JP7837726B2 - Lightweight suspended ceiling structure - Google Patents

Description

Article 30, Paragraph 2 of the Patent Law applies. On May 24, 2021, Ando Corporation opened the completed building to the public at 3180-1, Negishi Ugaiyata, Angyo-ryo, Kawaguchi City, Saitama Prefecture.

This invention relates to a lightweight suspended ceiling structure, and more particularly to a lightweight suspended ceiling structure that can achieve high design flexibility by avoiding specific ceiling structures.

A suspended ceiling that exceeds 6 meters in height, has a horizontal projection area exceeding 200 ^m² , and has a mass of components constituting the ceiling surface exceeding 2 kg/ ^m² , and is installed in a place where people regularly enter, is classified as a "specified ceiling" under the Building Standards Act. Specified ceilings are subject to building permit applications, and the Ministry of Land, Infrastructure, Transport and Tourism Notification No. 771 of 2013 sets out three criteria: (1) specification route, (2) calculation route, and (3) ministerial certification route, and one of these criteria must be met.

Regardless of the route taken, the strength of the ceiling substrate must be greater than that of a typical suspended ceiling, which increases costs and prolongs the application process. This applies not only to ceilings made of surface materials such as boards, but also to linear decorative materials such as louvers. In other words, when calculating the ceiling area, if the area including not only the area of the louvers themselves but also the gaps between the louvers exceeds 200 ^m² , it will be treated as a special type of ceiling.

To avoid the need for specific ceilings, the design must be excluded from the requirements mentioned above, but generally the following countermeasures are employed.
(1) Construction method that does not use a suspended ceiling: The ceiling material is attached directly to the main steel frame, or a trellis steel frame is installed and the ceiling material is attached directly to that steel frame. This can be treated as a semi-structural seismic-resistant ceiling and avoids being classified as a specific type of ceiling.
(2) A construction method that uses ceiling materials with a mass of 2 kg/ ^m² or less: Use non-combustible membrane materials, non-woven fabric panels, or other lightweight ceiling boards (Patent Document 1).

In the lightweight suspended ceiling structure disclosed in Patent Document 1, an inorganic non-combustible insulating foam board with a density of 0.88 kg/ ^m² is used for the ceiling board, resulting in a unit area mass of 1.87 kg/ ^m² for the suspended ceiling, and it is stated that it is possible to achieve a density of 2.0 kg/ ^m² or less.

Utility Model Registration No. 3210534 Publication

The methods described above for avoiding specific ceilings have the following problems:
(1) In order to construct the trellis steel frame that constitutes the semi-structural earthquake-resistant ceiling, construction costs and construction period will increase. In addition, since the trellis steel frame is manufactured in advance in a factory or similar facility in a predetermined shape, it will be difficult to flexibly accommodate changes to the ceiling design.
(2) Due to limitations in the fixing structure of the membrane material, there are limited design variations, and since there are many examples of use in existing facilities, differentiation is not possible. Construction costs will also increase. In the lightweight suspended ceiling structure described in Patent Document 1, it is necessary to paint the ceiling boards after the installation work of the normal ceiling boards, which may increase construction costs and lengthen the construction period.

When designing a louvered ceiling instead of lightweight ceiling boards, square pipes made of common aluminum extruded profiles are often used as louvers. However, in order to satisfy the requirement of having a ceiling material quantity of 2.0 kg/ ^m² or less, which is necessary to avoid the design of a specific type of ceiling, the spacing between the louvers must be quite wide. This results in a problem where, when viewed from above, the ceiling surface is almost completely exposed, with beams and other structural elements visible, creating a dull and uninspired design.

Therefore, the objective of the present invention is to resolve the problems of the conventional technology described above, to provide a lightweight suspended ceiling structure that uses the same joists used as ceiling underlayment as the ceiling decorative material, thereby reducing the weight of the ceiling and avoiding the need for special ceiling treatment, while also enabling the creation of ceiling surfaces with various designs by combining joists of different widths, adjusting the predetermined mounting pitch and arrangement order.

The present invention is characterized in that a louver ceiling is constructed by attaching the double joists and single joists at predetermined intervals to a ceiling base material suspended from the ceiling structure, wherein the double joists are arranged at predetermined adjacent intervals in the longitudinal direction of the ceiling surface so as to cover the entire ceiling surface, and the single joists, whose length is adjusted to form a predetermined geometric shape, are arranged between adjacent double joists, so that a predetermined geometric shape is arranged within the ceiling surface covered by the double joists, thereby forming a louver ceiling that covers the ceiling surface .

The aforementioned ceiling surface is preferably 6 m or more in height from the floor surface and has a horizontal projection area of 200 ^m² or more.

Preferably, the mass of the ceiling surface is 2.0 kg/ ^m² or less by adjusting the spacing between the double and single joists.

The ceiling surface is preferably a louvered ceiling that reflects light shining on the underside of the ceiling joists.

The ceiling surface is preferably a louvered ceiling, where the ceiling structure and the ceiling underlayment are finished in a dark color, creating a contrast between them and the metallic glossy surface of the underside of the numerous linearly arranged joists on its front surface.

By adopting the above-described configuration, the lightweight suspended ceiling structure of the present invention can avoid specific ceiling conditions due to its light weight, reduces the risk of ceiling material falling during major earthquakes, and enhances the aesthetic design of the ceiling surface.

A view from above showing an example of the arrangement of ceiling joists as one embodiment of the lightweight suspended ceiling structure of the present invention. Figure 1 shows a lightweight suspended ceiling structure installed in the atrium area of the building, and a schematic perspective drawing of a portion of the atrium area. Figure 2 shows an overhead view of the lightweight suspended ceiling structure. Figure 3 shows a magnified view of the area within the rectangular frame. A ceiling plan showing an example of the arrangement of each joist and the joist support members that hold each joist, as shown in Figure 1. A magnified partial perspective view showing the suspension and support of the ceiling joists within the parallelogram frame shown in Figure 4.

Hereinafter, an embodiment of the lightweight suspended ceiling structure of the present invention will be described with reference to the attached drawings.

Figure 1 is a view looking up from directly below (the center of the first floor of the atrium 1) of the ceiling surface 11 of the atrium 1, which is constructed as the ceiling surface 11 of the atrium 1 that extends from the first to the third floor within the building shown in Figure 2. The building shown in this example is constructed as a shopping center and has a plan shape in which the store buildings 2 extend in two directions, forming a bend of approximately 115° at the center of the building's plan, with the atrium 1 located at the bend of the building. As shown in Figure 2, the atrium 1, where the circulation routes of the store buildings 2 extending in two directions intersect, has a plaza on the first floor. In addition, handrails 3 are placed on each floor surrounding the atrium 1, creating a corridor that allows customers moving between the stores on each floor to walk around while overlooking the atrium space. On one side of the atrium 1, a large digital signage screen 4 is installed, supported by a steel frame extending from the first floor to the ceiling. An escalator 5, serving as a means of transportation between floors, is located behind it (Figure 2). The images displayed on the digital signage screen 4 can be viewed from the first floor and from the handrails on each floor facing the atrium 1.

The ceiling shape of this atrium 1 is a flat, roughly hexagonal shape, as shown in Figure 1, with a horizontal projection area exceeding 200 ^m² . A large digital signage 4, spanning from the second floor level to the third floor level, is installed on a part of one side at the central position where a protrusion is formed (Figure 2). In Figure 1, the installation positions of the digital signage 4 and the underlying steel frame supporting the digital signage 4 are shown with dashed lines to help understand the positional relationship between the ceiling surface 11 and the digital signage 4.

A louvered ceiling 12, representing one embodiment of the lightweight suspended ceiling structure 10 of the present invention, is installed on the ceiling surface 11 of this atrium 1. As the ceiling decorative material 20 constituting the ceiling surface 11 of the louvered ceiling 12, a double joist 21 covering almost the entire surface 11 along its longitudinal direction, and single joists 22, cut to predetermined lengths and arranged to form a predetermined geometric shape that enhances the design of the louvered ceiling 12, are used.

As shown in Figure 1, the louvered ceiling 12 is divided into a flat, roughly hexagonal shape, and double joists 21 are arranged along the longitudinal direction at equal intervals (300 mm) across the entire ceiling area. Furthermore, single joists 22 of a predetermined length are placed at intermediate positions between adjacent double joists 21. That is, where single joists 22 are placed, the spacing (adjacent) between the double joists 21 and the single joists 22 is 150 mm.

The furring strips used in this embodiment consist of off-the-shelf components made of 0.5 mm thick hot-dip galvanized steel sheets, designated as JIS 19 type CW (double furring strips) and CS (single furring strips 22). The web surfaces of the double furring strips 21 and single furring strips 22 are facing downwards and used as ceiling decorative material 20. The single furring strips 22 are arranged in combination with the double furring strips 21 arranged across the entire ceiling surface 11 so that the mass of the ceiling surface 11 is 2.0 kg/ ^m² or less. This makes it possible to avoid the louver ceiling 12 being treated as a specific type of ceiling.

In this embodiment, the louvered ceiling 12 is designed so that a predetermined geometric shape is formed on the ceiling surface 11 by using single joists 22 of a predetermined length between adjacent double joists 21, with double joists 21 arranged over almost the entire surface of the ceiling 11 as the background. For example, in this embodiment, as shown in Figure 1, the single joists 22 are first arranged to form a large, roughly isosceles triangle with a base of approximately 11m and a height of approximately 10m, with the installation position of the digital signage 4 being the base, at approximately the center of the ceiling surface 11. Furthermore, in order for the overall design of the elongated ceiling surface 11 to be symmetrical with respect to this roughly isosceles triangle portion 12A, two trapezoidal sections 12B are provided on one side, extending from a position corresponding to the hypotenuse 12Aa of the roughly isosceles triangle portion 12A to both ends in the longitudinal direction of the ceiling surface 11, forming a roughly trapezoidal shape 12B with two sides 12Ba and 12Bb parallel to the hypotenuse 12Aa of the roughly isosceles triangle portion 12A. Dimensionally, the single joists 22 are arranged to form a roughly trapezoidal section 12B with a side length of approximately 3.0 m in the longitudinal direction of the ceiling, at a distance of approximately 5.0 m from the position corresponding to the hypotenuse 12Aa of the roughly isosceles triangle section 12A, and to form a roughly trapezoidal section 12C with a side length of approximately 1.2 m in the longitudinal direction of the ceiling, along the edge of the ceiling surface 11. The ceiling mass of the louver ceiling 12 (Figure 1), designed to include each of these geometric shapes (12A, 12B, 12C), is 1.97 kg/ ^m² , which is less than or equal to 2.0 kg/ ^m² , thus avoiding being treated as a specific type of ceiling.

Figure 3 is a top view showing an example of how double joists 21 and single joists 22, arranged in the design shown in Figure 1, are actually installed as a louvered ceiling 12 in a building, for example, as shown in Figure 2. Figure 4 is a top view showing an enlarged view of the square frame (IV) in Figure 3. In the installation examples shown in Figures 3 and 4, the entire area demarcated as the ceiling surface 11, including the underside of the upper floor slab, beams, and ceiling base material 30 (composed of various components such as suspension fittings, suspension bolts, hangers, clips, and joist supports, as described later), is painted in a dark, dark brown color as an example, and the double joists 21 and single joists 22 are attached to the joist supports 31 (Figures 5 and 6) as the ceiling base material 30 at predetermined intervals. Since the double joists 21 and single joists 22 are made of unpainted hot-dip galvanized steel sheets, as shown in Figures 2 to 4, the undersides of each joist, with their metallic sheen and multiple linear lines positioned in front of the dark background, create a high-contrast arrangement. Furthermore, by arranging the single joists 22 within the arrangement of the double joists 21, the geometric shapes of the roughly isosceles triangle section 12A and roughly trapezoidal sections 12B and 12C are formed, resulting in a ceiling surface 11 that stands out. Needless to say, the geometric shapes formed by the single joists 21 can be various shapes other than the roughly isosceles triangles mentioned above, such as trapezoids, rectangles, squares, circles, ovals, ellipses, and randomly changing shapes.

Furthermore, in this embodiment, since the large screen of the digital signage 4 is located below the base of the roughly isosceles triangular section 12A, the various colors of the images displayed on the digital signage 4 screen are reflected by each of the metal joists that make up the ceiling surface 11. Therefore, the ceiling surface 11 forming the roughly isosceles triangular section 12A, composed of double joists 21 and single joists 22, functions as a louvered light ceiling utilizing the reflected light, resulting in a colorful effect.

Figure 5 is a floor plan of the ceiling surface 11, showing an example of the arrangement of the double joists 21 and single joists 22 that constitute the ceiling surface 11 shown in Figure 1, and the joist supports 31 that support each joist. Each joist support 31 is made from a pre-fabricated component processed from 1.2 mm thick hot-dip galvanized steel sheet as a C-shaped steel section. A sufficient number of supports are arranged parallel to the hypotenuse 12Aa of the approximately isosceles triangular section 12A shown in Figure 1, to hold each double joist 21 and single joist 22 in an even balance. They are suspended from the upper floor slab surface (not shown) via suspension bolts 32, which will be described later.

Figure 6 is a schematic partial perspective view showing the suspension state of the double furring strips 21 and single furring strips 22 in the area enclosed by the parallelogram frame (VI) in Figure 5. As shown in the figure, the single furring strips 22, which are of a predetermined length and are uniform, are firmly fixed and held to two furring strip supports 31 suspended from the upper floor slab via known clips 33 and fully threaded suspension bolts 32 of a predetermined bolt diameter, so as to form a substantially trapezoidal shape at the end of the ceiling surface 11, with sides parallel to the sides of the slanted end of the ceiling surface 11. The double furring strips extending in the longitudinal direction of the ceiling surface 11 are also fixed and held to these furring strip supports 31 via known clips 34, similar to the single furring strips 22. Since these double furring strips 21, single furring strips 22, and the members supporting them are common materials used as ordinary ceiling underlayment materials, the installation can be completed by interior decorators with ordinary skills. Therefore, cost reduction and shortening of construction period can be achieved. Furthermore, by varying the size and type of ceiling joists and arranging them in different ways, a wide range of innovative designs becomes possible.

Furthermore, the present invention is not limited to the embodiments described above, and various modifications are possible within the scope of each claim. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included within the technical scope of the present invention.

1. Open space 4. Digital signage 10. Lightweight suspended ceiling structure 11. Ceiling surface 12. Louvered ceiling 20. Ceiling decorative material 21. Double joists 22. Single joists 30. Ceiling base material 31. Joist hanger 32. Suspension bolts.

Claims (3)

A lightweight suspended ceiling structure is characterized in that a combination of double and single joists is attached to a ceiling base material suspended from the ceiling frame, the double joists are arranged at predetermined adjacent intervals in the longitudinal direction of the ceiling surface so as to cover the entire ceiling surface, and the single joists, whose length is adjusted to form a predetermined geometric shape, are arranged between adjacent double joists, so that a predetermined geometric shape is arranged within the ceiling surface covered by the double joists, thereby forming a louvered ceiling that covers the ceiling surface . The lightweight suspended ceiling structure according to claim 1, wherein the ceiling surface has a height of 6 m or more from the floor surface and a horizontal projection area of 200 ^m² or more. The lightweight suspended ceiling structure according to claim 1 or 2, characterized in that the ceiling surface has a mass of 2.0 kg/ ^m² or less, achieved by adjusting the spacing between the double and single joists.