JP6479351B2 - Hybrid beam - Google Patents

Description

  The present invention relates to a hybrid beam (composite beam) having a reinforced concrete structure at the end and a steel structure at the center.

In recent years, a beam of a composite structure composed of reinforced concrete (RC) and steel (S) structure as a beam frame of a building that makes a part of or all of a large span (hereinafter also referred to as a composite beam or a hybrid beam) Has been adopted. The beam having such a structure is a steel frame in which both ends are covered with RC, and is spanned and joined between columns such as RC structures. Hereinafter, in the hybrid beam, the center portion made of S is referred to as a steel beam portion, and both end portions covered with RC are referred to as a reinforced concrete beam portion (RC beam portion).
In a reinforced concrete beam section of a hybrid beam, generally, a plurality of beam reinforcement bars and a plurality of beam reinforcement bars and a plurality of lateral reinforcement bars surrounding the steel frame are laid out and embedded throughout the reinforced concrete beam section. . This lateral reinforcing bar also includes a concentrated reinforcing bar in which the bar arrangement at the end of the reinforced concrete beam part and the end of the steel beam part are dense.
The hybrid beam is attracting attention as a new construction method that can reduce the beam weight and reduce the length of the beam because the center part is made of S, and that can provide a long span of the beam.

On the other hand, in the hybrid beam, there is no example of providing the through hole for equipment in the reinforced concrete beam part.
The reinforced concrete beam part of the hybrid beam is designed as a general RC structure. When a general RC beam is provided with a through hole, the reinforcement of the through hole is an open reinforcing bar (ring-shaped one) This is done using buckling reinforcements (skewers).

JP2009-24462

However, when the reinforced concrete beam part of the hybrid beam is reinforced with an aperture reinforcement (ring-shaped) or a buckling reinforcement (skewer), reinforcement such as an aperture reinforcement or a buckling reinforcement Muscles become overcrowded.
When these reinforcing bars are overcrowded, the beam main bars and the lateral reinforcing bars are originally densely arranged in the reinforced concrete beam portion, so that it takes time to arrange the bars and the workability deteriorates.
In addition, when the opening of a general RC beam is reinforced from past research examples, shear cracks around the opening after experiencing an earthquake are conspicuous, and the degree of damage to the beam is also remarkable.
The present invention has been made in view of the above points, and can improve the workability of reinforcement of a reinforced concrete beam portion through which a hole for equipment is formed, and is advantageous in reducing the degree of damage in the event of an earthquake. An object of the present invention is to provide a reinforcing structure for a hybrid beam having a hole for equipment.

In order to achieve the above-mentioned object, the present invention covers both ends of a steel frame spanned between opposing columns with reinforced concrete, the central portion of the steel is a steel beam portion, both ends are reinforced concrete beam portions, and the reinforced concrete is provided. The beam portion includes a plurality of beam main bars and a plurality of lateral reinforcement bars surrounding the beam main bars, and the steel frame is a hybrid beam that is not penetrated by the opposing columns and has an internal span to a column face, In the reinforced concrete beam portion, an equipment hole penetrating both side surfaces of the reinforced concrete beam portion is formed, and an equipment hole reinforcing portion that reinforces the location of the reinforced concrete beam portion around the equipment hole is provided. When the hole reinforced portion is a plan view of the reinforced concrete beam portion, the hole reinforcing portion is located at the location of the reinforced concrete beam portion located within the outline of the facility hole. A first region of the reinforced concrete beam portion positioned in the direction and a second region of the reinforced concrete beam portion positioned below the facility hole, and the first region includes the first region of the reinforced concrete beam portion. A first beam main reinforcement row and a second beam main reinforcement row in which a plurality of beam main reinforcements are arranged at intervals in the width direction are arranged vertically, and the first beam main reinforcement row and the second beam main reinforcement row A third beam main reinforcing bar array and a fourth beam main reinforcing bar array, in which a plurality of beam main reinforcing bars are arranged in the second region at intervals in the width direction of the reinforced concrete beam portion. Are arranged in the vertical direction, and a second transverse reinforcing bar surrounding the third beam main bar array and the fourth beam main bar array is provided, and the first beam main bar array includes: The second beam main reinforcement row is provided on the facility hole, and the second beam main reinforcement row is in front of the first beam main reinforcement row. The third beam main reinforcement row is provided below the equipment hole, and the fourth beam main reinforcement row is formed between the third beam main reinforcement row and the equipment hole. provided al is between, in the first region, a third horizontal reinforcement, in the second region, a fourth lateral reinforcement, said third lateral reinforcement, the Surrounding two beam main bars in the width direction of each of the first beam main bar array and the second beam main bar array, the fourth lateral reinforcing bar includes the third beam main bar array and the fourth beam main bar array. It is characterized by surrounding two beam main bars inside each beam main bar row in the width direction .
In the present invention, both ends of a steel frame spanned between opposing columns are covered with reinforced concrete, the central portion of the steel is a steel beam portion, both ends are reinforced concrete beam portions, and the reinforced concrete beam portion includes a plurality of reinforced concrete beam portions. It is a hybrid beam comprising beam main bars and a plurality of lateral reinforcing bars surrounding the beam main bars, and the steel frame is an internal span extending to the column face without penetrating the opposing columns, and the reinforced concrete beam part, Equipment holes penetrating both side surfaces of the reinforced concrete beam part are formed, an equipment hole reinforcing part for reinforcing the location of the reinforced concrete beam part around the equipment hole is provided, and the equipment hole reinforcing part is When the reinforced concrete beam part is viewed in plan, the iron located above the equipment hole at the location of the reinforced concrete beam part located within the outline of the equipment hole. A first region of the concrete beam portion and a second region of the reinforced concrete beam portion located below the hole for equipment, and the first region is spaced apart in the width direction of the reinforced concrete beam portion. A first beam main reinforcement row and a second beam main reinforcement row in which a plurality of beam main reinforcements are arranged in the vertical direction, and a first surrounding the first beam main reinforcement row and the second beam main reinforcement row And a third beam main reinforcement row in which a plurality of beam reinforcement bars are arranged at intervals in the width direction of the reinforced concrete beam portion in the second region. Are arranged in the vertical direction, and a second horizontal reinforcing bar surrounding the third beam main bar array and the fourth beam main bar line is provided, and the first beam main bar line is located above the facility hole. And the second beam main reinforcement row is provided between the first beam main reinforcement row and the equipment hole. Is the third beam main reinforcement column is provided below the equipment holes, said fourth beam main reinforcement column, provided we are between the third beam main reinforcement column and the plant hole, wherein A pair of first lateral reinforcing bars are provided on both sides of the steel frame in the width direction of the reinforced concrete beam portion, and the pair of first lateral reinforcing bars are respectively located on both sides of the steel frame. A portion of the first beam main reinforcement row and a portion of the second beam main reinforcement row are further provided, and a fifth reinforcement bar is provided to cover the pair of first lateral reinforcement bars. A pair of lateral reinforcing bars are provided on both sides of the steel frame in the width direction of the reinforced concrete beam portion, and the pair of second lateral reinforcing bars are respectively located on both sides of the steel frame. Surrounding a portion of the main bar row and a portion of the fourth beam main bar row; A sixth reinforcing bar that covers the horizontal reinforcing bar is provided .

According to the present invention, the shear hole cracking and the degree of damage of the reinforced concrete beam portion around the equipment hole are improved by the equipment hole reinforcing portion.
In addition, because it is reinforced with beam main bars and lateral reinforcement bars designed for bending and shearing as columns, reinforcing bar reinforcement is originally used to reinforce the reinforced concrete beam part of hybrid beams. Compared to the case, it can be easily and quickly reinforced, the workability is improved, and it is advantageous for shortening the construction period and reducing the cost.
Further, the energy of the earthquake can be absorbed by the facility hole reinforcing portion, which is advantageous in reducing the degree of damage in the event of an earthquake.

It is a front view of the hole reinforcement part for facilities. 1A is a cross-sectional view taken along arrow A in FIG. 1, FIG. 1B is a cross-sectional view taken along arrow B in FIG. 1, and FIG. 1C is a cross-sectional view taken along arrow B in FIG. It is explanatory drawing at the time of carrying out intensity | strength calculation of the rectangular parallelepiped part of a reinforced concrete beam part as a column of a general reinforced concrete structure. It is the schematic of a hybrid beam. It is a detailed figure in the vicinity of the reinforced concrete beam portion of the hybrid beam.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, a general hybrid beam 10 to which the present invention is applied will be described with reference to FIG. 4 and FIG. 5. The hybrid beam 10 is a steel frame such as I steel or H steel spanned between opposing columns 12. It has a structure in which both ends of S are covered with reinforced concrete.
The central part of the steel S is a steel beam part 10A, both end parts are reinforced concrete beam parts 10B, and the steel S has an internal span (length to the column face) and does not penetrate the column 12, FIG. In FIG. 11, reference numeral 11A indicates a stud bolt, and reference numeral 11B indicates a floor slab.

The reinforced concrete beam portion 10B may be made of precast concrete manufactured in advance in a factory, or may be manufactured of on-site concrete. Alternatively, it may be made of half precast concrete, in which case the concrete is post-struck on site. The concrete may be ordinary concrete or fiber reinforced concrete.
The reinforced concrete beam portion 10B is reinforced by a plurality of beam reinforcing bars 14 and a plurality of lateral reinforcing bars 16 surrounding the beam reinforcing bars 14, and fixing of the beam reinforcing bars 14 to the column beam joint is performed by fixing hardware or bending fixing. .

  As shown in FIG. 1, the facility hole 20 penetrates the reinforced concrete beam portion 10B horizontally so as to pass through the center of the web of the steel frame S at a location near the column portion 12 of the reinforced concrete beam portion 10B.

As shown in FIGS. 1 to 2, the beam main reinforcing bars 14 are provided as beam main reinforcing bar arrays 1402 arranged at intervals in the width direction of the reinforced concrete beam 10B at the upper and lower parts of the reinforced concrete beam 10B. Yes.
This beam main bar example 1402 is an upper beam main bar row 1402A and a lower beam main bar row 1402B in which two beam main bar bars 1402 are vertically spaced apart in the upper part of the reinforced concrete beam portion 10B above the equipment hole 20. Is provided.
Further, in this beam main reinforcement example 1402, in the lower part of the reinforced concrete beam portion 10B below the equipment hole 20, an upper beam main reinforcement row 1402C and a lower beam main reinforcement row in which two beam main reinforcement examples 1402 are provided vertically apart from each other. 1402D is provided.

  As shown in FIG. 1, the facility hole 20 penetrates the reinforced concrete beam portion 10B horizontally so as to pass through the center of the web of the steel frame S at a location near the column portion 12 of the reinforced concrete beam portion 10B.

  As shown in FIG. 2 (A), the lateral reinforcing bars 16 include a reinforced concrete beam portion 10B between the column 12 and the facility hole 20, and a reinforced concrete beam between the facility hole 20 and the steel beam portion 10A. The portion 10B is arranged as a horizontal reinforcing bar 16A that surrounds all the beam main bars 14 of the upper beam main bar array 1402A and the lower beam main bar array 1402D, and two beam main bars inside the beam main bar array 1402 in the width direction. 14 is disposed as a lateral reinforcing bar 16B that surrounds 14.

In addition, as shown in FIG. 2B, the horizontal reinforcing bars 16 are provided at all the beams of the upper beam main reinforcing bar row 1402A and the lower beam main reinforcing bar row 1402B at the reinforced concrete beam portion 10B located above the equipment hole 20. It is arranged as a horizontal reinforcing bar 16C surrounding the main bar 14, and as a horizontal reinforcing bar 16D surrounding the two beam main bars 14 inside the beam main bar rows 1402A, 1402B in the width direction.
Further, as shown in FIG. 2 (B), the lateral reinforcing bars 16 are located in all the beams of the upper beam main bar array 1402C and the lower beam main bar array 1402D at the location of the reinforced concrete beam portion 10B located below the equipment hole 20. It is arranged as a horizontal reinforcing bar 16E that surrounds the main bar 14, and is also arranged as a horizontal reinforcing bar 16F that surrounds the two beam main bars 14 inside each beam main bar row 1402C, 1402D in the width direction.

  Note that, in the location of the reinforced concrete beam portion 10B located above the equipment hole 20, as shown in FIG. 2C, the lateral reinforcement bars 16 are four on the left and right sides of the upper beam main bar row 1402A and the lower beam main bar row 1402B. You may comprise by the horizontal reinforcement bar | burr 16G surrounding each separately, and the horizontal reinforcement bar | burr 16H which covers the horizontal reinforcement bar | burr 16G of these right and left. Similarly, at the location of the reinforced concrete beam portion 10B located below the equipment hole 20, the lateral reinforcing bars 16 are lateral reinforcing bars 16I that separately surround the left and right four main bars 1402C and 1402D. And you may comprise by the horizontal reinforcement bar | burr 16J which covers these lateral reinforcement bar | burr 16G.

  Further, as shown in FIG. 1, concentrated reinforcement in which the reinforcing bars of the lateral reinforcing bars 16 are densely arranged particularly at the ends corresponding to the pillar 12 side and the steel beam 10A side of the reinforced concrete beam part 10B. The muscle is 16K. In this way, by providing the concentrated reinforcing bars 16K at the end corresponding to the column 12 side and the end on the steel beam 10A side of the reinforced concrete beam portion 10B, stress can be transmitted from the steel frame to the reinforced concrete beam portion 10B. ing.

And the hole reinforcement part 22 for facilities of this invention which reinforces the location of the reinforced concrete beam part 10B in which the hole 20 for facilities was penetrated is provided, and the hole reinforcement part 22 for facilities is the reinforcement range around the hole 20 for equipments It is comprised including the beam main reinforcement 14 and horizontal reinforcement bars 16A-16F located in this.
The facility hole reinforcing portion 22 will be described in detail.
A predetermined region along the longitudinal direction of the reinforced concrete beam portion 10B reinforced by the facility hole reinforcing portion 22, that is, the reinforcing range L3 is determined by the following expression 1, and the center of the facility hole 20 is located at the center of the reinforcing range L3. doing.
L3 = L1 + 2 × L2 Equation 1
Here, L1 is the dimension of the inner diameter of the equipment hole 20.
L2 is a distance away from the inner peripheral surface of the equipment hole 20 on both sides of the equipment hole 20 along the longitudinal direction of the reinforced concrete beam portion 10B.
The height from the upper end of the inner peripheral surface of the facility hole 20 to the upper surface of the reinforced concrete beam portion 10B is defined as the upper beam D1, and the height from the lower end of the inner peripheral surface of the facility hole 20 to the lower surface of the reinforced concrete beam portion 10B. The lower beam is D2, and the larger dimension of the upper beam D1 and the lower beam D2 is L2.
If the reinforcing range L3 is increased, the amount of reinforcing bars to be used increases, and it takes time and effort to arrange the bars.
By adopting the above formula 1, the reinforcing range L3 close to the minimum necessary dimension can be mechanically easily obtained.

As shown in FIG. 3A, in the reinforcing range L3, a rectangular parallelepiped portion defined by the upper beam D1 and the width of the reinforced concrete beam portion 10B is defined as a first rectangular parallelepiped portion C1.
In addition, in the reinforcing range L3, a rectangular portion defined by the lower beam D2 and the width of the reinforced concrete beam portion 10B is defined as a second rectangular parallelepiped portion C2.
Then, the first rectangular parallelepiped portion C1 and the second rectangular parallelepiped portion C2 are regarded as separate columns, and the bending is designed in the same manner as a general reinforced concrete column without considering the steel frame S. The rectangular parallelepiped portion C1 is shown in FIGS. 3B and 3C, and the second rectangular parallelepiped portion C2 is shown in FIGS. 3D and 3E. Determine the amount of 16F reinforcement and concrete strength.
Alternatively, the first rectangular parallelepiped portion C1 and the second rectangular parallelepiped portion C2 are regarded as separate columns, and the design for shear is performed in the same manner as a general reinforced concrete column without considering the steel frame S. As shown in FIGS. 3B and 3C for the portion C1, as shown in FIGS. 3D and 3E for the second rectangular parallelepiped portion C2, the beam main bar 14 and the lateral reinforcing bars 16A to 16F are used. Determine the amount of reinforcing bars and concrete strength.
Here, the bending is a bending moment acting on the first rectangular parallelepiped portion C1 and the second rectangular parallelepiped portion C2, and is a bending moment acting on the hybrid beam 10.
The shear is a shearing force that acts on the first rectangular parallelepiped portion C1 and the second rectangular parallelepiped portion C2, and is a shearing force that acts on the hybrid beam 10.

In the present embodiment, the locations of the reinforced concrete beam portions 10B located above and below the facility hole 20 are regarded as separate columns, designed for bending and shearing to determine the amount of reinforcing bars and the concrete strength, and a normal beam main bar. 14, It is made to reinforce with the horizontal reinforcement 16 and concrete.
Therefore, it can be designed and constructed only with main bars, hoop bars, and concrete strength like ordinary reinforced concrete columns, and since complex opening reinforcement bars are not used, bar arrangement can be performed easily, greatly reducing the work of reinforcing bar processing and bar arrangement. It can be reduced, which is advantageous in improving workability and reducing costs.

Thus, if the hole reinforcement part 22 for facilities is comprised, the following effects AC will be exhibited.
Effect A: The shear crack and damage degree of the reinforced concrete beam portion 10B around the equipment hole 20 are improved.
Effect B: Compared to the case where the reinforced concrete beam 10B of the hybrid beam 10 where the reinforcing bar is originally dense is reinforced using the hole reinforcing bar, it can be easily and quickly reinforced, and the workability is improved. This is advantageous in reducing the cost and cost.
Effect C: The energy of the earthquake can be absorbed by the facility hole reinforcing portion 22, which is advantageous in reducing the degree of damage in the event of an earthquake.

10 …… Hybrid beam 10A …… Steel beam portion 10B …… Reinforced concrete beam portion 14 …… Beam main bar 1402 …… Beam main bar row 1402A, 1402C …… Upper beam main bar row 1402B, 1402D …… Lower beam main bar row 16, 16A ～ 16J …… Reinforcing bars 20 …… Equipment hole 22 …… Equipment hole reinforcement

Claims (5)

Cover both ends of the steel frame spanned between the opposing columns with reinforced concrete, the central part of the steel frame is a steel beam part, both ends are reinforced concrete beam parts, and the reinforced concrete beam part has a plurality of beam main bars and their beam main bars. A plurality of lateral reinforcing bars that surround the steel beam, and the steel frame is a hybrid beam that is not penetrated by the opposing column and has an internal span to the column face,
In the reinforced concrete beam portion, a hole for equipment penetrating both side surfaces of the reinforced concrete beam portion is formed,
A facility hole reinforcing portion for reinforcing a portion of the reinforced concrete beam portion around the facility hole is provided,
When the reinforced concrete beam part is viewed in plan, the hole reinforcing part for equipment is provided at a position of the reinforced concrete beam part located above the equipment hole at the location of the reinforced concrete beam part located within the outline of the equipment hole. A first region and a second region of the reinforced concrete beam portion located below the facility hole;
In the first region, a first beam main bar array and a second beam main bar array in which a plurality of beam main bars are arranged at intervals in the width direction of the reinforced concrete beam portion are arranged vertically, and A first beam reinforcing bar array and a first lateral reinforcing bar surrounding the second beam main bar array;
In the second region, a third beam main bar row and a fourth beam main bar row in which a plurality of beam main bars are arranged at intervals in the width direction of the reinforced concrete beam portion are arranged vertically, and 3 beam main reinforcement rows and a second lateral reinforcement bar surrounding the fourth beam main reinforcement row,
The first beam main reinforcement row is provided on the facility hole,
The second beam main reinforcement row is provided between the first beam main reinforcement row and the facility hole,
The third beam main reinforcement row is provided under the equipment hole,
The fourth beam main reinforcement column, provided we are between the third beam main reinforcement column and the plant hole,
The first region has a third lateral reinforcing bar;
In the second region, it has a fourth lateral reinforcing bar,
The third transverse reinforcing bar surrounds two beam main bars in the width direction inside of each of the first beam main bar array and the second beam main bar array,
The fourth lateral reinforcing bar surrounds two beam main bars in the width direction inside of each of the third beam main bar array and the fourth beam main bar array,
A reinforcing structure for a hybrid beam having a hole for equipment. Cover both ends of the steel frame spanned between the opposing columns with reinforced concrete, the central part of the steel as a steel beam part, both ends as a reinforced concrete beam part, the reinforced concrete beam part comprising a plurality of beam main bars and their beam main bars A plurality of lateral reinforcing bars that surround the steel beam, and the steel frame is a hybrid beam that is not penetrated by the opposing column and has an internal span to the column face,
In the reinforced concrete beam portion, a hole for equipment penetrating both side surfaces of the reinforced concrete beam portion is formed,
A facility hole reinforcing portion for reinforcing a portion of the reinforced concrete beam portion around the facility hole is provided,
When the reinforced concrete beam part is viewed in plan, the hole reinforcing part for equipment is provided at a position of the reinforced concrete beam part located above the equipment hole at the location of the reinforced concrete beam part located within the outline of the equipment hole. A first region and a second region of the reinforced concrete beam portion located below the facility hole;
In the first region, a first beam main bar array and a second beam main bar array in which a plurality of beam main bars are arranged at intervals in the width direction of the reinforced concrete beam portion are arranged vertically, and A first beam reinforcing bar array and a first lateral reinforcing bar surrounding the second beam main bar array;
In the second region, a third beam main bar row and a fourth beam main bar row in which a plurality of beam main bars are arranged at intervals in the width direction of the reinforced concrete beam portion are arranged vertically, and 3 beam main reinforcement rows and a second lateral reinforcement bar surrounding the fourth beam main reinforcement row,
The first beam main reinforcement row is provided on the facility hole,
The second beam main reinforcement row is provided between the first beam main reinforcement row and the facility hole,
The third beam main reinforcement row is provided under the equipment hole,
The fourth beam main reinforcement column, provided we are between the third beam main reinforcement column and the plant hole,
A pair of the first lateral reinforcing bars are provided on both sides of the steel frame in the width direction of the reinforced concrete beam portion,
The pair of first lateral reinforcing bars surrounds the first beam main reinforcement row portion and the second beam main reinforcement row portion which are respectively located at both sides of the steel frame,
Furthermore, a fifth reinforcing bar that covers the pair of first lateral reinforcing bars is provided,
A pair of the second lateral reinforcing bars are provided on both sides of the steel frame in the width direction of the reinforced concrete beam portion,
The pair of second lateral reinforcing bars surround the third beam main bar row portion and the fourth beam main bar row portion which are respectively located on both sides of the steel frame,
Furthermore, a sixth reinforcing bar that covers the pair of second lateral reinforcing bars is provided.
A reinforcing structure for a hybrid beam having a hole for equipment. The facility hole reinforcing portion is provided in a predetermined region L3 along the longitudinal direction of the reinforced concrete beam portion including the facility hole,
The dimension of the inner diameter of the equipment hole is L1, the height from the upper end of the inner peripheral surface of the equipment hole to the upper surface of the reinforced concrete beam part is the upper beam D1, and the lower end of the inner peripheral face of the equipment hole. When the height from the bottom to the lower surface of the reinforced concrete beam is the lower beam D2 and the larger dimension of the upper beam D1 and the lower beam D2 is L2, the predetermined region L3 is L3 = L1 + 2 × L2 The center of the hole for equipment is located at the center of L3,
3. A hybrid beam reinforcing structure having a facility hole according to claim 1 or 2 . When viewed from above, the first beam main reinforcement row to the fourth beam main reinforcement row are arranged at the location of the equipment hole reinforcing portion excluding the location of the reinforced concrete beam portion located within the contour of the equipment hole. A seventh lateral reinforcing bar is provided to surround the widthwise outer side of
The reinforcement structure of the hybrid beam which has the hole for facilities of any one of Claims 1-3 characterized by the above-mentioned. When viewed from above, the first beam main reinforcement row to the fourth beam main reinforcement row are arranged at the location of the equipment hole reinforcing portion excluding the location of the reinforced concrete beam portion located within the contour of the equipment hole. An eighth lateral reinforcing bar surrounding the two main bars of the beam in each width direction is provided,
The reinforcing structure of a hybrid beam having a facility hole according to claim 4 .

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