JPH05302399A - Steel pipe column for fire-proof structure - Google Patents

Abstract

PURPOSE:To provide a steel pipe column for fire-proof structure of which section is compact and also which is easy to produce and relatively light in the weight. CONSTITUTION:A steel pipe column is constituted of an outer pipe 1 and an inner pipe 2 to make a hollow space 3 between them. The temperature of the inner pipe 2 is delayed to rise up on a fire by the surrounding outer steel pipe 1 and the hollow space 3. The outer steel pipe 1 is connected to the inner steel pipe 2 with respective both ends through diaphragms 4. Accordingly, not only a fire-proof coating on the external surface of the steel pipe can be omitted but also a fire-proof structural column which is not broken for a required time by a fire can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fire-resistant structural steel pipe column mainly used in building structures.

[0002]

2. Description of the Related Art It is legally obligatory for pillars of building structures to have a fire resistant structure so that they do not collapse within a prescribed time in the event of a fire, depending on their scale and use. ing.

In the case of a steel structure column, generally, as shown in FIG.
As shown in (b), members (square steel pipe 21, H-shaped steel 2
It is recognized as a fire resistant structure by the method of applying a fire resistant coating 6 on the surface of 2) to suppress the temperature rise of the member in the event of a fire.

Further, as shown in FIG. 10, the concrete 8 is filled in the steel pipe 23 so that the steel pipe 23 can be used in case of fire.
There is an example of forming a column of fireproof structure by transmitting stress to 8 parts of the filled concrete, which has less strength deterioration than that of, and is mainly implemented in Europe. In addition, JP-A-6
Japanese Laid-Open Patent Publication No. 2-141235 discloses a column member characterized in that a steel pipe having a projection on the inner surface of a joint portion is used to transmit an axial force to concrete during a fire.

[0005]

As described above, when the surface of the member is coated with a fireproof material, the outer diameter of the column becomes large, which affects the plan of the building. Further, although the fireproof coating is mainly applied on site, the work is complicated and the construction cost is increased. In order to reduce the complexity of the fireproof coating on site, there is also a method of applying a fireproof coating to the members in advance before building the site, but since the fireproof coating itself is a soft material, when carrying in and out the members. There is a problem that the fire-resistant coating is apt to be impacted and defects such as cracks and cracks are likely to occur in the fire-resistant coating. Further, the surface of the fireproof coating material requires finishing work for design reasons, which also contributes to an increase in construction cost.

Further, when the steel pipe is filled with concrete, the above-mentioned problems in the case of the fireproof coating are solved, but the work of filling the steel pipe with concrete at the site is complicated, and the structure of the structural frame is A new problem such as an increase in weight arises.

An object of the present invention is to solve the above problems and to provide a steel pipe column for a refractory structure which is more economical and easy to manufacture.

[0008]

A steel pipe column for a refractory structure according to the present invention comprises an outer steel pipe having an outer cross section and an inner steel member having an inner cross section, and an insulating space is provided between the outer steel pipe and the inner steel member. Is provided with a hollow portion.

The outer steel pipe is a square steel pipe, a circular steel pipe, or the like,
As the inner steel member, in addition to a rectangular steel pipe and a circular steel pipe, shaped steels of various shapes used as columns such as H-shape and cross shape are used.

The stress transmission between the outer steel pipe and the inner steel member can be carried out, for example, by connecting the joint portions of the outer steel pipe and the inner steel member via a diaphragm or the like.

In the present invention, since the inner steel member is surrounded by the outer steel pipe, when the steel pipe columns for refractory structure of the present invention are joined in the vertical direction, or the beams are attached to the steel pipe column for refractory structure of the present invention. When stiffening the column-beam joints, it is not possible to join or stiffen the inner steel members by the usual method. For this, for example, the stiffening plate of the column-beam joint is an outer diaphragm for the inner steel member and a through diaphragm for the outer steel pipe, so that the outer steel pipe crosses horizontally, This can be dealt with by mounting the inner edge so as to contact the inner steel member.

Further, by using a steel material excellent in high temperature strength characteristics as compared with a normal steel member as a material of the inner steel member, it is possible to prolong the time for deterioration of the inner steel member, and to obtain the advantages of the structure of the present invention. It can be more fully demonstrated.

[0013]

In the present invention, the pillar of the fireproof structure is formed by surrounding the inner steel member with the outer steel pipe and the hollow portion, and at least the fireproof coating on the outer surface of the member in the prior art can be omitted. The dimensions can be made compact, the problems of fireproof coating construction on site can be solved, and since the steel material of the pillar member can be exposed and used, it is possible to obtain a pillar member that makes good use of the design of the steel material.

Further, since a material other than steel is not used as the structural material, it is superior to the above-mentioned prior art in that it is easier to manufacture than a steel pipe concrete column and the weight of the skeleton is less increased.

[0015]

EXAMPLES Next, the illustrated examples will be described.

1 (a) and 1 (b) show an embodiment of the steel pipe column for a refractory structure of the present invention. The cross-sectional structure of the steel pipe column is composed of an outer steel pipe 1 and an inner steel member 2, and the outer steel pipe 1 and the inner steel member 2 are completely cut off between the member lengths L, and between the outer steel pipe 1 and the inner steel member 2. A hollow portion 3 is formed in Further, the outer steel pipe 1 and the inner steel member 2 are connected via the diaphragm 4 only to the joints at the member ends to which the steel beams 5 are joined in order to transmit stress.

With such a structure, when the steel pipe column according to the present invention receives a fire during the member length L, the outer steel pipe 1 is directly exposed to the flame, so that the outer steel pipe 1 as shown in FIG.
Temperature rises early. However, since the inner steel member 2 is surrounded by the outer steel pipe 1 and the hollow portion 3, the heat generated by the fire is radiated from the inner surface of the outer steel pipe 1 and the convective heat transfer by the air in the hollow portion 3 causes the inner steel member 2 to flow. 2 is transmitted to the outer steel pipe 1, and the temperature rising speed becomes slower than that of the outer steel pipe 1.

That is, when a fire occurs, the outer steel pipe 1
Causes thermal expansion due to temperature rise, and since the member ends are joined by the inner steel member 2 and the diaphragm 4, the compressive force due to restraint is exerted, and the mechanical properties of the material deteriorate, causing local buckling relatively early. And the function as a pillar member is lost. However, since the temperature rising rate of the inner steel member 2 is slow even after that, it is possible to bear the stress only by the inner steel member 2, until the mechanical properties of the inner steel member 2 deteriorate, and the entire column collapses. Can delay the time. With such a mechanism, the steel pipe column according to the present invention can function as a column member of a fireproof structure that does not collapse due to a fire within a required time.

In the steel pipe column according to the present invention, both the outer steel pipe 1 and the inner steel member 2 function as structural members at room temperature, so that both sections are stressed against a short-term load such as a bending moment during an earthquake. It may be designed as a member to bear. On the other hand, in the event of a fire, the inner steel member 2 alone bears a long-term load (mainly the axial force due to the constant load) as a structural member due to the early deterioration of the outer steel pipe 1, and therefore the inner steel member 2 is subject to this load. On the other hand, design it so that it does not collapse within the required fireproof time.

Generally, a column designed for a bending moment during an earthquake has a high safety factor against an axial force due to a constant load, and reduces the ratio of the sectional performance of the inner steel member 2 to the overall sectional performance of the steel pipe column. Therefore, by appropriately designing the inner steel member 2 with respect to the constant load, it is possible to obtain a steel pipe column having a required fire resistance performance even in a fire.

In addition, the collapse temperature of the inner steel member 2 is increased by applying a steel material having higher high-temperature strength characteristics than the outer steel pipe 1 to the material of the inner steel member 2 of the steel pipe column in the present invention, That is, the fire resistance time can be lengthened, and a column member excellent in fire resistance performance can be obtained.

Further, for the purpose of further slowing down the temperature rising rate of the inner steel member 2, as shown in FIGS. 3 (a) to 3 (c), the inner surface of the outer steel pipe 1 of the steel pipe column or the inner steel member 2 Applying a fireproof coating 6 on the outer surface or both,
By disposing the heat insulating material 7 in the hollow portion 3 as shown in FIG. 4, it is possible to impart higher fire resistance performance to the steel pipe column of the present invention. In this case, the fireproof coating material 6 and the heat insulating material 7 can be applied at the time of manufacturing the steel pipe column, and since the fireproof coating material 6 and the heat insulating material 7 are not exposed on the outer surface of the column member, finishing work is particularly required. Therefore, the superiority of the steel pipe column according to the present invention over the prior art is not impaired.

5 (a) to 5 (f) show various cross-sectional shapes as examples of the steel pipe column of the present invention.

The outer steel pipe has a closed cross section that does not allow flame to penetrate.
If it functions as a structural member at room temperature, the square steel pipe 11 (see FIGS. 5 (a) to 5 (c)) and the circular steel pipe 13 (see FIG. 5).
Shapes such as (d) to (f)) are not limited.

The inner steel members are shaped steels 15, 16, 17 (see FIG. 5).
(b), (e), (f)), square steel pipe 12 (see Fig. 5 (a)), circular steel pipe 14 (see Fig. 5 (c), (d)), etc. It has dimensions that do not collapse due to earthquake loads, etc., and does not collapse within the required fireproof time due to room temperature load and thermal stress during fire, and has external dimensions that do not directly contact the inner surface of the outer steel pipe. And

The steel pipe column manufactured in this manner has a certain degree of fire resistance due to the presence of the hollow portion 3 inside, but in order to further improve the fire resistance, the outer surface of the inner steel member or the outer steel pipe is The inner surface or both may be provided with a fireproof coating, or a heat insulating material may be provided in the hollow portion 3,
In this case, a fireproof coating is applied to each component and a heat insulating material is applied to the hollow portion 3 before assembling the steel pipe column.

By the way, conventionally, when a member having a closed cross section such as a steel pipe or a rectangular steel pipe is used for a pillar of a building structure, the method of joining the pillars is as shown in FIG. The method of joining by welding is generally used. In the figure, 31a indicates an upper pillar member and 31b indicates a lower pillar member.

In addition, for the purpose of preventing local destruction of the steel pipe wall in the column-beam joint, a construction method is generally used in which a stress is transmitted between the columns and beams by providing a diaphragm. As shown in FIGS. 12 (a) and 12 (b), a through-diaphragm type in which the diaphragm is a stiffening plate 34 that horizontally penetrates the cross section of the steel pipe 31, and FIG.
, An inner diaphragm type in which a stiffening plate 35 is welded to the inner wall of the steel pipe 31 as shown in (b), and an outer diaphragm in which a stiffening plate 36 is welded to the outer wall of the steel pipe 31 as shown in FIGS. 14 (a) and 14 (b). There are diaphragm type etc.

However, when the columns of the steel pipe column for fireproof structure of the present invention are joined together, or when the column-beam joint is stiffened, the conventional joining type and stiffening type described above may be used. Can not. That is, due to the double structure of the outer steel pipe and the inner steel member, the inner steel members surrounded by the outer steel pipe cannot be joined to each other or joined to the diaphragm in the conventional method.

FIGS. 6 (a) and 6 (b) show an embodiment of the joining type for applying to the steel pipe column for refractory structure of the present invention. In this embodiment, a diaphragm 4 having a shape capable of contacting the inner steel member 2 at the inner edge is welded and joined from the outside of the cross section of the inner steel member 2, and the outer steel pipe 1 is connected to the diaphragm 4.
The inner steel member 2 and the outer steel pipe 1 are joined to each other in the form of an outer diaphragm and a through diaphragm by welding to the plate surface. Diaphragm 4 is outer steel pipe 1
The stress from the beam is applied to both the inner steel member 2 and the outer steel pipe 1 by transmitting stress between the inner steel member 2 and the inner steel member 2 and functioning as a stiffening plate, and by joining the flange of the beam member to the diaphragm 4. Can be communicated. Further, the columns can be joined to each other at the column-beam joint portion at the same time, and the above-mentioned problems can be solved.

FIGS. 7 (a) to 7 (e) show an example of the procedure for joining the steel pipe columns for a refractory structure of the present invention by the above-mentioned joining method. It should be noted that, in the figure, members newly installed in the procedure are shown by hatching.

First, to the inner steel member 2b of the lower floor pillar, the inner edge of the diaphragm 4b welded to the upper end of the outer steel pipe 1b of the lower floor pillar in advance is welded to the lower surface to form a pillar member up to the beam lower flange level. (See Fig. 7 (a)).

Next, the lower end of the inner steel member 2a of the upper column, which is continuous with the lower column and the beam-column joint, is welded to the upper surface of the diaphragm 4b (see FIG. 7B).

Next, the inner steel member 2a of the upper floor pillar is welded to the inner edge of the diaphragm 4a, which is previously welded to the lower surface of the outer steel pipe 1c of the pillar-beam joint, to the upper flange level of the beam. A member is formed (see FIG. 7 (c)).

Next, the lower end of the outer steel pipe 1b of the upper floor pillar is welded to the upper surface of the upper diaphragm 4a. At this time, by attaching a diaphragm to the upper end of the outer steel pipe 1a of the upper floor pillar, the procedure is returned to and the pillar of the upper floor can be formed (see FIG. 7 (d)).

Upper and lower flanges of the beam 5 are joined to the upper and lower diaphragms 4a and 4b, respectively, and the web of the beam 5 is joined to the outer steel pipe 1c of the joint portion to complete the column-beam joint portion ( See Fig. 7 (e).

FIGS. 8 (a) to 8 (e) show another example of the joining procedure according to the above joining method.

The plate surfaces of the diaphragm 4b and the diaphragm 4a are joined to the upper and lower ends of the outer steel pipe 1, respectively, and the inner steel member 2 is passed through the diaphragms 4a and 4b.
The inner edges of the diaphragms 4a and 4b are welded to the inner steel member 2 to form a pillar member. At this time, the end portion of the inner steel member 2 is made to project from the diaphragms 4a and 4b by a length to the middle of the beam-column joint portion (see FIG. 8 (a)).

An upper pillar member A and a lower pillar member B
The ends of the protruding inner steel members 2a and 2b are joined together by butt welding to form the inner steel member of the column-beam joint (see FIG. 8 (b)).

The outer steel pipe 1c of the joint portion divided into two or more in the portion sandwiched by the upper and lower diaphragms 4a and 4b.
Insert the parts (see Figure 8 (c)).

The parts of the outer steel pipe 1c are joined together by butt welding, and the upper and lower ends of the outer steel pipe 1c are joined to the plate surfaces of the diaphragms 4a and 4b, respectively (see FIG. 8 (d)).

The upper and lower flanges of the beam 5 are joined to the diaphragms 4a and 4b, respectively, and the web of the beam 5 is joined to the outer steel pipe 1c of the joint portion to complete the column-beam joint portion (FIG. 8). (See (e)).

[0043]

EFFECTS OF THE INVENTION The steel pipe column for refractory structure according to the present invention does not require the work such as the fireproof coating on site, so that the complexity of the work can be reduced and at least the conventional fireproof coating on the outer surface of the member can be achieved. Since it is not necessary, the cross section of the member becomes compact, and there is no fear that the fireproof coating will be damaged by the impact when the member is carried in and out. Further, the steel material can be exposed on the surface of the member, which is excellent in design. Furthermore, since no material other than steel is used as the structural material, it can be manufactured easily and economically.

Further, regarding the beam-column joint portion, the stiffening plate is configured to have an outer diaphragm with respect to the inner steel member and a through diaphragm with respect to the outer steel pipe, so that the column members having a double structure are joined together. It is possible to simultaneously stiffen the column and beam joints.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, in which (a) is a vertical sectional view and (b) is a horizontal sectional view.

FIG. 2 is a graph showing the relationship between the temperature rise and the time of a member constituting the steel pipe column of the present invention during a fire.

3 (a), (b), and (c) are horizontal cross-sectional views showing an example of arrangement of a fireproof coating.

FIG. 4 is a horizontal sectional view showing an arrangement example of a heat insulating material in a hollow portion.

5 (a) to 5 (f) are horizontal sectional views showing various sectional shapes as another embodiment of the steel pipe column of the present invention.

FIG. 6 is a cross-sectional view showing an embodiment of a joining type for applying to the steel pipe column for fireproof structure of the present invention.

FIG. 7 is an explanatory view showing an example of a procedure for joining the steel pipe columns for a refractory structure of the present invention.

FIG. 8 is an explanatory view showing another example of the procedure for joining the steel pipe columns for the refractory structure of the present invention.

9 (a) and 9 (b) are horizontal sectional views showing a refractory structure using a conventional refractory coating.

FIG. 10 is a horizontal cross-sectional view showing a conventional fireproof structure made of filled concrete.

FIG. 11 is a front view (partially sectional view) showing an example of a joint portion of a conventional steel pipe column.

FIG. 12 shows a structure of a conventional through diaphragm, (a) is a front view and (b) is a plan view.

FIG. 13 shows a structure of a conventional inner diaphragm, (a) is a front view and (b) is a plan view.

FIG. 14 shows a structure of a conventional outer diaphragm, (a) is a front view and (b) is a plan view.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Outer steel pipe, 2 ... Inner steel member, 3 ... Hollow part, 4 ... Diaphragm, 5 ... Steel beam, 6 ... Fireproof coating material, 7 ... Thermal insulation material, 8
…concrete,

Claims (6)

[Claims] 1. A column is composed of an outer steel pipe having an outer cross section and an inner steel member having an inner cross section, and a hollow portion is provided as a heat insulating space between the outer steel pipe and the inner steel member. Fireproof structural steel pipe columns. 2. The steel pipe column for a refractory structure according to claim 1, wherein the outer steel pipe and the inner steel member are connected only by a joint portion. 3. A cross-section of the outer steel pipe so that a stiffening plate is an outer diaphragm for the inner steel member and a through diaphragm for the outer steel pipe with respect to a column-beam joint portion to which the beam is joined. The steel pipe column for a fire resistant structure according to claim 1 or 2, further comprising a stiffening plate that horizontally penetrates through the steel plate and has an inner edge in contact with the inner steel member. 4. The steel pipe column for a refractory structure according to claim 1, 2 or 3, wherein a steel material having higher high-temperature strength characteristics than the material of the outer steel member is used as the material of the inner steel member. 5. The steel pipe column for a refractory structure according to claim 1, 2, 3 or 4, wherein the outer surface of the inner steel member and / or the inner surface of the outer steel pipe is provided with a fire resistant coating. 6. The heat insulating material is arranged in the hollow portion,
The steel pipe column for fireproof structure according to 2, 3, 4 or 5.