JP2000356041A - Method for placing concrete - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for placing concrete that can reduce the period of construction, achieve labor savings, and easily place different kinds of concrete for a support structure element and for a floor slab. SOLUTION: A form for a support structure element, for constituting a support structure element of a building, is constructed, and a half PC floor board 7 which constitutes the lower portion of a floor slab 2 is extended over the form for the support structure element. Precast concrete is placed on top of the half PC floor board 7 and the floor slab 2 is constructed using a complex method. Thereafter, post-cast concrete is placed in situ into the form for the support structure element to construct the support structure element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of placing concrete in a building composed of a supporting structure element such as a pillar or a beam and a floor slab, and more particularly to a method of placing concrete in a supporting structure element and a floor slab. TECHNICAL FIELD The present invention relates to a concrete placing method in which concrete is placed on a floor slab in a building that uses concrete before the concrete is placed on a support structural element.

[0002]

2. Description of the Related Art In recent years, precast reinforced concrete structures are frequently used when constructing buildings, and as shopping centers and high-rise reinforced concrete condominiums increase in size, buildings are required to have an even greater frame strength. It is becoming. In recent years, due to factors such as larger buildings and a decrease in the number of skilled workers, there has been a demand for more efficient construction, improved quality, and shorter construction periods of formwork and rebar than ever before. Various construction methods have been proposed in place of the driving method.

[0003] Precast reinforced concrete structures that replace the conventional cast-in-place method include columns with seismic design,
Earthquake-resistant supporting structural elements such as beams and shear walls, and floor slabs spanned between the supporting structural elements are used. High-strength concrete is often used for columns and the like designed for the above-mentioned seismic design in order to support the strength of the building frame and to provide the necessary seismic resistance.

In recent years, floor slabs having a precast reinforced concrete structure have been constructed by using a precast floor slab in which half is precast, that is, a composite system using a half PC floor slab, and a floor slab precast over the entire thickness of the floor slab. A method has been proposed.

[0005] In particular, regarding a composite floor slab construction method, conventionally, a precast concrete is poured into supporting structural elements such as columns, beams, and walls to form a supporting structure, and then these supporting structural elements are constructed. A post-cast concrete is cast on a half PC floorboard as a support main body to integrate the support structural element and the floor slab, and a floor slab is constructed while imparting sufficient strength to the support structural element.

[0006] In the above-mentioned construction method of a large building such as a high-rise reinforced concrete apartment building or a shopping center, a floor slab is first spanned between supporting structural elements,
In this case, concrete is cast, but in this case, in the conventional construction method, high-strength concrete is cast simultaneously on the above-mentioned support structural element and the floor slab formed by the composite method, A construction method is adopted in which high-strength concrete is cast first, and then ordinary concrete is cast on the floor slab.

[0007] The method of casting high-strength concrete on the supporting structural element and the floor slab is cost-effective because the high-strength concrete is cast on a floor slab that does not require strength than the supporting structural element. Concrete is
In general, there is an inconvenience that the cost efficiency at the time of construction is poor due to poor construction efficiency. To solve this inconvenience, Japanese Unexamined Patent Publication No. 10-46814 discloses a method in which high-strength concrete is cast in advance on a supporting structural element, and after the previously cast high-strength concrete hardens, a half PC is hardened.
A concrete casting method for casting ordinary concrete forming a floor slab upper surface on a floorboard is disclosed. In Japanese Patent Application Laid-Open No. 10-46814, it is possible to separate different types of concrete into support slabs such as columns and beams and floor slabs, thereby achieving cost reduction. Since it can be cast, labor saving and cost reduction of construction cost have been achieved.

[0008] As described above, by placing different types of concrete on the support structural element and the floor slab, labor saving and cost reduction of construction cost have been achieved. Work on the floor slab until the upper surface of the floor slab is hardened even after the placement of the pillar is completed,
For example, work on a floor slab such as blacking out of a floor slab on the upper floor cannot be performed, and it has not been sufficient in terms of work efficiency and labor saving.

Therefore, in the past, when constructing a floor slab in a complex system, it is necessary to perform an operation such as ink marking on the floor slab before or during concrete placement of the support structural element. There has been a need for a concrete placing method capable of making it possible to further shorten the construction period and achieve labor saving.

[0010]

Accordingly, the present invention provides
It is an object of the present invention to provide a concrete placing method capable of shortening a construction period and achieving labor saving, and further capable of easily separating different types of concrete into a supporting structural element and a floor slab. And

[0011]

The above object of the present invention is provided by providing a concrete placing method of the present invention.

That is, according to the first aspect of the present invention, a support structure element formwork for constituting a support structure element of a building is constructed, and a floor slab lower portion is formed on the support structure element formwork. Overlay the half PC floorboard to be configured, and
C. Pre-cast concrete is cast on the upper part of the floorboard, a floor slab is constructed by a composite method, and then post-cast concrete is cast in place on the support structural element formwork to construct the support structural element. A concrete casting method is provided.

According to a second aspect of the present invention, there is provided the concrete placing method according to the above-mentioned, wherein the pre-cast concrete has lower compressive strength than the post-cast concrete.

According to a third aspect of the present invention, there is provided a concrete casting method, characterized in that the precast concrete has a slump of 15 cm or less.

According to a fourth aspect of the present invention, there is provided a concrete placing method, wherein the half PC floor plate is a PC floor plate with truss bars, a flat PC floor plate, or a prestressed PC floor plate. Provided.

According to a fifth aspect of the present invention, there is provided a concrete placing method, wherein the floor slab is a hollow floor slab composed of a half PC floor plate.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram showing a building constructed by the concrete casting method of the present invention. This building is constructed using a half PC floorboard made of precast reinforced concrete, and includes a plurality of reinforced concrete columns 1a, 1b, 1c provided vertically from a foundation (not shown) embedded in the ground, and the columns 1a, 1b. 1b and 1c, and a floor slab 2 spanned between 1b and 1c. The columns 1 a, 1 b, 1 c are used as support structural elements in the present invention, and are constructed by cast-in-place to support the load of the floor slab 2. A portion adjacent to the ground of the building shown in FIG. 1 is a lower floor 3, and the floor slab 2 forms an upper floor 4. The floor slab 2 is formed in a composite system by casting a pre-cast concrete on an upper part of a half PC floorboard (not shown). The pre-cast concrete poured into the floor slab 2 is assumed to be ordinary concrete,
The post-cast concrete cast in place on the pillars 1a, 1b, 1c is made of high-strength concrete so that necessary strength can be obtained.

FIG. 1 shows that the reinforcing bar 5 is extended upward so that the columns 1a, 1b, 1c can be extended upward to form a floor further above. I have.

FIG. 2 is a view showing a building constructed by the concrete casting method according to the present invention before cast-in-place concrete. As shown in FIG. 2, the column form 6 is
It is constructed for placing columns 1a, 1b, 1c.
Also, between the column forms 6, a half PC floor plate 7a with truss bars is shown spanning the column form 6 before cast-in-place concrete to form the lower side of the floor slab 2. ing. The column form 6 is a conventional column form 6 comprising a vertical end 8, a horizontal end 9, a weir plate 10, a washer 11, a separator (not shown), and the like. No. 2 has a strength that can be supported before casting of post-cast concrete. As the ends 8, 9 used in the present invention, any endurance that can withstand a load can be used. In addition, FIG. 2 shows that the column formwork 6 is constructed before the precast concrete is cast. However, it is also possible to use a support structure other than the column formwork 6 as necessary. It is possible. In addition, it is also possible to construct only the shoring works of the column formwork 6 before placing the concrete in advance, and to construct the dams 10 and the like after placing the concrete in advance.

The half-PC floorboard shown in FIG. 2 has a trussed half-PC floorboard 7a into which a plurality of trusses 12 are driven.
It has been. At the upper end of the truss 12, the upper chord material 1
3 are provided, and an upper end bar 14 is bridged in the span direction of the pillars 1a, 1b, 1c.

In FIG. 2, the columns 1a,
Adjacent to the portion where 1b and 1c are installed, the top of the precast concrete is cast from the upper surface of the half PC floorboard 7a so that the precast concrete and the postcast concrete can be separately separated as described later. It is shown that a higher extended rose board 15 and a pier 16 are installed. As a method used to separate the precast concrete cast on the floor slab 2 portion and the postcast concrete cast on the columns 1a, 1b, 1c portion, any conventional method can be used. Can be
For example, a method using expanded metal or lath net for partition and a pier for holding, a method using foam rubber for partition and a tightening ruler for holding, etc. Are pillars 1a, 1
Any method and member can be used as long as it does not leak to the b and 1c sides.

In FIG. 2 described above, the half-PC floorboard 7a with truss bars is used as the half-PC floorboard. However, in the concrete casting method of the present invention, a flat plate with a reinforcing bar is used. In order to reduce the weight and provide appropriate strength, use a half PC floorboard with truss streaks as the bottom plate, place a discarded form such as a void form between the trusses, and cast in precast concrete. Using a hollow floor slab formed by a method or a method in which a corrugated iron plate conforming to the shape of the top slab 14 of the floor slab is laid along the top slab 14 of the floor slab, and a precast concrete is poured on the upper surface thereof. Can also.

FIGS. 3 and 4 show cross sections of the above-mentioned half PC floor boards 7b and 7c of the present invention.

FIG. 3 is a view showing a flat half PC floor plate 7b into which a reinforcing bar is used, which can be used in the present invention. The half-PC floorboard 7b is formed as a half-PC floorboard with flat upper and lower surfaces, and although it tends to be thicker than the half-PC floorboard 5 with truss lines to provide rigidity as a formwork, it is advantageous for transport stock and the like. Yes,
By using the present invention, further efficiency and labor saving can be achieved. In addition, in the half PC floorboard 7b shown in FIG. 3, the reinforcing bar 17 is shown to be driven in to further facilitate the integration with the cast-in-place concrete. The upper surface of the half-PC floorboard 7b of FIG. 3 into which the precast concrete is cast may be formed with a shallow recess to be further integrated with the cast-in-place concrete.

FIG. 4 is a view showing a prestressed half PC floor panel 7c which can be used in the concrete placing method of the present invention. The half PC floor plate 7c is provided with a plurality of channels 1 on a rubber member 18 such as hard urethane foam.
9 is formed by casting concrete to form a lower rib 9.
Prestressing is provided by the introduction of strands 20 formed from PC steel. Such a prestressed half PC floor panel 7c can be used when it is necessary to form a floor panel having a relatively long span without any support. The half PC floor panel 7c shown in FIG.
It is shown that a plurality of recesses 22 are provided in 1 to improve the integration with the pre-cast concrete, but when the integration with the pre-cast concrete can be sufficiently ensured, The above-mentioned concave portion is not always necessary, and the upper surface may simply be roughened.

FIG. 5 is a view showing a hollow floor slab 23 which can be used in the present invention. The hollow floor slab 23 used in the present invention is a half-PC floor plate 7a with a reinforcing truss.
The hollow floor slab 23
Are pillars 1a, like the prestressed half PC floorboard 7c.
When the span between 1b and 1c is long, it is relatively lightweight,
The floor slab 2 having rigidity and strength can be formed. Specifically, the hollow floor slab 23 can be formed by arranging a lightweight void form 24 between the trusses 12 and casting concrete in advance in that state. By using this hollow floor slab 23,
According to the concrete casting method of the present invention, the weight of the floor slab 2 can be reduced and the required strength can be obtained.
The half PC floor boards 7a, 7b, 7c and the hollow floor slab 23 can be appropriately selected in consideration of the span length, the strength of the floor slab, and the like.

According to the concrete casting method of the present invention, in the present invention, the upper surface of the floor slab 2 is firstly cast on the half PC floor plate 7a shown in FIG. It is characterized in that it is formed before casting. FIG. 6 shows that the precast concrete is cast on the half PC floorboard 7a shown in FIG. 2 and the postcast concrete is not cast on the column 1a. The column formwork 6 is shown to support the floor slab 2 formed by precast concrete. The column form 6 used for this purpose must be designed to support the above-mentioned load, and any conventionally known method can be used for this purpose. After the pre-cast concrete has been cast, it is possible to perform, for example, curing, blacking out, and start of various kinds of work irrespective of the concrete casting on the column 1a. At this time, the precast concrete can be cast by any conventionally known casting method, and at the time of casting, the concrete of each column form 6 for the columns 1a, 1b, 1c is cast. Half P spanned between
First, precast concrete is cast between 1b-1c on the C floor plate 7a to form the floor slab 2, and then the columns 1b, 1
c to form columns 1b, 1c, and then, for example, use the end of the post-cast concrete of the column 1b as a formwork to pre-cast concrete in another section between the columns 1a-1b. It is also possible to carry out the construction one by one, for example.

In the concrete casting method of the present invention, the members for preventing the poured concrete such as the loose plate 15 and the lath net from flowing out after the poured concrete is cast and hardened are removed, and the columns 1a and 1b are removed. , 1c. As the post-cast concrete used at this time, high-strength concrete can be usually used in order to secure required strength, but any type of concrete can be used. In the present invention, it is preferable to place the post-cast concrete so that the top of the post-cast concrete is at the level of the top of the pre-cast concrete, but the level of the post-cast concrete is kept below the level of the pre-cast concrete. It is also possible.

FIG. 7 shows that after the precast concrete has been cast on the half PC floorboard 7 by the concrete casting method of the present invention, the postcast concrete has been cast on the column 1a, and the column form 6 has been removed. FIG. The joint between the floor slab 2 and the column 1a is formed by the upper slab upper end line 14a and the upper end line 1 of the half PC floor plate 7 facing each other across the column 1a.
By joining each 4b with a reinforcing bar, etc.,
The same joint as in the past is formed.

In the concrete casting method of the present invention, as described above, it is necessary to design the strength of the column formwork 6 to be larger than that of the related art. However, considering the strength of the supporting structural elements such as the pillars 1a, the floor slab 2 and the
In addition, only the strength required to support other relatively lightweight equipment is required. For this purpose, high strength such as columns 1a, 1b, and 1c, which are constructed by casting high-strength concrete, is used. It is not required, and it is not always necessary to build the pillar 1a first. Pillar 1 as in the present invention
Before the concrete of a, 1b, and 1c, the pre-cast concrete is cast and hardened, so that the upper floor 4
In this way, it is possible to secure a work floor surface, and to perform work such as blacking out on the upper floor 4 prior to the placement of the pillars 1a, 1b, and 1c. it can. This makes it possible to reduce the number of working days, particularly when the slab span of a shopping center is relatively long, or when there are many operations on a floor slab, such as when the building is a higher-rise building, Further, since it is possible to prepare for placing the pillars 1a, 1b, 1c during this time, it is possible to further save labor.

Further, in the concrete casting method of the present invention, since the precast concrete is cast on the half PC floor plate 7 from the column form 6, the half PC floor plate 7 is liable to crack due to distortion. However, the present inventors have found that the use of concrete having a slump of 15 cm or less, specifically, a slump of about 12 cm, as a pre-cast concrete is sufficient to prevent cracks on the floor slab 2 and to solve the above-described problem. The point was solved. The value of the slump that can be used can be appropriately changed within the above range depending on the span width of the half PC floorboard 7, the amount of concrete to be poured, and the like.

FIG. 8 is a diagram schematically showing a joint portion between the half-cast floor plate 7 and the pre-cast concrete and post-cast concrete formed by the concrete casting method of the present invention. In FIG. 7, for the sake of convenience of explanation, only the reinforcing bars related to the joining are shown, and the other driven reinforcing bars are omitted. As shown in FIG. 7, the precast concrete 25 is cast on the upper surface of the half PC floorboard 5 to form the floor slab 2. The post-cast concrete 26 is cast to the top end of the pre-cast concrete 25 and is substantially flush with the floor slab 2. Reinforcing bars 27 are connected to the upper slab reinforcements 14a and 14b of the half PC floor panel 7 which are opposed to both sides of the column 1a by welding or the like so as to cross the column 1a. Further, a reinforcing bar 28 is similarly driven into the upper side surface of the half PC floor plate 7 so as to cross the column 1a, and the column and the floor slab are integrated. In the present invention, it is also possible to appropriately use a reinforcing bar arrangement or a joining method other than those described above. The joint between the column 1a and the half PC floor plate 7 can also be appropriately set so as to be sufficient when the column formwork 6 is installed. Although the concrete casting method of the present invention has been described with respect to the casting of the columns 1a, 1b, 1c and the half PC floorboard 7, the present invention can be applied to a case where joining with a beam is required instead of the columns 1a, 1b, 1c. It is possible. Further, although the present invention has been described by taking as an example the application of the present invention to shopping centers and high-rise reinforced concrete condominiums, the present invention can be applied to bridges and the like as long as the effects of the present invention are exhibited.

[0033]

According to the concrete casting method of the present invention, a form for a supporting structural element is constructed to constitute a supporting structural element of a building, and a slab lower portion is formed on the supporting structural element form. A half-PC floorboard to be stretched, a precast concrete is cast on the upper part of the half-PC floorboard, a floor slab is constructed by a composite method, and a post-cast concrete is cast in place on the support structural element formwork. Since a concrete casting method characterized by constructing a supporting structural element is provided, it is possible to shorten the construction period by enabling early construction such as preparation for the next process such as inking on the upper floor, It is possible to provide a concrete placing method that can achieve labor saving and can easily separate different types of concrete into the supporting structural element and the floor slab. To become.

[Brief description of the drawings]

FIG. 1 is a diagram showing a building constructed by a concrete casting method of the present invention.

FIG. 2 is a view showing a half PC floor plate with truss bars hung over a column formwork.

FIG. 3 is a view showing a flat half PC floorboard used in the present invention.

FIG. 4 is a view showing a prestressed half PC floorboard used in the present invention.

FIG. 5 is a diagram showing a hollow floor slab used in the present invention.

FIG. 6 shows a half-PC precast concrete according to the present invention.
The figure which showed the place cast on the floorboard.

FIG. 7 is a view showing a column-floor slab joint formed by casting post-cast concrete by the concrete casting method of the present invention.

FIG. 8 is a schematic view showing a column-floor slab joint in the concrete casting method of the present invention.

[Explanation of symbols]

 1a, 1b, 1c ... pillar 2 ... floor slab 3 ... lower floor 4 ... upper floor 5 ... rebar 6 ... pillar formwork 7 ... half PC floor board 7a, 7b, 7c ... half PC floor board 8 ... vertical end thick 9 ... side Ends 10 ... Screws 11 ... Washers 12 ... Truss 13 ... Top chords 14 ... Top bars 15 ... Rose plates 16 ... Piers 17 ... Splice bars 18 ... Rubber members 19 ... Channels 20 ... PC steel 21 ... Half PC floor plate upper surface 22 ... Concave portion 23 Hollow floor slab 24 Void formwork 25 Precast concrete 26 Postcast concrete 27 Reinforcing bar 28 Reinforcing bar

Claims (5)

[Claims] 1. A supporting structural element formwork for constituting a supporting structural element of a building is constructed, and a half PC floor plate constituting a lower part of a floor slab is spread over the supporting structural element formwork; A pre-cast concrete is cast on the upper part of the floorboard to construct a floor slab by a composite method, and then a post-cast concrete is locally cast on the support structural element formwork to construct the support structural element. Concrete casting method. 2. The concrete casting method according to claim 1, wherein the precast concrete has a lower compressive strength than the postcast concrete. 3. The method according to claim 1, wherein a slump of the precast concrete is 15 cm or less. 4. The half-PC floorboard is made of P with truss bars.
4. A C floorboard, a flat PC floorboard, or a prestressed PC floorboard.
Concrete casting method described in 1. 5. The concrete casting method according to claim 1, wherein the floor slab is a hollow floor slab composed of a half PC floor plate.