no joint of the beam bottom reinforcement 3 in the beam-to-column connection, the periphery is constrained by the end face of the concrete part 2, and a large number of column main reinforcements 9 stand up. In the space of the connection part, it is only necessary to perform a simple operation of sliding the beam connecting lower end bar 7 inserted in the sheath pipe 5 of one of the precast concrete beams 1 in advance, and the grout material 10 can be injected into the pillar beam. The workability is very good because the work is performed from outside the connection space.

In a state where the grout material 10 is hardened, the beam lower reinforcement 3 of the precast concrete beam 1 on both sides is formed.
The members are connected to each other via the beam connecting lower end muscle 7 and the high-strength sheath tube 5, and the stress transmission mechanism is clear.

When the ends of the two precast concrete beams 1 are linearly opposed to each other on the columnar concrete 8, the beam connecting lower reinforcement 7 is provided only on the sheath pipe 5 of one of the precast concrete beams 1. Is inserted, the other precast concrete beam 1 has no reinforcing bar protruding from the end face of the concrete portion 2, and the precast concrete beam 1 can be relatively easily suspended. In particular, if the sheath tube 5 into which the beam connecting lower reinforcing bar 7 is inserted in advance is set to be as long as the beam connecting lower reinforcing bar 7, the projecting length of the reinforcing bar of this precast concrete beam 1 is also reduced. In addition, both precast concrete beams 1 can be easily suspended.

[0025]

According to the present invention, precast concrete beams that are linearly opposed to each other are connected to each other at the beam-column joints. Is bound and
In the space of the narrow beam-to-column connection where many pillar main bars stand, only the simple work of sliding the lower beam for beam connection is required, and the workability is very good. There is.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a main part.

FIG. 2 is a schematic side view.

FIG. 3 is a side view of a main part shown partially broken away.

FIG. 4 is a plan view of a main part.

FIG. 5 is a longitudinal sectional side view of a main part showing a state after connection is completed.

FIG. 6 is an explanatory diagram of a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Precast concrete beam, 2 ... Concrete part, 3 ... Beam bottom reinforcement, 5 ... Sheath pipe, 6 ... Grout material injection path, 7 ... Beam connection bottom reinforcement, 8 ... Column concrete, 10 ...
Grout material, 11: Beam top reinforcement, 12: Concrete.

Claims (1)

[Claims] When connecting precast concrete beams linearly opposed to each other, a plurality of high-strength high-strength openings in the concrete portions at the opposite ends of the precast concrete beams are formed in advance at the end surfaces of the concrete portions. Embed the sheath tube in a state where it is connected to the lower end of the beam,
Further, a grout material injection passage communicating with the sheath pipes is formed, and the end of both precast concrete beams are linearly placed on the column concrete in a state where the beam connecting lower reinforcement is inserted into the sheath pipe. After that, the beam connecting lower end streaks are pulled out from the sheath pipe of one precast concrete beam so as to penetrate the beam-to-column connection, and the other precast concrete beams are opposed to each other. After inserting the grout material into the sheath pipes of both precast concrete beams from the grout material injection path in this state, and arranging the upper end of the beam at the top of both precast concrete beams, A method for connecting precast concrete beams in a beam-to-column connection, wherein concrete at an upper portion and a beam-to-column connection is cast.