JP2001262699A - Connecting structure of steel pipe column and steel beam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the connective strength of an external diaphragm of a steel pipe column and a joint plate (cover plate) connecting a steel beam to the external diaphragm. SOLUTION: In a beam-column connecting structure connecting an external diaphragm 22 and a steel beam 3 by adding a joint plate 41 to the tip of the external diaphragm 22 and the flange 3b of the steel beam 3 and fastening by a high strength bolt 50, the joint m of a high hardness joint plate 41 is worked into a rough face s by a shot blast method or the like, the rough face s is pressed against the joint n of the low hardness external diaphragm 22 by a bolt tightening force, by high friction connecting both joints m and n, the shear direction connective strength of the external diaphragm 22 and the steel beam 3 is secured highly stably.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a column-beam joint structure in which both joint surfaces of an outer diaphragm and a joint plate connecting the outer diaphragm and a steel beam flange are roughened.

[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.

[0004]

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 the column via the vertical stiffener 4. This acts as a compressive tensile stress on the surface, and local buckling B as shown in FIG. In order to increase the resistance to the local buckling B, it is necessary to release the bending moment M acting on the vertical stiffener 4 to the steel pipe column 1 via the outer diaphragm 2 as much as possible. Flange 3
In the joint structure between b and the outer diaphragm 2, it is necessary to take measures such as increasing the area of the connecting plate 5 to some extent and increasing the number of bolts 6, so that an increase in the amount of field work has been a problem.

[0005] It is an object of the present invention to improve the joint strength between a steel beam flange and an outer diaphragm without increasing the amount of on-site work.

[0006]

The technical means for achieving the above object of the present invention is to provide a flat plate at the end of the outer diaphragm fixed perpendicular to the column surface of the steel pipe column and the end of the flange of the steel beam. A steel plate joint plate is attached, and this joint plate is fastened to each end of the outer diaphragm and the flange of the steel beam beam with high-strength bolts, and the outer diaphragm and the flange of the steel beam beam are joined in series. The hardness of both joining surfaces of the outer diaphragm that are in surface contact with each other is made different, and at least the joining surface on the high hardness side of both joining surfaces of this joint plate and the outer diaphragm is roughened so that both joining surfaces have high strength. It is characterized in that high-friction joining is performed by the bolting force (the invention of claim 1).

Here, the hardness of both joining surfaces of the outer diaphragm and the joint plate is made different, and one of the joining surfaces having a high hardness is subjected to roughening treatment, and the high-hardness rough surface is applied to the other joining surface having a low hardness. When tightened with bolts, the unevenness of the high hardness rough surface cuts into the low hardness joint surface, increasing the joint strength in the shear direction of both joint surfaces, and the synergistic effect of this joint strength and the joint strength due to the tightening force of the high strength bolt As a result, the final bonding strength between the outer diaphragm and the joint plate is highly stabilized. This increase in joint strength can be expected sufficiently even if both joint surfaces of the outer diaphragm and the joint plate are roughened.

Further, the present invention is characterized in that the joint plate is made of a high-hardness steel material from the outer diaphragm, and the joint surface of the joint plate is roughened by a shot blast method (the invention of claim 2). And In this case, the rough surface treatment of the joint surface of the joint plate is effective for the entire surface of one side of the joint plate.
Such front surface roughening can be easily and advantageously performed in terms of equipment, and particularly when the surface is roughened by the shot blast method, it can be performed with high productivity.

Further, the present invention provides one of the above outer diaphragms.
The distal end for joining the flanges of the steel beams is composed of each distal end of a pair of divided diaphragms divided into two in the width direction of the column surface from the column surface of the steel pipe column. The present invention is characterized in that the distal end portion and the flange of one steel beam are joined to the joint plate with a high-strength bolt (the invention of claim 3). That is, when the flange ends of one steel beam are joined at the tips of the pair of divided diaphragms, the load of the steel beam is dispersed and applied to the pair of divided diaphragms, so that the joining strength between the two is higher and more stable. As described above, it is particularly effective to join the distal end portions of the pair of divided diaphragms to the joint plate with high friction as described above.

[0010]

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.

1A and 1B, one steel beam 3 is joined at the distal ends of a pair of upper and lower outer diaphragms 22 welded to one rectangular steel tubular column 1. The basic structure to be performed is shown. A pair of upper and lower outer diaphragms 22
It is a horizontal steel plate of the same shape orthogonal to one column surface 1a 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. The distal ends of the pair of upper and lower outer diaphragms 22 are joined to upper and lower flanges 3 b of the steel beam 3, and the connecting plate 30 is joined to the web 3 a of the steel beam 3.

Each of the pair of upper and lower outer diaphragms 22 can be a single steel plate or a double steel plate, and FIG. 1 shows a two-piece steel plate. This outer diaphragm 22 is shown in FIG.
(A), one column surface 1a of the steel pipe column 1 as shown in (B)
The left and right divided diaphragms 23 and 24 are equally divided into two in the width direction of each of the divided diaphragms 23 and 2.
The end of the flange 3b of one steel beam 3 is connected to the tip of the steel beam 4. The pair of left and right divided diaphragms 23, 24
A linearly symmetrical shape which is equally divided left and right from the center line of one columnar surface 1a of the rectangular steel tube column 1 and is fitted near the corner 1c between one columnar surface 1a and each adjacent columnar surface 1a. L-shaped mounting seats 23a and 24a, and the L-shaped mounting seat 23
beam joints 23b, 24 extending from one side of a, 24a
b. One of the divided diaphragms 23 has its L-shaped mounting seat 23a substantially half the width of one pillar surface 1a of the rectangular steel tubular column 1 and another one pillar surface 1a adjacent to the one pillar surface 1a.
Is welded, for example, by fillet welding as shown in the partial sectional views A and B of FIG. 12, and the concave surface of the L-shaped mounting seat portion 23a and the corner portion 1c of the square steel tubular column 1 are welded. Are separated without welding as shown in the partial cross-sectional view C of FIG. The partial cross section A in FIG. 12 shows an I-type fillet weld, and the partial cross section B shows a K-type fillet weld, but the present invention is not limited to these forms.

In the same manner as the above-mentioned one divided diaphragm 23, the other divided diaphragm 24 is also welded to the square steel tubular column 1 at the same height as the one divided diaphragm 23.
The left and right split diaphragms 23 and 24 are connected to the square steel tube column 1
When they are horizontally welded to each other at the same height, the divided surface portions 23c and 24c of the divided diaphragms 23 and 24 oppose each other.
The slits g having a predetermined width are positively formed between them, 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.

As shown in FIG. 1, when the H-shaped steel beam 3 is joined to the distal ends of the pair of left and right divided diaphragms 23 and 24, the bending moment of the beam load applied to the divided diaphragms 23 and 24 from the steel beam 3 Shear force is L-shaped mounting seat 23
a, 24a, and is applied 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 2
Fillet welding of 3a and 24a to column surface 1a is highly stable and always ensures high load resistance. Further, the L-shaped mounting seats 23a and 24a are connected to the column surface 1 in a direction parallel to the beam load direction.
The fillet welding is performed only at approximately half of the width direction a, so that a sufficiently high load resistance is ensured.
By setting a and 24b to be approximately 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. Also, L-shaped mounting seats 23a, 24a
By separating the concave concave surface of the rectangular steel tube column 1 without welding it to the corner portion 1c, the beam load is not applied to the corner portion 1c, and breakage such as crack generation due to concentration of load at the column corner portion is avoided. As a result, the strength of the weld between the column diaphragms is stabilized.

When the outer diaphragm 22 for joining one beam is divided into two as described above, about 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 the 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. In addition, the divided outer diaphragm 22 for joining one steel beam 3 is formed only on a half of the outer periphery of the square steel tubular column 1, so that the entire size and material can be reduced. Become. Furthermore, the inner surfaces of the divided diaphragms 23 and 24 and the square steel tube column 1 are formed by fitting the two divided diaphragms 23 and 24 to 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.

The pair of left and right divided diaphragms 23,
24, the width of the slit interval g formed between the tip portions is 1
The thickness is set to about the thickness of the connecting plates 30, and FIG.
(B) As shown in FIG.
The upper and lower ends of the connecting plate 30 are fitted and fixed in the second slit interval g. 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. Hereinafter, the pair of left and right divided diaphragms 23 and 24 will be referred to as an outer diaphragm 22 unless otherwise distinguished.

In the present invention, as shown in a partially enlarged view C of FIG. 1B, the hardness of the joint surface m on one side of the joint plate 41 and the hardness of the joint surface n of the outer diaphragm 22 are made different from each other to at least increase the hardness. In a state in which the joint surface is formed into a rough surface s by a shot blast method, both joint surfaces m and n are brought into surface contact with each other, and the contact surfaces are strongly joined by a high-strength bolt 50 to be joined together.

For example, the outer diaphragm 22 and the joint plate 41, both of which are steel plates, are usually formed of a steel plate product having a higher hardness than the diaphragm steel plate. Process into 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. High hardness joint plate 41
When the rough surface s is fastened to the joining surface n of the low hardness outer diaphragm 22 with the high-strength bolt 50, the unevenness of the high hardness rough surface s bites into the low hardness joining surface n, and the shear direction of both joining surfaces m and n Increases the bonding strength. 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.

By increasing the joining strength of the joint surfaces m and n of the joint plate 1 and the outer diaphragm 22 by high friction joining, the outer size of the outer diaphragm 22 can be reduced. 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.

When the upper and lower ends of the connecting plate 30 are projected from the pair of upper and lower outer diaphragms 22 as shown in FIG. 3, two joint plates 41 are arranged on both sides of the projected end. These two pieces are respectively bolted to the distal ends of the divided diaphragms 23 and 24 of the outer diaphragm 22. 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. 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.

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

The column-to-beam joint structure of the embodiment shown in FIG. 6 is to join two steel beams 3, 3 in the orthogonal direction at the same height to a rectangular steel tubular column 1, and in this case, the outer diaphragm 2
2 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 that of FIG. 1, and the other one corresponds to the two divided diaphragms 23 and 24 integrated back to back. This one divided diaphragm 25 is horizontally fitted to one corner 1c of the rectangular steel tube column 1 and partially fillet welded, and the other divided diaphragms 23 and 24 are horizontally fillet welded on both sides thereof. You. The distal end of one divided diaphragm 23 and one distal end of the divided diaphragm 25 facing the distal end are 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 beam-to-column joint structure of the embodiment shown in FIG. 7 joins three steel beams 3,... At the same height to a rectangular steel tube column 1 in three orthogonal directions. In this case, an outer diaphragm 22 is provided. Are two divided diaphragms 23 and 24 having the same shape.
And another two divided diaphragms 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. 1, and the remaining two divided diaphragms 25 and 25 have the same shape as the divided diaphragm 25 in FIG. These two divided diaphragms 2
5 and 25 are horizontally fitted to two corner portions 1c on both sides of one column surface 1a of the rectangular steel tubular column 1, and partially fillet-welded,
The two divided diaphragms 23 and 24 are fitted to the remaining two corners 1c of the rectangular steel tube column 1 and partially fillet welded. The leading ends of the two divided diaphragms 23 and 24 and the two divided diaphragms 25 and 25 facing the leading ends, respectively.
One of the steel beams 3 is joined to the outside tip of the two by a joint plate 41, and another steel beam 3 is joined to the inside tip of the two divided diaphragms 25, 25 by the joint plate 41. FIG. 9 shows a specific structure of such a steel beam joint.

The column-beam joint structure of the embodiment shown in FIGS. 10A and 10B is to join four steel beams 3 at the same height to a rectangular steel tubular column 1 in four orthogonal directions. The outer diaphragm 22 in this case is divided into four divided diaphragms 25 having the same shape. 4 divided diaphragms 2 each
.. Have the same shape as the divided diaphragm 25 in FIGS. 6 and 7. 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 beam-column joint structure of the embodiment shown in FIG. 14 and FIG. 15 is such that the steel beam 3 is eccentrically joined to the 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 of the outer diaphragm joined to one steel beam is divided into two parts. However, even if the outer diaphragm has the non-divided distal end, the present invention is applicable. 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.

[0030]

According to the present invention, since the outer diaphragm and the joint surface of the joint plate for joining the outer diaphragm and the steel beam flange are roughened, the area of the joint plate and the number of high-strength bolts to be tightened are increased. The joint strength between the outer diaphragm and the joint plate or steel beam can be increased without the need for the joint plate or steel beam, and the increase in joint strength makes it possible to reduce the size of the conventional joint plate or reduce the number of high-strength bolts required.

[Brief description of the drawings]

FIG. 1A is a plan view showing a first embodiment of the present invention, and FIG. 1B is a side view including an enlarged sectional view of a main part thereof.

2A is a plan view of an outer diaphragm in the joint structure of the embodiment of FIG. 1, and FIG. 2B is a side view thereof.

3A is a plan view when a connecting plate is connected to the outer diaphragm in FIG. 2, and FIG. 3B is a side view thereof.

FIG. 4 is a side view showing a modification of the connecting plate of the embodiment shown in FIG. 3;

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

FIG. 6 is a plan view of an outer diaphragm showing a second embodiment of the present invention.

FIG. 7 is a plan view of an outer diaphragm 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 plan view of an outer diaphragm 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 plan view of an outer diaphragm showing a fifth embodiment of the present invention.

FIG. 15 is a plan view of an outer diaphragm 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.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Square steel pipe column 1a Column surface 3 Steel beam 3b Flange 22 Outer diaphragm n Joint surface 23,24,25 Divided diaphragm 41 Joint plate (cover plate) m Joint surface s Rough surface 50 High strength bolt

 ────────────────────────────────────────────────── ─── 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 AA03 AA13 AB01 AB16 AB17 AC15 AC16 AG03 AG04 AG12 AG41 BB01 BB02 BB04 BB09 BB22 BC09 BD01 BD07 BE05 BE08 BF04 CA05 CA06 CA14 DA01 EA27

Claims (4)

[Claims] A joint plate is attached to an end of an outer diaphragm and an end of a flange of a steel beam fixed perpendicularly to a column surface of a steel pipe column, and the joint plate is attached to a flange of an outer diaphragm and a flange of a steel beam. In a joint structure in which the outer diaphragm and the flange of the steel beam are joined in series by tightening each end with a high-strength bolt, the hardness of both joint surfaces of the joint plate and the outer diaphragm that are in surface contact with each other are different, and this joint is A steel pipe column and a steel frame, characterized in that at least the joint surface on the high hardness side of both joint surfaces of the plate and the outer diaphragm is roughened, and both joint surfaces are joined by high friction with a high-strength bolt. Beam joint structure. 2. A joint structure between a steel pipe column and a steel beam, wherein the joint plate is a steel plate having a higher hardness than the outer diaphragm, and a joint surface of the joint plate is roughened by a shot blast method. 3. A front end of an outer diaphragm joined to a flange of one steel beam is provided at each front end of a pair of divided diaphragms divided into two in the width direction of the column surface from the column surface of the steel pipe column. 3. A joint between a steel pipe column and a steel beam according to claim 1 or 2, wherein each of the end portions of the pair of divided diaphragms and a flange of one steel beam are joined by a joint plate and a high-strength bolt. Construction. 4. The joint structure between a steel pipe column and a steel beam according to claim 1, wherein the steel pipe column is a square steel pipe column or a circular steel pipe column.