Lightning protection structure

Abstract

The objective is to provide a lightning protection structure that can protect a building with wooden pillars around its perimeter from lightning without compromising its aesthetic design. [Solution] A lightning protection structure 10 provided for a building 1 having a main body 23 comprising wooden poles 21 arranged on the outer perimeter of the building 1 and steel columns 22 arranged inside the wooden poles 21, wherein the lightning protection structure 10 is characterized by having a lightning receiving unit 11 installed on the rooftop 1c of the building 1 and a connecting unit 13 that electrically connects the lightning receiving unit 11 and the steel columns 22, and is configured to allow the lightning current received by the lightning receiving unit 11 to flow through the steel columns 22 into the ground 2.

Description

Technical Field

[0001] The present invention relates to a lightning protection structure provided in a building.

Background Art

[0002] In buildings having a height of a predetermined height or more such as office buildings, a lightning protection structure is provided to protect the building from lightning strikes (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a steel-frame building, the lightning protection structure is generally configured such that a lightning receiving part installed on the roof of the building is connected to a steel column arranged on the outer peripheral part of the building, and the lightning current received by the lightning receiving part flows into the ground through the steel column.

[0005] On the other hand, in recent years, a building has been developed in which a wooden column is used as a column arranged on the outer peripheral part of the building while the basic structure of the building body is made of steel frame, and the design quality is enhanced by making use of the texture of the wooden column in the appearance of the building.

[0006] However, in a building using a wooden column as a column on the outer peripheral part of the building, since the lightning receiving part cannot be connected to the non-electrically conductive wooden column, it is necessary to attach a metal exterior member or a conducting wire for flowing the lightning current received by the lightning receiving part into the ground to the outer surface of the building, and there is a problem that the design quality of the appearance of the building is impaired.

[0007] This invention has been made in view of these problems, and its purpose is to provide a lightning protection structure that can protect a building with wooden pillars arranged around its perimeter from lightning without impairing its aesthetic appearance. [Means for solving the problem]

[0008] The present invention provides a lightning protection structure for a building having a main structure comprising wooden pillars arranged on the outer perimeter of the building and steel pillars arranged inside the wooden pillars, wherein the structure includes a lightning receiving unit installed on the roof of the building and a connecting unit that electrically connects the lightning receiving unit and the steel pillars, and is configured to allow the lightning current received by the lightning receiving unit to flow into the ground through the steel pillars.

[0009] In the lightning protection structure of the present invention, it is preferable that the connecting portion is a steel beam joined to the steel column and the wooden column. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a lightning protection structure that can protect a building with wooden pillars arranged around its perimeter from lightning without compromising the aesthetic design of its appearance. [Brief explanation of the drawing]

[0011] [Figure 1] This is a diagram showing the building frame structure equipped with a lightning protection structure according to one embodiment of the present invention. [Figure 2] Figure 1 is a plan view of the structural frame. [Figure 3] This is a diagram showing the lightning strike mechanism. [Figure 4] This diagram shows the flow of lightning current from the lightning receiving unit to the ground in the building shown in Figure 1. [Modes for carrying out the invention]

[0012] The following describes in detail an embodiment of a lightning protection structure, with reference to the drawings.

[0013] The building 1 shown in Figures 1 and 2 is to which a lightning protection structure 10 according to one embodiment of the present invention is applied. Building 1 is used, for example, as an office building and has multiple floors. Note that in Figures 1 and 2, only the structural frame 20 of building 1 is shown, and the floor slabs, exterior walls, etc. of building 1 are omitted.

[0014] As shown in Figure 1, in this embodiment, the building 1 has a lower floor section 1a (the section from the 1st to the 3rd floor above ground) supported by a plurality of pile foundations 3 constructed underground 2, and an upper floor section 1b (the section from the 4th to the 8th floor above ground) constructed on top of the lower floor section 1a. As shown in Figure 2, in a plan view, the upper floor section 1b (the section enclosed by hatched wooden beams 24) has a smaller area than the lower floor section 1a.

[0015] Furthermore, the number of floors in building 1 to which the lightning protection structure 10 is applied is not particularly limited. Also, the shape of building 1 to which the lightning protection structure 10 is applied is not particularly limited, such as having the upper floor portion 1b and the lower floor portion 1a having the same area in a plan view.

[0016] The structural frame 20 of building 1 has a main frame section 23 which includes wooden columns 21 arranged on the outer perimeter of building 1 and steel columns 22 arranged inside the wooden columns 21. The wooden columns 21 are made of wood.

[0017] Although not shown in detail, the wooden columns 21 positioned around the perimeter of building 1 are visible from the outside of building 1. As a result, the upper floor portion 1b of building 1 has a highly aesthetic appearance that takes advantage of the texture of the wooden columns 21. Furthermore, by having a main structural body 23 with steel columns 22 positioned inward from the wooden columns 21, building 1 can achieve the desired strength in its structural body 20 even when the columns on the perimeter are made of wooden columns 21 to enhance the aesthetic appearance.

[0018] As shown in Fig. 2, in this embodiment, a plurality (14) of wooden columns 21 are arranged around the entire perimeter of the outer peripheral portion of the upper floor part 1b of the building 1. More specifically, among the columns in the outer peripheral portion of the upper floor part 1b of the building 1, all the columns from the rooftop 1c of the building 1 to the middle of the 5th floor are wooden columns 21. Also, in this embodiment, all the beams joined to adjacent wooden columns 21 and arranged on the outer peripheral portion of the upper floor part 1b of the building 1 are wooden beams, that is, wooden beams 24. Thus, in this embodiment, the building structure 20 in the outer peripheral portion from the rooftop 1c to the middle of the 5th floor of the upper floor part 1b of the building 1 is wooden. Thereby, the design property of the appearance of the upper floor part 1b of the building 1 is further enhanced.

[0019] In this embodiment, six steel columns 22 constituting the building structure body part 23 are provided inside the wooden columns 21. As shown in Fig. 1, each steel column 22 extends from the rooftop 1c to the ground floor 4 and is supported by the corresponding pile foundation 3. Also, as shown in Figs. 1 and 2, all the beams joined between each steel column 22 and the wooden column 21 and between adjacent steel columns 22 are steel beams 25.

[0020] Also, the building structure body part 23 has steel columns 26 joined to the lower ends of the wooden columns 21 respectively to support the wooden columns 21. These steel columns 26 also extend to the ground floor 4 respectively and are supported by the corresponding pile foundation 3. Furthermore, the building structure body part 23 also has steel columns 27 on the outer peripheral portion of the part that projects horizontally from the lower floor part 1a to the upper floor part 1b. These steel columns 27 also extend to the ground floor 4 respectively and are supported by the corresponding pile foundation 3. Moreover, all the beams joined to adjacent steel columns 22, 26, 27 of the building structure body part 23 are steel beams 28.

[0021] Note that the steel columns 22, 26, 27 constituting the building structure body part 23 are not limited to steel structures such as square steel pipes, and may also be concrete-filled steel pipes (CFT).

[0022] The lightning protection structure 10 is provided in the building 1 to protect the building 1 from lightning strikes. As shown in FIG. 1, the lightning protection structure 10 has a lightning receiving part 11 installed on the rooftop 1c of the building 1. The lightning receiving part 11 is the part that receives lightning.

[0023] As shown in FIG. 3, in this embodiment, the lightning receiving part 11 is a conducting wire supported by a support 12 and installed along the upper surface of a parapet 1d provided along the outer peripheral part of the rooftop 1c of the building 1 along the parapet 1d. Although not shown in detail, the lightning receiving part 11 is electrically connected to the uppermost steel frame beam 25 that constitutes the main body part 23 of the structure.

[0024] Note that the lightning receiving part 11 is not limited to a conducting wire installed along the parapet 1d, and may have various configurations as long as it can receive lightning, such as a lightning rod installed on the rooftop 1c.

[0025] As shown in FIG. 1, the lightning protection structure 10 has a connection part 13 that electrically connects the lightning receiving part 11 and the steel frame column 22. In this embodiment, the connection part 13 is a steel frame beam 25 joined to the steel frame column 22 and the wooden column 21. That is, the lightning receiving part 11 is electrically connected to the steel frame column 22 via the steel frame beam 25 which is the connection part 13.

[0026] Note that in this embodiment, the connection part 13 is constituted by the steel frame beam 25 joined to the steel frame column 22 and the wooden column 21, but it is not limited to this. For example, it may be constituted by a conducting wire electrically connected to the lightning receiving part 11 and the steel frame column 22, and other configurations may also be possible as long as they can electrically connect the lightning receiving part 11 and the steel frame column 22.

[0027] As shown in FIG. 4, the lightning protection structure 10 according to this embodiment having the above configuration is configured such that the lightning current received by the lightning receiving part 11 installed on the rooftop 1c of the building 1 flows into the ground 2 through the steel frame column 22 (main body part 23 of the structure). In FIG. 4, the thick arrow indicates the flow of the lightning current.

[0028] In other words, when the lightning striker 11 installed on the rooftop 1c of building 1 is struck by lightning, the lightning current flows from the lightning striker 11 through the steel beam 25, which is the connecting part 13, to the steel column 22, which is located inside building 1, below the wooden pole 21. Although lightning current has the property of flowing toward the outer perimeter of building 1, in the part where the outer perimeter of building 1 is made up of wooden poles 21, the lightning current cannot flow from the steel column 22 through the steel beam 25 toward the outer perimeter of building 1, and instead flows downward along the steel column 22. Then, the lightning current that has flowed down the steel column 22 below the lower end of the wooden pole 21 flows through the steel beam 28 below the wooden pole 21 to the steel column 26 on the outer perimeter of building 1. Then, the lightning current that has flowed through the steel column 26 on the left side in Figure 4 flows from the lower end of the steel column 26 into the ground 2. Furthermore, in Figure 4, the lightning current that flows through the steel column 26 on the right side flows through the steel beam 28 extending from the upper floor section 1b to the steel column 27, and then flows into the ground 2 from the lower end of the steel column 27.

[0029] Furthermore, in the case where wooden poles 21 are arranged around the perimeter of all floors from the rooftop 1c to the ground floor 4 of the building 1, the lightning current received by the lightning receiving unit 11 should be directed to the ground 2 only through the steel poles 22 located inside the wooden poles 21.

[0030] Thus, in the lightning protection structure 10 according to this embodiment, in the portion where wooden poles 21 are arranged around the outer perimeter of the building 1, the lightning current received by the lightning receiving unit 11 is directed to the ground 2 through steel columns 22 located inside the building 1, without flowing through the outer perimeter of the building 1. This allows the building 1 to be protected from lightning while maintaining a high level of aesthetic appeal using wooden poles 21.

[0031] Furthermore, in the lightning protection structure 10 according to this embodiment, the connection part 13 is a steel beam 25 joined to the steel column 22 and the wooden column 21. Therefore, without wiring separate conductors or the like for the connection part 13, the lightning current received by the lightning receiving part 11 can be transmitted to the steel column 22 with a simple configuration that only requires grounding the lightning receiving part 11 to the steel beam 25. This simplifies the configuration of the lightning protection structure 10 and reduces its cost.

[0032] The present invention is not limited to the embodiments described above, and it goes without saying that various modifications are possible without departing from the spirit of the invention. [Explanation of Symbols]

[0033] 1. Building 1a Lower floor part 1b Upper floor part 1c Rooftop 1d Parapet 2 underground 3. Pile foundation 4 Ground 10 Lightning protection structure 11 Lightning receiver 12 Support 13 Connection part 20 Frame structure 21 wooden pillar 22 Steel columns 23 Main body of the frame 24 Wood beam 25 Steel beam 26 Steel columns 27 Steel columns 28 Steel beam

Claims

1. A lightning protection structure provided for a building having a main frame with wooden columns arranged on the outer perimeter of the building and steel columns arranged inside the wooden columns, A lightning striker installed on the roof of the aforementioned building, It has a connection part that electrically connects the lightning receiving part and the steel column, A lightning protection structure characterized in that it is configured to channel the lightning current received by the lightning receiving section into the ground through the steel column.

2. The lightning protection structure according to claim 1, wherein the connecting portion is a steel beam joined to the steel column and the wooden column.

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