JP2015140635A - Rigid frame having wide flat beam, and building using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rigid frame having a wide flat beam, which facilitates calculation of bending strength of the wide flat beam and which can easily increase bending ultimate strength of the beam by reinforcing a joint between the beam and a column, and a building using the same.SOLUTION: A rigid frame having a wide flat beam 10 comprises a column 1 and a beam 2 of reinforced concrete construction, and a beam width Bb of the beam 2 is greater than a column width Bc of the column 1. A yield hinge of the wide flat beam 10 is set on the opposed side of the adjacent column 1. Bending ultimate strength of the wide flat beam 10 is calculated by being reduced on the basis of a difference Ba between the beam width Bb and the column width Bc.

Description

  The present invention relates to a rigid frame having wide flat beams and a building using the same.

A structure in which the beam is rigidly connected to the column is called a ramen frame (or a ramen structure). In the case of a rigid frame, when a horizontal force is applied due to an earthquake or the like, the maximum bending moment acts on the joint between the beam and the column, and there is a possibility that this part will be damaged. Therefore, it is necessary to design the reinforced concrete (RC) rigid frame so that the building does not collapse even if the beam reinforcement at the joint between the beam and the column (the end face of the beam) yields.
Hereinafter, the yield surface of the beam at the joint between the beam and the column is referred to as a “yield hinge”, and the maximum bending moment expected for safety in the yield hinge is referred to as “the ultimate bending strength of the beam”.

  It has been proposed to use flat beams to increase the height of the opening while maintaining the height of the beams on each floor in apartment buildings such as condominiums with a ramen frame consisting of beams and columns (for example, Patent Documents 1 and 2).

The “balcony” of Patent Document 1 uses a flat beam whose beam width is larger than the column width of the column and whose beam length is ½ or less of the beam width, and the upper surface of the flat beam is the floor surface of the balcony. .
The “dwelling unit” of Patent Document 2 is a flat beam in which at least one of the beam portions erected between the column portions standing facing the outside of the beam portions of the dwelling unit.

Japanese Patent No. 4754506 JP 2012-7406 A

  The flat beam of Patent Document 1 is a flat beam in which the beam width of the beam is larger than the column width of the column. Hereinafter, such a flat beam is referred to as a “wide flat beam”. A ramen frame using a wide flat beam has an advantage that it can take a larger dimension under the beam than a normal frame frame at a predetermined floor height and can widen the opening.

  On the other hand, in a rigid frame, a large bending moment is generated at the joint between a beam and a column during an earthquake. Therefore, even if it is a wide flat beam, the joint part of a beam and a column needs to have sufficient intensity | strength. However, the wide flat beam has a problem that it is difficult to ensure the strength of the joint between the column and the wide flat beam because the beam is smaller than a normal beam.

In patent document 1, the protrusion part integrated with the pillar is provided in the junction part of a pillar and a wide flat beam. This protruding part protrudes in the axial direction of the wide flat beam and in a direction perpendicular to the axial direction, and is reinforced so that its proof strength is sufficiently larger from the column to the protruding part than the proof strength of the wide flat beam end. Yes.
With this configuration, the joint end portion of the wide flat beam is supported substantially evenly over the width of the beam, and the support span of the wide flat beam is substantially shortened by the protruding portion in the axial direction of the reinforced wide flat beam. can do. Thus, making the support span substantially shorter is referred to as “hinge relocation”. Hinge relocation has the advantage that the size under the beam can be increased and the stress burden on the beam can be reduced.

  However, since the means of Patent Document 1 reinforces the proof strength from the pillar to the protruding portion to be sufficiently larger than the proof strength of the wide flat beam end portion, a large amount of reinforcing bars are required at the protruding portion. In some cases, there is a problem that it is difficult to perform the bar arrangement of the protruding portion.

On the other hand, when hinge relocation is not applied, the support span is the interval between adjacent columns, and the bending moment generated at the joint between the beam and the column during an earthquake or the like is large. Therefore, it is necessary to increase the allowable bending moment by reinforcing the joint between the beam and the column.
However, the calculation of bending strength of wide flat beams is very complicated, and there has been no established method for calculating bending strength.

Further, when a wide flat beam is used in a building (for example, a balcony of an apartment), it may be desired to provide the wide flat beam with a vertical through hole through which a drain pipe or the like passes.
However, as in Patent Document 1, when the protruding portion is protruded in the axial direction of the flat beam and in the direction perpendicular to the axial direction, the vertical through hole is provided in the protruding portion. It was very difficult and practically impossible.

  The present invention has been developed to solve these problems. That is, an object of the present invention is to easily calculate the bending strength of a wide flat beam, and to reinforce the joint between the beam and the column to easily increase the bending ultimate strength of the beam. It is to provide a building using this.

According to the present invention, it is a rigid frame having a flat beam composed of a reinforced concrete column and a beam, the beam width of the beam being larger than the column width of the column,
The yielding hinge of the wide flat beam is set on the opposite side of an adjacent column;
There is provided a rigid frame having a wide flat beam, wherein the bending ultimate strength M of the wide flat beam is calculated based on a difference Ba between the beam width and the column width.

  The bending ultimate strength M of the wide flat beam is calculated by a reduction factor γ based on the ratio Ba / Bc between the difference Ba between the beam width and the column width and the column width Bc.

The bending ultimate strength Mu of a normal flat beam in which the beam width of the beam is smaller than the column width of the column is
Mu = 0.9 · at · σy · d, where at is the tensile main bar cross-sectional area, σy is the main bar yield strength, and d is the beam's fault.
The reduction coefficient γ is obtained by γ = 1.0−μ · Ba / Bc, where μ is a positive constant of 0.1 or more and 0.3 or less,
The bending ultimate strength M of the wide flat beam is obtained by the product of the bending ultimate strength Mu of the normal flat beam and the reduction factor γ.

The wide flat beam is a toroid having a beam only on one side of the column,
A mechanical fixing device mechanically fixed to the outermost end of the beam main bar located in the column;
And a cap bar that enhances fixability at the end of the beam main bar.

The wide flat beam has a cross shape with beams on both sides of the column,
A vertical through hole penetrating up and down the protruding portion of the wide flat beam located on the front or rear surface of the column;
A U-shaped through-hole reinforcing bar that surrounds the vertical through-hole and extends into the pillar.

Moreover, according to the present invention, the building has a rigid frame composed of columns and beams of reinforced concrete with at least two structural surfaces in the direction of the girder of the building,
There is provided a building using a ramen frame characterized by having the above-described ramen frame on at least one surface.

  It is preferable that a balcony is provided on the wife side of the building, and a vertical evacuation port is provided at a position without the wide flat beam on the balcony.

According to the present invention, since the yield hinge of the wide flat beam is set on the opposite side surface of the adjacent column, there is no need to provide a protruding portion that requires a large amount of reinforcing bars, and the bar arrangement work is easy. Become.
In addition, since the ultimate bending strength M of the wide flat beam is calculated based on the difference Ba between the beam width and the column width, the wide flat beam is formed despite the fact that a yield hinge is set on the opposite side of the adjacent column. The strength of the joint between the beam and column can be easily calculated.

  Therefore, it is easy to calculate the strength of the joint between the wide flat beam and the column, and the bending ultimate strength M of the wide flat beam can be easily increased by reinforcing the joint between the wide flat beam and the column.

It is a schematic diagram of a cross-sectional view of a normal beam. It is explanatory drawing of the wide flat beam which this invention makes object. It is a typical perspective view of a normal flat beam and a wide flat beam. It is a figure which shows a test result. It is 1st Embodiment figure of the wide flat beam by this invention. It is 2nd Embodiment figure of the wide flat beam by this invention. It is a section side view of the building using the frame frame of the present invention. It is a top view of the building by this invention. It is side surface sectional drawing of the wide flat beam of FIG.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the common part in each figure, and the overlapping description is abbreviate | omitted.

FIG. 1 is a schematic diagram of a cross-sectional view of a normal beam 2. This figure shows a cross section of a joint portion (opposite side face of the adjacent column 1) of the column 1 and the beam 2 in a rigid frame structure composed of a reinforced concrete (RC) column 1 and a beam 2.
In this figure, 3 is a beam main reinforcement and 4 is concrete. When a bending moment acts on the beam 2, the beam main reinforcement 3 is arranged at positions where tensile stress acts (near the upper end and near the lower end) as shown in the figure.

For the ordinary beam 2 shown in FIG. 1, the Architectural Institute of Japan “Reinforced Concrete Structure Calculation Standards / Comment 2010” (page 165) uses the formula (1) to calculate the “yield bending moment My” of reinforced concrete members. Stipulated in
My = 0.9 · at · σy · d (1)
Similarly, the “2007 Structure-Related Technical Standards Manual for Buildings” (page 623) defines the formula for calculating the ultimate bending strength Mu of a beam by equation (2).
Mu = 0.9 · at · σy · d (2)
Here, at is a tensile main bar cross-sectional area, σy is a main bar yield strength, and d is a beam fault of the beam 2. The tensile main bar cross-sectional area at is the total cross-sectional area of the beam main bar 3 arranged at the position where the tensile stress acts.
Expressions (1) and (2) are substantially the same expressions. This equation can also be applied to a normal flat beam in which the beam width Bb of the beam 2 is smaller than the column width Bc of the column 1 (hereinafter referred to as “normal flat beam”).

FIG. 2 is an explanatory diagram of the wide flat beam 10 targeted by the present invention.
In the present invention, the “wide flat beam” means a flat beam in which the beam width Bb of the beam 2 is larger than the column width Bc of the column 1 as shown in the figure.
In this figure, Ba is the difference between the beam width Bb and the column width Bc, and d is the beam fault of the beam 2. Hereinafter, the difference Ba = Bb−Bc between the beam width Bb and the column width Bc is referred to as “extrusion width”. If there are overhangs on both sides of the column, the larger protruding width is the protruding width.

  The ultimate bending strength Mu of the beam 2 obtained by the above equation (2) is applied to a rigid frame having a normal flat beam in which the beam width Bb is smaller than the column width Bc. Therefore, in the case of the wide flat beam 10 in which the beam width Bb of the beam 2 is larger than the column width Bc of the column 1, a part of the beam main bar protrudes outside the column, so that the stress sharing is greater than the beam main bar in the column. Therefore, it is necessary to estimate the ultimate bending strength M of the beam 2 (the wide flat beam 10) lower than the formula (2).

FIG. 9 is a side sectional view of the wide flat beam 10 of FIG. In this figure, part A shows a part that can be evaluated by the above-described formula (2), and part B shows a part that needs to be estimated smaller than formula (2).
The frame structure to which the present invention is applied is composed of a reinforced concrete column 1 and a beam 2, and has a wide flat beam 10 in which the beam width Bb of the beam 2 is larger than the column width Bc of the column 1.
Further, the yield hinge of the wide flat beam 10 is set on the opposite side surface of the adjacent column 1.
Further, the ultimate bending strength M of the wide flat beam 10 is calculated based on the difference Ba between the beam width Bb and the column width Bc.

That is, as shown in FIG. 9, the ultimate bending strength of the beam 2 in the portion A where the beam main reinforcing bar 3 is accommodated in the column 1 can be obtained by the conventional formula (2). However, it is necessary to estimate the ultimate bending strength of the beam 2 extending from the column 1 lower than the value obtained by the conventional equation (2), and it is necessary to reduce it.
The reason why the bending ultimate strength of the beam 2 having the beam main reinforcement 3 in the portion B projecting from the column 1 needs to be estimated lower than the value obtained by the conventional equation (2) is as follows. It is based on the fact that in the deformation of about R = 1/50, it is confirmed that all the beam main bars 3 passing through the inside of the column yield, and some of the beam main bars 3 protruding from the column 1 also yield.
Details will be described below.

Calculation of the ultimate bending strength of the beam 2 is important in the design of the building. That is, if the force is less than the ultimate bending strength of the beam 2, the beam main bar 3 will not yield. Therefore, the higher the ultimate bending strength of the beam 2, the higher the rigidity of the column 1 and the beam 2, and the stronger the building. It can be said.
Therefore, since the ultimate bending strength of the beam 2 is the strength at which the beam main bar 3 yields, in the wide flat beam 10, it is necessary to first confirm by experiment how much the beam main bar yields.
When a force sufficient to cause deformation of about R = 1/50 is applied to the beam 2, the beam main bar 3 yields, and this force is the ultimate bending strength of the beam 2. The ultimate bending strength of the beam 2 is a force obtained by the equation (2), and the beam 2 is deformed by about R = 1/50. Moreover, as a result of the experiment described later, it was confirmed that all the beam reinforcement 3 passing through the inside of the column yielded, and part of the beam reinforcement 3 protruding from the column 1 also yielded.
In addition, when it is smaller than the force calculated | required by Formula (2), it can be said that the deformation | transformation of R = 1/50 does not arise in the beam 2, and the beam main reinforcement 3 does not yield.

The problem is why a part of the beam main bar 3 protruding from the column 1, specifically, the beam main bar 3 at the tip of the beam 2 protruding from the column 1 did not yield. It can be said that the portion protruding from 1 (B portion) originally has a weak bonding force with the column 1.
That is, the portion protruding from the column 1 (B portion) has a weak coupling force with the column 1, and even if a bending force is applied to the beam 2, the beam protruding from the column 1 is twisted and bent at a small angle. This is because the main part 3 of the beam did not reach the yield point.
As can be seen from FIG. 9, it can be imagined that the beam portion protruding from the column 1 has a weak bonding force with the column 1. It can be said that it was confirmed experimentally.
And the higher the ultimate bending strength of the beam 2 is, the higher the rigidity of the pillar 1 and the beam 2 and the stronger the building. For that purpose, the amount of beam main reinforcement 3 should be increased more and more, as described above. As for the beam 2 extending from the column 1, the joining force between the column 1 and the beam 2 is weak and the rigidity of the column 1 and the beam 2 is low for the ramen structure although the beam main reinforcement 3 is large. The ultimate bending strength of 2 needs to be estimated to be lower than the amount of the main reinforcement.

  Specifically, in FIG. 9, there are 14 beam main bars 3 in total, with seven beam main bars 3 above and below. Among them, there are 8 beam reinforcements 3 that can be stored in the column 1, and 6 beam reinforcements 3 are added to the extended beam 2. When the total cross-sectional area of the beam reinforcement 3 is at, the formula (2) As for whether the ultimate bending strength of the beam 2 is required, it is necessary to estimate the strength of the portion protruding from the column 1 low as described above, and therefore some strength reduction is required.

Therefore, in the example described later, the bending ultimate strength M is expressed by the following formula (3), that is, γ · 0.9 · at · σy · d, but 0.9 · (γ · at) · σy · d, Alternatively, 0.9 · (γ · at · σy) · d can be considered.
That is, in equation (4) described later, γ = 1.0−μ · Ba / Bc, but, for example, γ = 1.0−β · Ba, and a new γ is set and calculated with a coefficient of β. May be. Alternatively, 0.9 · at · σy · d−δ may be set, and δ = λ · 0.9 · at · σy · d and λ = 1.0−ε · Ba may be used.
In any case, from the results of the experiment, it is necessary to estimate the ultimate bending strength by the amount Ba that the beam 2 protrudes from the column 1 as described above, and it is necessary to reduce it based on the difference Ba between the beam width and the column width. is there.

FIG. 3 is a schematic perspective view of a normal flat beam (normal flat beam 9) to which the formula (2) can be applied and a wide flat beam 10 targeted by the present invention. In this figure, (A) is a normal flat beam 9, which has a cross shape with beams 2 on both sides of the column 1, and the column core and the beam core coincide.
On the other hand, (B)-(E) are the wide flat beams 10 which this invention makes object. Among these, (B) is a cross-shaped flat beam 10 similar to (A), in which the column core and the beam core coincide with each other (hereinafter referred to as “cross-distribution”). Further, (C) is a wide flat beam 10 having a cross shape similar to (A), but the column core and the beam core are deviated (hereinafter referred to as “cross-shifting”).
Further, (D) is a wide flat beam 10 having a beam 2 on only one side of the column 1 and the column core and the beam core coincide with each other (hereinafter referred to as “T-shaped distribution”). (E) is a wide flat beam 10 having a toroidal shape in which the column core and the beam core are displaced (hereinafter, referred to as “t-justified”).

  Examples of the present invention will be described below.

  The inventors of the present invention manufactured a test body corresponding to each of the flat beams (A) to (E) shown in FIG. 3 and measured the actual bending ultimate strength of the beam 2.

The strength until the beam main bar 3 yields (the beam main bar 3 loses its resistance to tension and enters the plastic deformation region) is the “beam bending ultimate strength”.
In the deformation of about R = 1/50 rad, it was confirmed that all beam main bars passing through the inside of the column yielded, and some beam main bars protruding from the column also yielded.

  Hereinafter, the bending ultimate strength Mt of the wide flat beam 10 obtained in this test will be referred to as “experimental value Mt”, and the bending ultimate strength M of the wide flat beam 10 obtained by calculation described later will be referred to as “calculated value M”.

(Test results)
FIG. 4 shows the test results of this test. In this figure, the horizontal axis is the ratio Ba / Bc between the difference Ba (protrusion width Ba) between the beam width Bb and the column width Bc and the column width Bc. The vertical axis represents the ratio Mt / M between the experimental value Mt obtained in this test and the calculated value M.
Also, each symbol in the figure corresponds to FIG. 3, A is a normal flat beam, B is a cross-distribution, C is a cross-cut, D is a cross-shaped, and E is a cross-cut. Further, the subscript “1” is a test result shown in a conference paper or the like, and “2” is a test result by this test.

In FIG. 4, the bending ultimate strength M (calculated value M) of the wide flat beam 10 by calculation is calculated by the following formulas (3) and (4).
M = γ · 0.9 · at · σy · d = γ · Mu (3)
γ = 1.0−μ · Ba / Bc (4)
Here, γ is a reduction coefficient, and μ is a constant. The constant μ is 0.2 in this example.

From FIG. 4, when the constant μ is 0.2, the ratio Mt / M between the experimental value Mt and the calculated value M is in the range of Ba / Bc from 0 to 1.1 and from 1 to 1.5. It can be seen that all the values are within the range, and the experimental values Mt are all 1 to 1.5 times the calculated values M.
Further, from the formulas (3) and (4), when the constant μ is larger than 0.2, the reduction coefficient γ is decreased, and the calculated value M is further smaller than the experimental value Mt. Accordingly, when μ is set to 0.2 or more and is larger than 0.2, the actual strength (experimental value Mt) becomes larger than the calculated value M. Therefore, the design using the calculated value M is more secure. It turns out that it becomes the design of.

In FIG. 4, a straight line indicated by a solid line passes through points Ba / Bc = 1.0 and Mt / M = 1.1. This straight line can be assumed to correspond to the ultimate bending strength Mu of the beam in equation (2), and in this case, Mu / M = 1.1 (5).
From Expressions (5) and (3), the reduction coefficient γ = M / Mu = 1 / 1.1 = 0.909, and from Expression (4), the constant μ is about 0.10. That is, even when the constant μ is 0.10, the design using the calculated value M described above is a safer design than the ultimate bending strength Mu of the beam according to the equation (2).
Accordingly, the constant μ is preferably 0.1 or more and 0.3 or less, and particularly preferably 0.2 or more.

The present invention is based on new findings based on the test results described above.
That is, the frame structure of the present invention includes a reinforced concrete column 1 and a beam 2, and has a wide flat beam 10 in which the beam width Bb of the beam 2 is larger than the column width Bc of the column 1. In the present invention, the yield hinge of the beam 2 is set on the opposite side surface of the adjacent column 1. Further, the ultimate bending strength M of the wide flat beam 10 is calculated by a reduction factor γ based on the ratio Ba / Bc between the protruding width Ba and the column width Bc.

Further, as described above, in the present invention, the ultimate bending strength Mu of the normal flat beam 9 in which the beam width Bb of the beam 2 is smaller than the column width Bc of the column 1 is Mu = 0.9 · at · σy · d ( 2).
Further, the reduction coefficient γ is obtained by the equation (4) where γ = 1.0−μ · Ba / Bc. Here, μ is a positive constant between 0.1 and 0.3.
Further, the bending ultimate strength M of the wide flat beam 10 is usually obtained by the product of the bending ultimate strength Mu of the flat beam 9 and the reduction factor γ.

  As described above, in the present invention, by setting the yield hinge of the beam 2 to the side surface of the column 1 (opposite side surface of the adjacent column 1), the protruding portion from the column 1 that requires a large amount of reinforcing bars is provided. Eliminating and simplifying the bar arrangement of beam 2 (wide flat beam 10). Further, as a result, a reduction in the ultimate bending strength of the beam 2 due to the reduction of the reinforcing reinforcing bars is introduced, and a reduction factor γ which is a positive number of 1.0 or less is introduced, and a reduction factor γ is normally added to the bending ultimate strength Mu of the flat beam 9. The seismic performance of the building 20 was ensured by calculating by applying.

That is, conventionally, a complicated calculation is required to determine how low the bending ultimate strength Mu of the flat beam 9 is to be estimated. In contrast, the inventors of the present invention have introduced a reduction factor γ and found that it can be easily and simply estimated as the product of the bending ultimate strength Mu of the normal flat beam 9 and the reduction factor γ.
Thereby, even if it is the wide flat beam 10, the earthquake resistance performance when the yield hinge of the beam 2 (wide flat beam 10) is set to the side surface of the column 1 can be calculated more easily and accurately. It became possible to simplify the bar installation work of the flat beam 9.

FIG. 5 is a first embodiment of the wide flat beam 10 according to the present invention.
In this figure, (A) is a plan view, and (B) is a sectional view taken along line BB of (A). This example shows a case where the wide flat beam 10 has a toroidal shape (see FIG. 3) in which the beam 2 is provided only on one side of the column 1.

As shown in FIG. 5A, the wide flat beam 10 of the present invention has a plurality of mechanical fixing tools 12 and a plurality of cap bars 13.
The plurality of mechanical fixing tools 12 are mechanically fixed to the outermost end (left end in the figure) of each beam main bar 3 located in the column 1 and have a function of increasing the tensile resistance of the beam main bar 3.
The plurality of cap bars 13 are U-shaped bars embedded in the end portion (left end portion in the figure) in the wide flat beam 10 and have a function of improving the fixing property of the end portion of the main beam bar.

  Further, in this example, as shown in FIG. 5 (B), a U-shaped reinforcing bar 14 embedded in the protruding portion 11 of the wide flat beam 10 positioned on the front surface (left side or rear surface in the drawing) of the column 1 and the beam A plurality of constraining muscles 15 for constraining the position of the main muscle 3.

  With the configuration described above, even if the wide flat beam 10 is a toroidal shape with the beam 2 on only one side of the column 1, the ultimate bending strength equivalent to the cross shape with the beam 2 on both sides of the column 1 (see FIG. 3). It was confirmed by the test described above that the above can be maintained.

  That is, by setting the yield hinge of the wide flat beam 10 on the side surface of the column 1, the reinforcing reinforcing bars in the vicinity of the column 1 can be reduced, but the fixing force of the beam main bar 3 of the protruding portion 11 protruding from the column 1 is reduced. . This tendency is remarkable at the extreme end of the wide flat beam 10. Therefore, in the present invention, the outermost end portion of the beam main bar 3 in the wide flat beam 10 is mechanically fixed by the mechanical fixing device 12, and the U-shaped cap bar 13 is connected to the end portion of the wide flat beam 10. Inserted from the side. Thereby, the restraining force of the edge part of the wide flat beam 10 can be raised, and the fixing force of the beam main bar edge part can be raised.

FIG. 6 is a second embodiment of the wide flat beam 10 according to the present invention.
In this figure, (A) is a plan view, and (B) is a sectional view taken along line BB of (A). In this example, the wide flat beam 10 has a cross shape (see FIG. 3) in which the beam 2 is on both sides of the column 1.

  As shown in FIG. 6 (A), the wide flat beam 10 of the present invention has a vertical through hole 16 and a through hole reinforcing bar 17.

The vertical through hole 16 vertically penetrates the protruding portion 11 of the wide flat beam 10 located on the front surface or the rear surface of the column 1. The position of the vertical through hole 16 is preferably within d / 2 from the column side surface of the projecting portion of the column 1 and within d / 2 from the front surface of the column 1. Here, d is the beam's fault.
Moreover, the diameter of the vertical through-hole 16 is good to be 0.15 times or less of a pillar, and 200 mm or less. The number of vertical through holes 16 is one in this example, but may be two or more as long as the center interval is sufficiently separated.

The through-hole reinforcing bar 17 is U-shaped, and is arranged so as to surround the vertical through-hole 16 and extend into the column 1.
Furthermore, in this example, as shown in FIG. 6 (B), a U-shaped reinforcing bar 18 embedded in the protruding portion 11 of the wide flat beam 10 located on the front surface (left side or rear surface in the drawing) of the column 1 and the beam And a plurality of restraining muscles 15 for restraining the position of the main muscle 3.

  With the above-described configuration, in the cross-shaped wide flat beam 10 having the beam 2 on both sides of the column 1, the vertical penetration that vertically penetrates the protruding portion 11 of the wide flat beam 10 while maintaining the ultimate bending strength of the beam 2. It was confirmed by the test described above that the holes 16 can be provided.

That is, as in Patent Document 1, when reinforcing from the column 1 to the protruding portion so that the proof strength is sufficiently larger than the proof strength of the flat beam end, a large amount of reinforcing bars are required in the protruding portion. However, there is a problem that it is difficult to perform the bar arrangement at the protruding portion.
Also, in this case, on the other hand, when it is necessary to penetrate the facility piping such as a gutter on the side surface of the pillar 1, there is a problem that the vertical penetration hole cannot be provided due to the bar arrangement.
In the present invention, since the yield hinge of the wide flat beam 10 is set on the side surface of the column 1, the reinforcing reinforcing bars near the column 1 can be reduced, and the vertical through-hole 16 for equipment piping is provided between the main bar and the stirrup of the beam 2. Can be formed.
Further, by arranging the U-shaped through-hole reinforcing bar 17 so as to surround the vertical through-hole 16 and extend into the column 1, it is possible to prevent a decrease in the proof stress of the wide flat beam 10 by the vertical through-hole 16.

FIG. 7 is a cross-sectional side view of a building 20 using the above-described frame frame of the present invention.
The building 20 according to the present invention is an apartment house such as an apartment, and has a frame structure composed of reinforced concrete columns 1 and beams 2 having at least two planes in the girder direction (left and right in the drawing) of the building 20.
Further, the building 20 has the above-described ramen frame of the present invention on at least one surface.

  With this configuration, it is possible to increase the opening height while maintaining the height of the beam 2 on each floor.

FIG. 8 is a plan view of a building 20 according to the present invention.
In this example, a balcony 22 is provided on the wife side (right side in the figure) of the building 20, and a vertical evacuation port 24 is provided on the balcony 22 where the wide flat beam 10 (shown by a broken line) is not provided. The vertical evacuation port 24 is preferably large enough to allow people to pass, for example, 650 mm × 650 mm or more.
With this configuration, the vertical evacuation port 24 can be provided even in the building 20 having the wide flat beam 10.

As described above, according to the present invention, since the yield hinge of the wide flat beam 10 is set on the opposite side surface of the adjacent column 1, there is no need to provide a protruding portion that requires a large amount of reinforcing bars, Reinforcement construction becomes easy.
Further, the ultimate bending strength M of the wide flat beam 10 is calculated based on the protrusion width Ba. Therefore, it is possible to easily calculate the strength of the joint between the wide flat beam 10 and the column 1, although the yield hinge is set on the opposite side surface of the adjacent column 1.

  Therefore, it is easy to calculate the strength of the joint between the wide flat beam 10 and the column 1 and the bending ultimate strength M of the wide flat beam 10 can be easily increased by reinforcing the joint between the wide flat beam 10 and the column 1. .

  In addition, this invention is not limited to embodiment mentioned above, Of course, it can change variously, unless it deviates from the summary of this invention.

at tension main bar cross-sectional area, σy main bar yield strength, d beam, Ba protrusion width,
Bb Beam width, Bc Column width, Mu Normal ultimate bending strength of flat beam,
Mt Ultimate bending strength of wide flat beams (experimental value), M Ultimate bending strength of wide flat beams (calculated value),
γ reduction factor, μ constant, 1 column, 2 beams, 3 beam main bars, 4 concrete,
9 Normal flat beam, 10 wide flat beam, 11 protruding part, 12 mechanical fixing device,
13 cap bars, 14 U-shaped reinforcement bars, 15 restraint bars, 16 longitudinal through holes,
17 Reinforcing bar reinforcement, 18 U-shaped reinforcement, 20 Building, 22 Balcony,
24 Vertical exit

Claims (7)

The frame is composed of reinforced concrete columns and beams, and has a wide flat beam whose beam width is larger than the column width of the columns,
The yielding hinge of the wide flat beam is set on the opposite side of an adjacent column;
A frame structure having a wide flat beam, wherein the bending ultimate strength M of the wide flat beam is calculated based on a difference Ba between the beam width and the column width.   The bending ultimate strength M of the wide flat beam is calculated by a reduction factor γ based on a ratio Ba / Bc between a difference Ba between a beam width and a column width and a column width Bc. Ramen frame with wide flat beams. The bending ultimate strength Mu of a normal flat beam in which the beam width of the beam is smaller than the column width of the column is
Mu = 0.9 · at · σy · d, where at is the tensile main bar cross-sectional area, σy is the main bar yield strength, and d is the beam's fault.
The reduction coefficient γ is obtained by γ = 1.0−μ · Ba / Bc, where μ is a positive constant of 0.1 or more and 0.3 or less,
The rigid frame structure having a wide flat beam according to claim 2, wherein the bending ultimate strength M of the wide flat beam is obtained by a product of the bending ultimate strength Mu of the normal flat beam and the reduction factor γ. . The wide flat beam is a toroid having a beam only on one side of the column,
A mechanical fixing device mechanically fixed to the outermost end of the beam main bar located in the column;
The frame frame having a wide flat beam according to claim 2, further comprising a cap bar that enhances fixability of an end portion of the beam main bar. The wide flat beam has a cross shape with beams on both sides of the column,
A vertical through hole penetrating up and down the protruding portion of the wide flat beam located on the front or rear surface of the column;
The frame structure having a wide flat beam according to claim 2, further comprising a U-shaped through-hole reinforcing bar surrounding the vertical through-hole and extending into the column. A building having a rigid frame composed of columns and beams of reinforced concrete with at least two frames in the direction of the beam of the building,
A building using a ramen frame characterized by having the ramen frame according to any one of claims 1 to 5 on at least one frame.   The building using a ramen frame according to claim 6, wherein a balcony is provided on the wife side of the building, and a vertical evacuation port is provided at a position without the wide flat beam on the balcony.

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