JPH068176Y2 - Long precast concrete member - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a long precast concrete member.

[Conventional technology]

The applicant has previously found that the material is dense and has high strength,
As a member that functions as a mold while forming a part of a structure in a reinforced concrete structure, etc., a long precast concrete member formed by centrifugal force has been proposed (see, for example, Japanese Utility Model Application No. 60-191318).

[Problems to be solved by the invention]

Since the long precast concrete member of the centrifugal force molded product described above has a large strength, it has an advantage that it can reduce or completely eliminate the supporting work when it is installed between the beams and used for constructing the floor slab. However, in the case of the above-described conventional configuration, the resistance to the load is exerted only by the concrete, and there is a limit to the distance over which this long precast concrete member can be erected without supporting work.

Further, in order for the floor slab formed by synthesizing the long precast concrete member and the concrete cast on site to exhibit the required strength, the thickness of the concrete cast on site had to be large. .

In view of the above situation, an object of the present invention is to provide a long precast concrete member having a higher yield strength.

[Means for solving problems]

The feature of the long precast concrete member according to the present invention is that a long concrete portion of a centrifugal force molded product is provided, and a reinforcing member is provided by connecting upper and lower chord members in a posture along the longitudinal direction of the concrete portion. One chord member of the reinforcing member is in the concrete portion, the concrete portion and the reinforcing member as a whole are symmetrical in the longitudinal sectional view, and on the arrangement surface of the reinforcing member arranged in the concrete portion. The point is that it is buried so that it is located.

[Action]

In addition to being composed of centrifugal force molded products, reinforcing parts such as reinforcing bars are provided to strengthen the concrete part by itself, and
By embedding and fixing one chord member of the reinforcing member in the concrete part so that the whole becomes symmetrical, the reinforcing member resists bending and shearing due to the load acting on the long precast concrete member. However, since one of the chord members of the reinforcing member is located on the arrangement surface of the reinforcing member by providing the reinforcing member on the concrete portion as a part of increasing the yield strength, the reinforcing member and the reinforcing member are To efficiently transmit the stress between
The reinforcing member and the concrete portion can be reliably and strongly integrated so that the reinforcing member can be effectively reinforced, and at the same time, the reinforcing member is relied upon to position and position the reinforcing member during creation by centrifugal force molding. The position can be fixed easily and accurately, and the accuracy can be improved.

Moreover, since the other chord member side of the reinforcing member is projected without being embedded in the concrete portion, in the form of use as a formwork, by embedding the projecting side portion of the reinforcing member in the concrete cast on site, Shearing force can be transmitted by the reinforcing member, and it can be integrated with the concrete cast on site without specially providing a shear connector or the like.

In addition, when a floor slab is created by combining it with on-site cast concrete, the reinforcing member and the concrete in which this reinforcing member is embedded together function as a beam. It is possible to reduce the thickness of the concrete cast on site that is required to achieve the above requirements, compared to conventional methods.

[Effect of device]

As described above, according to the present invention, not only the structural aspect but also the precision aspect, that is, the quality control aspect can be strengthened, and the yield strength of the long precast concrete member can be significantly increased. As a result, when using this long precast concrete member as a formwork / member for floor slabs, it can be erected over a longer distance than before without supporting work, and a further reduction in construction cost can be achieved, Early start of other work on the floor directly below concrete pouring can now be more effectively realized.

In addition, by reducing the thickness of the concrete cast on site in the floor slab, it has become possible to reduce the size of other structures such as columns and beams as the material cost is reduced and the structure itself is made lighter. .

Therefore, as a whole, it has become possible to further shorten the construction period and reduce the cost.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the long precast concrete member (1) is mainly composed of a long concrete portion (1a) of a centrifugal molded product.

This concrete portion (1a) has a semi-cylindrical cross-sectional shape, and inside it, a plurality of tension steel materials (2) for introducing prestress are provided along the longitudinal direction as one of the reinforcing bodies. It is buried.

Each tension steel material (2) is a long precast concrete member (1)
A tensile force is applied at the time of molding, and the tensile force is released when the concrete hardens, and the long precast concrete member (1) is in a state in which a compressive force is applied. Therefore, it is possible to resist a tensile force larger than usual.

The tension steel members (2) are arranged one at each end edge on the open side of the long precast concrete member (1) and five at the center. Therefore, the very long precast concrete member (1) has a peeling (M) to the open side at the center in the longitudinal direction at the time of molding, as shown in FIG. About 20mm ~ 30mm). Then, at the place where this long precast concrete member (1) is used, a load or the like is applied from the open side thereof so that the peeling is offset.

Further, inside the concrete portion (1a), a reinforcing bar (3) arranged in a state of connecting the respective tensile steel materials (2) is also embedded as one of the reinforcing bodies, and this reinforcing bar (3) Bears the shear stress.

Further, as shown in FIGS. 1 to 3, one upper chord member (4A), one lower chord member (4B), and upper and lower chord members (4A).
A reinforcing member (4) including a plurality of connecting members (4C) connecting A) and (4B) is provided.

Each of the one upper chord member (4A) and the one lower chord member (4B) is a deformed steel bar, that is, a reinforcing bar material. Also, multiple connecting materials (4C)
Is a flat steel, that is, a steel aggregate, and by its both ends,
By holding the upper and lower chord members (4A) and (4B) in between,
They are connected and fixed. And the reinforcing member (4) is
As shown in FIG. 4, its side view shape is a ladder shape.

The reinforcing member (4) is placed in a state in which the upper chord member (4A) is located on the rotation center side during centrifugal force molding, and is arranged in a posture along the longitudinal direction of the concrete portion (1a). Four
B) is embedded in the concrete portion (1a) so as to be located on the surface where the reinforcing body is arranged. Furthermore, as shown in FIG. 1, the entire reinforcing member (4) and concrete part (1a) are
It is formed in a substantially symmetrical shape in a longitudinal sectional view.

The reinforcing member (4) resists bending and shearing due to the load acting on the long precast concrete member (1), thereby increasing the yield strength of the long precast concrete member (1). Therefore, when this long precast concrete member (1) is used as a mold and a member for constructing a floor slab described later, it can be erected over a long distance without supporting work.

Further, when the long precast concrete member (1) is used as a semi-prepared member that also serves as a formwork, the reinforcing member (4) is embedded in the concrete poured into the groove space (1b). By doing so, it functions as a shear connector that contributes to the integration of the long precast concrete member (1) and the concrete cast on site.

In the floor slab described later, this reinforcing member
Since the beam function is exerted by (4) and the concrete portion (1a) in which it is buried, the thickness of the floor slab can be made small.

Further, when the long precast concrete member (1) is suspended and moved by a crane or the like, a suspension hook can be hung on the reinforcing member (4) to be suspended.

Next, a method for producing the long precast concrete member (1) will be described. This long precast concrete member (1) is produced by using a circular form (5) for centrifugal force forming, which is used when making a concrete pile or the like for centrifugal force forming. As shown in FIG. 5, the circular form (5) is formed by fixing a pair of groove type steel materials (5a) and (5b), which are obtained by dividing a steel pipe in two in the longitudinal direction, so as to face each other.

Explaining the fixing structure, each channel steel (5a),
On the edge of (5b), the flange (6a),
(6b) is welded and two channel steels (5a), (5b) are made to face each other into a tubular shape, and each flange (6a),
(6b) The two are bolted together. As shown in FIG. 5 and FIG. 6, the joint surfaces of the pair of channel steels (5a), (5b) and the joint surfaces of the flanges (6a), (6b) are made of concrete from inside. The positions are slightly different to prevent leakage.

Then, inside the circular form (5), a pair of partition members (7) that divide the internal space into two in the circumferential direction in a cross-sectional view.
Is provided. As shown in FIG. 6, the partition member (7) is composed of two steel plates (7A), and the two steel plates (7A) are bolted with a spring steel plate (7B) sandwiched therebetween. It is joined. Then, one side edge of the spring steel plate (7B) is inserted and locked in the joint portion of the pair of channel steel members (5a), (5b) forming the circular form (5).

That is, the elastic force of the spring steel plate (17B) is configured to resist the concrete pressure applied to the partition member (7) during centrifugal force forming.

The width of each of the pair of partition members (7) is substantially equal to the thickness of the long precast concrete member (1) to be molded. In other words, during centrifugal force molding, excess concrete will get over this partition member (7) and round formwork.
The long precast concrete member (1) is evenly distributed on the inner circumference of (5) and finally has a substantially constant thickness.

Then, as shown in FIG. 7, lids (9A) and (9B) are fixed to both ends of the circular form (5) in the longitudinal direction. Further, a pair of discs (11A) and (11B) are provided further outside the pair of lids (9A) and (9B). One disk (11A)
A rod (10) is fixed to the.

And, across this pair of discs (11A), (11B),
A tension steel material (2) for introducing prestress to this long precast concrete member (1) is installed, and a nut
It is locked and fixed by (12). The disc (11A) on the side where the rod (10) is fixed has a slit (11a) to enable relative movement with the pair of partition members (7) described above, as shown in FIG. ) Is formed.

When molding the long precast concrete member (1),
By moving the disk (11A) together with the rod (10) outward (to the right in FIG. 7), the tension steel material (2) is given an initial tension. Then, after the concrete inside the circular form (5) is solidified by centrifugal molding, the initial tension is released. As a result, prestress is introduced into the long precast concrete member (1).

The process of creating long precast concrete members (1) is
One of the channel steel (5a) constituting the above-mentioned circular formwork (5) is positioned horizontally, and in this channel steel (5a), a pair of discs (11A) holding tension steel (2), Install (11B) and the lids (9A) and (9B) on both sides. At this time, the reinforcing steel (3) is bound to the tension steel material (2) and the reinforcing member (4) is set.

Then, a predetermined amount of concrete obtained from the thickness and length of the long precast concrete member (1) is put into the channel steel (5a) in advance. Then, set the partition member (7) on the edge of this channel steel (5a), and the other channel steel
Align (5b) and fix with bolts. Then, a predetermined tensile load is applied to the rod (10) to give an initial tension to the tensile steel material (2).

In this state, the circular form (5) is rotated around the longitudinal centerline (X). The rotation speed depends on the conditions,
It is performed in the range of 200 rpm to 600 rpm, and the rotation speed is increased at a low speed at first, and then the rotation speed is increased for 10 to 30 minutes. When the molding is completed, the tensile load applied to the rod (10) is released, and the long precast concrete member (1) is demolded from the circular form (5). After that, if necessary, autoclave curing is performed.

As a result, a long precast concrete member (1) that is dense and has uniform density and high strength can be obtained.

Further, the cross-sectional shape of the long precast concrete member (1) was changed to the semi-cylindrical shape described in the previous embodiment, that is, a circle divided into two, and the circle was divided into three or more pieces. It may be one. For example, as shown in FIG. 9 (a), it may have a sectional shape obtained by dividing a circle into three parts, or as shown in FIG. 9 (b), it has a substantially trapezoidal shape obtained by dividing a circle into 18 parts. It may have a cross-sectional shape.

Further, in place of the circular formwork (5) as the centrifugal force forming form, if a formwork having a polygonal cross section or a flat dish form is used, long precast concrete members (1 ) Can be made. Next, several examples will be described.

<1> What is shown in FIG. 10 (a) is a centrifugal molding frame (5) having a substantially square cross section. Further, (7) in the figure is a partition member, which is attached with a configuration substantially similar to that described in the previous embodiment. Long precast concrete member (1) formed using this formwork (5)
Has a cross-sectional shape shown in FIG. 11 (a).

<2> As shown in FIG. 10 (b), when a centrifugal force forming frame (5) having a substantially square cross section is used and a partition member (7) having a relatively thick wall is used, A long precast concrete member (1) having a rectangular cross section of a basket shown in FIG. 11B is obtained.

<3> What is shown in FIG. 10 (c) is a centrifugal force forming frame (5) having a substantially octagonal cross section. And this formwork
A partition member (7) is attached to each corner of (5). This formwork
The long precast concrete member (1) formed by using (5) has the cross-sectional shape shown in FIG. 11 (C).

<4> What is shown in FIG. 10 (d) is a flat plate-shaped centrifugal force forming frame (5). And this formwork (5) is a support arm (5A)
Thus, it is rotatably attached to the rotary shaft (5B) that serves as the center of rotation during centrifugal force molding. The long precast concrete member (1) formed using this formwork (5) is the 11th
It has a flat cross-sectional shape shown in FIG.

Further, the structure of the reinforcing member (4) can be changed appropriately. Next, several examples will be described.

<5> The one shown in FIG. 12 (a) is a modification of the one shown in FIG. 4, in which the connecting members (4C) for connecting and fixing the upper and lower chord members (4A) and (4B) are The upper and lower chord members (4A) and (4B) are inclined to form a lattice member. In this embodiment, the entire reinforcing member (4) forms a truss in a side view. The upper and lower chord members (4A) and (4B) are both rebar members, and the connecting member (4C) is a steel aggregate member. In addition, connecting material (4
The upper and lower chord members (4A) and (4B) can be caught and held by C) in the same manner as in the previous embodiment.

<6> As shown in FIG. 12 (b), one upper chord member (4A) is provided, two lower chord members (4B) are provided, and two lower chord members (4B) and upper chord members (4A) are provided. Are connected and fixed by a connecting member (4C) in a posture substantially orthogonal to each of the upper and lower chord members (4A) and (4B). Then, the upper chord (4A) and one lower chord (4A)
A connecting member (4C) for connecting with B) and a connecting member (4C) for connecting the upper chord member (4A) and the other lower chord member (4B) are alternately arranged. The upper and lower chord members (4A) and (4B) are both rebar members, and the connecting member (4C) is a steel aggregate member.

<7> The one shown in FIG. 12 (c) is a modification of the one shown in FIG. 12 (b), which is a connecting member (4C) for connecting the upper chord member (4A) and one lower chord member (4B). ) And the upper chord (4A) and the other lower chord (4A)
The connecting material (4C) for connecting with B) is integrally formed by bending one flat steel. The upper and lower chord members (4
Each of A) and (4B) is a reinforcing bar material, and the connecting material (4C) is a steel aggregate material.

<8> What is shown in FIG. 12 (d) is a modification of that shown in FIG. 12 (b), in which the connecting member (4C) is attached to the upper and lower chord members (4A) and (4B) respectively. It is made to be a lattice material.
The upper and lower chord members (4A) and (4B) are both rebar members and connecting members.
(4C) is a steel aggregate.

<9> FIG. 12 (e) shows the structure of the reinforcing member (4) shown in FIG. 12 (a), and the upper and lower chord members (4A) and (4B) are made of steel angle steel. Used, also the connecting material
(4C) is a steel frame member, and the connecting member (4C) and the upper and lower chord members (4A) and (4B) are connected and fixed by welding. Incidentally, the reinforcing member (4) shown in FIG. 4 or FIG. 12 (b) or (2) can have the same structure.

<10> What is shown in FIG. 12 (f) is that in the structure of the reinforcing member (4) shown in FIG. 12 (a), deformed steel bar which is a reinforcing bar material is used as the connecting material (4C). . Further, the connecting material (4C) is a reinforcing bar material, and the connecting material (4C) and the upper and lower chord members (4A) and (4B) are connected and fixed by welding. It should be noted that FIG. 4 or FIG.
The reinforcing member (4) shown in (b) to (d) can have the same structure.

<11> Fig. 12 (g) shows one upper chord bar (1a)
And two lower chord reinforcements (1b), connecting material (4C) made of reinforcement
These are connected and fixed by welding and are so-called omni muscles.

Next, the long precast concrete member according to the present invention
An example of using (1) will be described. First, as shown in FIGS. 1 to 3, a case will be described in which a long precast concrete member (1) having a semicylindrical cross-sectional shape in the longitudinal direction is used as a semi-prepared member that also serves as a floor formwork.

FIGS. 13 (a) to 13 (d) are schematic views showing a process of constructing a floor slab (S) in a building having a steel-framed reinforced concrete structure.

Explaining in the order of steps, first, in the same manner as in the conventional method, a bar reinforcement (14) is arranged around the steel column (13), and a column formwork (15) is raised by surrounding the bar reinforcement (14) ( See Fig. 13 (a). Next, the beam formwork (17), (18) in a state of covering the steel beam (16) from below is installed across the tops of the adjacent column formwork (15) (Fig. 13 (b)).
reference).

After that, a floor form (F) is formed in a portion surrounded by the four beam forms (17) and (18) (see FIG. 13C). Floor formwork
(F) is a plurality of long precast concrete members installed across the beam formwork (17) installed in the girder direction.
(1) and adjacent long precast concrete member (1)
It consists of a weir board (19) laid between them.

The long precast concrete member (1) is formed by centrifugal force, has a substantially U-shaped cross section, and is installed so that its open side faces upward. In addition, weir plate (1
9) is specifically a keystone plate. And
This dam plate (19) is, as shown in FIG. 14, a notch (1c) formed on the outer edge of the long precast concrete member (1).
It is placed in.

Also, explaining the connection between the long precast concrete member (1) and the beam formwork (17) installed in the girder direction,
As shown in FIG. 15, on both sides of the long precast concrete member (1), steel plates (21) welded with round steel (20) are embedded and fixed, and the long precast concrete member
The round steel (20) protruding from both ends of (1) and the steel beam (16) are fixed by welding. The side plate (17a) of the beam formwork (17) erected in the girder direction is cut out according to the shape of the outer periphery of the long precast concrete member (1).

After forming the floor formwork (F) as described above, the reinforcement of beams and floors is reinforced, and this floor formwork (F), and beam formwork (17), (18) and column formwork ( 15) Place concrete inside and. Floor formwork (F)
In, concrete enters the groove space (1b) formed in the long precast concrete member (1), and the reinforcing member (4) located in the groove space (1b) is buried.

As a result, the ready-made concrete part (1a) that constitutes the long precast concrete member (1) and the concrete (C) that has been cast on site are integrated to form the floor slab (S). (See Fig. 13 (d)).

That is, the long precast concrete members (1) with high strength obtained by centrifugal force molding are erected across the beam formwork (17) at appropriate intervals, and these long precast concrete members (1) are By laying a keystone plate as the weir plate (19) in the meantime, it is possible to simplify or eliminate the use of the thick log material and the pipe support as the support work.

Therefore, it becomes possible to start the next process immediately below the floor slab (S) immediately after the concrete is poured, and the material cost and labor cost are reduced due to the reduction of the form material used. It will be possible to reduce.

Next, the case where the long precast concrete member (1) having the cross-sectional shape shown in FIG. 11 (b) or FIG. 11 (c) is used as a semi-ready-made member that also serves as a wall form will be briefly described.

As shown in FIG. 16, in the wall portion to be constructed, this flat plate-shaped long precast concrete member (1), the recessed portion (1
Set up in two rows so that b) face each other. Adjacent long precast concrete members (1) are shaped by the concavo-convex shape of the centrifugal force forming mold (5) or the partition member (7) at the time of molding, by the joint portion (J) consisting of fruit and small holes. It is connected.

Then, the opposing long precast concrete members (1) are used as wall formwork (W), and concrete is placed between them to form a wall. At this time, provided in the recessed portion (1b) of the long precast concrete member (1), the reinforcing member (4) described in the previous example, is buried in the concrete (C) cast on site. Thus, the concrete part (1a) of the long precast concrete member (1) and the concrete (C) cast on site are integrated.

The wall constructed in this way has a dense surface layer and has an excellent shielding effect. Moreover, since the progress of neutralization is slow and it is not easily affected by the outside air, buildings along the coast, or
It is effective when used on the outer walls of buildings that handle radioactivity.

Further, although not shown, a long precast concrete member (1) having a substantially rectangular cross-sectional shape shown in FIG. 11 (a) and FIG. 11 (b) is used in a building over a relatively long span. It can be used as a ready-made or semi-prepared beam that can be installed.

It should be noted that, in the previous example, the long precast concrete member (1) in which prestress was introduced in advance was explained, but the long precast concrete member according to the present invention is described.
(1) may not necessarily have prestress introduced.

It should be noted that reference numerals are added to the claims of the utility model for convenience of comparison with the drawings, but the present invention is not limited to the structure of the accompanying drawings by the entry.

[Brief description of drawings]

The drawings show an embodiment of a long precast concrete member according to the present invention. FIG. 1 is a cross-sectional view of the long precast concrete member, FIG. 2 is a side view of the long precast concrete member, and FIG. Fig. 4 is a plan view of a precast concrete member, Fig. 4 is a perspective view of a reinforcing member, Fig. 5 is a cross-sectional view of a circular formwork, Fig. 6 is an enlarged cross-sectional view of a joint surface of channel steel, and Fig. 7 is a circular mold. FIG. 8 is a vertical cross-sectional view of the frame, FIG. 8 is a plan view of the disc, and FIGS. 9A and 9B are schematic cross-sectional views corresponding to FIG. 1 showing another embodiment of the long precast concrete member. FIGS. 10 (a) to 10 (d) are cross-sectional views corresponding to FIG. 5 showing a modification of the centrifugal force forming frame, and FIG. 11 respectively.
(A) to (d) correspond to FIG. 1 showing still another embodiment of the long precast concrete member obtained by using the centrifugal force forming frame of (a) to (d), respectively. Schematic cross-sectional view, FIG. 12 (a) to (g) shows another embodiment of the reinforcing member, respectively, (a) is a side view, (b) to (g) is a perspective view, 13th
Figures (a) to (d) are schematic perspective views showing the construction process of the floor slab, FIG. 14 is a sectional view of the floor formwork, and FIG. 15 is in FIG.
XV-XV line sectional view, FIG. 16 is a horizontal sectional view of the wall formwork. (1a) …… Concrete part, (4) …… Reinforcement member, (4A)…
… Upper chord, (4B) …… Lower chord, (4C) …… Connecting material.

Claims (11)

[Scope of utility model registration request] 1. A long concrete part (1) of a centrifugal force molded product.
a), and a reinforcing member (4) formed by connecting the upper and lower chord members (4A) and (4B) in a posture along the longitudinal direction of the concrete portion (1a)
The one chord member (4B) of the reinforcing member (4) is provided in the concrete portion (1a), and the concrete portion (1a) and the reinforcing member (4) are entirely symmetrical in a longitudinal sectional view. And a long precast concrete member that is embedded so as to be located on the arrangement surface of the reinforcing member arranged in the concrete portion (1a). 2. The long precast concrete member according to claim 1, wherein the concrete portion (1a) has a semi-cylindrical cross-sectional shape in the longitudinal direction. 3. The long precast concrete member according to claim 1, wherein the concrete portion (1a) has a plane along the longitudinal direction. 4. The long precast concrete member according to claim 3, wherein the concrete portion (1a) has a flat plate-like cross-sectional shape in the longitudinal direction. 5. The reinforcing member (4) comprises one upper chord member (4A), one lower chord member (4B) and a plurality of connecting members for connecting the upper and lower chord members (4A), (4B). (4C) The long precast concrete member according to any one of claims 1, 2, 3, and 4, which is a utility model registration claim. 6. The long precast concrete member according to claim 5, wherein the connecting material (4C) is a lattice material. 7. The reinforcing member (4) comprises one upper chord member (4A), two lower chord members (4B), and a plurality of connecting members connecting the upper and lower chord members (4A), (4B). (4C) The long precast concrete member according to any one of claims 1, 2, 3, and 4, which is a utility model registration claim. 8. The long precast concrete member according to claim 7, wherein the connecting material (4G) is a lattice material. 9. The upper chord member (4A), the lower chord member (4B) and the connecting member (4C)
Is a steel aggregate, the long precast concrete member according to any one of claims 5, 6, 7, and 8. 10. The upper chord member (4A), the lower chord member (4B) and the connecting member (4)
C) and the utility model registration claim 5 which is a reinforcing bar material,
The long precast concrete member according to any one of items 6, 7, and 8. 11. A utility model registration claim in which the upper chord member (4) and the lower chord member (4B) are rebar members, and the connecting member (4C) is an iron frame member. The long precast concrete member according to any one of items 7 and 8.