JP2002206282A - Cft structural column - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a CFT structural column capable of promoting safety and being economically executed by fitting a ring reinforced member into the outside of a steel pipe body and bearing the confined effect on the ring reinforced member. SOLUTION: The CFT structural column includes the steel pipe body 2 filling the inside thereof with a concrete and connecting beams 11 to each other at a predetermined story height H and the ring reinforced member 5 fitted and loaded to the outside of the steel pipe body 2 within a range of the inside measurement column height Ho, and the ring reinforced member 5 is constituted of a steel pipe. The ring reinforced member 5 is made as a longitudinal length L1 approximately over the whole area within a range of the inside measurement column height.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete filled steel tube (CFT) in which steel pipes are filled with concrete.
ube: Concrete filled steel pipe) C applied to a column
It relates to an FT structural column.

[0002]

2. Description of the Related Art FIG. 7 is a longitudinal sectional view showing an example of a conventional CFT structure column.

In FIG. 7, reference numeral 1 denotes a CFT structure column,
It comprises a steel pipe main body 2 erected on a foundation not shown and concrete 4 filled in the steel pipe main body 2. In the steel pipe main body 2, the inner diaphragm 3 is joined by, for example, welding to positions corresponding to upper and lower flanges of an H-shaped steel constituting the beam 11 described later.

[0004] Reference numeral 11 denotes a beam, two end H-shaped steel members 12 joined to the opposite steel pipe main body 2 at a predetermined floor height H by predetermined means, for example, welding, and the two end H-shaped steel members 12.
And a central H-shaped steel 13 joined between them. The end H-beam 12 and the central H-beam 13 are
The web and the upper and lower flanges are
4. Joined using HTB (High Tension Bolt) 15. Gh indicates the beam structure (beam height), and Ho indicates the length of the inner column formed between the beams 11 on the upper and lower floors.

[0005] The CFT structural column 1 shown in FIG.
As a substitute for the formwork, the formwork becomes unnecessary, and the reinforcing bar disposed inside becomes unnecessary, so that the construction cost can be reduced and the construction period can be shortened. Further, since the steel pipe main body 2 functions as a restraining member that exerts an effect (confine effect) of restraining deformation of the cross-sectional shape of the concrete 4, the apparent strength of the concrete 4 increases, and a large shaft as a pillar material. The column diameter can be reduced by obtaining the directional strength and the bending strength.

[0006]

A conventional CFT structure column 1
Since the confined effect is obtained after the steel pipe main body 2 yields in the axial direction, the ultimate maximum strength is very high, but the axial deformation at that time is large. Therefore, even if the bearing has sufficient performance to withstand a higher load, it is necessary to set the upper limit of about 2% of the degree of axial strain in practical use, consider that point as the maximum proof stress, and reflect it in the design. There is.

When a horizontal force acts on a building during an earthquake, from the viewpoint of limiting the degree of axial strain, the steel pipe main body 2 yields during a moderate earthquake and avoids expecting a confined effect. Should. For this purpose, it is necessary to set a certain safety factor with respect to the axial proof stress at the time when the confined effect is not expected, and to design the respective members while providing an axial force limit. The axial force limitation is therefore uneconomical in the case of a design section with a very large confining effect, since it must be given a fairly safe evaluation.

The present invention has been made in order to solve the above-mentioned inconvenience. A ring reinforcing member is fitted to the outside of a steel pipe main body, and the ring reinforcing member is provided with a confined effect, thereby improving safety. An object of the present invention is to provide a CFT structural column that can be improved and can be constructed economically.

[0009]

According to the present invention, there is provided a steel pipe main body in which concrete is filled and a beam is joined at a predetermined floor height, and an inner space formed between the beams on the upper and lower floors. A ring reinforcing member fitted and mounted on the outside of the steel pipe main body in the range of the length of the pillar, wherein the ring reinforcing member is formed of a steel member having a predetermined longitudinal length,
It is a CFT structural column characterized by the above.

According to a second aspect of the present invention, there is provided the CFT structural column according to the first aspect, wherein the ring reinforcing member is formed of a steel pipe.

According to a third aspect of the present invention, in the CFT structural column according to the first or second aspect, a predetermined mounting clearance is provided between an inner surface of the ring reinforcing member and an outer surface of the steel pipe main body. A CFT structural column characterized by the following.

According to a fourth aspect of the present invention, in the CFT structural column according to any one of the first to third aspects,
A CFT characterized in that the ring reinforcing member has a longitudinal length extending over substantially the entire area of the inner pillar.
It is a structural pillar.

According to a fifth aspect of the present invention, in the CFT structural column according to any one of the first to third aspects,
A CFT structural column characterized in that two of the ring reinforcing members are attached to the column head and the column base in the range of the length of the internal column in proximity to the beams on the upper and lower floors.

According to a sixth aspect of the present invention, in the CFT structural column according to any one of the first to third aspects,
A CFT structural column, wherein three or more of the ring reinforcing members are mounted in the range of the length of the inner law column at a distance from each other.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 is a front view of a CFT structure column according to a first embodiment of the present invention, FIG. 2 is a longitudinal sectional view of the CFT structure column shown in FIG. 1, and FIG. 3 is an enlarged cross section of the CFT structure column shown in FIG. FIG. 4 and FIG. 4 are explanatory diagrams of column axial force, bending moment, and the like.

A CFT structural column 1A according to a first embodiment of the present invention has a steel pipe main body 2 filled with concrete 4 and joined to a beam 11 at a predetermined floor height H, and a beam 1 on upper and lower floors.
1 and a ring reinforcing member 5 fitted and mounted on the outside of the steel pipe main body 2 within the range of the inner column length Ho formed between them.

As shown in FIG. 3, the steel pipe main body 2 is a circular steel pipe having a circular cross-sectional shape, and the inner diaphragm 3 is joined inside the position where the beam 11 is joined. The cross-sectional shape of the steel pipe main body 2 is, for example, elliptical, in addition to circular.
Other shapes such as a square, a rectangle, a pentagon, and a hexagon may be used.

The ring reinforcing member 5 has a predetermined longitudinal length,
For example, the cross section of the steel pipe main body 2 is made of a steel member, for example, a steel material or a steel pipe having a length between the beams 11 on the upper and lower floors, that is, a longitudinal length L1 over substantially the entire area of the inner column length Ho. It functions as a restraining member that restrains deformation of the shape. The inner surface (inner shape) of the cross-sectional shape of the ring reinforcing member 5 is formed in a shape similar to the outer surface (outer shape) of the cross-sectional shape of the steel pipe main body 2.

Further, as shown in FIG. 3, a predetermined mounting clearance CL1 is provided between the inner surface of the ring reinforcing member 5 and the outer surface of the steel pipe main body 2. The mounting clearance CL1 is set in consideration of the clearance in the manufacture of the steel frame, the cross-sectional shape of the standard product between the steel pipe main body 2 and the ring reinforcing member 5, the synergistic effect of the confined effect between the steel pipe main body 2 and the ring reinforcing member 5, and the like. I do.

BB is the outer diameter of the concrete 4 (the steel pipe body 2
, Bi is the outer diameter of the steel pipe body 2 and Ti is the steel pipe body 2
, Bo is the outer diameter of the ring reinforcing member 5, To is the thickness of the ring reinforcing member 5, S1 is the gap between the ring reinforcing member 5 and the beam 11 (for example, 20 mm), N is the column axial force, and Ht1 is the steel pipe. Ht2 is the circumferential tensile force of the ring reinforcing member 5, and M is the bending moment.

By fitting the ring reinforcing member 5 on the outside of the steel pipe main body 2 in this manner, as shown in FIG. 4, the bending moment M of the column during an earthquake and the column axial force (compressive force, tensile force) 3) The steel pipe main body 2 can bear the ability to resist N and the confining effect of restraining the deformation of the cross-sectional shape of the steel pipe main body 2 can be played by the ring reinforcing member 5 functioning as a restraining member. Then, the ring reinforcing member 5 can exhibit the confined effect from the state where the steel pipe main body 2 is in the elastic range (before yielding).

As described above, the timing when the confined effect is exerted on the ring reinforcing member 5 from the state where the steel pipe main body 2 is in the elastic range (before yielding) can be freely designed by the mounting clearance CL1. If the mounting clearance CL1 is set to zero, the steel pipe main body 2 and the ring reinforcing member 5 can simultaneously exert a confined effect.

Accordingly, since the steel pipe body 2 can obtain the confined effect and the ring reinforcing member 5 can also obtain the confined effect, safety can be improved. In addition, the total thickness of the steel pipe main body 2 and the ring reinforcing member 5 can be designed in consideration of the type and size of the acting load of the column member, so that the ring reinforcing member 5 is fitted to the outside of the steel pipe main body 2 and mounted. In this case, the thickness of the steel pipe main body 2 alone can be made smaller than that in the case of only the steel pipe main body 2, so that the construction for achieving the intended purpose can be economically performed.

Since the gap S1 is provided between the ring reinforcing member 5 and the beam 11, the column axial force N is reduced.
Will not work directly. Furthermore, when the mounting clearance CL1 is provided between the steel pipe main body 2 and the ring reinforcing member 5, since the steel pipe main body 2 develops the confined effect and expands, the confined effect by the ring reinforcing member 5 develops. It can be designed to serve a double safety enhancement. Since the ring reinforcing member 5 is made of a steel pipe, the ring reinforcing member 5 can be obtained simply and at low cost.

FIG. 5 shows a CF according to a second embodiment of the present invention.
It is a longitudinal section of a T structure pillar.

A CFT structural column 1B according to a second embodiment of the present invention has a steel pipe main body 2 in which concrete 4 is filled and a beam 11 is joined at a predetermined floor height H, and a beam 1 on upper and lower floors.
1, two ring reinforcing members 6 fitted and mounted on the outer side of the steel pipe main body 2 in the range of the inner column length Ho formed between the two.
It is composed of

The ring reinforcing member 6 is located close to the beam 11 on the upper and lower floors at the position of the column head and column base where the bending moment M (see FIG. 4) during an earthquake becomes large within the range of the inner column length Ho. A steel member having a longitudinal length L2, for example, a steel material or a steel pipe, which functions as a restraining member for restraining deformation of the cross-sectional shape of the steel pipe main body 2. is there. And the ring reinforcing member 6
Is formed in a shape similar to the outer surface of the cross-sectional shape of the steel pipe main body 2. Furthermore, as shown in FIG. 3, a mounting clearance CL1 is provided between the steel pipe main body 2 and the ring reinforcing member 6.

According to the CFT structural column 1B of the second embodiment, the same effect as that of the CFT structural column 1A of the first embodiment can be obtained, and a small number of ring reinforcing members 6 are arranged at effective positions. This makes it possible to more economically perform the construction that achieves the intended purpose. In addition,
The length L2 in the vertical direction of the ring reinforcing member 6 is determined in consideration of the type and magnitude of the load acting on the column material.

FIG. 6 shows a CF according to a third embodiment of the present invention.
It is a longitudinal section of a T structure pillar.

A CFT structural column 1C according to a third embodiment of the present invention has a steel pipe main body 2 in which concrete 4 is filled and a beam 11 is joined at a predetermined floor height H, and a beam 1 on upper and lower floors.
6, six ring reinforcing members 7 fitted and mounted on the outer side of the steel pipe main body 2 in the range of the inner column length Ho formed between the two.
It is composed of

The ring reinforcing member 7 is fitted to the outside of the steel pipe main body 2 at a distance within the range of the inner column length Ho, and is made of a steel member having a longitudinal length L3, for example, a steel material or a steel pipe. It functions as a restricting member for restricting deformation of the cross-sectional shape of the steel pipe main body 2. The inner surface of the cross-sectional shape of the ring reinforcing member 7 is formed in a shape similar to the outer surface of the cross-sectional shape of the steel pipe main body 2. Further, between the steel pipe main body 2 and the ring reinforcing member 7, as shown in FIG.
A mounting clearance CL1 is provided.

According to the CFT structure pillar 1C of the third embodiment, the CFT structure pillars 1A, 1 of the first and second embodiments are provided.
The same effect as B can be obtained, and by arranging a small number of the ring reinforcing members 7 at more effective positions, construction that achieves the intended purpose can be performed more economically. Note that the longitudinal length L3 of the ring reinforcing member 7 is determined in consideration of the type and size of the load acting on the column material. In the case of the third embodiment, the same effect can be obtained even when three or more ring reinforcing members 7 are used.

In the above embodiment, a gap S1 is provided between the ring reinforcing members 5, 6, 7 and the beam 11, a space between the ring reinforcing members 6, 7 is secured, and the steel pipe main body 2 and the ring In order to provide the mounting clearance CL1 between the members 5, 6, and 7, an inclusion may be inserted.

[0034]

According to the first aspect of the present invention, the ability to withstand the bending moment of the column and the column axial force at the time of the earthquake by fitting and mounting the ring reinforcing member on the outside of the steel pipe main body. It is possible to cause the steel pipe main body to carry the confine effect that restrains the deformation of the cross-sectional shape of concrete, and to cause the reinforcing member that functions as the restraining member to carry the confine effect that restrains the deformation of the cross-sectional shape of the steel pipe body. .

Accordingly, the steel pipe main body and the ring reinforcing member can each obtain a double-structured confined effect, so that safety can be improved. Further, the total thickness of the steel pipe main body and the ring reinforcing member can be designed in consideration of the type and size of the applied load of the column member, so that the total thickness can be made thinner than in the case of the steel pipe main body alone. It is possible to economically carry out construction to achieve the objectives of the period.

According to the second aspect of the present invention, since the ring reinforcing member is formed of a steel pipe, the ring reinforcing member can be obtained simply and at low cost. According to the third aspect of the present invention, since the mounting clearance is provided between the steel pipe main body and the ring reinforcing member, the confined effect of the ring reinforcing member develops after the steel pipe main body expands due to the manifest effect. As a result, safety can be double improved. The timing of the manifestation effect of the ring reinforcing member can be freely designed by adjusting the mounting clearance.

According to the fourth aspect of the present invention, since the ring reinforcing member has a longitudinal length extending substantially over the entire range of the length of the inner pillar, the intended purpose can be achieved over the entire length of the inner pillar. Can be achieved. According to the fifth aspect of the present invention, two ring reinforcing members are attached to the column head and the column base in the range of the inner column length in proximity to the beams on the upper and lower floors. By arranging them in an appropriate manner, construction that achieves the intended purpose can be performed more economically. According to the sixth aspect of the present invention, three or more ring reinforcing members are mounted in the range of the length of the inner column, spaced apart from each other. Construction that achieves the object can be performed more economically.

[Brief description of the drawings]

FIG. 1 is a front view of a CFT structure column according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the CFT structure column shown in FIG.

FIG. 3 is an enlarged cross-sectional view of the CFT structure column shown in FIG.

FIG. 4 is an explanatory diagram of column axial force, bending moment, and the like.

FIG. 5 is a longitudinal sectional view of a CFT structure column according to a second embodiment of the present invention.

FIG. 6 is a longitudinal sectional view of a CFT structure column according to a third embodiment of the present invention.

FIG. 7 is a longitudinal sectional view showing an example of a conventional CFT structure column.

[Explanation of symbols]

 1, 1A-1C FT structural column 2 Steel pipe main body 3 Inner diaphragm 4 Concrete 5-7 Ring reinforcing member 11 Beam L1-L3 Vertical length BB, Bi, Bo Outer diameter Ti, To Wall thickness S1 Gap CL1 Mounting clearance Gh beam Form H Floor height Ho Inner column length N Column axial force Ht1, Ht2 Circumferential tensile force M Bending moment

Claims (6)

[Claims] 1. A steel pipe main body in which concrete is filled and a beam is joined at a predetermined floor height, and the steel pipe main body is formed within a range of an inner column length formed between the beams on the upper and lower floors. A CFT structural column comprising: a ring reinforcing member fitted and mounted on the outside; and the ring reinforcing member is formed of a steel member having a predetermined longitudinal length. 2. The CFT structural column according to claim 1, wherein the ring reinforcing member is made of a steel pipe. 3. The CFT according to claim 1 or claim 2.
A structural column, wherein a predetermined mounting clearance is provided between an inner surface of the ring reinforcing member and an outer surface of the steel pipe main body. 4. The CFT structural column according to any one of claims 1 to 3, wherein the ring reinforcing member has a longitudinal length substantially over the entire area within a range of the inner column length. A CFT structural column comprising: 5. The CFT structural column according to claim 1, wherein the ring reinforcing member is located in a range of the length of the inner column and in proximity to the beams on the upper and lower floors. A CFT structural column, wherein two columns are mounted on a column cap and a column base. 6. The CFT structural column according to any one of claims 1 to 3, wherein three or more of the ring reinforcing members are mounted in the range of the length of the inner column, separated from each other. A CFT structural column characterized by the above-mentioned.