JPH0663284B2 - Steel construction method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for constructing a steel frame in the construction of a steel structure building or the like.

[Conventional technology]

Construction of a steel frame in a conventional steel frame structure building or the like is performed as follows. First, a steel frame such as a pillar or a beam processed into a predetermined shape and a predetermined size at a steel frame factory is brought into a construction site and assembled at the site. Then, a fireproof coating material such as wet sprayed rock wool or semi-wet sprayed rock wool is sprayed onto the assembled steel frame surface to form a fire resistant coating.

[Problems to be solved by the invention]

However, in the conventional fireproof coating construction using sprayed rock wool, a large amount of dust of rock wool is generated during construction, and the working environment is poor, and improvement thereof is urgently desired.

As one of the improvement measures for this, a so-called fireproof coating pre-attachment construction method in which a steel frame before assembly is previously provided with a fireproof coating in a factory or the like, and the steel frame is carried to the site and assembled is considered.
This method can improve the working environment because the spraying can be done by using the machine in the factory or the temporary work place at the construction site, and the work on the site is reduced and the construction efficiency is increased.
Construction safety is also high. However, this method has the drawback that the mechanical strength of the fireproof coating made from sprayed rock wool is very low, and the fireproof coating is missing or damaged when the steel frame is carried in or assembled, and the desired fireproof performance cannot be obtained. The reality is that it has not been put to practical use.

[Means for solving problems]

Therefore, in the present invention, by using a fireproof coating material capable of forming a fireproof coating having a very high mechanical strength,
The above problems have been solved and a highly efficient pre-attachment construction method can be adopted.

According to the steel frame construction method of the present invention, a steel frame pre-coated with a fire-resistant coating material is assembled except for a joint portion with another steel frame, and an uncoated portion is coated with the fire-resistant coating material. And this fireproof coating material is a low temperature conductive inorganic material 10 to 20% by weight, a high endothermic inorganic material 10 to 30% by weight, an expansive inorganic material 5 to 25% by weight, a heat resistance improving inorganic material 5 to 15% by weight, and room temperature binding. Material 5 to 20% by weight High-temperature binding material 15 to 40% by weight, and for this high-temperature binding material, granular water glass having a water resistance improving impregnation coating and a carbonation-resistant coating is preferably used. It

As the low temperature conductive inorganic material constituting the fireproof coating material suitably used in the present invention, various inorganic materials having a small thermal conductivity (a) defined by the following formula are used.

a: Thermal conductivity (m ² / hr) λ: Thermal conductivity (kcal / m · hr · ° C) ρ: Density (kg / m ² c: Specific heat (kcal / kg · ° C) Specifically, clay, Thermal conductivity of gypsum, expanded pearlite, expanded vermiculite, rock wool, asbestos, diatomaceous earth, etc. is 0.001 m ² /
Those of hr or less are preferable. This material has a small amount of heat conduction, and when heated by a flame, it prolongs the time during which heat is transmitted to a steel frame or the like, and consequently exhibits fire resistance. The blending amount of this material is 10 to 20% by weight based on the fireproof coating material. 10
If it is less than 20% by weight, the heat shield property is insufficient and the temperature rise of the steel frame is large, which is inconvenient. It is bad and inconvenient.

Further, as the high endothermic inorganic material, graphite, which contains a large amount of bound water and stored water, hydrite, magnesium chloride, borax, hiruishibara ore, etc. are mainly used. When this material receives heat, these bound water and occluded water evaporate, and the latent heat of vaporization absorbs heat, resulting in fire resistance. Preferably, the endothermic amount is 50 cal / g or more. It is desirable to use the above materials. The compounding amount of this highly endothermic inorganic material is 10 to 30% by weight. If it is less than 10% by weight, the endothermic amount is small and the temperature rise is large, which is disadvantageous. It becomes difficult to maintain the value, which is also inconvenient.

Further, as the expansive inorganic material, when heated, it expands itself to become porous and exhibits high heat insulating properties and exhibits fire resistance. For example, graphite, hiruishihara ore, water glass, etc. It is preferable that the expansion coefficient is 50% or more. The total compounding amount of this material is 5 to 25% by weight. If it is less than 5% by weight, the amount of expansion is insufficient and fire resistance cannot be obtained, which is inconvenient. If it exceeds 25% by weight, the amount of expansion is excessive and it becomes difficult to maintain a stable shape.

Heat-resistant improved inorganic materials, when the above various materials are exposed to high temperatures for a long time, gradually deteriorate to lose their shape retention properties, prevent their collapse, and ensure a higher degree of fire resistance. For example, amorphous silica or slaked lime can be used. The compounding amount of this material is 5 to 15% by weight. If it is less than 5% by weight, the fire resistance is inferior, which is inconvenient, and if it exceeds 15% by weight, the fire insulation properties are inferior.

Further, the room-temperature caking material is a material that solidifies the above materials together to solidify them as a fireproof coating material, and in particular, a material that exhibits a solidification effect during the coating operation and at normal times after the coating operation,
Hydraulic materials such as gypsum and various cements are used. The blending amount of the room temperature binder is 5 to 20% by weight of the whole. If the amount is less than 5% by weight, the strength is insufficient and chipping or damage is likely to occur, which is inconvenient. If the amount exceeds 20% by weight, the strength is too large and the expansion reaction is suppressed, which is inconvenient.

Furthermore, the high-temperature caking material exhibits a consolidation effect especially when heated, and secures shape retention at high temperatures and improves fire resistance. As the high-temperature binding material, granular water glass having a particle size of 2 to 5 mm and having a water resistance improving impregnation coating and a carbonation resistance coating formed thereon is used. This granular water glass does not show any consolidating action at room temperature, but when heated, it will be about 20
It begins to melt at 0 to 300 ° C and foams to solidify each material, and the solidifying action is maintained up to about 800 ° C. In particular, since the granular water glass coated with the water-resistant improved impregnation coating and the carbonation-resistant coating is used here, the water glass is prevented from being melted due to water splash during the construction, and after the construction. Carbonation of the water glass by carbon dioxide gas in the air is prevented, whereby the foamability of the granular water glass is maintained for a long period of time, and as a result, the durability as a high temperature binding material is improved.

As the water-resistant coating, those that have been impregnated with a water repellent such as stearic acid and calcium stearate, and as the carbonation-resistant coating are polymer materials such as rubber such as chloroprene and resins such as acrylic resin having a thickness of 0. A coating of 5 to 1 mm is used. The coating composition is such that the water resistant enhanced impregnation coating is first provided on the surface of the particulate water glass and then the carbonation resistant coating is provided thereon.

The compounding amount of this high-temperature binding material is 15 to 40% by weight of the whole.
It is said that If the amount is less than 15% by weight, the expanded layer cannot be held well, and if the amount exceeds 40% by weight, the cost is unprofitable.

The refractory coating material having such a composition is kneaded with water to obtain a mortar-like kneaded product. The blending amount of water is 40 to 50 parts by weight with respect to 100 parts by weight of the fireproof coating material. A normal mortar mixer or the like is used for kneading.

Next, as shown in FIG. 1, this mortar-like kneaded product is sprayed onto a steel frame 1 (a beam made of H-shaped steel in the drawing) processed into a predetermined shape and a predetermined size to form a fireproof coating 2. For spraying, a spraying device such as an ordinary mortar spraying machine can be used. Iron coating can also be used. The sprayed kneaded product usually hardens in one day, and a strong fireproof coating 2
Becomes In spraying, the joint portion 1a of the steel frame 1 is naturally removed as shown in FIG. Further, in the H-shaped steel that becomes the beam, the flange surface on which the upper floor rests is also excluded. Further, the fireproof coating 2 can be formed in advance also on the beam-column composite portion 3 as shown in FIG. 2 except for the joint portions 3a with the beam. Such construction of the fireproof coating 2 may be carried out in a steel frame processing factory, or a temporary work place may be provided in the construction site to apply the fireproof coating to the steel frame once loaded.

In this way, the steel frame 1, on which the fireproof coating 2 is previously formed,
3 is assembled by a conventional method. Then, fireproof coating 2
The above-mentioned kneaded material is sprayed on site to the joint portion or the like that has not been subjected to the above treatment, and the fire-resistant coating 2 is formed on the entire required surface of the assembled steel frame.

[Action]

In such a steel-frame building method, since the fire-resistant coating material of the above-mentioned composition is used for the fire-resistant coating, the mechanical strength is remarkably high and the adhesive force is also good, so that the steel frame can be carried in or when the steel frame is assembled. The fireproof coating will not be lost or damaged. Table 1 shows bending strength and compressive strength of the fire resistant coating used in the present invention and conventional wet and semi-wet rock wool.

From the data in Table 1, it can be understood that this fireproof coating has a markedly higher mechanical strength than conventional blown rock wool, and that the fireproof coating can be implemented without any problem.

Further, since the fire-resistant coating material used in the present invention contains the above-mentioned various materials in a well-balanced composition, the thickness of the fire-resistant coating can be reduced to about 1/2 of that of the conventional sprayed rock wool. . In the case of the conventional rock wool refractory coating, 1 hour fire resistance is 30 mm, 2 hours fire resistance is 45 mm, 3 hours fire resistance is about 60 mm, while this fire resistance coating material is an experimental result of 15 mm The fire resistance for 2 hours is 25 mm, the fire resistance for 3 hours is 30 mm, and about half. Therefore, the amount of fireproof coating material for the entire building is halved, and the construction time can be shortened. Further, since the coating thickness is thin, the finished dimensions of the pillars and beams can be small, and the base of the interior finishing material hits the fireproof coating, which can prevent construction defects such as scraping off.

Further, since granular water glass having a water resistance improving impregnation coating and a carbonation resistant coating is used as the high temperature caking material constituting the fire resistant coating material, the consolidating action of the water glass at a high temperature is long-term (1
Retained for over 0 years). That is, in normal water glass, water glass is dissolved and flows out due to water splashing during construction, or after the construction reacts with carbon dioxide gas in the air and water glass is carbonized as shown in the following formula, and foaming property is reduced. However, Na ₂ SiO ₃ + CO ₂ → Na ₂ CO ₃ + SiO ₂ The granular water glass used in the present invention has a water resistance improving impregnation coating and a carbonation resistance coating. There is nothing to do.

Also, when spraying, since the kneaded product is mortar-like, less dust is scattered like sprayed rock wool,
Work can be performed in a good working environment.

〔The invention's effect〕

As described above, according to the steel construction method of the present invention,
A prefabricated construction method that can ensure construction safety with high efficiency can be adopted. Further, since the fire-resistant coating material having a specific composition and high strength is used, the fire-resistant coating does not fall off, is not damaged during the work, and the work is easy. Therefore, the amount of on-site work can be reduced, the construction period can be shortened, and it is possible to avoid on-site work that involves a risk of construction around the core and the outer circumference. Further, since the specific compounding materials are compounded in a well-balanced manner, the fire resistance as a fire resistant coating is good and the coating thickness can be made about 1/2 that of the conventional sprayed rock wool. further,
A granular water glass having a water-resistant improved impregnation coating and a carbonation-resistant coating is used as the high-temperature binding material of the fire-resistant coating material, and the solidifying action of the high-temperature binding material is preserved for a long period of time to provide a highly reliable fire-resistant coating material. A steel structure having is obtained. Furthermore, when spraying the kneaded material of the fire-resistant coating material, it is possible to obtain the advantages that no dust is generated and the working environment is good.

[Brief description of drawings]

1 and 2 are each a schematic perspective view showing an example of a steel frame coated with a fireproof coating by the steel frame building method of the present invention. 1 ... Steel frame, 2 ... Fireproof coating.

Claims (2)

[Claims] 1. A method for constructing a steel frame, comprising assembling a steel frame pre-coated with a refractory coating material, excluding a joint with another steel frame, and coating an uncoated portion with the refractory coating material. However, the refractory coating material has the following composition. Low temperature conductive inorganic material 10 to 20% by weight High endothermic inorganic material 10 to 30% by weight Expandable inorganic material 5 to 25% by weight Heat resistance improving inorganic material 5 to 15% by weight Room temperature binding material 5 to 20% by weight High temperature viscosity Binder 15-40% by weight 2. The method for constructing a steel frame according to claim 1, wherein the high-temperature caking material is a granular water glass on which a water resistance improving coating and a carbonation resistant coating are formed.