JPS62141235A - Steel pipe concrete pillar - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a column in a building structure, and more particularly to a steel pipe concrete column with excellent fire resistance and structural strength.

(Prior Art) Columns used as building structural members include those made of pure steel, reinforced concrete, and steel reinforced concrete. Figure 5 is a cross-sectional view showing a pure steel column, where (a) is an H-shaped m 1 column, (b) is a refractory liquid that is required depending on the fire resistance time over the entire length around the steel pipe 2. N (concrete) 3 has been applied.

However, such pure steel columns are expensive, so as shown in Fig. 6(a), relatively small H-shaped steel columns 1a are used.
A steel-framed reinforced concrete column with reinforcing bars 4 arranged around it and a fireproof coating 3 applied thereto, or a filled-type steel pipe concrete column in which concrete 5 is filled inside a relatively small steel pipe 2a (as shown in Figure b1). We are trying to reduce costs.

Furthermore, in order to make effective use of the filled concrete in filled steel pipe concrete columns, it has recently been proposed to use steel pipes with protrusions over the entire length of the inner surface. It is said that the steel pipe's ability to transmit the force of concrete and its integration with concrete are extremely high.

[Problem that the invention seeks to solve]

The conventional pillars mentioned above all have fireproof coating 3 on their outer surface.
However, this fireproof coating 3 has the following characteristics: (1) Although it occupies a large specific weight in terms of cost, it does not contribute in any way to the structure.

(The outer diameter of the pillar becomes larger.

■ It is brittle against impact from the outside, and the corners are easily chipped and fall off.

(4) Construction is complicated (formwork work may be required).

(5) Compared to the case where the steel frame surface is exposed, the design is inferior.

If possible, we would like to omit the fireproof sheath N3, but it is generally not required by law.

In addition, even when using a filled steel pipe concrete column made of steel pipes with internal protrusions, if a fireproof coating is applied over the entire length of the column, not only will the above problems not be solved, but also (θ Although it has sufficient force transmission ability, its characteristics cannot be fully utilized, resulting in a wasteful design.

A problem arises.

(Means for Solving the Problems) The present invention has been made to solve many of the problems as described above. The present invention provides a steel pipe concrete column having a fireproof coating on a fireproof area of the outer periphery of the steel pipe, which is a predetermined length added to the joint part of the steel pipe.

[Effect]

Since the area to be coated with fireproof coating is small, costs can be significantly reduced, and steel pipe concrete columns with excellent fireproof performance, structural strength, and design can be obtained.

〔Example〕

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is an enlarged view of its main parts. In the figure, reference numeral 10 indicates a filled-type steel pipe concrete column, in which a steel pipe 11 having a protrusion 12 on the inner surface is filled with concrete 13. Reference numeral 15 is a steel beam fixed perpendicularly to the steel pipe concrete frame 10, and a concrete floor slab 16 is constructed on the upper surface, and a fireproof coating 17 with the required thickness b is applied on the lower surface and both sides. .

In the present invention, the cross-sectional shape of the steel pipe 11 may be any shape, such as round or square, as long as it is closed, and the protrusions 12 provided on the inner surface may have various shapes, for example, as shown in FIG. be able to. Further, the protrusion 12 may be provided within a length h necessary for transmitting force from the steel pipe beam 15 to the steel pipe concrete column 10 at least. The above length h varies depending on the shape of the protrusion, but it may be about the pipe diameter d at the minimum, and about 2d at the maximum, and in most cases it is sufficient if it is within the height H of the joint part 18. It is more effective if the projections 12 are provided over the entire length of the pillar.

In the frame consisting of the steel pipe cochlear columns 10 and the steel beams 15 as described above, the present invention further provides a structure in which the steel pipes 11 and A predetermined length determined from the properties of the filled concrete 13
Fireproof coating 1 only on the outer periphery of the area (hereinafter referred to as fireproof area)
9 has been applied. Generally, fireproof coating work is carried out on the steel beams 15 at the joint section 18, so if this work is also done on the column 10 at the same time within the height H of the joint section 18, special arrangements for the company-use covering work can be made. Floor slab 16 without
In addition to the thickness t, it can cover around 700mm. Only when this height H is smaller than the fireproof range (h+29),
The work is extremely easy because the steel pipe concrete column 10 only needs to be coated with fireproof coating for the difference.

As is well known, in the event of a fire, the steel pipe concrete column 10 is exposed to high temperatures, but if a fireproof coating is provided on the way, the temperature T of the steel pipe 11 gradually decreases as it reaches the fireproof range, as shown in FIG. After a predetermined fireproof time (1 to 2 hours), the heat-resistant temperature T0 of the steel pipe 11 becomes approximately equal to the heat-resistant temperature T0 at a distance l from both ends of the fireproof coating, and becomes even lower in the middle. Therefore, the strength of the steel material is maintained at the 9° portion, which is obtained by subtracting 29 from the fireproof range. This Ω.

is longer than the length h required for the aforementioned force transmission, the steel beam 1
The force from 5 is transmitted to the concrete 13 filled in the steel pipe 11 within that range.

By the way, the economic effect of the present invention is small if the column capacity during fire is significantly reduced compared to the column capacity under normal conditions, but the present invention can reduce the difference by using the following concept. .

Column strength under normal conditions Fl-^S-5fC+ AC-CfC
Column strength in the event of a fire F2 @ O+AC, Cf'C (Assuming that the steel frame is not effective at all on the safe side) However, A: Cross-sectional area of the steel pipe sfc: m Long-term permissible compressive stress of the pipe Ac: For the steel pipe Cross-sectional area of the filled concrete cfc: Long-term allowable compressive stress of the concrete filled in the steel pipe cf'c: Allowable compressive stress in the event of a fire (short term) of the concrete filled in the steel pipe (generally cf'c>cfc) Therefore, Fl −F2, i.e. AH, dc+ Ac
, cfc = AC1Cf'C, it is the most economical as it maintains the same column strength as normal even in the event of a fire.
This can be approximated by using steel pipes with a relatively large diameter-thickness ratio.

As described above, the steel pipe concrete column according to the present invention has the following features: (1) The protrusion 12 is provided on the inner surface of the steel pipe at least in a range h of length necessary for transmitting force from the steel beam 15 to the column 10.

(R) A fireproof coating 19 is applied only to the fireproof area (h+2Q) of the pillar joint part 18, and no fireproof coating is applied to the other parts.

By configuring it in this way, it normally exhibits high strength as a steel pipe concrete column, and in the event of a fire, the force can be transmitted from the steel beam 15 to the concrete 13 filled in the steel pipe 11 in the fire-resistant area. I can do it. In this case, only the concrete 13 filled in the steel pipe 11 is considered to be on the safe side when calculating the strength in the event of a fire, but even if the strength of the steel material has decreased due to high temperature,
By having the steel pipe 11 that envelops the concrete 13, the concrete 13 can exhibit performance that cannot be obtained with concrete pillars in terms of strength and performance after fire resistance.

In the above explanation, the present invention is applied to a filled steel pipe concrete column, but the present invention is not limited to this, and any member that mainly receives compressive axial force can be used as a three-dimensional truss material, a place, etc. It can also be carried out.

(Effects of the Invention) As is clear from the above description, according to the present invention, the following remarkable effects can be achieved.

(1) Since the construction of fireproof coating only needs to be carried out in the fireproof area, and there is only a slight increase in the fireproof coating work for steel beams, the cost required for fireproofing can be significantly reduced.

Most of the parts to which fireproof coating is applied according to the present invention are joint parts, which are not visible to the public, so a simple finishing is sufficient, and costs can be reduced in this respect as well.

(3) Because the thin and smooth steel pipes are exposed, a smart design can be obtained, and since the steel pipes are exposed in the living room, it is easy to use for painting, cross-covering, etc.
n ★Shibu stem ka no 1＼ 6 / η慴
Since there is no fire-resistant coating applied to areas other than the fire-resistant area, the fire-resistant coating will not become brittle or the corners will be missing due to impacts, etc., as in the case of conventional products.

(5) Since concrete is simply filled into the steel pipe, there is no need for formwork work, etc., and construction is easy.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the configuration of an embodiment of the present invention, FIG. 2 is an enlarged view of the main part thereof, FIG. 3 is a diagram showing the temperature distribution of the column according to the present invention, and FIGS. 4(a) and (b) ) and (c) are sectional views of main parts showing other embodiments of the steel pipe used in the present invention, and FIG. 5(a)
, (b) and FIGS. 6(a) and 6(b) are vertical cross-sectional views showing the structure of a conventional column, respectively. lO: Steel pipe concrete column, ll: Steel pipe, 12: Protrusion 1
3: Concrete, 15: Steel beam, 16: Floor slab 17
: Beam fireproof coating, 18: Joint part, 19: Column fireproof coating. Agent Patent Attorney Tadashi Sato Figure 4 (a) (bl (c)
5th r! ! l Figure 6 Procedural Amendment (-j5K) Dear Commissioner of the Patent Office, Akane, February 28, 1999, 1.
Indication of the case Japanese Patent Application No. 60-282079 2, Name of the invention Steel Pipe Concrete Column 3, Person making the amendment Relationship to the case Patent applicant name (412) Nippon Kokan Co., Ltd. 4, Agent address Tora, Minato-ku, Tokyo 7-no-mon-chome-21-19 5. Date of amendment order: February 5, 1985 (Shipping date: February 25, 1986) 6. Contrary drawings of amendment.゛, 7 Goo 2〉- (a) Amended drawings

Claims (1)

[Claims] A steel pipe having a protrusion on the inner surface of at least the joint area and filled with concrete is provided, and a fire-resistant covering is applied to a fire-resistant area of the outer periphery of the steel pipe that is a predetermined length added to the joint part. A steel pipe concrete column.