JP2001262705A - Steel construction structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve strength of a steel construction structure in which plural concrete-filled steel pipe columns are vertically connected to each other, with steel beams jointed with outer diaphragms of the respective steel pipe columns. SOLUTION: In vertically connecting plural concrete-filled angular steel pipe columns 1 having outer diaphragms 22 fixed on their outer circumference to each other, opening ends of the upper and the lower steel pipe columns 1, 1 are abutted with both of upper and lower surfaces of a stiftener ring 10 having a smaller inner diameter and a larger outer diameter than the opening ends of the upper and the lower steel pipe columns 1, 1 of the same size to be welded with and connected to them, and concrete 6 is filled to a connection part, so an inner diameter end part 10a of the stiftener ring 10 bites the concrete 6 for strongly restraining it in a buckling direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel structure in which steel beams are joined by an outer diaphragm fixed to a concrete-filled steel tubular column.

[0002]

2. Description of the Related Art As a method of joining a rectangular steel tubular column and a flange portion of a steel beam in a steel structure, a diaphragm connecting the steel tubular column and the beam flange portion traverses the column and projects a predetermined length outside the column. There is known a through-diaphragm system and an outer-diaphragm system in which the diaphragm does not penetrate the column. The former through-diaphragm method has the advantage that the outside projection length of the diaphragm can be relatively short, so it is easy to transport from the factory to the site and the diaphragm does not get in the way during construction, but to penetrate the diaphragm through the pillar Once the column is cut and the diaphragm is inserted, the small end of the column must be welded again, and the welding and structural design are performed because the welded part is located at the most stressful place of the column Strict conditions are required, which is disadvantageous in terms of cost.

On the other hand, the latter outer diaphragm method has a problem in that it has a difficulty in transportability from the factory to the site because the outside projection length of the diaphragm is longer than the through-diaphragm, and there is a problem that the diaphragm hinders the construction. Fillet welding of the diaphragm to the column surface is sufficient without cutting the column, so that the strength of the column can be easily maintained, and it tends to be widely used for seismic resistance and cost advantages. In this outer diaphragm system, as shown in FIG. 16 (A), a diaphragm 2 around a square steel tubular column 1 is constituted by a single diaphragm, and a single diaphragm 1 is inserted through an insertion hole 2a formed in the center of the diaphragm 2. There are a diaphragm type and a divided diaphragm type in which the diaphragm 2 is formed of four small pieces and the small piece diaphragms are welded to each other near the corner of the column (indicated by a dotted line W in FIG. 16A). In either case, as shown in FIG. 16B, the upper and lower diaphragms 2 are usually welded and connected by vertical stiffeners 4, and the vertical stiffeners 4 are welded to the center portions of the respective column surfaces to reinforce the diaphragms 2. . Then, the flange portion 3b of the H-beam 3 and the diaphragm 2,
And the beam web part 3a and the vertical stiffener 4 are connected by the connection plate 5 and the bolt 6, respectively.

However, in the conventional outer diaphragm system, when a vertical bending moment M acts on a beam as shown in FIG. 16B, the bending moment M is applied to a column surface via a vertical stiffener 4 to generate a compressive tensile stress. , And local buckling B as shown in FIG. In order to increase the resistance to the local buckling B, an advanced construction technique such as joining the diaphragm 2 and the column surface by complete penetration welding is required, and there is a problem in terms of construction period and construction cost.

Therefore, in order to sufficiently secure the strength of the steel pipe column wall, a concrete-filled steel pipe column in which concrete is filled in a steel pipe column has been proposed and implemented. FIGS. 17 (A) and 17 (B) show an outline of an outer diaphragm type column-beam building structure using this concrete-filled steel tube column. The concrete-filled steel tube column 1 shown in FIG. 17 is a square steel tube column. A plurality of pipes of the same size are connected in the vertical direction in a straight tube shape, and a pair of outer diaphragms 2 are fixed to the upper and lower portions of each steel pipe column 1, and one H-shaped steel is provided for each pair of upper and lower outer diaphragms 2. Steel beams 3 are joined. The pair of upper and lower outer diaphragms 2 have the same shape, and have four pillar surfaces 1a of the square steel tubular column 1.
And has a rectangular frame-shaped ring portion 2a which is fitted and welded to the frame. The steel beam 3 is an H-shaped steel in which a flange is integrally formed on upper and lower ends of a vertical web, and tips of upper and lower flanges are abutted against tips of a pair of upper and lower outer diaphragms 2 to weld, joint plates, connecting plates, and the like. It is connected by intervening.

An outer diaphragm 2 is factory-welded to a column surface 1a of a rectangular steel pipe column 1, and a plurality of steel pipe columns 1 are transported to a construction site. The pillars 1 are connected vertically one after another. The connection between the steel pipe columns 1 is made by connecting the upper end of the opening of the lower steel pipe column 1 to the upper steel pipe column 1.
Butt welding at the lower end of the opening. Before connecting the steel pipe columns, concrete 6 is filled into the vertically built steel pipe columns 1. Such concrete filling is performed for each steel pipe column 1 or for each of a plurality of connected steel pipe columns.

The concrete-filled steel pipe column 1 used in the above-mentioned outer diaphragm type column-beam joint structure is constructed by reinforcing the pipe wall with the filled concrete 6.
Has improved buckling resistance.

[0008]

The outer diaphragm type steel pipe column 1 shown in FIG. 17 does not particularly hinder the concrete filling property, but has a weak fixing force between the filled concrete 6 and the inner surface of the steel pipe column 1. Therefore, the compression load resistance and the bending load resistance of the steel pipe column 1 were not sufficient.

It is an object of the present invention to improve the mutual restraining force between a concrete-filled steel pipe column used in the form of an outer diaphragm and a filled concrete to improve the compressive load resistance and the bending load resistance of the steel pipe column. Is to improve.

[0010]

The technical means for achieving the above object of the present invention is to provide an outer diaphragm which is fixed perpendicularly to a column surface of a plurality of concrete-filled steel pipe columns which are vertically connected in a straight tube. The steel building structure in which the steel beam is joined to the upper end of the lower concrete-filled steel pipe column connected vertically and the lower end of the upper concrete-filled steel pipe column of the same opening size as the lower end of the opening, Butt-weld through a ring-shaped flat steel plate stiffener ring with an inner diameter smaller than the opening size and a larger outer diameter, and filled into the upper and lower steel pipe columns at the inner diameter end of the stiffener ring projecting into the upper and lower steel pipe columns It is characterized by restraining concrete.

Here, the stiffener ring has a substantially central portion on both sides butt-welded to the open ends of the two steel pipe columns to connect and integrate the two steel pipe columns into a straight pipe shape.
When concrete is filled in the connecting portion of the steel pipe columns, the inner diameter end portion of the stiffener ring projecting inward from the open end of the steel pipe column bites into the concrete, and the concrete is strongly restrained by the two steel pipe columns. This binding force improves the stress transmission between the steel pipe column and the outer diaphragm, and increases the overall steel joint strength.

Further, according to the present invention, the steel pipe column is a square steel pipe column, and a tip end of one steel beam of an outer diaphragm fixed to the column surface of the square steel pipe column is one of the same square steel pipe column.
It is characterized by comprising a pair of divided diaphragms each of which is divided into two in the width direction of the column surface from one column surface, and one steel beam is joined to each of the distal ends of the pair of divided diaphragms. .

[0013] By dividing the outer diaphragm into two for one steel beam in this manner, it is easy to reduce the overall size of the outer diaphragm, etc., and the concrete-filled type used in the outer diaphragm type is used. Convenient transportation and construction of steel pipe columns can be achieved.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Various embodiments of the present invention will be described with reference to FIGS. Note that the same or corresponding parts are denoted by the same reference symbols throughout the drawings including FIG.

1 (A), (B) and FIG. 2 show a steel frame structure in which one steel beam 3 is formed at the tip of a pair of upper and lower outer diaphragms 22 welded to a concrete-filled steel tubular column 1. The basic structure to be joined is shown. The pair of upper and lower outer diaphragms 22 are horizontal steel plates having the same shape orthogonal to one column surface 1 a of the rectangular steel tube column 1. A vertically long steel plate connecting plate 30 is fixed between the tip portions of the pair of upper and lower outer diaphragms 22 as needed. Also, the upper and lower flanges 3 of the H-shaped steel beam 3 are formed at the tips of a pair of upper and lower outer diaphragms 22.
b is connected to the joint plate 41 by a high-strength bolt 50,
0 is the joint plate 61 and the high-strength bolt 7 on the web 3a of the steel beam 3.
Linked with 0.

The concrete-filled steel tubular column 1 is a square steel tubular column or a round steel tubular column to be filled with concrete 6 after construction, and the rectangular steel tubular column 1 is shown in the drawings. One steel pipe column 1
Has a column length in units of floor height, and a pair of outer diaphragms 22 is fixed to the upper and lower portions of one steel tube column 1 in a manner orthogonal to the column surface 1 a of the steel tube column 1. A plurality of steel pipe pillars 1 of the same size are vertically connected to each other in a straight tube to construct one steel pipe pillar of a building. In the present invention, the upper end p of the lower steel pipe column 1 connected vertically and the lower end q of the opening of the upper steel column 1 are shown in FIG.
Is butt-welded via a stiffener ring 10 having the shape and size shown in FIG.

The stiffener ring 10 is a substantially rectangular flat steel plate having a smaller inner diameter and a larger outer diameter than the rectangular opening size of the steel pipe column 1. The open ends p and q of the two steel pipe columns 1 and 1 are butt-welded. After this welding, the concrete 6 is filled in the lower steel column 1 and the upper steel column 1. When concrete 6 is filled in the connecting portion between the upper and lower steel pipe columns 1 and 1 in this way, the inner end 10a of the stiffener ring 10 protruding from the inner surface of the steel pipe columns 1 and 1 bites into the concrete 6 and the filled concrete 6 is removed. Restrain in buckling direction. By this restraint, the entire concrete 6 filled in the upper and lower steel pipe columns 1, 1 is firmly restrained, and the stress transmission between the upper and lower steel pipe columns 1, 1 and the outer diaphragms 2,. As a result, the steel frame joint strength of the entire steel structure increases. Also,
By increasing the binding force of the upper and lower steel pipe columns 1, 1 and the stiffener ring 10 of the concrete 6, it is easy to make the pipe wall of the steel pipe columns 1, 1 thinner, and the outer diaphragm 2 can be divided as described later. It becomes easy and it is desirable to divide. In addition, if necessary, in FIG. 1B, both side surfaces of the web 3a of the steel beam 3 are sandwiched by bolting using a pair of connecting plates (not shown), and the upper and lower edges of the pair of connecting plates are Fillet welding is performed on the diaphragm 22 and the tip edges of the pair of connecting plates are also welded with the column surfaces 1a of the steel pipe columns 1 so that the load of the steel beam 3 in the gravitational direction is reduced by the pair of connecting plates and the column surface 1a. May be stably supported by a shearing force having a margin between them.

That is, the outer diaphragm 22 shown in FIG. 2 is a divided steel plate divided into two for one steel beam 3. This outer diaphragm 22 is shown in FIG.
As shown in FIG. 2 (B), two left and right divided diaphragms 2 equally divided in the width direction of one column surface 1a of a rectangular steel tube column 1
The end of the flange 3b of one steel beam 3 is connected to the distal end of each of the divided diaphragms 23, 24. The pair of left and right divided diaphragms 23 and 24 is a line-symmetrical shape that is equally divided left and right from the center line of one columnar surface 1a of the rectangular steel tubular column 1, and is formed of one columnar surface 1a and each adjacent columnar surface 1a. L-shaped mounting seats 23a, 24a fitted near the corner 1c between the L-shaped mounting seats 23a, 23a, 2a.
It has beam joints 23b and 24b extending from one side of 4a. One of the divided diaphragms 23 has an L-shaped mounting seat 23a that is substantially half the width direction of one pillar surface 1a of the square steel tubular column 1 and the width direction of another pillar surface 1a adjacent to the one pillar surface 1a. Welding to approximately half the part, for example, a partial sectional view A of FIG.
B, and the L-shaped mounting seat 23
FIG. 12A shows the corner concave surface of FIG.
Are separated without welding as shown in the partial sectional view C of FIG.

The other divided diaphragm 24 is also welded to the rectangular steel tube column 1 at the same height as the one divided diaphragm 23. When the two left and right divided diaphragms 23 and 24 are horizontally welded to the rectangular steel tube column 1 at the same height, the divided surface portions 23 of the divided diaphragms 23 and 24 facing each other are opposed to each other.
A slit gap g having a predetermined width is positively formed between c and 24c, and the divided diaphragms are not directly welded to each other. The end of the connecting plate 30 is fitted to the tip of the slit interval g and fixed by welding. The fixing of the connecting plate 30 reinforces the distal end portions of the pair of upper and lower outer diaphragms 22, makes it difficult for the outer diaphragm 22 to be deformed even when an external force acts on the outer tube 22 at the time of conveying the steel tube column, and improves the workability of conveying the steel tube column.

The tip of each of the divided diaphragms 23 and 24 of the pair of upper and lower outer diaphragms 22 and the flange 3b of the steel beam 3
The two ends are fastened and connected to a pair of upper and lower joint plates 41 with a plurality of high-strength bolts 50 as shown in FIG. A pair of left and right web joint plates 6 are joined by abutting the connecting plates 30.
One and a plurality of high strength bolts 70 are connected. The joint plate 41 is a substantially rectangular cover plate steel plate that also serves as a reinforcing plate against the bending moment of the flange 3b of the steel beam 3, and one surface of the joint plate 41 is brought into surface contact with a corresponding joint surface of the pair of left and right divided diaphragms 23 and 24.

Incidentally, as shown in FIG.
When the upper and lower ends of the outer diaphragm 22 protrude from the pair of upper and lower outer diaphragms 22, two joint plates 41 are arranged on both sides of the protruding end, and the two joint plates 41 are divided into the diaphragms 23, 23 of the outer diaphragm 22 respectively. 24 and bolted to the tip. When the upper and lower ends of the connecting plate 30 are not projected from the pair of upper and lower outer diaphragms 22 as shown in FIG. 4, one of the joint plates 41 is divided into the respective diaphragms 23 and 24 as shown in FIG. Bolts may be fastened to the tip of the.

When the pair of left and right divided diaphragms 23 and 24 are not particularly distinguished from each other, they are referred to as an outer diaphragm 22, as shown in a partially enlarged view C of FIG. Joint surface n of diaphragm 22
In a state where at least the joint surface having high hardness is formed as a rough surface s by a shot blast method or the like, the joint surfaces m and n are brought into surface contact with each other, and the contact surfaces are brought together with a high-strength bolt 50. And press-fit to join. In both cases, the outer diaphragm 22 and the joint plate 41 of the steel plate are formed by processing the joint surface m of the joint plate 41 having a high hardness into a rough surface s because the joint plate 41 is usually a steel plate product having a higher hardness than the diaphragm steel plate. This rough surface processing method is desirable because the shot blasting method can be performed advantageously with equipment and can be performed with good mass productivity. The rough surface s of the high hardness joint plate 41 is replaced with the low hardness outer diaphragm 22.
When the joint surface n is tightened with the high-strength bolt 50, the unevenness of the high-hardness rough surface s bites into the low-hardness joint surface n, and the joint strength of the two joint surfaces m and n in the shear direction increases. By securing the joining strength and securing the joining strength by the tightening force of the high-strength bolt 50, the joining strength between the outer diaphragm 22 and the joint plate 41 is always high and stably secured, and the joining between the outer diaphragm 22 and the steel beam 3 is ensured. The strength is reliably and easily set in the field within the high hardness range. In addition, the joining strength of the joint surfaces m and n of the joint plate 1 and the outer diaphragm 22 is increased by high friction joining,
It is possible to reduce the outer size of the outer diaphragm 22 or the number of bolts. In the case where there is no great difference in hardness between the joint surfaces m and n of the joint plate 41 and the outer diaphragm 22, both the joint surfaces m and n may be roughened so that both surfaces are joined with high friction. Thus, the bonding strength can be sufficiently improved.

The pair of left and right divided diaphragms 23,
When the H-shaped steel beam 3 is joined to the distal end of the beam 24, the bending moment and the shear force of the beam load applied to the divided diaphragms 23 and 24 from the steel beam 3 are reduced by the L-shaped mounting seats 23a and 24a.
To the column surface 1a of the rectangular steel tube column 1 parallel to the load direction. The strength against the shearing force applied to the column surface 1a parallel to the beam load direction and the load resistance are L-shaped mounting seats 23a and 24.
By welding fillet "a" to the column surface 1a, it is highly stable and always has high load resistance. In addition, the L-shaped mounting seat 23
Fillers are welded only to approximately half the width direction of the columnar surface 1a in a direction parallel to the beam load direction, so that sufficient high load resistance is secured, and the L-shaped mounting seat 23a , 24b
Is set to be only about half the length in the width direction of one columnar surface 1a, an empty space without an outer diaphragm is secured on the columnar surface 1a. Further, by separating the concave concave surfaces of the L-shaped mounting seat portions 23a and 24a without welding to the corner portion 1c of the square steel tubular column 1, the beam load is not applied to the corner portion 1c, and the load is concentrated on the column corner portion. Breakage such as generation of cracks is avoided beforehand, and the strength of the weld between the column diaphragms is stabilized.

When the outer diaphragm 22 to be joined to one steel beam 3 is divided into two parts, a half of the outer surface of the steel tube column 1 on the opposite side to the outer diaphragm 22 is provided with a projecting member such as an outer diaphragm. Since there is no flat empty space secured, the above-mentioned empty space is used when the outer diaphragm 22 is factory-welded to the steel pipe column 1 and transported, so that the efficiency of the steel pipe column transportation is improved. Further, if the thickness of the outer diaphragm 22 is increased to reduce the size, the transportation efficiency is further improved. Further, the divided outer diaphragm 22 for joining one steel beam 3 is formed only on a half of the outer periphery of the rectangular steel tubular column 1, so that the entire size and material can be reduced. Become. Further, the inner surfaces of the divided diaphragms 23 and 24 and the square steel tube column 1 are formed by fitting the divided diaphragms 23 and 24 into the square steel tube column 1 so as to face each other at a predetermined slit interval g. Some relative dimensional errors in the outer circumference of the rectangular steel pipe are absorbed by the slit interval g, and it becomes easy to fit and weld the pair of divided diaphragms 23 and 24 to the outer circumference of the square steel tubular column 1 without play.

Next, various modifications of the present invention will be described.

The steel joint structure of the embodiment shown in FIG. 6 joins two steel beams 3 at the same height and orthogonally to a concrete-filled square steel tubular column 1. The diaphragm 22 is divided into three divided diaphragms 23, 24 and 25 having a shape as shown in FIG. Two of the three divided diaphragms 23 and 24 have the same shape as in FIG. 3, and the other one corresponds to the one obtained by integrating the two divided diaphragms 23 and 24 back to back. The one divided diaphragm 25 is a square steel tube column 1
Is horizontally fitted to one corner portion 1c of the first portion and partially welded with fillet, and the other divided diaphragm 2 is horizontally provided on both sides thereof.
3, 24 are fillet welded. One split diaphragm 2
3 and a divided diaphragm 2 opposed to the leading end
5 is joined to one steel beam 3 by a joint plate 41. The distal end of the other divided diaphragm 24 and the other distal end of the divided diaphragm 25 facing the distal end are joined to another steel beam 3 by a joint plate 41. FIG. 8 shows a specific structure of such a steel beam joint.

The steel joint structure of the embodiment shown in FIG. 7 has the same height as the concrete-filled square steel tubular column 1 at the same height.
Are joined in three orthogonal directions. In this case, the outer diaphragm 22 is composed of two divided diaphragms 23 and 24 having the same shape and another two divided diaphragms 25 and 25 having the same shape. Divided into a total of four. Two of the four divided diaphragms 23 and 24 have the same shape as in FIG. 2, and the remaining two divided diaphragms 25 and 25 are the same as those in FIG.
Has the same shape as the divided diaphragm 25. The two divided diaphragms 25, 25 are horizontally fitted to two corners 1c on both sides of one column surface 1a of the rectangular steel tube column 1 and partially fillet welded, and the remaining two portions of the rectangular steel tube column 1 are formed. Corner 1
Two divided diaphragms 23 and 24 are fitted to c and partially fillet welded. Two divided diaphragms 23,
Each of the steel beams 3 is joined to the distal end portion of the steel beam 3 by a joint plate 41 at the outer distal end portion of the two divided diaphragms 25 facing the distal end portion of each of the two divided diaphragms 2.
Another steel beam 3 is connected to the joint plate 4
1 is joined. FIG. 9 shows a specific structure of such a steel beam joint.

The steel joint structure of the embodiment shown in FIGS. 10A and 10B is a concrete-filled square steel tubular column 1.
Are joined at the same height in four orthogonal directions. In this case, the outer diaphragm 22 is divided into four divided diaphragms 25 having the same shape. Each of the four divided diaphragms 25 has the same shape as the divided diaphragm 25 shown in FIGS. The four divided diaphragms 25 are horizontally fitted to the four corners of the square steel tubular column 1 and partially welded with fillets. A total of four steel beams 3,... Are joined to joint ends of two adjacent four diaphragms 25 by joint plates 41,. FIGS. 11A and 11B show a specific structure of such a steel beam joint.

The steel joint structure of the embodiment shown in FIGS. 14 and 15 is an eccentric joint of a steel beam 3 to a concrete-filled square steel tubular column 1.

FIG. 14 shows one outer diaphragm 22 for joining one steel beam 3 into a narrow divided diaphragm 23 ′.
And a wide divided diaphragm 24 '. A narrow dividing diaphragm 23 'and a wide dividing diaphragm 24' having the same height and a narrow width are welded to one column surface 1a of the rectangular steel tubular column 1, and a slit interval g formed between the two.
Is shifted from the center line of the columnar surface 1a toward the narrow dividing diaphragm 23 ', and the connecting plate 3 fixed at the slit interval g
By connecting 0 to the central web of one steel beam 3,
The steel beam 3 is eccentrically joined to the square steel tubular column 1. In this case, the joint plate 41 for joining the tip end of each of the divided diaphragms 23 'and 24' and one steel beam 3 is a single steel plate similar to that shown in FIG.
It is desirable to compensate for the decrease in strength caused by reducing the width of 3 ′.

FIG. 15 shows two steel beams 3,
3 are joined at right angles, and the outer diaphragm 22 in this case is divided into three divided diaphragms 23 ′, 23 ′, 2 ′.
It is divided into 5 '. Two split diaphragms 23 ', 2
3 'has the same shape as the narrow divided diaphragm 23' of FIG. 14, and the remaining one divided diaphragm 25 'has the same shape as that of FIG.
Corresponds to the one obtained by integrating two wide divided diaphragms 24 ′ back to back. The one divided diaphragm 25 'is fitted to one corner 1c of the rectangular steel tubular column 1 and partially welded with a fillet, and two divided diaphragms 23' and 23 'are arranged on both sides thereof. Each of the orthogonal steel beams 3, 3 is eccentrically joined to the square steel tubular column 1 by joint plates 41, 41. Also in this case, the joint steel plate 41 is desirably a single steel plate that also serves as a reinforcing plate for the narrow divided diaphragm 23 ′.

In each of the embodiments described above, the distal end portion of the outer diaphragm joined to one steel beam is divided into two parts. However, the present invention is applicable to an outer diaphragm having a non-divided distal end portion. The application is valid. Further, the steel beam has been described as an H-beam single beam structure, but may be a double beam or an assembled beam.
The present invention is of course applicable to circular steel pipe columns as well as square steel pipe columns.

[0033]

According to the present invention, the upper and lower two concrete-filled steel pipe columns having an outer diaphragm are connected and integrated by butt welding the respective open ends to the central portions on both sides of the stiffener ring. When concrete is filled into the connection between the two steel pipe columns, the inner end of the stiffener ring that projects inward from the open end of the steel pipe column cuts into the concrete, and the concrete is firmly restrained by the two steel pipe columns. As a result, the wall strength of the concrete-filled steel tubular column itself is increased by this restraining force, the stress transmission between the steel tubular column and the outer diaphragm is improved, and the overall steel joint strength is increased. In addition, by increasing the steel joint strength, it is possible to reduce the wall thickness of the concrete-filled steel tubular column and reduce the size and weight of the outer diaphragm.

Further, a rectangular steel pipe column is used as the concrete-filled steel pipe column, and the tip end of one steel beam of the outer diaphragm fixed to the column surface of the square steel pipe column is connected to one of the square steel pipe columns. The outer diaphragm is made even smaller and lighter by constructing each end of a pair of divided diaphragms divided into two in the width direction of the pillar surface from two pillar surfaces, and the outer diaphragm is factory-welded and filled with concrete. This facilitates the transportation and construction of concrete-filled steel pipe columns in a state where they are not used.

[Brief description of the drawings]

FIG. 1A is a side view including a partial cross section showing a first embodiment of the present invention, and FIG. 1B is a cross sectional view taken along line T1-T1.

FIG. 2 is a plan view of the embodiment of FIG.

3A is a partial plan view of the embodiment of FIG. 1, and FIG.
Is its side view.

FIG. 4 is a side view showing a partially modified example of the embodiment of FIG. 3 (B).

FIG. 5 is a plan view when a steel beam is joined to the joining structure of FIG. 4;

FIG. 6 is a partial plan view showing a second embodiment of the present invention.

FIG. 7 is a partial plan view showing a third embodiment of the present invention.

FIG. 8 is a plan view when a steel beam is joined to the joining structure of FIG. 6;

FIG. 9 is a plan view when a steel beam is joined to the joining structure of FIG. 7;

FIG. 10A is a partial plan view showing a fourth embodiment of the present invention, and FIG. 10B is a side view thereof.

11A is a plan view when a steel beam is joined to the joint structure of FIG. 10, and FIG. 11B is a side view thereof.

FIG. 12 is an exploded plan view including a partially enlarged cross-sectional view of a divided outer diaphragm in the joint structure of FIG. 1;

FIG. 13 is an exploded plan view of a divided outer diaphragm in the joint structure of FIG. 6;

FIG. 14 is a partial plan view showing a fifth embodiment of the present invention.

FIG. 15 is a partial plan view showing a sixth embodiment of the present invention.

FIG. 16A is a plan view of a conventional column-beam joint structure using an outer diaphragm, FIG. 16B is a side view taken along line bb of FIG.
(C) is a sectional view of a locally buckled column.

17A is a side view including a partial cross section of a conventional concrete-filled steel frame building structure, and FIG. 17B is an enlarged cross-sectional view taken along line T2-T2.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Concrete filled steel pipe column 1a Column surface p Upper end of opening q Lower end of opening 3 Steel beam 3b Flange 6 Concrete 10 Stiffener ring 10a Inner diameter end 22 Outer diaphragm 23, 24, 25 Divided diaphragm

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Ryuichi Matsuo 2-26 Tsumon Nishiguchicho, Nishinomiya City, Hyogo Prefecture Arai Gumi Co., Ltd. (72) Inventor Takeyuki Ochi 947-6 Yuge, Tatsutacho, Kumamoto F-term (reference) 2E125 AA04 AA14 AB01 AB12 AC01 AC15 AC16 AG03 AG04 AG12 AG49 AG57 BB01 BB09 BB22 BB29 BB31 BB34 BC09 BD01 BE08 BF08 CA05 CA06 EA33

Claims (3)

[Claims] 1. A steel building structure in which a steel beam is joined to an outer diaphragm fixed perpendicularly to a column surface of a plurality of concrete-filled steel pipe columns connected vertically in a vertical tube, wherein the steel beams are connected vertically. The upper end of the lower concrete-filled steel pipe column and the lower end of the upper concrete-filled steel pipe column having the same opening size as the upper end of the lower pipe are stiffened by a ring-shaped flat steel plate having an inner diameter smaller than the opening size and a larger outer diameter. A steel building structure, wherein concrete filled in the upper and lower steel pipe columns is restrained at the inner end of the stiffener ring projecting into the upper and lower steel pipe columns by butt welding through a ring. 2. The steel pipe column is a square steel tube column, and a tip end of one steel beam of an outer diaphragm fixed to the column surface of the square steel tube column is connected to one column surface of the same square steel tube column. 2. A steel beam is joined to each end of a pair of divided diaphragms divided into two in the width direction of the column surface, and each end of the pair of divided diaphragms is joined. Steel structure. 3. The steel pipe column is a circular steel pipe column, and a tip end of one steel beam of an outer diaphragm fixed to the column surface of the circular steel pipe column is connected to one column surface of the circular steel pipe column. 2. A steel beam is joined to each end of a pair of divided diaphragms divided into two in the width direction of the column surface, and each end of the pair of divided diaphragms is joined. Steel structure.