Ceiling structure and construction method

Abstract

To provide a ceiling structure capable of preventing the ceiling from falling off during an earthquake while securing a large ceiling space.SOLUTION: A ceiling structure 1 includes a steel beam 10, a steel support structure 11 friction-bonded to a web 23 of the steel beam 10 with high-strength bolts 46 and 56, a joist 12 provided on the lower surface of the support structure 11, and a gypsum board 13 attached to the lower surface of the joist 12. According to the present invention, the steel beam 10, the support structure 11, the joist 12, and the gypsum board 13, which are the structural frame, resist the horizontal force during an earthquake as a unit. Therefore, it is possible to prevent the ceiling from falling off by suppressing damage to the members constituting the ceiling in the event of an earthquake while securing a large ceiling space.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a ceiling structure for a building and a method for constructing the ceiling structure. [Background technology]

[0002] BACKGROUND ART Ceiling structures have been proposed in the past with the aim of preventing ceilings from falling off during earthquakes (see Patent Documents 1 to 3). Patent Document 1 discloses an earthquake-resistant reinforcement member that reinforces a ceiling equipped with rafters, rafters, and ceiling finishing materials in an attic space. This earthquake-resistant reinforcement member includes a lower plate attached to the underside of a steel beam in the attic, a first support member provided on the lower plate to support the rafters, and a second support member provided on the lower plate to support the rafters.

[0003] Patent Document 2 shows a ceiling finishing member mounting structure that includes a rafter with a groove provided below the ceiling slab, and a ceiling finishing member attached to the rafter with multiple fasteners. The multiple fasteners are relatively movable along the rafter. Patent document 3 shows a suspended ceiling structure comprising a roughly rod-shaped tension member whose end is connected to the building frame below the ceiling material, a fall prevention member arranged to cover the ceiling surface, and a flat strip-shaped connecting member arranged along the ceiling surface and holding the fall prevention member together with the tension member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-173395 [Patent Document 2] Japanese Patent Application Publication No. 2017-214797 [Patent Document 3] Japanese Patent Application Publication No. 2019-011640 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention aims to provide a ceiling structure and a method for constructing the same that can prevent the ceiling from falling off during an earthquake while ensuring a large space above the ceiling. [Means for solving the problem]

[0006] The inventors of the present invention focused on the fact that, in the ceiling structure of a building, the support structure is friction-joined to the web of the steel beams with high-strength bolts and nuts, and the ceiling underlayment and ceiling surface material are directly joined to the underside of the support structure, thereby rigidly joining the steel beams that make up the structural body of the building to the support structure; in the event of an earthquake, the steel beams and support structure deform as a unit, thereby reducing the amount of deformation of the ceiling underlayment and ceiling surface material joined to the underside of the support structure and preventing the ceiling surface material from falling, and thus arrived at the present invention. The ceiling structure of the first invention (for example, the ceiling structure 1 described below) is A new ceiling structure obtained by renovating an existing ceiling structure, the new ceiling structure comprising: existing steel beams arranged in contact with the underside of a floor slab and including existing steel girders and existing sub-girders arranged between the existing steel girders, a steel support structure in which high-strength bolts are inserted into through holes formed in the webs of the existing steel girders and the existing sub-girders and which is friction-joined to the existing steel girders and the existing sub-girders with the high-strength bolts and nuts, a ceiling substrate arranged on the underside of the support structure, and a ceiling surface material attached to the underside of the ceiling substrate, the steel support structure being arranged in a lattice shape in a plan view and having H-shaped steel beams arranged on the top the end of the beam member is friction-connected to the web of the existing steel frame main girder with the high-strength bolts and the nuts, and the middle part of the beam member is disposed in contact with the bottom flange of the sub-girder and friction-connected to the web of the sub-girder with the high-strength bolts and the nuts via a pair of connecting members, and the support structure is rigidly connected to the existing steel frame main girder and the sub-girder by friction welding. It is characterized by:

[0007] According to this invention, the steel beams that make up the structural frame and the supporting structure are rigidly joined together to form an integrated unit, and the ceiling underlayment and ceiling surface materials are provided on the underside of the supporting structure. Therefore, the steel beams that make up the structural frame and the supporting structure deform together in response to horizontal forces during an earthquake, which reduces deformation of the ceiling underlayment and ceiling surface materials that are joined to the underside of the supporting structure, and prevents the ceiling from falling off. In addition, the support structure is rigidly connected to the webs of the steel beams that make up the structural body, and the ceiling underlayment and ceiling surface material are connected to the underside of that support structure.Therefore, compared to conventional ceiling structures in which hanging materials are attached to the structural body and the ceiling underlayment and ceiling surface material are supported via the hanging materials, there are no hanging materials extending from the structural body, so a larger space above the ceiling can be secured.

[0008] As a reference example of the ceiling structure of the present invention, the support structure is characterized by comprising steel beam members (e.g., beam members 30A and 30B described below) arranged in a lattice pattern in a plan view and friction-welded to the steel beams, vertical members (e.g., vertical member 31 described below) extending downward from the beam members, connecting members (e.g., intermediate connecting member 32 and lower connecting member 33 described below) connecting the vertical members to each other, braces (e.g., brace 34 described below) extending at an angle to the horizontal and connecting the beam members, the vertical members, and the connecting members to each other, and ceiling support members (e.g., ceiling support member 35 described below) arranged at predetermined intervals on the underside of the connecting members.

[0009] In conventional suspended ceilings, vertical members must be installed at a fine pitch of about 900 mm, and the placement of these vertical members requires the installation of a large number of braces. However, according to this invention, the support structure installed in the attic space is composed of steel beam members made of steel materials such as H-shaped steel and angle steel, vertical members, connecting members, and braces (quasi-structure). This eliminates the need to install vertical members and braces at a fine pitch as in the past, and improves the degree of freedom in designing the attic space. In addition, by using various shapes for the support structure that is connected to the steel beams that form the structural frame, even if the ceiling surface is sloped, it is possible to secure a large space above the ceiling while firmly supporting the ceiling surface material. In addition, for example, through holes are drilled in the webs of the steel beams, and high-strength bolts are inserted into the through holes to frictionally fasten the support structure to the webs of the steel beams. This eliminates the need to use firearms when installing the support structure, preventing fires during construction. Furthermore, because no cross-sectional defects occur in the flanges of the steel beams, the bending strength of the steel beams can be prevented from decreasing. In addition, the support structure is integrated with the web of the steel beam by friction welding. This allows the support structure to be attached higher than when it is attached to the bottom flange of the steel beam, which means the ceiling surface material supported by the support structure can be placed at a higher height, ensuring a larger interior space from the floor to the ceiling surface material.

[0010] No.2 The method for constructing a ceiling structure of the invention is as follows: The existing ceiling structure having the existing steel beams and existing sub-beams is renovated to the new claim 1. A method for constructing a ceiling structure comprising: The method includes the steps of forming through holes in the webs of the existing steel girder and the existing sub-girder, inserting high-strength bolts into the through holes, and tightening nuts to frictionally join the webs of the existing steel girder and the existing sub-girder to the support structure, and attaching the ceiling underlayment material and the ceiling surface material to the underside of the support structure, wherein in the step of frictionally joining the existing steel girder and the existing sub-girder to the support structure, the end of the beam member is frictionally joined to the web of the existing steel girder with the high-strength bolt and the nut, and the middle part of the beam member is placed in contact with the bottom flange of the sub-girder and frictionally joined to the web of the sub-girder with the high-strength bolt and the nut via a pair of joining members, thereby rigidly joining the support structure to the existing steel girder and the sub-girder. It is characterized by:

[0011] According to this invention, through holes are formed in the webs of existing steel beams, high-strength bolts are inserted into these through holes, and the support structure is friction-joined to the existing steel beams using these high-strength bolts and nuts, making it easy to renovate existing ceiling structures. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a ceiling structure and a method for constructing the same that can prevent the ceiling from falling off during an earthquake while ensuring a large space above the ceiling. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a plan view of a ceiling structure according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of the ceiling structure of FIG. 1. [Figure 3] FIG. 2 is a cross-sectional view of the ceiling structure of FIG. 1 taken along line II-II. [Figure 4] 4 is an enlarged view of a portion surrounded by dashed line A in FIGS. 1 to 3 and a cross-sectional view taken along the line III-III. [Figure 5] FIG. 3 is an enlarged view of the area surrounded by the dashed line B in FIGS. 1 and 2. [Figure 6] FIG. 6 is a cross-sectional view taken along line IV-IV of FIG. 5. [Figure 7] FIG. 3 is an enlarged view of the area surrounded by the dashed line C in FIG. 2. [Figure 8] FIG. 8 is a cross-sectional view of FIG. 7 . [Figure 9] 1 is a flowchart of a procedure for renovating an existing ceiling structure and constructing a new ceiling structure. [Figure 10] FIG. 1 is a cross-sectional view showing an existing ceiling structure. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present invention is a ceiling structure in which a support structure is friction-joined to the web of a steel beam using high-strength bolts and nuts, and a ceiling underlayment and ceiling surface material are attached to the underside of the support structure. Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a plan view of a ceiling structure 1 according to one embodiment of the present invention. Fig. 2 is a cross-sectional view of the ceiling structure 1 taken along line II in Fig. 1. Fig. 3 is a cross-sectional view of the ceiling structure 1 taken along line II-II in Fig. 1. The ceiling structure 1 comprises existing steel beams 10, which are H-shaped steel beams that support a floor slab 2, a steel support structure 11 joined to the existing steel beams 10, a joist 12 as a ceiling base material provided on the underside of the support structure 11, and gypsum board 13 as a ceiling surface material attached to the underside of the joist 12. The space between the floor slab 2 and the gypsum board 13 as the ceiling surface material forms an attic space 3.

[0015] The existing steel beam 10 includes existing steel girders 20A and 20B and an existing steel-framed sub-girder 21 provided between the existing steel girders 20A. Here, the steel girders 20A are beams that extend in the X direction, and the steel girders 20B are beams that extend in the Y direction. The steel girders 20A, 20B, and sub-girders 21 are each H-shaped steel and include upper and lower flanges 22 and a web 23 that connects the upper and lower flanges 22 together (see FIGS. 4 to 6).

[0016] The support structure 11 comprises beam members 30A and 30B made of H-shaped steel as steel material arranged in a lattice pattern in a plan view and joined to the steel beam 10, vertical members 31 made of H-shaped steel as steel material extending downward from the beam members 30A and 30B, intermediate connecting members 32 made of channel steel as steel material connecting the middle portions of the vertical members 31, lower connecting members 33 made of H-shaped steel as steel material connecting the lower ends of the vertical members 31, braces 34 made of angle steel as steel material extending at an angle to the horizontal and connecting the beam members 30A and 30B, the vertical members 31, and connecting members 32 and 33 to each other, and ceiling support members 35 made of channel steel as steel material provided on the underside of the lower connecting members 33.

[0017] The beam member 30A is a member extending in the X direction, and the beam member 30B is a member extending in the Y direction. One end of the beam member 30A is joined to the web 23 of the steel girder 20B. Both ends of the beam member 30B are joined to the webs 23 of the steel frame main girder 20A. Also, the middle part of the beam member 30B is joined to the webs 23 of the sub-girders 21. Each of the beam members 30A and 30B is made up of upper and lower flanges 36 and a web 37 that connects the upper and lower flanges 36 together (see FIGS. 4 to 6).

[0018] Fig. 4(a) is an enlarged view of a portion surrounded by dashed line A in Fig. 1 to Fig. 3. Fig. 4(b) is a cross-sectional view taken along III-III in Fig. 4(a). Joint members 40 are attached to the ends of the beam members 30A and 30B, and these joint members 40 are friction-joined to the webs 23 of the steel girder 20B. The upper and lower flanges 36 have been removed from the ends of the beam members 30A and 30B, leaving only webs 37. The connecting member 40 includes a plate-shaped base 41 that is joined to the webs 23 of the steel girders 20A and 20B, and a plate-shaped beam connecting portion 42 that extends substantially perpendicularly from the base 41 and is joined to the webs 37 of the beam members 30A and 30B. The beam joint portion 42 of the joint member 40 is joined to the webs 37 of the beam members 30A and 30B by high-strength bolts 43 and nuts 44. Through holes 24 are formed in the webs 23 of the steel girders 20A and 20B. Through holes 45 are formed in the bases 41 of the connecting members 40. By inserting high-strength bolts 46 into the through holes 24 of the steel girders 20A and 20B and the through holes 45 of the connecting members 40 and tightening nuts 47, the connecting members 40 are friction-joined to the steel girders 20A and 20B.

[0019] Fig. 5 is an enlarged view of a portion surrounded by dashed line B in Fig. 1 and Fig. 2. Fig. 6 is a cross-sectional view taken along line IV-IV in Fig. 5. A pair of connecting members 50 are attached to the middle portion of the beam member 30B, and the pair of connecting members 50 are frictionally joined to the webs 23 of the sub-beams 21. A pair of joining plates 38 are provided on the upper surface of the upper flange 36 in the middle part of the beam member 30A. The pair of connecting members 50 are arranged on either side of the web 23 of the sub-beam 21. Each connecting member 50 includes a plate-shaped base 51 that is connected to the web 23 of the sub-beam 21, and a plate-shaped beam connecting portion 52 that extends substantially perpendicularly from the base 51 and is connected to the connecting plate 38 of the beam member 30A. The beam joint portion 52 of the joint member 50 is joined to the joint plate 38 of the beam member 30A by a high-strength bolt 53 and a nut 54. A through hole 25 is formed in the web 23 of the sub-beam 21. A through hole 55 is formed in the base 51 of the connecting member 50. The connecting members 50 are friction-joined to the sub-beam 21 by inserting high-strength bolts 56 into the through holes 25 of the sub-beam 21 and the through holes 55 of the pair of connecting members 50 and tightening nuts 57.

[0020] Fig. 7 is an enlarged view of a portion surrounded by a dashed line C in Fig. 2. Fig. 8 is a cross-sectional view taken along line VV in Fig. 7. The ceiling support members 35 are provided at predetermined intervals in the Y direction and extend in the X direction. The joists 12 are provided at predetermined intervals in the X direction and extend in the Y direction. The joists 12 are fixed to the ceiling support material 35 with metal fittings (not shown). The gypsum boards 13 are fixed to the joists 12 with screws (not shown).

[0021] The procedure for renovating an existing ceiling structure 60 and constructing a new ceiling structure 1 will be described below with reference to the flowchart of FIG. In the initial state, as shown in FIG. 10, in the ceiling space 61 of the existing ceiling structure 60, a fire-resistant covering material 62 is applied to the existing steel beams 10. In step S1, the existing ceiling structure 60 is dismantled. At this time, the fire-resistant covering material 62 of the existing steel beam 10 is removed from the portion where the beam members 30A and 30B of the support structure 11 are joined, exposing the web 23 of the existing steel beam 10. In step S2, the support structure 11 is constructed. Specifically, through holes 24, 25 are formed in the webs 23 of the steel girders 20A, 20B and the sub-girders 21, and high-strength bolts 46, 56 are inserted into the through holes 24, 25 and nuts 47, 57 are tightened to frictionally join the webs 23 of the steel girders 20A, 20B and the sub-girders 21 to the beam members 30A, 30B of the support structure 11. In step S3, horizontal brace materials (not shown) are provided on the underside of the support structure 11, and the rough framing 12 and gypsum board 13 are joined directly to the underside of the support structure 11.

[0022] In the ceiling structure of the present invention, the support structure 11 is friction-welded to the webs 23 of the existing steel beams 10, and the girders 12 and gypsum boards 13 are fixed directly to the support structure 11. This gives the ceiling structure high rigidity, and in the event of an earthquake, the ceiling structure, which is made up of the steel beams that make up the building frame and the support structure, will deform as a whole. Specifically, the natural period of the ceiling structure is designed to be less than 0.1 seconds, which is generally considered to be a rigid ceiling (for example, a vertical ceiling). Furthermore, by friction-joining the support structure 11 to the web 23 of the steel beam 10, the rigidity of the joint between the steel beam 10 and the support structure 11 is increased without reducing the bending strength of the steel beam 10. Furthermore, as shown in Figure 10, existing steel beams 10 are often provided with fire-resistant covering material 62, but the ceiling structure of the present invention can also be applied to steel beams that are not provided with fire-resistant covering material 62.

[0023] According to this embodiment, the following effects are obtained. (1) The steel beams 10, which form the structural frame, and the supporting structure 11 are integrated with friction joints, and the underside of the supporting structure 11 is provided with a joist 12 and gypsum board 13. Therefore, the structural frame, consisting of the steel beams 10, supporting structure 11, joist 12, and gypsum board 13, deforms as a unit to resist horizontal forces during an earthquake. This allows the ceiling space 3 to be large, while suppressing damage to the components that make up the ceiling during an earthquake and preventing the ceiling from falling off. Furthermore, through holes 24, 25 are provided in the web 23 of the steel beam 10, and high-strength bolts 46, 56 are inserted into these through holes 24, 25. The beam members 30A, 30B of the support structure 11 are friction-joined to the web 23 of the steel beam 10 by the high-strength bolts 46, 56 and nuts 47, 57. This eliminates the need to use firearms when installing the support structure 11, preventing the outbreak of a fire during construction. Furthermore, since no cross-sectional loss occurs in the flanges 22 of the steel beam 10, a reduction in the bending strength of the steel beam 10 can be prevented. In addition, the support structure 11 is integrated with the web 23 of the steel beam 10 by friction welding. Therefore, the support structure 11 is attached higher than when the support structure is attached to the bottom flange of the steel beam, so the height of the gypsum board 13 as the ceiling surface material supported by the support structure 11 can be raised, ensuring a large indoor space from the floor to the ceiling surface material.

[0024] (2) The support structure 11 provided in the attic space 3 is composed of beam members 30A, 30B, vertical members 31, connecting members 32, 33, braces 34, and ceiling support members 35, all of which are made of steel materials such as H-shaped steel and angle steel (quasi-structure). This eliminates the need to install vertical members and braces at a fine pitch as in the past, improving the design freedom of the attic space 3. Furthermore, by making the support structure 11 that is joined to the steel beams 10, which are the structural body, into various shapes, even if the ceiling surface is sloped, it is possible to secure a large space above the ceiling 3 while firmly supporting the gypsum board 13, which is the ceiling surface material. (3) The fire-resistant covering material 62 of the existing steel beam 10 is partially removed to expose the web 23, and the beam members 30A and 30B of the support structure 11 are friction-joined to this exposed web 23 with high-strength bolts 46 and 56, so that the existing ceiling structure 60 can be easily renovated.

[0025] The present invention is not limited to the above-described embodiment, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention. For example, in the above-described embodiment, the support structure 11 is configured from beam members 30A, 30B made of H-shaped steel, vertical members 31 made of H-shaped steel, intermediate connecting members 32 made of channel steel, lower connecting members 33 made of H-shaped steel, braces 34 made of angle steel, and ceiling support members 35 made of channel steel, but this is not limitative and braces 34 may not be provided. Furthermore, the shape of the steel material for each component (beam members, vertical members, intermediate connecting members, lower connecting members, braces, ceiling support members) is not particularly limited, and steel materials of various shapes may be used. Furthermore, in the above embodiment, the upper and lower flanges 36 are removed from the ends of the beam members 30A and 30B, leaving only the webs 37, but this is not limitative, and the flanges do not have to be removed. [Explanation of symbols]

[0026] 1...Ceiling structure 2...Floor slab 3...Attic space 10...Steel beam 11...Support structure 12...Rough frame (ceiling underlayment material) 13...Gypsum board (ceiling surface material) 20A...Steel beam extending in the X direction 20B...Steel beam extending in the Y direction 21... Beam 22... Flange 23... Web 24, 25... Through-hole 30A...Beam member extending in the X direction 30B...Beam member extending in the Y direction 31...Vertical member 32...Intermediate connecting member 33...Lower connecting member 34...Brace 35...Ceiling support member 36...Flange 37...Web 38...Connection plate 40...Connection member 41...Base 42...Beam connection portion 43...High-strength bolt 44...Nut 45...Through hole 46...High strength bolt 47...Nut 50... Joint member 51... Base 52... Beam joint 53... High-strength bolt 54... Nut 55... Through hole 56... High strength bolt 57... Nut 60...Existing ceiling structure 61...Attic space 62...Fireproof covering material

Claims

1. A new ceiling structure that renovates an existing ceiling structure, an existing steel beam that is arranged in contact with the underside of the floor slab and supports the floor slab, and that includes an existing steel beam and an existing sub-beam provided between the existing steel beams; a steel support structure in which high-strength bolts are inserted into through holes formed in the webs of the existing steel girder and the existing sub-girder, and the support structure is friction-connected to the existing steel girder and the existing sub-girder by the high-strength bolts and nuts; A ceiling base material provided on the underside of the support structure; a ceiling surface material attached to the underside of the ceiling base material, The steel support structure is arranged in a lattice shape in a plan view, and is configured to include beam members made of H-shaped steel arranged at the top, vertical members made of H-shaped steel extending downward from the beam members, lower connecting members made of H-shaped steel connecting the vertical members, and ceiling support members provided at predetermined intervals on the underside of the lower connecting members, The end of the beam member is friction-connected to the web of the existing steel frame main girder by the high-strength bolt and the nut, and the middle part of the beam member is disposed in contact with the bottom flange of the sub-girder and friction-connected to the web of the sub-girder by the high-strength bolt and the nut via a pair of connecting members, A ceiling structure characterized in that the supporting structure is rigidly connected to the existing steel beams and sub-beams by friction joints.

2. A method for constructing a new ceiling structure according to claim 1 by renovating an existing ceiling structure having existing steel beams and existing sub-beams, forming through holes in the webs of the existing steel girder and the existing sub-girder, inserting high-strength bolts into the through holes, and tightening nuts to frictionally join the webs of the existing steel girder and the existing sub-girder to the support structure; and attaching the ceiling underlayment and the ceiling surface material to the underside of the support structure, In the step of friction-joining the existing steel main girder and the existing secondary beams to the supporting structure, the end of the beam member is friction-joined to the web of the existing steel main girder using the high-strength bolt and the nut, and the middle portion of the beam member is positioned in contact with the bottom flange of the secondary beam and friction-joined to the web of the secondary beam using the high-strength bolt and the nut via a pair of connecting members, thereby rigidly joining the supporting structure to the existing steel main girder and the secondary beam. This is a method for constructing a ceiling structure.

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