JP2007154565A - Joint structure and construction method of column and beam-less slab - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a joint method and construction method of a column and a slab without a beam, wherein there is no need of divisionally placing concrete according to concrete strength in the vicinity of a panel zone, so that a precedent construction can be effectively and economically carried out and furthermore a construction period can be shortened. <P>SOLUTION: The joint structure, wherein a column 10 and a beam-less slab 11 connected to the column 10 for composing a floor, is composed in such a way that a recess 12 is formed around a periphery of the column 10 and the beam-less slab 11 is fitted in the recess 12 without firmly fixing a reinforcement 11a of the beam-less slab 11 to the column 10. Moreover, reinforcements 15, 17 for surrounding the column are placed in the beam-less slab 11 around the column 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a joining structure for joining a beamless slab to a reinforced concrete column and a method for constructing the column and the beamless slab.

  Conventionally, as a structure of a reinforced concrete structure, a ramen structure in which a column and a beam are rigidly connected is the most common regardless of the structural type of the frame. However, in the above-mentioned ramen structure, the columnar shape or beam shape protrudes into the room, and there are many restrictions on the structural plan such as span, floor height, or frame cross-sectional dimension, so the degree of design freedom is not necessarily high.

  Especially in high-rise or super-high-rise apartments, the section of columns and beams is inevitably large, which often impairs the ease of use of the interior space. There are restrictions on the position or size, and it is not easy to create a space with a high degree of freedom.

  Therefore, in recent years, in high-rise apartment buildings and ultra-high-rise apartment buildings, the outer peripheral frame and the inner peripheral frame of the building are used to resist the total horizontal load, and the dwelling unit between the outer frame and the inner frame is made of no beams. A frame structure with flat slabs is being adopted.

According to the above-described frame structure, for example, as can be seen in Patent Document 1 and Patent Document 2 below, the slabs on each floor spanned between the outer frame and the inner frame can be made into a flat slab structure to eliminate beams. There is an advantage that it becomes possible.
JP 2003-206567 A Japanese Patent No. 3110946

  By the way, in such a reinforced concrete high-rise building or super-high-rise building, the burden axial force of the column increases as the floor becomes lower, but from the viewpoint of the usability of the building, the cross-sectional dimension of the column is limited. is there. For this reason, the design which raises the concrete intensity is common for the pillar of the lower floor of the above-mentioned building.

On the other hand, the non-beam slab constructed between the columns is not required to be as strong as the columns. For this reason, for the non-beam slab, cheaper ordinary concrete is used without using expensive high-strength concrete or ultra-high-strength concrete such as columns.
However, the joint between the column and the beamless slab requires the same strength as the column, so when building the column and the beamless slab in parallel at the work site, However, there is a problem that it is necessary to divide and put in order for each concrete strength, which requires a lot of labor for the construction.

  Also, in order to streamline the process, even when a precast (hereinafter abbreviated as PCa) column is used as a column and a half PCa plate is used as a non-beam slab, the panel zone has a high strength equivalent to that of the column. Therefore, when constructing the non-beam slab in the same way, different types of concrete must be placed according to the strength required for each of the vicinity of the panel zone and other parts. There was a problem.

  The present invention has been made in view of such circumstances, and it is possible to omit the placement for each concrete strength in the vicinity of the panel zone, and therefore, it is possible to efficiently and economically perform the prior construction of the column, It is an object of the present invention to provide a connection structure and a construction method of a column and a beamless slab that can shorten the length of the structure.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a joint structure of a column and a non-beam slab connected to the column and constituting a floor, wherein a recess is formed on the outer periphery of the column. The rebar of the non-beam slab is engaged with the recess without fixing the rebar of the non-beam slab to the column, and reinforcing bars surrounding the column are arranged in the non-beam slab around the column. It is characterized by that.

  Here, in the invention described in claim 2, the reinforcing bar according to claim 1 is a well-shaped reinforcing bar that surrounds the column like a cross in a plan view and / or a ring bar that surrounds the column in a circular shape. It is characterized by being.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein one of the columns is continuous over a plurality of floors, and the recesses are connected to the non-beam slabs on each floor. It is characterized by being formed of PCa.

  Next, the invention according to claim 4 is a method for constructing a column and a non-beam slab, wherein a column having a recess formed at a position where a non-beam slab on the outer peripheral portion is to be constructed is constructed in advance, and then the recess A formwork for placing the non-beam slab is placed at a position sandwiching the upper and lower sides, and a reinforcing bar that surrounds the pillar around the pillar is not fixed to the pillar in the formwork. After the bar arrangement, the non-beam slab is constructed by placing concrete in the formwork.

  The invention according to claim 5 is the invention according to claim 4, wherein one of the columns is continuous over a plurality of floors, and the recesses are formed in advance at the connecting positions with the non-beam slabs on each floor. It is characterized by being made of PCa.

  According to the joining structure according to any one of claims 1 to 3 or the construction method according to claim 4 or 5, the non-beam slab is fixed to the outer periphery of the column without fixing the reinforcing bar of the non-beam slab to the column. Since the vertical load is supported by the column by engaging the formed recess, concrete having different strengths required for the column and the non-beam slab can be used.

  Therefore, it is possible to reduce the number of times of placing concrete when constructing the column and the beamless slab, and the trouble of fixing the reinforcing bar of the beamless slab to the column. In addition, since it is possible to construct a plurality of pillars in advance, the number of joints in the pillars can be reduced. As a result, it is possible to reduce the construction cost required for the construction of the column and the non-beam slab and shorten the construction period.

  Furthermore, a reinforcing bar surrounding the column is placed in a non-beam slab around the column, and the amount of the reinforcing bar concentrated around the column is adjusted to act on the column. The bending moment to be adjusted can be adjusted.

  In particular, as in the invention described in claim 3 or 5, if the column is made of a PCa structure in which one pillar is continuous in a plurality of layers, the outer peripheral portion to which the non-beam slab on each floor is connected in advance. By forming the concave portion, the construction becomes easier and the construction accuracy is improved.

(First embodiment)
1 to 4 show a first embodiment in which a joint structure of a column and a non-beam slab according to the present invention is applied to a building having a double tube frame. It is an outer frame that is placed and bears a horizontal force as an earthquake-resistant element.
The outer frame 1 includes a plurality of main pillars 2 (28 in the figure) standing upright along the outer periphery of a building and a large beam 3 spanned between the main pillars 2. It is a rectangular tube-like frame structure integrated by joining, and an inner peripheral frame 4 that bears a horizontal force like the outer peripheral frame 1 is arranged inside the outer frame 1.

  The inner frame 4 is provided coaxially with the outer frame 1 on the inner side of the main column 2 of the outer frame 1 at a distance of two spans. The main pillar 5 (in the figure, 12) and the large beam 6 spanned between them are rigidly joined to form a rectangular tubular ramen structure. Incidentally, the internal space of the inner peripheral frame 4 is used as, for example, an atrium or a multi-story parking lot.

  A plurality of (20 in the figure) PCa columns 10 are erected at equal positions between the main columns 2 and 5 at an intermediate position between the outer frame 1 and the inner frame 4, and these outer frames A flat slab (non-beam slab) 11 constituting a floor of each floor is bridged between 1 and the inner frame 4.

  Here, as shown in FIG. 2 to FIG. 4, a concave portion 12 is formed at the joint position of the column 10 with the flat slab 11, the outer peripheral portion being cut out over the entire circumference. The concave portion 12 is formed by an inclined surface 12 a whose upper and lower end portions are inclined toward the outer peripheral surface of the column 10, while an intermediate portion in the vertical direction is formed with a constant depth.

  On the other hand, the flat slab 11 is constructed of cast-in-place concrete without the internal reinforcing bar 11a being fixed to the column 10. In addition, in the flat slab 11, a plurality of upper end well reinforcing bars (reinforcing bars) 15 arranged in a cross beam shape so as to surround the pillar 10 along the outer periphery of the pillar 10 are flat. The bar is arranged on the upper side in the thickness direction of the slab 11. Further, in the flat slab 11 located around the column 10, a plurality of ring bars (reinforcing bars) 17 are arranged coaxially with the axis of the column 10 so as to surround the column 10 similarly. ing.

(Second Embodiment)
5 and 6 show another embodiment of the joint structure of the column and the non-beam slab according to the present invention. In this joint structure, as the flat slab 20, the lower chord member of the truss bar (rebar) 21 is shown. Is embedded between the outer frame 1 and the inner frame 4 using a half PCa plate 22 such as an omni plate (Omnia: trade name) in which an oblique material and an upper chord material are projected from the upper surface. Things are used.

Also in the flat slab 20, the internal truss bars 21 and the like are not fixed to the column 10, but are joined to the recess 12 formed in the column 10, and are further arranged in a grid pattern along the outer periphery of the column 10. The upper end well reinforcing bar (reinforcing bar) 15 and the lower end well reinforcing bar (reinforcing bar) 16 are arranged at the upper and lower portions in the thickness direction of the flat slab 11 and surround the column 10. Thus, a plurality of ring bars (reinforcing bars) 17 are arranged coaxially.
In addition, the code | symbol 23 in a figure is a joint for the crack induction of the pillar 10 formed in the joining edge with the pillar 10 of the flat slab 20, and soundproofing.

Next, an embodiment in which the method for constructing a column and a beamless slab according to the present invention is applied to the joint structure between the column and the beamless slab shown in the first embodiment will be described with reference to FIG. .
First, in a factory or the like, a column 10 made of PCa having a length dimension extending over a plurality of layers (two layers in the figure) and having a recess 12 formed in a joint portion of the flat slab 11 is manufactured.

  Next, as shown in FIGS. 7A and 7B, after this pillar 10 is carried into the construction site and built by grout integration on the upper part of the preceding pillar 10, it is placed on the preceding flat slab 11. A standing frame 30 is used to place a frame 31 for placing the flat slab 11 between the outer frame 1 and the recess 12 below the column 10 and between the recess 12 and the inner frame 4. To do. The flat slab 11 is constructed as shown in Fig. 7 (c) by placing concrete in the mold 31 and then placing concrete.

Next, as shown in FIG. 7 (d), a temporary support 32 is erected on the constructed flat slab 11, and between the recess 12 above the column 10 and the outer frame 1 and the inner frame 4, Similarly, a mold 33 for placing the flat slab 11 on the upper floor is installed, and after placing the reinforcing bars 11a in the mold 33, concrete is placed, thereby FIG. 7 (e). The upper flat slab 11 is constructed as shown in FIG.
Then, by repeating the steps shown in FIGS. 7A to 7D sequentially upward, a high-rise or super-high-rise building frame is constructed.

  When applied to the joint structure of the second embodiment shown in FIGS. 4 and 5, the end of the half PCa plate 22 for placing the flat slab 20 on the column 10 side is attached to the support metal 25. Support by. Then, after placing the upper end well reinforcement 15, the lower end well reinforcement 16 and the ring reinforcement 17 on the half PCa plate 22, by placing the cast-in-place concrete 26 on the half PCa plate 22, The flat slab 20 is constructed.

  In addition, in the said embodiment, while using the thing made from PCa as the pillar 10, as for the flat slabs 11 and 20, the thing by the cast-in-place concrete which installed the general formwork 31 and 33, and half PCa boards 22, such as an omni board, etc. However, the present invention is not limited to this, for example, the column is also constructed by a general cast-in-place concrete. A thing may be used.

  If the construction method in this case is illustrated, the reinforcement of a pillar and a formwork will be first constructed in the field. At this time, the mold is manufactured in such a manner that the concave portion 12 is formed at the joint portion between the column and the flat slab. Then, by placing concrete in the mold, the pillar 10 with the recess 12 is constructed, and after the concrete of the pillar 10 is cured to a degree sufficient to form a joint, the flat 10 Concrete is placed in the formwork for the slab 11. Thereby, the column 10 and the flat slab 11 can be joined to each other without being integrated.

  At this time, in order to join the column 10 and the flat slab 11 together without integrating them, a release agent is applied to the surface of the concave portion 12 which becomes the concrete interface between the column 10 and the flat slab 11 in advance. Alternatively, the sheet may be sandwiched.

  Furthermore, in the above-described embodiment, the upper well reinforcement 15 and the ring reinforcement 17 and the lower well reinforcement 16 that surround the pillar 10 are disposed in the flat slabs 11 and 20 positioned around the pillar 10. Although cases have been shown, it is possible to omit one or two of these when the strength allows.

  In addition, the concave portion 12 is also formed by the inclined surface 12 a shown in FIGS. 2 and 5, in which an intermediate portion in the vertical direction is formed to have a certain depth and the upper and lower end portions are inclined toward the outer peripheral surface of the column 10. It is not limited to the formed shape, for example, a U-shaped cross section in which the inclined surface 12a is not formed as shown in FIG. 8A, or an up-and-down inclination as shown in FIG. A concave portion having various shapes such as a V-shaped cross section formed by the surface 13a or an arc-shaped concave curved surface 14a as shown in FIG.

  According to the joining structure and construction method of the column and the non-beam slab having the above configuration, the flat slabs 11 and 20 are fixed to the outer periphery of the column 10 without fixing the reinforcing bars 11 a and 21 of the flat slabs 11 and 20 to the column 10. Since the vertical load is supported by engaging with the concave portion 12 formed in the above, concrete having different strengths required for the columns 10 and the flat slabs 11 and 20 can be used.

  Therefore, it is possible to reduce the number of times of placing concrete when constructing the column 10 and the flat slabs 11 and 20, and the trouble of fixing the reinforcing bars 11 a and 21 of the flat slabs 11 and 20 to the column 10. In addition, since the pillars 10 for a plurality of layers can be constructed in advance, the number of joints in the pillar 10 can also be reduced. As a result, it is possible to reduce the construction cost required for the construction of the column 10 and the flat slabs 11 and 20 and shorten the construction period.

  Furthermore, in the flat slabs 11 and 20 around the column 10, reinforcing bars such as the upper end well reinforcing bar 15, the lower end well reinforcing bar 16, and the ring bar 17 surrounding the column 10 are arranged. The bending moment acting on the column 10 can be adjusted by adjusting the amount of the reinforcing bars concentrated around the column 10.

  In particular, as shown in the above embodiment, if the pillar 10 is made of PCa, one of which is continuous in a plurality of layers, the recess 12 is provided in the outer peripheral portion to which the flat slabs 11 and 20 on each floor are connected in advance. By forming it, construction becomes easier and construction accuracy can be improved.

It is a top view which shows 1st Embodiment of the junction structure of this invention. It is a longitudinal cross-sectional view which shows the junction part of the pillar of FIG. 1, and a flat slab. It is a longitudinal cross-sectional view of the flat slab around the pillar of FIG. It is a cross-sectional view which shows arrangement | positioning of the reinforcing bar around the pillar of FIG. 2 and its periphery. It is a longitudinal cross-sectional view which shows the junction part of the pillar and flat slab in the 2nd Embodiment of this invention. It is AA sectional view taken on the line of FIG. It is process drawing which shows one Embodiment of the construction method of this invention. It is a longitudinal cross-sectional view which shows the other shape of the recessed part of the pillar which concerns on this invention.

Explanation of symbols

10 Pillars 11, 20 Flat slab (Non-beam slab)
11a Reinforcing bar 12 Recess 15 Upper end well reinforcement (reinforcing bar)
16 Bottom well type reinforcement (reinforcement)
17 Ring bars (reinforcing bars)
21 truss bars (reinforcing bars)
22 Half PCa board

Claims (5)

It is a joint structure of a pillar and a non-beam slab connected to this pillar and constituting the floor,
A concave portion is formed on the outer periphery of the column, and the non-beam slab is engaged with the concave portion without fixing the reinforcing bar of the non-beam slab to the column, and in the non-beam slab around the column, the A joint structure between a column and a non-beam slab characterized by reinforcing bars that surround the column.   2. The column and the non-beam slab according to claim 1, wherein the reinforcing bar is a well-shaped reinforcing bar that surrounds the column like a cross in a plan view and / or a ring bar that surrounds the column in a circular shape. Bonding structure with.   The pillar according to claim 1 or 2, wherein the pillar is made of PCa, wherein one pillar is continuous over a plurality of floors, and the concave portion is formed at a connection position with the non-beam slab on each floor. Joint structure with non-beam slab.   A pillar having a recess formed at a position where a non-beam slab on the outer peripheral portion should be constructed is constructed in advance, and then a formwork for placing the non-beam slab is installed at a position sandwiching the recess vertically. After placing reinforcing bars surrounding the pillars in the formwork without fixing them to the pillars, concrete is placed in the formwork to construct the beamless slab. A construction method of a pillar and a beamless slab characterized by   5. The pillar according to claim 4, wherein the pillar is made of PCa in which one of the pillars is continuous over a plurality of floors and the concave portion is formed in advance at a connection position with the non-beam slab on each floor. Construction method with beam slab.

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