Fireproofing of composite materials

Abstract

To provide a fire resistance structure of a composite member capable of reassuring a fire resistance efficiency of a connection part of a wooden covering material and other non-wooden fire resistance covering material.SOLUTION: A fire resistance structure 10 of a connection part 20 between a first region R1 and a second region R2 at a composite member 18 comprises a steel frame member 12, a thick wooden covering material 14 covering the first region R1 of a surface of the steel frame member 12 and a thin non-wooden fire resistance covering material 16 covering the second region R2 of the surface of the steel frame member 12 adjacent to the first region R1 and has a non-wooden fire resistance covering material 22 covering the surface of the steel frame member 12 of the connection part 20 with a thickness equal to or greater than the thickness of the fire resistance covering material 16 of the second region R2 and an inorganic type fire resistance material 26 covering a header surface 24 of the wooden covering material 14 and the fire resistance covering material 22 of the connection part 20 continuously.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a fire-resistant structure of composite members, including wood-steel hybrid members made of wood and steel. [Background technology]

[0002] Previously, the applicant of this patent has developed a wood-steel hybrid beam (hereinafter referred to as a wood-steel beam), which is a structural member with a fire resistance of one hour, in which a steel beam is fire-resistant-coated with wood (hereinafter referred to as a wood coating material) (see, for example, Patent Document 1). This wood coating material burns at 0.7 to 1.0 mm / min during a fire, but stops burning after the fire, thereby suppressing the temperature rise of the steel beam supporting the load and preventing collapse.

[0003] When applying wood-steel beams to buildings, there may be places where the wood covering material and other fire-resistant covering materials come into contact with each other. For example, in the outer periphery of a steel frame structure, through holes are provided in the steel beams to allow piping to pass through, but from the standpoint of ease of construction, cost reduction, and appearance, it is possible to consider covering the through hole part and its surroundings with a fire-resistant covering material other than the wood covering material (for example, fire-resistant paint or sprayed rock wool).

[0004] When the type of fire-resistant covering material changes in the axial direction of the beam as described above, several techniques are known to ensure fire resistance at the boundary between different types of fire-resistant covering materials (see, for example, Patent Documents 2 and 3). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent application No. 2020-148315 (currently unpublished) [Patent Document 2] JP 2020-143528 A [Patent Document 3] JP 2020-172808 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, when the above-mentioned wood-steel beam is applied to a building, there is a risk that a predetermined fire resistance performance cannot be achieved at the places where the wood coating material and the other non-wood-based fire-resistant coating materials meet. When the steel frame members are coated with fire-resistant coating materials such as fire-resistant paints and sprayed rock wool, the thickness and specifications of the fire-resistant coating material are determined so that the steel temperature is 350°C or less on average and 450°C or less at the maximum. On the other hand, the ignition temperature of wood is about 200 to 260°C. Therefore, at the places where the wood coating material meets the other fire-resistant coating materials, the heat is transferred from the steel frame member coated with the other non-wood-based fire-resistant coating material to the steel frame member coated with the wood coating material, and the steel temperature of the steel frame member on the wood coating material side may reach 200 to 260°C. Then, the wood coating material burns from the inside and does not stop burning, and the steel temperature of the steel frame member may reach 450°C or more. In addition, at the joints between wood covering materials and other non-wood-based fire-resistant covering materials, the end faces of the wood covering materials may be exposed or gaps may appear between the wood covering materials and other non-wood-based fire-resistant covering materials, which may make it difficult to ensure the specified fire resistance performance.

[0007] The present invention has been made in consideration of the above, and aims to provide a fire-resistant structure of composite members that can ensure the fire resistance performance of the joint between a wood covering material and another non-wood-based fire-resistant covering material. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, the fire-resistant structure of a composite member of the present invention is a fire-resistant structure of a joint between a first region and a second region in a composite member comprising a steel member, a thick wood-based covering material covering a first region of the surface of the steel member, and a thin non-wood-based fire-resistant covering material covering a second region of the surface of the steel member adjacent to the first region, characterized in that it has a non-wood-based fire-resistant covering material that covers the surface of the steel member near the joint with a thickness equal to or greater than the thickness of the fire-resistant covering material of the second region, and an inorganic fire-resistant material that continuously covers the end surface of the wood-based covering material and the fire-resistant covering material of the joint.

[0009] The fire-resistant structure of another composite member according to the present invention is characterized in that, in the above-mentioned invention, the non-wood-based fire-resistant coating material is a fire-resistant paint and its thickness is increased.

[0010] In addition, in the above-mentioned invention, the inorganic fire-resistant material in the fire-resistant structure of another composite member according to the present invention is a reinforced gypsum board attached to the small end surface of the wood covering material, and an inorganic filler is provided in the gap between this reinforced gypsum board and the steel member. Effect of the Invention

[0011] According to the fire-resistant structure of a composite member of the present invention, there is provided a fire-resistant structure for a joint between a first region and a second region in a composite member which comprises a steel member, a thick wood-based covering material covering a first region on the surface of the steel member, and a thin non-wood-based fire-resistant covering material covering a second region on the surface of the steel member adjacent to the first region, and the fire-resistant covering material includes a non-wood-based fire-resistant covering material which covers the surface of the steel member near the joint with a thickness equal to or greater than the thickness of the fire-resistant covering material of the second region, and an inorganic fire-resistant material which continuously covers the end face of the wood-based covering material and the fire-resistant covering material of the joint, thereby achieving the effect of ensuring fire resistance of the joint between the wood-based covering material and another non-wood-based fire-resistant covering material.

[0012] In addition, according to the fire-resistant structure of another synthetic member of the present invention, by using a fire-resistant paint as a non-wood-based fire-resistant coating material and increasing its thickness, it is possible to ensure the fire resistance of the joint between the wood coating material and the fire-resistant paint.

[0013] In addition, according to another fire-resistant structure of a composite member of the present invention, the inorganic fire-resistant material is a reinforced gypsum board that is attached to the end surface of the wood covering material, and an inorganic filler is provided in the gap between this reinforced gypsum board and the steel member, thereby suppressing the inflow of heat and combustion from the end surface and suppressing the rise in the steel temperature of the steel member on the wood covering material side. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a side view showing an embodiment of a fire-resistant structure of a composite member according to the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Diagram 3] FIG. 3 is a cross-sectional view taken along line BB in FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line CC in FIG. [Diagram 5] FIG. 5(1) is a graph showing the average temperature change at each cross-sectional position, and (2) is a table showing the maximum temperature at each cross-sectional position. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the fire-resistant structure of a composite member according to the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to these preferred embodiments.

[0016] As shown in Figures 1 to 4, a fire-resistant structure 10 of a composite member in an embodiment of the present invention is a fire-resistant structure of a joint 20 between a first region R1 and a second region R2 in a composite member 18 which includes a steel beam 12 (steel member), a thick wood coating material 14 which covers a first region R1 on the surface of the steel beam 12, and a thin fire-resistant paint 16 (non-wood-based fire-resistant coating material) which covers a second region R2 on the surface of the steel beam 12 adjacent to the first region R1.

[0017] This fireproof structure 10 has a fireproof paint 22 that covers the surface of the steel beam 12 at the joint 20 with a coating thickness equal to or greater than the coating thickness of the fireproof paint 16 in the second region R2, and a reinforced gypsum board 26 (inorganic fireproof material) that continuously covers the end surface 24 of the wooden covering material 14 and the fireproof paint 22 at the joint 20. In this embodiment, the fireproof paints 16, 22 are applied to a predetermined length range (length range up to the fireproof covering material 42) in the second region R2 with the same thickness equal to or greater than the required coating thickness. On the lateral and downward outer parts of the end surface 24 of the wooden covering material 14, a finishing wood 28 and an ordinary gypsum board 30 are laminated adjacent to the reinforced gypsum board 26. Instead of providing the finishing wood 28 and the ordinary gypsum board 30, the reinforced gypsum board may be attached to the entire end surface 24 of the wooden covering material 14.

[0018] The steel beam 12 is made of an H-shaped steel extending in a substantially horizontal direction, and has a web 32, an upper flange 34, and a lower flange 36. The steel beam 12 in the first region R1 and the steel beam 12 in the second region R2 are butted together at a joint 20, and are joined to each other by a plate 38 and a bolt 40 provided on the web 32. The beam formed by the steel beam 12 in the first region R1 and the wood covering material 14 corresponds to a wood-steel beam. In the example shown in the figure, the steel beam 12 on the second region R2 side is provided with a fireproof covering material 42 made of a calcium silicate board and a through hole 44 for passing a pipe, but these can be omitted. The steel beams 12 in the first region R1 and the second region R2 do not have to be butted together by the bolt 40 and the plate 38. For example, the steel beams 12 in the first region R1 and the second region R2 may be continuous in the beam axis direction.

[0019] The wooden covering material 14 is made of laminated timber provided in a manner to cover the top, bottom, left and right sides of the steel beam 12, and is formed of a tree species such as Japanese cypress or larch having a fire resistance of one hour. The wooden covering material 14 is fixed to the web 32 of the steel beam 12 by a fixing member 46 such as a lag screw. As shown in FIG. 4, this fixing member 46 is a metal rod-shaped body having a plate-shaped head 48 and a shaft-shaped screw portion 50. The screw portion 50 has a sharp tip and a screw thread on its outer periphery. The fixing member 46 is screwed into the wooden covering material 14 through through holes 52 provided on the upper and lower sides of the web 32 in the same cross section. The through holes 52 are blocked with filler wood 54. As shown in FIG. 1, a plurality of fixing members 46 are arranged at predetermined intervals in the horizontal direction in which the steel beam 12 extends, and are arranged so that the screwing directions are staggered in the horizontal direction.

[0020] The fire-resistant paints 16 and 22 are made of a foaming fire-resistant material that foams at a predetermined temperature range when heated to suppress the temperature rise of the steel material. For example, there is a fire-resistant paint that starts foaming at about 250°C when heated during a fire and foams 20 to 30 times to form a heat insulating layer. In this embodiment, the coating thickness of the fire-resistant paint 16 in the second region R2 and the coating thickness of the fire-resistant paint 22 in the joint portion 20 are both set to a coating thickness that satisfies the two-hour fire resistance performance, but the present invention is not limited to this. In this embodiment, the fire-resistant paints 16 and 22 are provided in a length range from the end surface 24 of the wood coating material 14 to the fire-resistant coating material 42, and have a coating thickness that satisfies the two-hour fire resistance performance, but the present invention is not limited to this. For example, fire-resistant paints 16, 22 with a coating thickness that satisfies a two-hour fire resistance performance may be applied to a length range extending beyond the above-mentioned range from the end surface 24 of the wood coating material 14, and fire-resistant paint with a coating thickness that satisfies a one-hour fire resistance performance may be applied to the range beyond that.

[0021] The reinforced gypsum board 26 is a plate-like member that is attached to the end surface 24 of the wooden covering material 14. For construction purposes, a certain gap (clearance) is required between the reinforced gypsum board 26 and the steel beam 12. To prevent heat from entering through this gap, an inorganic filler 56 (for example, a calcium carbonate-based filler) is placed in the gap.

[0022] As described above, in this embodiment, in the area where the wooden coating material 14 of the wooden-steel beam and the fire-resistant coating 16 (non-wood-based fire-resistant coating material) meet, the coating thickness of the fire-resistant coating is increased to satisfy the one-hour fire resistance performance, and reinforced gypsum board 26 (inorganic fire-resistant material) is provided at the interface 20 between the wooden coating material 14 and the fire-resistant coating 22. According to this embodiment, the following effects can be obtained.

[0023] (1) By changing the coating thickness of the fire-resistant paint from a 1-hour fire-resistant specification to a 2-hour fire-resistant specification, the increase in the temperature of the steel on the fire-resistant paint 16 side (second region R2) is reduced, and the increase in the temperature of the steel due to heat transfer to the steel beam 12 on the wood coating material 14 side (first region R1) is suppressed. (2) By attaching the reinforced gypsum board 26 to the edge 24 of the wooden covering material 14, the inflow of heat from the edge 24 is suppressed. In addition, the edge 24 of the wooden covering material 14 is prevented from being burned by direct exposure to flames. (3) By providing a reinforced gypsum board 26 between the wood covering material 14 and the fire-resistant coating 16, the reinforced gypsum board 26 absorbs the heat of the steel beam 12 on the fire-resistant coating 16 side, thereby suppressing the rise in the temperature of the steel on the wood covering material 14 side.

[0024] <Example> Next, an embodiment of the present invention will be described. The following is a specification for verifying fire resistance performance in a one-hour fire resistance test. The specifications of the joints between the wood-steel beam and the fire-resistant paint verified in the fire resistance test are as shown in Figs. 1 to 4. The dimensions and steel type of the steel beam used for the test specimen are BH-900 x 150 x 16 x 19, and a total length of 3450 mm (SS400). The wood covering material is hiba laminated lumber (symmetrical different grade E95-F270), the covering material thickness is 80 mm, and the cross-sectional dimensions of the wood-steel beam are 1067 mm x 317 mm. In the fire resistance test, a case where a through hole is provided in the steel beam is assumed.

[0025] (Fireproof paint thickness) Generally, if the structure is fire-resistant for one hour, it is sufficient to apply fire-resistant paint with a coating thickness specified for one-hour fire resistance. However, for fire-resistant paint that comes into contact with wooden steel beams, in order to reduce the rise in the temperature of the steel on the fire-resistant paint side and to suppress the rise in the temperature of the steel due to heat transfer to the steel beam on the wooden covering material side, a fire-resistant paint with a coating thickness that achieves two-hour fire resistance was applied. This fire-resistant paint was applied within a length of 650 mm from the small end of the wooden covering material.

[0026] (Installation of reinforced gypsum board) Multiple reinforced gypsum boards were installed on the short edges of the wooden covering material. In the fire resistance test, reinforced gypsum boards (21 mm thick x 3 sheets) were layered on top of reinforced gypsum boards (12.5 mm thick) for a total thickness of 75.5 mm. It is believed that increasing the thickness of the reinforced gypsum boards improves the insulation performance and increases the amount of heat absorbed by the reinforced gypsum boards, thereby improving fire resistance. Therefore, if the total thickness of the reinforced gypsum boards installed on the short edges of the wooden covering material is 75.5 mm or more, it is believed that fire resistance will be guaranteed even if the number and thickness of the reinforced gypsum boards are changed.

[0027] (Gap filling) In construction, a clearance is required between the reinforced gypsum board attached to the edge of the wooden covering material and the steel beam. To prevent heat from entering through this gap, an inorganic filler (such as calcium carbonate filler) is injected to fill the gap.

[0028] Additionally, for the fire resistance tests, test specimens were manufactured so that the clearance between the reinforced gypsum board and the steel beams was 3 mm. However, by reducing the clearance between the reinforced gypsum board and the steel beams, it is believed that the reinforced gypsum board can more easily absorb the heat from the steel beams, and that the inflow of heat through the gaps can be minimized. Therefore, it is believed that fire resistance can be guaranteed if the clearance between the reinforced gypsum board and the steel beams is 3 mm or less.

[0029] (Installation of finishing wood) To improve the appearance, finishing wood (Japanese cypress laminated wood, 55mm thick) and ordinary gypsum board (12.5mm thick) were laminated around the outer periphery of the end surface of the wooden covering material. Also, if finishing wood is not installed, it is believed that fire resistance can be guaranteed by attaching reinforced gypsum board to the entire end surface of the wooden covering material.

[0030] (Fire resistance test results) Next, we will explain the results of a one-hour fire resistance test on the joint using the above test specimen. The fire resistance test was completed by heating the test specimen for one hour and then leaving it to cool in the furnace for 48 hours. At the end of the test, no red heat or smoke was observed and the wood covering material had stopped burning. In addition, the finishing wood (55 mm thick) and the ordinary finishing gypsum board (12.5 mm thick) had fallen off, but the reinforced gypsum board (21 mm thick x 3 sheets + 12.5 mm thick) on the small edge remained.

[0031] Figure 5 (1) shows the time progression of the average temperature at each cross-sectional position measured by thermocouples installed on the upper and lower flanges and web. The legend in the figure indicates the horizontal distance from the end face of the wooden covering material. Figure 5 (2) shows the maximum temperature at each cross-sectional position. As shown in Figure 5 (2), the maximum steel temperature of the steel beam coated with fire-resistant paint was 341.5°C, and the maximum steel temperature of the steel beam coated with wooden covering material was 202.0°C, both of which were below the allowable temperature of 350°C for steel in the fire resistance test. Therefore, it can be said that the specifications of this embodiment have a fire resistance performance of 1 hour.

[0032] According to this embodiment, by using reinforced gypsum board at the interface between the wood covering material and the fireproof paint, it is possible to realize specifications that are easy to process and install on-site. Also, by using fireproof paint and assuming the installation of finishing wood, it is possible to take into consideration the appearance of the finished product.

[0033] In the above embodiment, a fire-resistant paint is used for a non-wood-based fire-resistant coating material that competes with a wood-based coating material, but the present invention is not limited to this. If the specifications of the non-wood-based fire-resistant coating material are such that the steel temperature is 340°C or less in a one-hour fire resistance test, a non-wood-based fire-resistant coating material other than a fire-resistant paint (such as sprayed rock wool or wet ceramic fire-resistant coating material) may be used.

[0034] As described above, the fire-resistant structure of a composite member of the present invention provides a fire-resistant structure for a joint between a first region and a second region in a composite member which includes a steel member, a thick wood-based covering material covering a first region on the surface of the steel member, and a thin non-wood-based fire-resistant covering material covering a second region on the surface of the steel member adjacent to the first region, and which includes a non-wood-based fire-resistant covering material which covers the surface of the steel member near the joint with a thickness equal to or greater than the thickness of the fire-resistant covering material of the second region, and an inorganic fire-resistant material which continuously covers the end face of the wood-based covering material and the fire-resistant covering material of the joint, thereby ensuring the fire resistance of the joint between the wood-based covering material and another non-wood-based fire-resistant covering material.

[0035] In addition, according to the fire-resistant structure of another composite member of the present invention, by using a fire-resistant paint as a non-wood-based fire-resistant coating material and increasing its thickness, the fire resistance of the joint between the wood coating material and the fire-resistant paint can be ensured.

[0036] In addition, according to another fire-resistant structure of a composite member of the present invention, the inorganic fire-resistant material is a reinforced gypsum board that is attached to the edge of the wood covering material, and an inorganic filler is provided in the gap between this reinforced gypsum board and the steel member, thereby suppressing the inflow of heat and combustion from the edge and suppressing the temperature rise of the steel member on the wood covering material side. [Industrial Applicability]

[0037] As described above, the fire-resistant structure of the composite member according to the present invention is useful for a composite member having a steel member and a wood-based covering material, and is particularly suitable for ensuring the fire resistance of the joint between the wood-based covering material and other non-wood-based fire-resistant covering materials. [Explanation of symbols]

[0038] 10 Fire resistance of composite members 12 Steel beams (steel members) 14 Wood cladding 16,22 Fireproof paint (non-wood-based fireproof coating material) 18 Composite Materials 20 Connection 24 Fore side 26 Reinforced gypsum board (inorganic fireproof material) 28 Finishing Wood 30 Normal gypsum board 32 Web 34 Upper flange 36 Lower flange 38 Plate 40 Volts 42 Fireproof cladding 44 Through hole 46 Fixing member 48 Head 50 Threaded part 52 Through hole 54 Buried Wood 56 Filler R1 First area R2 second area

Claims

1. A fireproof structure of a joint between a first area and a second area of ​​a composite member comprising a steel member, a thick wood covering material covering a first area of ​​the surface of the steel member, and a thin non-wood based fireproof covering material covering a second area of ​​the surface of the steel member adjacent to the first area, A non-wood-based fire-resistant coating material that covers the surface of the steel member near the joint with a thickness equal to or greater than the thickness of the fire-resistant coating material in the second region; A fireproof structure of a composite member, characterized in that it has an inorganic fireproof material that continuously covers the end surface of a wood covering material and the fireproof covering material at the joint.

2. 2. The fireproof structure of composite members according to claim 1, characterized in that the non-wood based fireproof coating material is made of fireproof paint and its thickness is increased.

3. The fireproof structure of composite members as described in claim 1 or 2, characterized in that the inorganic fireproof material is a reinforced gypsum board attached to the edge surface of the wood covering material, and an inorganic filler is provided in the gap between the reinforced gypsum board and the steel frame member.

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