JP2018104993A - Reinforcing structure for opening - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solution to a problem of a prior art in accordance with the present invention, that is, to provide a reinforcing structure for an opening capable of meeting increased reinforcing bars in a limited effective area as well as allowing an installation of the reinforcing bars to be easier than that of the prior art.SOLUTION: A reinforcing structure for an opening includes side reinforcing bars and center reinforcing bars. The side reinforcing bars are curved steel bars each having a horizontal part and a ramp part, and are disposed on right and left side surfaces of a concrete beam while securing a predetermined covering, by making four reinforcing bars as one set. The center reinforcing bars are disposed between the side reinforcing bars positioned on the right and left side surfaces. The opening is surrounded with four ramp parts (of four side reinforcing bars) on the side surface sides, and is contained in a closed area formed by all or part of the center reinforcing bars on the cross-sectional center side.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a technique for reinforcing an opening provided in a concrete beam. More specifically, the present invention relates to a reinforcing structure in which various reinforcing bars are arranged around the opening.

  In general, in a building, as shown in FIG. 7, a foundation beam that connects pillar foundations (footings) may be constructed. This foundation beam is also called “underground beam” because it is built underground, and it increases the rigidity of the entire foundation and prevents uneven settlement of the building. It is generally made of reinforced concrete. The The foundation beam is often provided with an opening for passing a person or for equipment.

  Usually, the cross-sectional shape of the opening is circular, and its diameter is conventionally 1/3 or less of the beam. In addition, the opening is a so-called cross-sectional defect that penetrates the beam, and of course the necessary strength is insufficient in this portion, so the periphery thereof is reinforced by reinforcing bars and the like. The range in which the reinforcing reinforcing bars can reinforce the opening (reinforcement effective range C) is limited to the boundary between the main bar and the line extending from the center of the opening in the direction of 45 degrees as shown in FIG. Area.

  The opening should have as large an area as possible due to its nature, but the beam should be as small as possible for economic reasons. For this reason, the diameter of the opening is often set to 1/3 of the beam, and in other words, the design in which the size of the beam is three times the diameter of the opening is the mainstream. For example, since a diameter of 600 mm is required for a person to pass through a human through hole, the beam is designed to be 1,800 mm. Depending on the scale, even if the beam required for the structural calculation is 1,800 mm or less, the beam required to secure 1,800 mm, which is three times the diameter of the opening.

  Thus, various techniques for reinforcing the opening of the foundation beam have been proposed so far. For example, in Patent Document 1, an assembled reinforcing bar in which two reinforcing bars are stacked in an X shape is arranged around a through hole. Reinforcement structure is proposed.

JP 2013-087504 A

  Two sets of X-shaped assembled rebars shown in Patent Document 1 are arranged across a through hole, and further, these two sets are arranged on both sides of the beam, and a total of four sets of X-shaped assembled rebars are through holes. It is arranged around And although each end of each reinforcing bar constituting the X-shaped assembled reinforcing bar is fixed to the concrete, the other end (hook) is tightly connected to the main reinforcing bar. Since this binding work is performed in a narrow space and in a state where various reinforcing bars are densely packed, it is a difficult work and requires a lot of work.

  Further, in the reinforcement structure of Patent Document 1, one end (hook) of the X-shaped assembled reinforcing bar is always tightly coupled to the main reinforcing bar, so the number of reinforcing reinforcing bars that can be arranged inside the beam is the number obtained by subtracting two at both ends from the main reinforcing bar. Therefore, it is difficult to cope with cases where the amount of reinforcing steel bars must be increased, such as when a relatively large load is assumed. Even if the design is such that the X-shaped rebar is placed between the X-shaped rebars arranged on both sides (that is, the center of the beam cross section), the installation work, including the connection to the main bar, is even more difficult. Will increase.

  In addition, in the conventional reinforcing structure including Patent Document 1, it is difficult to install the reinforcing bars provided above and below the opening. This reinforcing reinforcing bar is installed so as to surround the main reinforcing bar, and has a closed shape (no open portion) as shown in FIG. 9, and its tip is a 135 ° hook. Therefore, in order to install this reinforcing steel bar, it is pushed from the tip of the main bar, or it is pre-assembled with a plurality of main bars in advance.

  The problem of the present invention is to solve the problems of the prior art, that is, the installation work of the reinforcing reinforcing bars is easier than before, and even in the limited reinforcing effective range C, the reinforcing reinforcing bars An object of the present invention is to provide a reinforcing structure of an opening that can flexibly cope with an increase.

  In the present invention, in addition to a set of four side reinforcing bars arranged on both sides of a concrete beam, the reinforcing steel bar is reinforced by a central reinforcing bar arranged at the center of the beam cross section. The invention is made based on the idea that the opening is contained in the formed closed region and is based on an unprecedented idea.

  The reinforcement structure of the opening part of this invention is a structure provided with the side reinforcement bar and the center reinforcement bar. The side reinforcing bars are bent reinforcing bars having a horizontal portion and an inclined portion, and are arranged with four pieces as one set while securing a predetermined cover on the left and right side surfaces of the concrete beam. The central reinforcing bar is disposed between the side reinforcing bars disposed on the left and right side surfaces. Here, the “side surface” refers to a substantially vertical (including vertical) surface along the axial direction (longitudinal direction) of the concrete beam. The opening is surrounded by four inclined portions (of the four side reinforcing bars) on the side surface side, and is housed in a closed region formed by all or part of the central reinforcing bar on the center side of the cross section.

  The reinforcement structure of the opening part of this invention can also be set as the structure provided with the upper side reinforcement bar and the lower side reinforcement bar. The upper side reinforcing reinforcing bar has a horizontal portion arranged above the opening, and one lower side reinforcing reinforcing bar has a horizontal portion arranged below the opening. In this case, the two upper side reinforcing bars are arranged to face each other so that the inclined portions sandwich the opening, and further, the horizontal portions and the inclined portions intersect each other, and both horizontal portions are It arrange | positions so that it may become a substantially straight line (a straight line is included). Similarly, the two lower side reinforcing bars are also arranged to face each other so that the inclined portions sandwich the opening, and further, the horizontal portions and the inclined portions intersect with each other. It arrange | positions so that it may become a substantially straight line (a straight line is included).

  The opening reinforcing structure of the present invention may further include an opening reinforcing steel bar. The opening reinforcing bar has a U-shape that is partially open so that it can be slid and inserted from the side of the main bar, and is arranged so as to surround the main bar by a pair of left and right opening reinforcing bars. Note that hooks provided at both ends of the opening reinforcing steel bars are hooked on a part of the main bars.

  The reinforcement structure of the opening part of this invention can also be made into the structure which surrounds an opening part by a multiple center reinforcement bar. In this case, a plurality of central reinforcing bars having different sizes of the closed regions are prepared, and these central reinforcing bars are arranged in substantially the same plane (including the same plane) around the opening.

The opening reinforcing structure of the present invention has the following effects.
(1) The side reinforcing bars arranged in a set of four act on the reinforcing bars because they are fixed at the top and bottom of the opening in addition to the shear reinforcing effect as the reinforcing reinforcing bars arranged in the effective reinforcement range C. The vertical component of tensile force contributes to further improvement in shear strength. As a result, the beam of the concrete beam can be reduced to less than 3 times the opening diameter. (Note that as a result of tests conducted by the inventors, it has been confirmed that the beam can be reduced to 2.3 times the diameter of the opening.)
(2) Reducing the beam length of concrete beams not only reduces the amount of concrete material, but also reduces the amount of excavation required to build concrete beams, greatly reducing the cost of the conventional technology. can do. Furthermore, since the amount of greenhouse gas (CO2 etc.) emitted at the time of construction can be suppressed, it can be said that the structure is superior to the prior art in terms of environment.
(3) Since the side reinforcing steel bars can be fixed to the concrete at the horizontal portion, it is possible to omit the tightening work to the main bars and the like, and can be easily installed as compared with the prior art.
(4) Since the central reinforcing bar has a closed region formed in advance, the amount of reinforcing bars can be reduced as compared with conventional reinforcing bars, and it can be easily installed without requiring any special labor. it can.
(5) Also, the opening reinforcing steel bars can be placed at a predetermined position while sliding from the side of the main bars, so that they can be easily installed as compared with the prior art.

Sectional drawing cut | disconnected along the axial direction of a concrete beam. (A) is sectional drawing cut | disconnected in the orthogonal direction of the axial direction of a concrete beam at the position of an opening part, (b) is sectional drawing cut | disconnected in the orthogonal direction of the axial direction of a concrete beam at the position without an opening part. (A) is a front view which shows one side reinforcement bar, (b) is a front view which shows four side reinforcement bars which reinforce an opening part. (A) is a front view which shows the single center reinforcement bar which reinforces an opening part, (b) is a front view which shows the double center reinforcement bar which reinforces an opening part. The front view which shows the center reinforcement reinforcing bar which made one reinforcing bar double with one stroke. (A) is sectional drawing of the concrete beam which shows the condition before installing an opening part reinforcement, (b) is a sectional view of the concrete beam which shows the situation after installing an opening part reinforcement. Sectional drawing which shows the foundation beam which connects the footing of a pillar. The model figure explaining the reinforcement effective range C in which a reinforcing steel bar can reinforce an opening part. (A) is a front view which shows the conventional reinforcing bar, (b) is sectional drawing which shows the state in which this reinforcing bar surrounded and installed the upper and lower main bars.

  An example of the reinforcement structure of the opening part of this invention is demonstrated based on figures.

1. General Outline The reinforcing structure of the opening of the present invention reinforces the opening provided in a concrete beam such as a foundation beam, and includes a side reinforcing bar and a central reinforcing bar. With reference to FIGS. 1 and 2, the overall configuration of the opening reinforcing structure of the present invention will be described. FIG. 1 is a cross-sectional view taken along the axial direction of a concrete beam 100 (hereinafter simply referred to as “beam axial direction”). 2 is a cross-sectional view cut along a direction orthogonal to the beam axis direction (hereinafter referred to as “beam axis perpendicular direction”), and FIG. 2A is a cross-sectional view cut at the position of the opening 110 (FIG. 1). (B) is a cross-sectional view (cross-section taken along arrow B in FIG. 1) cut at a position where the opening 110 is not provided.

  As shown in FIGS. 1 and 2, the concrete beam 100 has a shape in which the same cross section (generally a substantially rectangular shape) continues in the beam axis direction, and the main bars 120 are arranged vertically along the beam axis direction. It is a reinforced concrete structure. Further, the stirrups 130 extending vertically are arranged at regular intervals in the beam axis direction, and these stirrups 130 are respectively locked to the upper and lower main bars 120.

  The concrete beam 100 is provided with an opening 110, and various reinforcing bars for reinforcing the opening 110 are arranged around the opening 110. Specifically, the four side reinforcing bars 200 are arranged so as to surround the opening 110, and the central reinforcing bar 300 is also arranged so as to surround the opening 110. Then, above and below the opening 110, opening reinforcing bars 400 surrounding the main bars 120 are arranged at predetermined intervals in the beam axis direction, and at positions close to the sides (left and right in FIG. 1) of the opening 110, An open stirrup 500 is formed by bundling a plurality of stirrups 130 together. Note that these side reinforcing bars 200 (excluding a part of the tip), the central reinforcing bar 300, the opening reinforcing bar 400, and the open stirrup reinforcing bar 500 are arranged in the effective reinforcement range C, respectively. Further, between the upper main bar 120 and the opening 110 and between the lower main bar 120 and the opening 110, axial reinforcing reinforcing bars 600 extending in the beam axis direction are respectively arranged.

  Hereafter, it explains in full detail for every main element which comprises this invention.

2. 3 (a) is a front view showing one side reinforcing bar 200, and FIG. 3 (b) is a front view showing four side reinforcing bars 200 that reinforce the opening 110. FIG. is there. As shown in FIG. 3A, the side reinforcing bar 200 is obtained by bending a single reinforcing bar, and includes a horizontal part 201 arranged substantially horizontally (including horizontal) and an inclination arranged obliquely. Part 202. Note that a connection point between the horizontal portion 201 and the inclined portion 202, that is, a point at which the shape of the side reinforcing bar 200 changes is referred to as a “folded portion 203” here for convenience.

  The side reinforcing steel bars 200 reinforce the opening 110 by making four as a set. The arrangement of the four side reinforcing bars 200 will be described in detail with reference to FIG. As shown in this figure, the two side reinforcing bars 200 of the set of four are arranged so that the horizontal portion 201 is located above the opening 110. The remaining two side reinforcing bars 200 are arranged such that the horizontal portion 201 is positioned below the opening 110. Here, for the sake of convenience, the side reinforcing bar 200 in which the horizontal part 201 is located above the opening part 110 will be referred to as “upper side reinforcing bar 210”, and the horizontal part 201 is located in the side reinforcing part below the opening part 110. The reinforcing bar 200 is particularly referred to as a “lower side reinforcing bar 220”.

  As shown in FIG. 3 (b), the two upper side reinforcing bars 210 are arranged so that the inclined portions 202 face each other with the opening 110 interposed therebetween, and intersect with each other at the bent portions 203 (overlapping). ), And both horizontal portions 201 are arranged in a substantially straight line. Similarly, the two lower side reinforcing bars 220 are arranged such that the inclined portions 202 face each other with the opening 110 interposed therebetween, and intersect with each other at the bent portions 203, and both horizontal portions 201 are It arrange | positions so that it may become a substantially straight line. The linear direction formed by the horizontal portions 201 of the two upper side reinforcing bars 210 and the linear direction formed by the horizontal portions 201 of the two lower side reinforcing bars 220 are respectively the directions of the main bars 120 (that is, the beam axis direction). ) And substantially parallel. As a result of this arrangement, the opening 110 is surrounded by four inclined portions 202 (of the four side reinforcing bars 200).

  The side reinforcing steel bars 200 that form a set of four are disposed on the side surfaces of both sides of the concrete beam 100. That is, after securing a predetermined cover on the right side surface (right side surface), a set of four side reinforcing bars 200 is arranged on the left side surface (left side surface) as shown in FIG. In addition, after securing a predetermined cover, a set of four side reinforcing bars 200 is arranged as shown in FIG. As used herein, the term “side surface” refers to a substantially vertical (including vertical) surface along the beam axis direction.

3. FIG. 4 is a front view showing the central reinforcing bar 300, (a) is a front view showing a single central reinforcing bar 300 that reinforces the opening 110, and (b) reinforces the opening 110. It is a front view which shows the double center reinforcement bar 300 which does (The black dot in a figure shows the junction location of a reinforcing bar). As shown in FIG. 4A, the central reinforcing bar 300 is closed, and a closed region (hereinafter referred to as “closed region 310”) is formed therein. When the central reinforcing bar 300 is actually arranged, the opening 110 is accommodated in the closed region 310. In FIG. 4A, the closed region 310 is formed by the entire central reinforcing bar 300 (that is, by joining both ends), but the reinforcing bar is placed at a position with a predetermined length (for example, several centimeters) from both ends. The closed region 310 may be formed by a part of the central reinforcing bar 300 such as intersecting (in this case, the vicinity of the end protrudes outside the closed region 310).

  The central reinforcing bar 300 is arranged between a set of four side reinforcing bars 200 arranged on both side surfaces (left and right side surfaces) of the concrete beam 100, specifically, near the center of the cross section in the direction perpendicular to the beam axis. The Further, the central reinforcing bar 300 may reinforce the opening 110 by itself (single layer) as shown in FIG. 4 (a), or it may be doubled as shown in FIG. 4 (b). May be reinforced. Furthermore, the opening 110 can be reinforced with a central reinforcing bar 300 of three or more layers according to the amount of reinforcing bars required in the design. When arranging a plurality of central reinforcing bars 300 around the opening 110, the central reinforcing bars 300 having different sizes of the closed regions 310 are prepared, and the closed regions 310 are arranged from the inner side in order from the smallest. At this time, the plurality of central reinforcing bars 300 may be arranged so as to be in substantially the same (including the same) plane, specifically, in a vertical plane.

  When reinforcing the opening 110 with the multiple central reinforcing bars 300, as shown in FIG. 5, a central reinforcing bar 300 in which one reinforcing bar is double-processed with a single stroke can be used. The central reinforcing bar 300 shown in this figure is formed by bending a reinforcing bar, and a small substantially rectangular shape is formed on the inner side, and a larger substantially rectangular shape is formed on the outer side. Has been. Of course, not only the shape shown in this figure but the opening part 110 can also be reinforced using the center reinforcement bar 300 of the other shape used as one stroke.

  By the way, since one set of four side reinforcing bars 200 is disposed on each side surface (left and right side surfaces), the amount of reinforcing bars cannot be increased so much. On the other hand, the central reinforcing bars 300 can be arranged in multiple layers as described above, and can be arranged in parallel in the direction perpendicular to the beam axis (that is, in a plurality of vertical planes), so the amount of reinforcing bars can be increased relatively easily. can do. That is, the opening reinforcing structure of the present invention can flexibly cope with an increase in reinforcing reinforcing bars even in the limited effective reinforcement range C. In order to avoid an extreme imbalance between the load load of the side reinforcing bars 200 and the load load of the central reinforcing bar 300, the amount of reinforcing bars of the central reinforcing bar 300 is the total of the side reinforcing bars 200 and the central reinforcing bar 300 combined. It may be designed to be 90% or less of the amount of reinforcing bars (that is, more than 0% and 90% or less).

4). FIG. 6 is a cross-sectional view of the concrete beam 100 showing a state in which the opening reinforcing bar 400 is arranged, (a) shows the situation before the opening reinforcing bar 400 is installed, and (b) shows the opening. The situation after installing the part reinforcement bar 400 is shown. As can be seen from FIG. 6 (a), the opening reinforcing steel bar 400 has a so-called “U-shape” in which a part thereof is opened, and hooks are formed at both ends.

  The opening reinforcing steel bars 400 are arranged so as to surround the main bars 120. At this time, the main reinforcement 120 is surrounded by two opening reinforcing bars 400 as a set. Specifically, as shown in FIG. 6A, the main bar 120 is surrounded so as to be sandwiched between the left and right opening reinforcing bars 400. The left and right sets of opening reinforcing bars 400 are arranged in the upper range and the lower range of the opening 110, and are arranged at predetermined intervals in the beam axis direction on the upper and lower main bars 120, respectively.

  When the opening reinforcing steel bar 400 is arranged, the open part is set to the main bar 120 side and is inserted into the main bar 120 while being slid in the direction perpendicular to the beam axis. By installing in this way, it is not necessary to push in from the front end of the main bar 120 in the beam axis direction, the installation work can be performed as it is at the designed position, and the slide can be simply slid, resulting in an extremely smooth installation work. When the opening reinforcing bar 400 is arranged so as to surround the main bar 120, the hook at the tip is locked (hanged) to the main bar 120 as shown in FIG.

5. Concrete beam structure According to the reinforcing structure of the opening portion of the present invention, a sufficient amount of reinforcing bars can be disposed even in a limited range such as the effective reinforcement range C. Therefore, the beam of the concrete beam 100 is made smaller than that of the prior art. can do. In other words, the reinforcing structure of the opening of the present invention can be effectively applied to the concrete beam 100 whose beam is smaller than that of the prior art. Specifically, the present invention can be applied to the concrete beam 100 in which the beam is less than three times the diameter of the opening 110, and as described above, from the results of the tests conducted by the inventors, the beam is made of the opening 110. It can be applied up to a concrete beam 100 that is twice the diameter. That is, the reinforcing structure of the opening of the present invention can be effectively applied to the concrete beam 100 in which the beam is in the range of 2 to 3 times the diameter of the opening 110.

  The reinforcing structure of the opening of the present invention can be used not only in detached houses and apartment houses, but also in various buildings such as production facilities such as factories, warehouses, and gymnasiums. The opening reinforcement structure of the present invention is an invention that can provide a high-quality building to firmly reinforce the opening, and as described above, an invention that can suppress greenhouse gas emissions during construction. Given that, it can be said that the invention can be used not only industrially but can also make a great social contribution.

DESCRIPTION OF SYMBOLS 100 Concrete beam 110 Opening part 120 Main reinforcement 130 Stirrup reinforcement 200 Side reinforcement reinforcement 201 Horizontal part (of side reinforcement reinforcement) 202 Inclination part (of side reinforcement reinforcement) 203 Bending part (of side reinforcement reinforcement) 210 Upper side Reinforcing bar reinforcement 220 Lower side reinforcing bar 300 Central reinforcing bar 310 Closed region (formed within the central reinforcing bar) 400 Opening reinforcing bar 500 Opening staggered bar 600 Axial reinforcing bar

Claims (4)

In the reinforcement structure of the opening provided in the concrete beam,
Four lateral reinforcing bars arranged with a predetermined cover secured on the left side of the concrete beam;
Four lateral reinforcing bars arranged with a predetermined cover secured on the right side of the concrete beam;
A central reinforcing bar arranged between the side reinforcing bars arranged on the left side and the side reinforcing bars arranged on the right side;
The side reinforcing bars are bent reinforcing bars having a horizontal part and an inclined part, and the four side reinforcing reinforcing bars are arranged so as to surround the opening by the inclined part,
A closed region is formed by all or part of the central reinforcing bar, and the opening is stored in the closed region.
A structure for reinforcing an opening. Two of the four side reinforcing bars are four upper side reinforcing bars in which the horizontal portion is disposed above the opening, and the other two side reinforcing bars are the horizontal reinforcing bars. Part is a lower side reinforcing bar disposed below the opening,
In the two upper side reinforcing bars, the inclined portions are opposed to each other across the opening, and the horizontal portions and the inclined portions intersect with each other. Arranged in a straight line,
In the two lower side reinforcing bars, the inclined portions are opposed to each other across the opening, and the horizontal portions and the inclined portions intersect with each other. Arranged in a straight line,
The reinforcing structure for an opening according to claim 1. Further comprising an opening reinforcing bar disposed so as to surround the upper and lower main bars of the opening,
The opening reinforcing steel bar is a U-shape that is partially open so that it can be slid and inserted from the side of the main bar,
The main reinforcing bar is surrounded by a pair of left and right opening reinforcing bars, and hooks provided at both ends of the opening reinforcing bar are hung on the main reinforcing bars.
3. The opening reinforcing structure according to claim 1, wherein the opening is reinforced. A plurality of the central reinforcing bars having different sizes of the closed region are arranged in substantially the same plane, and the opening is surrounded by multiple central reinforcing bars.
The opening reinforcing structure according to any one of claims 1 to 3, wherein:

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