JPH07150652A - Steel frame with fireproof coating, and precoating method for fireproof coating on steel frame - Google Patents

Abstract

PURPOSE:To save labor greatly in erection work by a method wherein a plate material is attached to the upper part of a steel frame and semidry fireproof coating material and cement slurry are sprayed over the steel frame. CONSTITUTION:A pad 2 made of thin iron plate in bevelled shape section is attached to an upper flange 1a of a steel girder 1 in H shape section, and fireproof coating 3 is formed to the surroundings of the steel girder 1 by spraying semidry fireproof coating material made by kneading rock wools, cement slurry and the like. The surface of the fireproof coating 3 is pressed with a trowel, and cement slurry is sprayed to the surface of the fireproof coating 3, and thereby a cement layer 4 is formed. Therefore, coming-off or breakage of the fireproof coating can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for pre-applying a fire-resistant coating, particularly a fire-resistant coating made of a semi-dry material, to a steel frame before being built.

[0002]

2. Description of the Related Art In recent years, interest in fire-resistant coating technology for steel frames has increased with the increase in steel-framed buildings.
In addition to requirements such as labor saving of work, improvement of environment, improvement of safety, etc., demands for reduction of construction cost are becoming severer year by year. In view of such circumstances, it has been proposed to use an inexpensive semi-dry type fire-resistant coating material in place of an expensive material such as a wet material, a ceramic material, or a fire-resistant paint which has been conventionally used, and it is actually used. Things are also increasing.

By the way, in consideration of workability and safety, it is preferable that the semi-dry type fireproof covering material is also used in advance of the steel beam. However, since the semi-dry fire resistant coating material has high water absorption, it cannot be exposed to rain, that is, rain curing is impossible, so it must be fully cured and then constructed, which shortens the construction period. However, it has the drawback that it cannot be implemented unless there is enough room to stock steel beams on the site.

Further, since the surface strength of the fire-resistant coating made of semi-dry type material is small, it may be damaged or fallen off due to collision or other causes when it is attached in advance, and it must be handled very carefully. , The work was more troublesome than necessary. Since the upper flange surface of the steel frame comes into contact with the floor of the next floor, the fireproof coating material must be sprayed so as not to adhere to the upper flange surface. Therefore, even in the case of pre-attachment, it is not possible to previously provide a fireproof coating on the edge portion of the upper flange by a predetermined thickness,
After the construction, the spraying work had to be performed again on the edge of the upper flange.

[0005]

DISCLOSURE OF THE INVENTION An object of the present invention is to enable rain curing of a semi-dry type fire-resistant coating which is preliminarily applied in the construction work of a steel frame building, and the labor for constructing a steel frame beam is significantly reduced. Is to provide a steel frame refractory coating advance technology that can shorten the construction period and is less likely to cause problems such as falling off or damage of the refractory coating.

An object of the present invention is to provide a steel frame in which a refractory coating is provided on the steel frame prior to the method of constructing the steel frame, the steel frame, a plate material provided on the upper part of the steel frame, and the steel frame. It is achieved by a steel frame provided with a fireproof coating, characterized in that it comprises a semi-dry fireproof coating provided opposite thereto. Further, the steel frame is a steel frame provided with a fireproof coating prior to the method of constructing the steel frame, the steel frame, a plate material provided on the upper part of the steel frame, and a semi-dry fireproof provided on the steel frame. The present invention is achieved by a steel frame provided with a fireproof coating characterized by comprising a coating material and a cement-based layer provided on the surface of the semi-dry fireproof coating material.

[0007] Also, a method for prior to building the steel frame, a fireproof coating on the steel frame in advance, the step of attaching a plate material to the upper part of the steel frame, and the step of spraying a semi-dry fireproof coating material on the steel frame. And a step of pressing the surface of the fire-resistant coating formed by this spraying step, which is achieved by the steel frame fire-resistant coating preliminarily applying method.

[0008] Also, a method for preliminarily attaching a fireproof coating to the steel frame prior to the construction of the steel frame, the step of attaching a plate material to the upper part of the steel frame, and the step of spraying a semi-dry fireproof coating material on the steel frame. And a step of pressing the surface of the refractory coating formed by this spraying step, and a step of spraying a cement slurry on the surface of the refractory coating.

That is, according to the technique of the present invention, the plate material is attached to the upper portion of the steel frame, and the semi-dry type fire-resistant coating material is sprayed on the steel frame to form the fire-resistant coating. Even so, the plate material effectively protects it from rain and enables rain curing. In addition, a cement-based layer is formed on the surface of the fireproof coating, which significantly increases the surface strength, which makes it easy to handle when building, and synergizes with the effect of providing a plate material to further absorb rainwater. It is unlikely to occur, and there will be no problems such as damage or loss of the fireproof coating.

Therefore, the work of pre-applying the fireproof coating using the semi-dry fireproof coating material can be carried out efficiently and easily, and the construction period can be greatly shortened. In addition, since the plate material is provided on the upper part of the steel frame, the adhesion of the fireproof coating material on the flange portion of the upper flange of the steel frame is increased, and it becomes possible to provide the fireproof coating with a predetermined thickness on the steel frame by one spraying operation, which is good. It is possible to obtain excellent fire resistance performance.

When the steel frame is H-section steel, the plate material may be attached to the upper flange surface of the H-section steel, and the plate material is preferably constructed in a hat-shaped cross section. With such a configuration, a high drainage action can be obtained during rainfall.

[0012]

1 to 4 show an embodiment of the present invention.
1 is a cross-sectional view showing a state where a backing plate is attached to an upper flange of a steel frame beam, FIG. 2 is a cross-sectional view showing a state where a semi-dry type fire-resistant coating material is sprayed, and FIG. 3 is a cross-sectional view showing a state of surface pressing work, FIG. 4 is a cross-sectional view after spraying the cement slurry.

In the drawings, 1 is a steel frame beam having an H-shaped cross section, 1a, 1
Reference symbols b are upper and lower flanges of the steel beam 1, 2 is a cauldron-shaped patch plate made of a thin iron plate, 3 is a fire-resistant coating formed by spraying a semi-dry fire-resistant coating material obtained by kneading rock wool, cement slurry, etc. Reference numeral 4 denotes a cement layer formed by spraying cement slurry on the surface of the fireproof coating 3, and reference numeral 5 denotes a trowel used for pressing the surface of the fireproof coating 3.

In the fireproof coating pre-applying method of the present invention,
First, as shown in FIG. 1, a backing plate 2 is attached to the upper flange 1a of the steel beam 1 by an appropriate method, and then a semi-dry fireproof coating material is sprayed around the steel beam 1 to give a predetermined thickness as shown in FIG. The refractory coating 3 is formed. Further, as shown in FIG. 3, a trowel 5 is used to press the surface of the fireproof coating 3 to adjust the material specific gravity required for fireproofing, and the surface of the fireproof coating 3 is adjusted. When the cement slurry is sprayed, the cement slurry is absorbed only by the surface layer portion of the fireproof coating 3.

Finally, as shown in FIG. 4, cement slurry is sprayed on the surface of the fireproof coating 3 to form a cement layer 4. The refractory coating pre-applied to the steel beam 1 by the method as described above has a sufficiently large surface strength in a curing period of about one day, that is, the steel beam 1 after curing for a short period of time.
Can be built.

Therefore, the space for stocking the steel beams for curing the fireproof coating may be the one that is commensurate with the amount produced in one day, and does not require much space for use. Moreover, since the fireproof coating 3 is effectively protected from rainwater by the backing plate 2, it can be rain-cured, so that the fireproof coating made of semi-dry material can be easily preliminarily applied even in a site where there is no room on the site. The workability is improved and the construction period is greatly shortened.

Since the thickness of the fireproof coating material adhered to the upper flange edge of the steel beam 1 by the contact plate 2 is predetermined, it is possible to apply the fireproof coating to the entire steel beam by one spraying operation. Sufficient fire resistance can be obtained. Furthermore, the fire-resistant coating is easily pre-applied on the ground, and work at high places is as simple as connecting joints, which increases work safety and reduces the scattering of sprayed fire-resistant coating material. Therefore, cleaning is simplified.

Since the refractory coating is preliminarily set on the ground, it is easy to introduce an automatic robot or the like, and further improvement in work efficiency can be expected. Then, assuming the actual handling situation and environmental conditions for the steel beam with the fireproof coating pre-attached as obtained above, the following (1) to
The test of (7) was conducted. As the test body, a steel frame beam sprayed with a semi-dry fire-resistant coating material to a thickness of 65 mm (fire resistance for 3 hours) was used, and a thin iron plate having a thickness of 0.5 mm was used as a pad. (1) Lifting test The test piece was lifted by a crane, and it was checked whether the fireproof coating would fall off or be damaged at this time, but there was no problem at all.
Further, the fireproof coating was not damaged at all even though it was dropped from the suspended state onto the pedestal. (2) Impact test Assuming a collision with another member during lifting, an impact force was applied by smashing the steel beam end with a hammer.

As a result, extremely minute cracks and lifts were observed at the end on the impacted side, but there was no damage or loss that could be easily discerned by the naked eye, and no practical use. There was no problem. (3) Deflection test A concentrated load was applied to the center of the test piece with both ends supported by the frame legs, and it was examined whether the fireproof coating would fall off or be damaged.

The applied load was set to 2 t when a floor concrete load was assumed, and 3 t when an impact load at the time of placing concrete was assumed. As a result, no damage to the fireproof coating such as cracking was observed in any case. (4) Windstorm test Assuming that the exposed fireproof coating was exposed to windstorms during construction, a blower was used to generate a strong wind with a wind speed of 40 m / s, and it was examined whether the fireproof coating was dropped or scattered. However, no dropout or scattering was observed.

Further, after intentionally damaging the end portion of the fire-resistant coating, it was similarly exposed to strong wind, and it was examined whether or not peeling occurred in a chained manner from this portion, but there was no problem in this case as well. (5) Rainfall test A test piece formed by spraying a semi-dry type fireproof coating material on a steel beam to a thickness of 65 mm and curing it for one day was 5.5 l / mi.
Water was sprinkled for 10 minutes at a ratio of n.

As a result, the rock wool was observed to absorb water for 3 minutes immediately after the start, but after that, the sprinkled water was not absorbed and no problem occurred in the fireproof coating. (6) Storm rain test A semi-dry / wet refractory coating material is sprayed onto a steel beam to a thickness of 65 mm and aged for 2 days, and a strong wind with a wind speed of 40 m / s or more is sprayed onto the test body by the device used in the storm test. At the same time, water was sprinkled at a rate of 5.5 l / min for 30 minutes, but no damage to the fireproof coating was confirmed. (7) Adhesion test Specimen A (fireproof coating is applied under the same conditions as the rain test,
And the test body B (the test body A sprayed with the cement slurry) and the test body C (the fireproof coating applied under the same conditions as the storm test). Got ready.

Then, a force was applied to the test piece attached to the fireproof coating of each test body, and the force at the time of peeling was measured, and the following table was obtained. Specimen Test site Test area Tensile load Cross-section area Adhesive strength Damage A Beam center web 4.3kg 90 × 100mm 47.7g / cm ² Base material fracture A Beam end web ── ──── Base metal crack B Beam center web 4 0.5 kg 95 × 95 mm 49.9 g / cm ² base material fracture C beam center web 4.4 kg 85 × 70 mm 73.9 g / cm ² base material fracture As a result of this test, damage due to impact was observed in some areas, It turned out that it had no effect on the whole.

Further, it was confirmed that the surface strength could be increased by spraying the cement slurry, and a very large strength could be obtained by curing for only one day. Above (1)
As a result of performing the test of (7), the fire-resistant coating formed by the steel frame fire-resistant coating pre-attachment method of the present invention is unlikely to fall off or be damaged even under harsh environmental conditions, and is sufficiently durable for actual use. I understand.

[0025]

[Effects] According to the present invention, in constructing a steel frame building, it is possible to carry out rain curing of a semi-dry type fireproof coating that is attached in advance, and the labor for constructing the steel frame beam is greatly reduced. It is also possible to reduce the fire resistance, and it is difficult for problems such as falling off or damage of the fireproof coating to occur.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state where a patch plate is attached to an upper flange of a steel beam.

FIG. 2 is a cross-sectional view showing a state in which a semi-dry type fireproof coating material is sprayed.

FIG. 3 is a cross-sectional view showing a state of a work of pressing a fireproof coating surface.

FIG. 4 is a cross-sectional view showing a state in which cement slurry is sprayed.

[Explanation of symbols]

 1 Steel beam 1a Upper flange 1b Lower flange 2 Patch plate 3 Fireproof coating 4 Cement layer

Front page continuation (71) Applicant 591143906 Nippon Design Co., Ltd. 2-1-1 Nishishinjuku, Shinjuku-ku, Tokyo (72) Inventor Katsunori Terao 1-25-1 Nishishinjuku, Shinjuku-ku, Tokyo Taisei Corporation (72) Inventor Norihiko Yaguchi 1-25-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo Taisei Construction Co., Ltd. (72) In-house Masahiro Inoue 21-2-1 Ginza, Chuo-ku, Tokyo Takenaka Corporation Tokyo (72) Inventor Masafumi Fuji, 6-1, Kashiwara, Ishioka, Ibaraki Prefecture (72) Inventor Tetsuo Naito 2-1-1 Nishishinjuku, Shinjuku-ku, Tokyo Shinjuku Mitsui Building Co., Ltd.

Claims (6)

[Claims] 1. A steel frame in which a fireproof coating is provided on the steel frame prior to building the steel frame, the steel frame, a plate member provided on the steel frame, and the steel frame. A steel frame provided with a fireproof coating, characterized by comprising a semi-dry fireproof coating material. 2. A steel frame comprising a refractory coating provided on the steel frame prior to building the steel frame, the steel frame, a plate material provided on the steel frame, and the steel frame. A steel frame provided with a fire resistant coating, comprising a semi-dry fire resistant coating and a cement-based layer provided on the surface of the semi-dry fire resistant coating. 3. The steel frame provided with the fireproof coating according to claim 1 or 2, wherein the steel frame is an H-shaped steel, and the plate member is attached to an upper flange surface of the H-shaped steel. 4. The steel frame provided with the fireproof coating according to claim 1, wherein the plate material is configured to have a hat-shaped cross section. 5. A method for preliminarily attaching a fireproof coating to the steel frame prior to constructing the steel frame, the step of attaching a plate material to the upper part of the steel frame, and the step of spraying a semi-dry fireproof coating material on the steel frame. And a step of pressing the surface of the fireproof coating formed by this spraying step, the steel frame fireproof coating pre-applying method. 6. A method for pre-applying a fireproof coating to the steel frame prior to constructing the steel frame, the step of attaching a plate material to the upper part of the steel frame, and the step of spraying a semi-dry fireproof coating material on the steel frame. And a step of pressing the surface of the fire-resistant coating formed by this spraying step, and a step of spraying cement slurry on the surface of the fire-resistant coating, the steel frame fire-resistant coating pre-applying method.