JP2003293475A - Bolt joint part structure with high heat shielding property - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide bolt joint part structure capable of impeding a lowering of high temperature strength of a structural steelwork caused by a fireproof bolt even with the use of the fireproof bolt with a high temperature strength of a 600°C level in the case of attaining fireproofing protection-free structure using fireproof steel with excellent high-temperature strength at 800°C-850°C, for instance, in the structural steelwork in a construction field exposed to a fire. <P>SOLUTION: In this bolt joint part structure with high thermal shielding property, at least a bolt, a nut and a washer in a bolt joint part used for the structural steelwork exposed to a fire are covered with a thermal shield such as a ceramic blanket, a ceramic mold, a ceramic sheet, ceramic paint, other fireproof paint or a metal cover (such as a cap) capable of shielding heat radiation. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a bolt joint structure used for a steel structure in the field of construction which is subject to fire.

[0002]

2. Description of the Related Art Conventionally, in the construction field, for example, as shown in FIG. 10, a bolt joint structure of a square steel pipe column 1 and an H-shaped steel beam 4 using split tees 2a, 2b and bolts 3, 5 is adopted. There is a steel structure, and if this steel structure receives a fire, it is required to use it at a surface temperature of 350 ° C or less. Therefore, in many cases, a fireproof coating such as sprayed rock wool is required. However, since the competitiveness of the steel structure is significantly impaired due to problems in construction cost, process, environment and aesthetics, there has been a demand for a steel material (fire resistant steel) that has excellent high temperature strength and can be used with a non-refractory coating.

In recent years, in order to meet this demand, many so-called fire-resistant steels having high-temperature strength for a short time have been developed mainly for the purpose of using non-fireproof coating of steel materials, for example, JP-A-2-77523. A large number of steel materials (fireproof steels) excellent in high temperature strength at 600 ° C. are disclosed including the invention described in the publication. Further, according to the invention of Japanese Patent Application Laid-Open No. 9-209077, a steel material (fireproof steel) excellent in high temperature strength at 700 ° C.
Is disclosed. Furthermore, Japanese Patent Application No. 2000-29733
No. 8 and Japanese Patent Application No. 2000-297339 disclose steel materials (fireproof steel) excellent in high temperature strength at 800 ° C. and 850 ° C. by the present inventors. On the other hand, as the bolt, a bolt (fireproof bolt) excellent in high temperature strength at 600 ° C. is known as seen in the invention of JP-A-8-67943, but at present, it is superior in high temperature strength to fire resistant steel. Since the temperature range is low, in order to realize a steel frame structure with no fireproof coating, there is a demand for a fireproof bolt having a higher temperature range and a higher temperature range.

[0004]

It is known that when a steel structure is heated for 30 minutes or longer due to a fire, the member is generally exposed to a high temperature of more than 700 ° C, depending on the member cross section. . Therefore, in order to enable a non-fireproof coating structure in a steel frame structure that is exposed to a fire for 30 minutes or more, it is sufficient to use refractory steel excellent in high temperature strength at 800 to 850 ° C. If bolt joints are present when building things, the high temperature strength of the bolts used also becomes a problem. As a material for fireproof bolts, the above 8
Even if a refractory steel excellent in high temperature strength at 00 ° C to 850 ° C is used, a refractory bolt capable of ensuring sufficient bolt characteristics in a high temperature region of 800 ° C to 850 ° C cannot be obtained. Because 8
Since the yield strength of the refractory steel at 00 ° C to 850 ° C is 94 MPa or more in the temperature range, the room temperature yield strength is 23
Yield strength ratio (high temperature strength / room temperature strength) of 0.4 or more is given to steel of 5MPa class, but 980MPa at room temperature
For high-strength bolts required to have the above tensile strength (yield strength of 900 MPa or more), only a yield strength ratio (high temperature strength / room temperature strength) of about 0.1 or more is given, which is not suitable as high temperature strength. It is enough.

As a fireproof bolt having excellent high-temperature strength, a fireproof bolt having excellent high-temperature strength at 600 ° C. is known at present, but this fireproof bolt sufficiently meets the demand for non-fireproof coating structure. I can't. The present invention relates to a steel structure having a bolt joint in the field of construction that receives a fire,
Basically, it is possible to use a fire-resistant steel having excellent high-temperature strength at 800 ° C to 850 ° C for the main member to form a non-refractory coating structure, and even if a high-strength 600 ° C-level fireproof bolt is used, An object of the present invention is to provide a bolt joint structure capable of compensating for the decrease in high temperature strength of the entire steel frame structure due to the fireproof bolt.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention is summarized as the following (1) to (6). (1) In a bolt joint structure of a steel frame structure that is subject to fire, the joint area including bolts and nuts (and washers) is covered with a heat shield that shields radiant heat, and has a high heat shield property. Bolt joint structure. (2) In a bolt joint structure of a steel frame structure that receives a fire, the portion of the bolt and nut (and washer) that protrudes outward from the joint object is covered with a heat shield that shields heat radiation. A bolt joint structure with high heat shielding properties. (3) In (1) or (2), the heat-shielding body is a fire-resistant blanket, a fire-resistant mold, a fire-resistant paint, and a metal cover. (4) In (1) or (2), the heat shield is a metal cap, which is a bolt joint structure with high heat shield. (5) In any one of (1) to (4), the bolt joint used for the steel structure receiving a fire is a column-beam joint, a beam joint, or a part or all of the column joint. A bolt joint structure with high heat shielding properties. (6) In any one of (1) to (5), a part or all of a column, a beam member, and a joint metal used for a steel frame structure subjected to a fire is a refractory steel, which is a heat shielding property. High bolt joint structure.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION When a steel structure in the field of construction is exposed to a high temperature for a relatively short time due to a fire, the temperature rise of the steel material forming the steel structure is caused by heat radiation rather than heat conduction. Therefore, in order to reduce the temperature rise of the steel material, it is based on the finding that it is important and effective to shield this heat radiation.
That is, in the present invention, the bolted portion forming the steel frame structure is partially shielded from heat radiation by the heat shield,
A new "bolt joint with high heat shielding property" is adopted, whereby, for example, even if a fireproof bolt excellent in high temperature strength at 600 ° C is used, 700 ° C to 850 ° C.
It is possible to realize a non-refractory coating structure of a steel frame structure by using refractory steel excellent in high temperature strength at ℃. The steel frame structure subject to fire in the present invention is mainly composed of main members made of refractory steel such as columns and beams, various joining metal parts (split stays, angle members, end plates, splice plates, etc.) and bolts. It means a steel structure in the field of construction constructed by joining together.

The present invention is applied to a column-beam joint portion, a beam joint, and a bolt joint portion in a part or all of the column joint in the case of constructing this steel structure.
Basically, these main members and various joining hardware are
Bolt joints, especially bolts and nuts (and washers), in the case of realizing a steel frame structure with a non-fireproof coating structure by forming it from a refractory steel material excellent in high temperature strength of 0 ° C to 850 ° C
Is a bolted joint structure that can cover the lack of high temperature strength by shielding it with a material that shields thermal radiation. Used in the present invention,
As the heat shield material, basically, a refractory material that does not lose its shielding performance by being melted in a fire, for example, a ceramic refractory material (including fibers), other refractory materials, fire resistant paint (fire resistant adhesive material), Metal (mainly steel plate and stainless steel plate)
Is suitable.

The objects of heat shielding are the bolts and nuts (and washers), which are the main members that receive high-temperature heat radiation,
It suffices to mainly shield the portion (exposed portion) protruding from the metal joint to the outside. The minimum unit of heat shield is each bolt / nut and washer, but a row unit consisting of multiple bolts / nuts and washers or a unit of metal fittings, that is, the entire joint area including bolts / nuts (and washers), Alternatively, it is also effective to shield the bolts and nuts (and washers) and their surrounding areas. As a usage mode of the heat shield, in consideration of a unit of heat shield, workability of heat shield, etc., for example, a ceramic blanket, a ceramic mold, a ceramic sheet, a ceramic paint, other fire resistant paint, a metal cover (for example, A cap or the like can be selectively used (including combined use).

Of these heat shields, a ceramic blanket, a ceramic mold, a ceramic sheet, a metal cover (for example, a cap), etc. are fixed by clips, locking, engagement (fitting), stud welding or adhesion. be able to. Particularly when the cap is used as a heat shield, it is effective to provide a locking structure between the cap and the washer. If there is a gap between these heat shields and the object to be fixed, apply fire resistant paint,
It is effective to increase air tightness. Known refractory materials and fireproof paints suitable as heat shields include the following at present.・ High temperature fire-resistant heat-insulating fiber ・ Ceramic fiber product (S-fiber SC) (Shin Nikka Thermal Ceramic Co., Ltd.) ・ Paint type heat insulating material (ceramic cover CC100) Eniro Torow Co., Ltd. ・ Heating foam type fire resistant paint (Nullifier System S) ) Nullifire

[0011]

[Embodiment 1] An embodiment of the present invention will be described below with reference to FIGS. 1 (a), 1 (b) and 1 (c). In this Example 1, the flanges 2f of the upper and lower split tees 2a and 2b are joined to the two opposite sides of the rectangular steel tube column 1 with bolts 3, and the upper flange 4a of the H-shaped steel beam 4 is connected to the web 2u of the upper split tee 2a. In the bolt joint structure of the square steel tube column 1 and the H-section steel beam 4 which are joined by the bolt 5 and the lower flange 4b of the H-section steel beam 4 is joined to the web 2u of the lower split tee 2b by the bolt 5, Is applied to the outer surface of each bolt joint area to cover the ceramic blankets 6a, 6b, 6c as heat shields to shield the heat radiation to each bolt joint area. There is.

The bolt joint portion in this bolt joint structure is
The joint between the rectangular steel pipe column 1 and the flange 2f of the upper and lower split tees 2a and 2b, and the web 2 of the split tees 2a and 2b.
Although there is a joint between u and the flanges 4a and 4b of the H-shaped steel beam 4, in the first embodiment, the upper split tee 2a side is a pair of left and right lower units, and the ceramic blanket 6a is provided in each unit. Cover and fix, and on the lower split tee 2b side, the left and right pairs on the upper side are 2 units,
Cover and fix the ceramic blanket 6b,
Further, with the lower side as one unit, the ceramic blanket 6c is covered and fixed to form the heat shield structure of the bolt joint.

More specifically, the upper split tee 2a
Of the flange 2f, the bolts and nuts 3 (and washers 7) protruding (exposed) from the outer surface of the flange 2f, the lower surface of the web 2u of the upper split tee 2a, and the web 2u. The upper flange 4a of the H-shaped steel beam 4 (only in the contact area) and the bolts and nuts 5 protruding (exposed) from the lower surface of the upper flange 4a of the H-shaped steel beam 4.
Using (and washer 8) as one unit, the ceramic blanket 6a was covered and fixed so as to wrap them together to form a heat shield structure for the bolt joint on the lower side of the upper split tee 2a. Since the lower side of the upper split tee 2a is on both sides of the web 4u of the H-shaped steel beam 4,
Similarly, one unit of the ceramic blanket 6a was coated and fixed on each side to form a heat shield structure for the bolt joint on the lower side of the upper split tee 2a.

On the other hand, the lower side of the flange 2f of the lower split tee 2b, the bolt / nut 3 (and the washer 7) protruding (exposed) from the outer surface of the flange 2f, and the web 2u of the lower split tee 2b. The lower surface and the side surface of the web 2u and the bolts and nuts 5 (and washers 8) protruding (exposed) from the lower surface of the web 2u are regarded as one unit, and the ceramic blanket 6c is encased at the same time.
Was covered and fixed to form a heat shield structure for the bolt joint on the lower side of the lower split tee 2b. Also, the upper side of the flange 2f of the lower split tee 2b, the bolt / nut 3 (and the washer 7) protruding (exposed) from the outer surface of the flange 2f, and the upper surface of the web 2u of the lower split tee 2b. , H-shaped steel beam 4 abutting on this web 2u
Lower flange 4b portion (abutting portion area only) and H-shaped steel beam 4
With the bolt / nut 5 (and washer 8) protruding (exposed) from the upper surface of the lower flange 4b as one unit, the ceramic blanket 6b is covered / fixed so as to wrap them together, and the lower split tee 2b A heat shield structure for the upper bolt joint was formed.

The upper side of the lower split tee 2b is
Since it is on both sides of the web 4u of the H-shaped steel beam 4, one unit of ceramic blanket 6b is similarly coated and fixed on each side to provide a heat shield structure for the upper bolt joint of the lower split tee 2b. Formed. Regarding the covering and fixing of each ceramic blanket 6a, 6b, 6c, the rectangular steel pipe pillar 1 is provided with the flange 2f of the upper and lower split tees 2a, 2b.
Were joined with bolts 3, and the upper and lower flanges 4a, 4b of the H-shaped steel beam 4 were joined with the webs 2u of the upper and lower split tees 2a, 2b with bolts 5, then covered and fixed by stud welding 9. In order to improve the airtightness by coating the ceramic blankets 6a, 6b, 6c, it is considered to surely fill the gap with a fireproof paint or the like. In this way, the ceramic blankets 6a, 6b and 6c are used to form the heat shield structure in each bolt joint region,
When a fire occurs, the temperature rise of the heat shielded part can be suppressed, so it is possible to use bolts and nuts 3 and 5 (and washers 7 and 8) whose high temperature strength is lower than that of the main member. Since the upper and lower split tees 2a, 2b can also be shielded from heat, a material having a high temperature strength equal to or lower than the high temperature strength of the main member can be used.

[Embodiment 2] Hereinafter, Embodiment 2 of the present invention will be described with reference to FIGS. 2 (a), (b) and (c), FIG. 3 and FIG.
(A) and (b) will be described with reference to FIG. This Example 2
In the joint structure of the rectangular steel tube column 1 and the H-shaped steel beam 4 in which the H-shaped steel beam 3 is bolted to the two opposite side surfaces of the rectangular steel tube column 1 via the upper and lower split tees 2a and 2b, as in the first embodiment. Although applied, as a heat shield that shields heat radiation, thin steel caps 12 and 12a are used, and each bolt and nut of each bolt joint and each washer are covered. It is different. Detailed description of the parts common to the first embodiment will be omitted, and different parts will be mainly described below.

In the second embodiment, as shown in FIG. 2, the bolts protruding (exposed) to the outside at the bolt joints are exposed.
The nuts 3 and 5 and the washers 7 and 8 were subjected to heat shielding, and the bolts and nuts and washers were covered with thin steel plate caps 12 and 12a to form a heat shielding structure for the bolts and nuts and washers. . The cap 12 covering the nut side has a shape having a plurality of steps as shown in FIGS. 4 (a) and 4 (b). Basically, as shown in FIG. Although the washer 7 or the washer 8 is pushed into the nuts 3 and 5 and fitted therein, the washer 7 or the washer 8 is cut out at its outer peripheral portion as shown in FIGS. When you push in, the binding force with the end is increased. In addition, a fireproof adhesive 14 is provided between the end of the bolt 3 or 5 and the top of the cap 12.
I tried to glue it with wood. The cap 12a covering the head side of the bolt 5 is basically pushed into the head of the bolt 5 as shown in FIGS. 4 (c) and (d), as shown in FIG. 3 (b). In order to prevent the washer 8 from easily falling off, the washer 8 is cut out at its outer peripheral portion as shown in FIGS. I tried to increase the bond strength. Also, the head of the bolt 5 and the top of the inside of the cap 12a are bonded with a fireproof adhesive 14.

In this way, the bolts and nuts 3 and 5 and the washers 7 and 8 of the bolt joints are locally provided with a heat shield structure, so that the temperature rise of the heat shield parts can be suppressed. Fireproof bolts / nuts and washers whose high temperature strength is lower than that of the main member can be used. In the case of the second embodiment, the heat shield region is a local region of each bolt unit of each bolt unit, so that the heat shield range can be narrowed as compared with the case of the first embodiment, and the stud welding is performed. Since it is not necessary, the heat shield construction is simple, and the heat shield cost and the heat shield construction cost can be reduced.

[Third Embodiment] A third embodiment of the present invention will be described below with reference to FIGS. 6 (a) and 6 (b). Similar to the second embodiment, the third embodiment is such that each bolt / nut and each washer of each bolt joint is covered with a heat shield. However, the second embodiment is different from the metal cap in that the heat-foaming type is used. Fireproof paint (for example, Nullifier System S above)
Is different in that it uses. Here, the heat-foamable fireproof paint 13 is projected (exposed) to the outside at each bolt joint.
Each of the bolts and nuts 3 and 5 and the washers 7 and 8 were covered with the heat-foamable refractory paint 13 to form a heat shield structure for the bolts and nuts and washers. Figure 6 (a)
Shows the nut side, and FIG. 6B shows the head side, both of which are shown in a state in which the heat-foamable refractory paint 13 is heated and foamed. Also in the third embodiment, substantially the same effect as in the second embodiment can be obtained.

[Experimental Example 1] In order to evaluate the characteristics of a bolted joint having a heat shield structure according to the present invention, as shown in FIG. 7, a rectangular steel pipe column 1 as shown in Examples 1 and 2 was split. The joint structure of the rectangular steel tube column 1 and the H-shaped steel beam 4 in which the H-shaped steel beam 4 is joined with the bolts 3 and 5 via the tee 2a is used as a test piece, and thermocouples are arranged at each part to prevent fire. Perform an experiment to heat under a certain condition so that it becomes a high temperature atmosphere,
The temperature of each site was measured. However, in this experiment, the joint between the square steel tube column 1 and the flange 2f of the split tee 2a, the web 2u of the split tee 2a, and the H-shaped steel beam 4 were used.
The upper surface of the upper flange 4a of the split tee 2a is exposed, and a ceramic blanket 15 is covered and fixed to the bolt joint region between the web 2f of the split tee 2a and the lower surface of the upper flange 4a of the H-shaped steel beam 4 to provide heat shielding. The structure was formed, the heat insulating board 16 was arranged on the upper surface side of the split tee 2a, and the square steel tube column 1, the H-shaped steel beam, and the bolt joint were heated from the lower surface of the heat insulating board 16.

[Experimental conditions] Specimen Square steel tube column 400 × 19 (BCR295) Effective heating length 3 m H-shaped steel beam 600 × 200 × 11 × 17 (SS40
0) Effective heating length: 3.2 m, three-sided heating ceramic blanket (thickness: 25 mm) (high temperature refractory insulation fiber S fiber SC SC blanket 1260, manufactured by Shin Nikka Thermal Ceramic Co., Ltd.) Heating means Multipurpose heating furnace (burner heating) Heating Method The heating was heating for 1 hour based on ISO834. Temperature measurement Measured with a thermocouple attached to the test body.

The results of measuring the temperature of each part will be described below with reference to FIGS. 8 and 9. FIG. 8 shows the temperature measurement results of the rectangular steel tube column 1 and the H-shaped steel beam 4, and FIG. 9 shows the temperature measurement results of the exposed bolt joints and the bolt joints having the heat shield structure. . In FIG. 8, the temperature of the exposed portions of the rectangular steel tube column 1 and the H-shaped steel beam 4 gradually approaches the atmosphere in the furnace,
820 ℃ or more after heating for 60 minutes, 900 after heating for 60 minutes
It indicates that the temperature reaches over ℃. In FIG. 9, the temperature of the bolt 3 in the exposed state of the rectangular steel pipe column 1, the flange 2f of the split tee 2a, and the flange of the split tee 2a is 4
It shows that the temperature reaches 750 to 800 ° C. after heating for 5 minutes and reaches 850 to 900 ° C. after heating for 60 minutes.

On the other hand, at the joint between the split tee 2a having a heat shield structure with the ceramic blanket 15 and the flange 4a of the H-shaped steel beam 3, the temperatures of the split tee 2a and the bolts / nuts 5 are 45 minutes after heating. 350-40
Even after heating at 0 ° C. for 60 minutes, the temperature remains below 550 ° C., showing that the heat shielding effect is large. Therefore, even if the 600 ° C fireproof bolt described above is used, the high temperature at the time of fire can be sufficiently maintained by partially thermally shielding the bolt joint (eg, only the bolt / nut (and washer) locally). It can be confirmed that it can withstand.

When a similar heating experiment was performed using the bolt joint having the heat shield structure of Example 1 as a test body, the bolt joint region had the heat shield structure, and therefore, Experimental Example 1 Split tee 2 with heat shield structure in
The temperature is the same as that of a and the bolt / nut 5, and the 600 ° C. refractory bolt described above can be used to withstand a high temperature in a fire. Further, when the same heating experiment was performed using the bolt joint portion having the heat shield structure of Examples 2 and 3 as a test body, the heat shield region was in units of bolts and nuts (and washers). Because the heat shield area is narrower than the case,
The heat shielding effect is slightly smaller than that of the first embodiment due to the heat effect from the exposed portions of the rectangular steel tube column 1, the split tee 2a and the H-shaped steel beam 4, but in the case of the cap 8, the gap is completely filled with fireproof paint or the like to be airtight. By increasing the sex
After heating for 60 minutes, the temperature can be kept at 600 ° C or lower, and the above-mentioned 600 ° C refractory bolt can be used to withstand the high temperature at the time of fire.

The present invention is not limited to the contents of the above embodiments and experimental examples. For example, the pillar may be an H-shaped steel pillar or a circular steel pipe pillar, and the beam material may be an I-shaped steel beam, a channel steel beam, or the like. The joining hardware may be an angle material, a splice plate, or the like. Also, a ceramic blanket and a thin steel plate cap were used as the heat shield,
Regarding the material, shape, fixing means, etc. of this heat shield,
It is subject to change depending on the steel structure conditions and bolt joint conditions.

[0026]

INDUSTRIAL APPLICABILITY The bolt joint structure of the present invention is applied to a steel frame structure that is likely to receive a fire, and has a heat shield structure by a heat shield that shields radiant heat. When a fire-resistant steel excellent in high-temperature strength at 800 to 850 ° C is used for the main member and a steel frame structure having a non-fireproof coating structure for 30 minutes or more is used, a fireproof bolt excellent in high-temperature strength at 600 ° C is used. It can be used, and it becomes possible to easily and inexpensively realize a steel frame structure with a non-refractory coating.

[Brief description of drawings]

FIG. 1 (a) is a plan view showing a structural example of a bolt joint portion according to a first embodiment of the present invention, and FIG. 1 (b) is an Aa in FIG. 1 (a).
-Ab arrow partial cross section explanatory view, (c) figure is a partial cutaway side view explanatory drawing of (b) figure.

FIG. 2 (a) is an explanatory plan view showing a structural example of a bolt joint portion according to a second embodiment of the present invention, and FIG. 2 (b) is an Aa in FIG. 2 (a).
-Ab arrow partial cross section explanatory view, (c) figure is a partial cutaway side view explanatory drawing of (b) figure.

FIG. 3 (a) is a side sectional explanatory view showing an example of coupling a bolt / nut (and a washer) and a cap in a bolt joint structure example of Embodiment 2 of the present invention shown in FIG. 2; ) The figure is
FIG. 6 is a side cross-sectional explanatory view showing an example of coupling a bolt head (and a washer) and a cap in a bolt joint structure example of Embodiment 2 of the present invention shown in FIG. 2.

4 (a) is a side cross-sectional explanatory view showing an example of the shape of a cap used on the nut (and washer) side in the bolt joint structure example of Embodiment 2 of the present invention shown in FIG. 2; The figure is
The side explanatory drawing of (a) figure, the side sectional explanatory drawing which shows the example of a shape of the cap used by the head side, (c) figure,
(C) Side explanatory drawing of a figure.

5A is a side cross-sectional explanatory view of a washer in the bolt joint structure example of the second embodiment of the present invention shown in FIG. 2, and FIG. 5B is a side explanatory view of FIG.

FIG. 6 (a) is a side cross-sectional explanatory view showing a heat shielding structure of a bolt / nut (and a washer) by a heat-foamable fireproof coating material in Embodiment 3 of the present invention. FIG. 6B is a side cross-sectional explanatory view showing a heat shield structure made of a heat-foaming fireproof paint on the bolt head side.

FIG. 7 is a partially cutaway cross-sectional explanatory view of a bolt joint structure used as a test object to be heated in Experimental Example 1.

FIG. 8 is an explanatory diagram showing a temperature measurement result of a body portion of a pillar-beam.

FIG. 9 is an explanatory diagram showing a temperature measurement result of a bolt joint portion having no heat shield structure and a temperature measurement result of a bolt joint portion having a heat shield structure in an experimental example of the present invention.

FIG. 10 is a three-dimensional explanatory view showing an example of a bolt connection structure of a known prismatic steel tube column and an H-shaped steel beam.

[Explanation of symbols]

1 Square Steel Pipe Column 2a Upper Split Tee 2b Lower Split Tee 2f Flange 2u Web 3 Bolt 4 H-Shaped Steel Beam 4a Upper Flange 4b Lower Flange 4u Web 5 Bolt 6a, 6b, 6c Ceramic Blanket 7, 8 Washer 9 Stud Welding 12 Cap (Nut side) 12a Cap (bolt head side) 13 Heat-foaming fire-resistant paint 14 Fire-resistant adhesive 15 Ceramic blanket 16 Insulation board

Claims (6)

[Claims] 1. A heat shield property, characterized in that, in a bolt joint structure of a steel structure subjected to a fire, a joint region including bolts and nuts (and washers) is covered with a heat shield for shielding radiant heat. High bolt joint structure. 2. In a bolt joint structure of a steel structure subjected to a fire, a portion of a bolt / nut (and a washer) protruding from an object to be joined to an outer surface side is covered with a heat shield that shields heat radiation. A bolt joint structure with high heat shielding properties. 3. The bolt joint structure with high heat shielding properties according to claim 1, wherein the heat shield is a fireproof blanket, a fireproof mold, a fireproof paint and a metal cover. 4. The bolt joint structure having high heat shielding properties according to claim 1 or 2, wherein the heat shielding body is a metal cap. 5. The bolt-joint used for a steel structure subjected to a fire is a column-beam joint, a beam joint, or a part or all of a column joint, according to claim 1. The bolt joint structure having high heat shielding property according to any one of the above. 6. Use in a steel structure subject to fire,
Part or all of the pillar, the beam member and the joint metal are made of refractory steel, and the bolt joint structure having a high heat shielding property according to any one of claims 1 to 5.