Vibration-damping truss frame and vibration control method

Abstract

To provide a vibration-damping truss frame that can effectively suppress vertical vibrations of the floor structure. [Solution] The vibration-damping truss frame 10 supports the rooftop floor 201 of the building 20. The vibration-damping truss frame 10 comprises a plurality of main trusses 1 arranged in parallel, vibration-damping trusses 2 arranged in a direction intersecting the main trusses 1 and joined to the plurality of main trusses 1, and an oil damper 3 provided on the lower chord member 22 of the vibration-damping truss 2 at the center of the vibration-damping truss 2 in the span direction.

Description

Technical Field

[0001] The present invention relates to a vibration-damping truss frame, a vibration control method using the same, and the like. Background Art

[0002] In a flat-roofed building having a large column-free space inside, when the roof floor is used as an athletic park, an event space, or the like, standing vibration (vertical vibration) occurs when a large number of people jump simultaneously on the roof floor, which may cause discomfort to other users on the roof and users inside the building.

[0003] As a method for suppressing such vertical vibration, it is conceivable to provide a TMD (tuned mass damper) on the roof frame to exert a vibration damping effect against vertical vibration. For example, Patent Document 1 describes a method of configuring a TMD using a catwalk supported by a roof frame as a weight portion. Prior Art Documents Patent Documents

[0004] Patent Document 1 Japanese Unexamined Patent Publication No. 2023-83921 Summary of the Invention Problems to be Solved by the Invention

[0005] In the above-described TMD, adjustment is initially performed in accordance with the natural frequency of the roof frame. However, if the natural frequency changes due to a change in the loaded load of the roof frame, a change in rigidity over time, or the like, the vibration damping effect may be reduced. In addition, the method of Patent Document 1 has a problem that it cannot be adopted in buildings that do not have a catwalk serving as a weight portion.

[0006] The present invention has been made in view of the above problems, and an object thereof is to provide a vibration-damping truss frame or the like that can effectively suppress vertical vibration of a floor body. Means for Solving the Problems

[0007] The first invention for solving the above problems is a vibration-damping truss frame that supports the floor of a building, comprising: a plurality of first trusses arranged in parallel; a second truss arranged in a direction intersecting the first trusses and joined to the plurality of first trusses; and a damping member provided on the lower chord of the second truss at the center of the second truss in the span direction.

[0008] In the vibration-damping truss frame of the present invention, by supporting the floor body with a truss, rigidity can be increased with a small amount of steel, thereby suppressing vertical vibrations of floor bodies such as rooftop floors. Furthermore, by providing a damping member on the second truss, vibration energy can be absorbed by utilizing the deformation of the second truss during vertical vibrations of the floor body. In this invention, by using a damping member instead of a TMD, vertical vibrations can be effectively suppressed even if there are changes in the live load of the vibration-damping truss frame or changes in rigidity due to aging, and special configurations such as using a catwalk as a weight are not required. In addition, the damping member is provided on the lower chord member at the center in the span direction where the deformation of the second truss is greatest during vertical vibrations of the floor body, so that vibration energy can be absorbed efficiently.

[0009] It is preferable that the second truss be provided in the central part of the first truss in the span direction. As a result, the damping member is placed in the center of the plane of the vibration-damping truss frame, where deformation tends to be large during vertical vibrations of the floor body, thus effectively suppressing vertical vibrations of the floor body.

[0010] The second truss has a triangular corrugated diagonal member connecting the upper chord and the lower chord, and it is desirable that one damping member be provided on each side of the joint between the diagonal member and the lower chord. By using two damping members, the extension length, and thus the vibration absorption effect, can be doubled. Furthermore, by installing one damping member on each side of the joint between the diagonal member and the lower chord member, it is possible to accommodate the vertical vibrations of higher-order modes of the floor body where the joint acts as a node.

[0011] The second invention is a vibration control method for a floor supported by a vibration-damping truss frame, wherein the vibration-damping truss frame comprises a plurality of first trusses arranged in parallel, a second truss arranged in a direction intersecting the first trusses and joined to the plurality of first trusses, and a damping member provided on the lower chord of the second truss at the center of the second truss in the span direction, and the vibration control method is characterized by damping the vertical vibration of the floor using the damping member. The second invention is a vibration control method using the vibration-damping truss frame of the first invention. [Effects of the Invention]

[0012] The present invention provides a vibration-damping truss frame and the like that can effectively suppress vertical vibrations of a floor. [Brief explanation of the drawing]

[0013] [Figure 1] A diagram showing the vibration-damping truss frame 10. [Figure 2] A diagram showing the central part of the vibration-damping truss 2 in the span direction. [Figure 3] A schematic diagram showing the deflection of a vibration-damping truss 2, etc. [Figure 4] An example where the oil damper 3 is installed in a different location. [Modes for carrying out the invention]

[0014] Preferred embodiments of the present invention will be described in detail below with reference to the drawings.

[0015] Figure 1 shows a vibration-damping truss frame 10 according to an embodiment of the present invention. The vibration-damping truss frame 10 of this embodiment is used in a building 20 with a flat roof. The vibration-damping truss frame 10 is installed on the underside of the rooftop floor 201 of the building 20 and supports the rooftop floor 201. The rooftop floor 201 is a floor made of concrete slab, but is not limited to this.

[0016] A sports park, an event space, and the like are provided on the rooftop floor 201. The vibration-damping truss frame 10 of the present embodiment suppresses vertical vibration of the rooftop floor 201 generated by users on the rooftop.

[0017] The vibration-damping truss frame 10 includes a main truss 1 (a first truss), a vibration-damping truss 2 (a second truss), an oil damper 3, a secondary beam 4, and the like.

[0018] The main truss 1 is a truss-shaped steel beam, and includes an upper chord member 11, a lower chord member 12, a diagonal member 13, and the like. The main truss 1 is formed using a steel frame material such as JIS rolled H-section steel with stable quality. The building 20 has a rectangular planar shape, and the main truss 1 is provided along the short-side direction of the building 20.

[0019] The upper chord member 11 and the lower chord member 12 are horizontal members disposed vertically apart from each other. The diagonal members 13 are each disposed to be inclined with respect to the vertical direction, and the upper chord member 11 and the lower chord member 12 are connected by the plurality of diagonal members 13. These diagonal members 13 are disposed in a triangular wave shape as a whole.

[0020] A plurality of main trusses 1 are arranged in parallel at intervals in the long-side direction of the building 20. Both end portions of each main truss 1 are rigidly joined to outer-perimeter steel frames 202 located at the outer-perimeter portion of the building 20. Note that the frame at the outer-perimeter portion of the building 20 is not limited to a steel structure (the outer-perimeter steel frames 202), and may be another structural type such as a reinforced concrete structure.

[0021] The vibration-damping truss 2 is a truss-shaped steel beam disposed in a direction intersecting the main truss 1, and is formed using a steel frame material such as JIS rolled H-section steel with stable quality, similarly to the main truss 1. In the present embodiment, the vibration-damping truss 2 is disposed in the long-side direction of the building 20, and is orthogonal to the main truss 1 in a plan view. The vibration-damping truss 2 is provided at a central portion in the span direction of the main truss 1. Both end portions of the vibration-damping truss 2 are rigidly joined to the outer-perimeter steel frames 202 of the building 20.

[0022] The vibration-damping truss 2 has an upper chord 21, a lower chord 22, and diagonal members 23. As before, the upper chord 21 and lower chord 22 are horizontal members arranged vertically. The diagonal members 23 are arranged at an angle to the vertical direction, and multiple diagonal members 23 connect the upper chord 21 and the lower chord 22. These diagonal members 23 are arranged in a triangular wave shape as a whole.

[0023] The vibration-damping truss 2 is joined to multiple main trusses 1. Specifically, the upper chord members 21 of the vibration-damping truss 2 are composed of connecting members 211 that connect adjacent upper chord members 11 of main trusses 1, or upper chord members 11 to the outer perimeter steel frame 202, and both ends of the connecting members 211 are joined to the upper chord members 11 of the adjacent main trusses 1, or to the upper chord members 11 and the outer perimeter steel frame 202. Similarly, the lower chord members 22 are composed of connecting members 221 that connect adjacent lower chord members 12 of main trusses 1, or to the lower chord members 12 and the outer perimeter steel frame 202, and both ends of the connecting members 221 are joined to the lower chord members 12 of the adjacent main trusses 1, or to the lower chord members 12 and the outer perimeter steel frame 202. The upper end of the diagonal member 23 is joined to the intersection of the upper chord members 11 and 21, and the lower end of the diagonal member 23 is joined to the lower chord member 22.

[0024] Figure 2 shows the central part of the vibration-damping truss 2 in the span direction. One oil damper 3 is installed on each side of the joint between the lower chord member 22 and the diagonal member 23 in the central part of the vibration-damping truss 2 in the span direction. The oil dampers 3 absorb vibration energy when they expand and contract, and dampen the vertical vibration of the roof floor 201.

[0025] Figures 3(a) and 3(b) schematically show the deflection of the damping truss 2, etc., during vertical vibration of the rooftop floor 201. In Figures 3(a) and 3(b), the deflection of the damping truss 2, etc., is exaggerated for illustrative purposes.

[0026] The vibration-damping truss 2 typically experiences deflection as shown in Figure 3(a) due to vertical vibrations of the rooftop floor 201. Since the deformation (expansion and contraction) of the vibration-damping truss 2 is greatest in the center in the span direction, the oil damper 3 is installed on the lower chord member 22 in the center in the span direction of the vibration-damping truss 2 so as to maximize the expansion and contraction during vertical vibrations of the rooftop floor 201. This allows the oil damper 3 to efficiently absorb vibration energy and effectively dampen vertical vibrations of the rooftop floor 201. Furthermore, two oil dampers 3 are installed, doubling the vibration absorption effect.

[0027] Furthermore, by installing the oil dampers 3 on both sides of the joint between the diagonal members 23 and the lower chord member 22, in accordance with the arrangement of the diagonal members 23 of the vibration-damping truss 2, it is possible to respond to the vertical vibrations of higher-order modes of the rooftop floor 201 where the joint becomes a node, as shown in Figure 3(b).

[0028] Returning to the explanation of Figure 1, the secondary beams 4 are arranged along the long side of the building 20 so as to connect adjacent upper chord members 11 of the main truss 1, or the upper chord members 11 with the outer perimeter steel frame 202. Steel materials such as H-shaped steel are used for the secondary beams 4.

[0029] As described above, in the vibration-damping truss frame 10 of this embodiment, the rooftop floor 201 is supported using trusses such as the main truss 1 and vibration-damping truss 2, thereby increasing rigidity with a small amount of steel and suppressing vertical vibration of the rooftop floor 201. Furthermore, by providing an oil damper 3 on the vibration-damping truss 2, vibration energy can be absorbed by utilizing the deformation of the vibration-damping truss 2 when the rooftop floor 201 vibrates vertically, and resonance can also be prevented. In this embodiment, by using an oil damper 3 instead of a TMD, vertical vibration can be effectively suppressed even if there are changes in the load on the vibration-damping truss frame 10 or changes in rigidity due to aging, and special configurations such as using a catwalk as a weight are not required.

[0030] Furthermore, the oil damper 3 is installed on the lower chord member 22 at the center in the span direction where the deformation of the vibration-damping truss 2 is greatest during vertical vibration of the rooftop floor 201, so that the expansion and contraction during vertical vibration of the rooftop floor 201 is maximized, and thus it can efficiently absorb vibration energy.

[0031] In contrast, as shown in Figure 4(a), it is conceivable to install oil dampers 3 on the diagonal members 23 at the ends of the vibration-damping truss 2, but the efficiency decreases because the expansion and contraction length of the oil dampers 3 during vertical vibration of the rooftop floor 201 becomes small. Alternatively, as shown in Figure 4(b), it is conceivable to install oil dampers 3 like braces between the ends of the lower chord members 22 of the vibration-damping truss 2 and the outer perimeter steel frame 202, or as shown in Figure 4(c), to install oil dampers 3 at the ends of the lower chord members 22 of the vibration-damping truss 2. However, in the examples of Figures 4(b) and 4(c), the rigidity of the outer perimeter steel frame 202 needs to be sufficiently high in order to obtain a high vibration-damping effect.

[0032] Furthermore, in this embodiment, the vibration-damping truss 2 is provided in the central part of the main truss 1 in the span direction, and the oil damper 3 is positioned in the central part of the plane of the vibration-damping truss frame 10, which tends to deform significantly when the rooftop floor 201 vibrates vertically. Therefore, vertical vibrations of the rooftop floor 201 can be effectively suppressed.

[0033] Furthermore, in this embodiment, by providing two oil dampers 3 on the lower chord member 22 of the vibration-damping truss 2, the expansion and contraction length, i.e., the vibration absorption effect, can be doubled. In addition, by installing one oil damper 3 on each side of the joint between the diagonal member 23 and the lower chord member 22, it is possible to respond to higher-order mode vertical vibrations of the rooftop floor 201 where the joint acts as a node. However, this is not the only way, and the vibration-damping truss 2 only needs to have at least one oil damper 3.

[0034] In this embodiment, vertical vibrations are damped by the oil damper 3, but damping members other than the oil damper 3, such as viscoelastic dampers, friction dampers, and rotational inertia tops (RDTs), may also be used. However, the oil damper 3 has the advantage that its damping coefficient and stroke can be easily adjusted to optimize it for the frame structure. It is also possible to make the damping member active by electrical control or semi-active by mechanical control.

[0035] In this embodiment, steel materials such as JIS rolled H-beams were used for the components of the vibration-damping truss 2 (upper chord 21, lower chord 22, diagonal members 23, etc.), but this is not limited to these materials. It is also possible to use sawn timber, laminated timber, LVL (Laminated Veneer Lumber), and other wood materials for the components of the vibration-damping truss 2. In addition, structural plywood, OSB (Oriented Strand Board), CLT (Cross Laminated Timber), and other wood materials can be used as the webs of the components.

[0036] When wood is used as a structural component, creep deformation of the wood may occur, but since the oil damper 3 can follow the progression of creep deformation, this is not considered a problem. Regarding the joints of the wood, it is desirable to minimize play as much as possible in order to reflect the deformation of the vibration-damping truss 2 in the expansion and contraction of the oil damper 3.

[0037] Furthermore, it is possible to make the vibration-damping truss 2 or its constituent members a hybrid structure composed of steel (such as iron) and wood. When making the vibration-damping truss 2 a hybrid structure, it is conceivable to use wood or steel for each constituent member, such as using wood for compression members and steel for tension members. Another example of making the constituent members of the vibration-damping truss 2 a hybrid structure is to make the constituent member a member in which steel is stiffened by wood, such as sandwiching a steel plate between pieces of wood.

[0038] The above is an example of vibration-damping truss 2, but the main truss 1 can also use wood materials for its constituent members, similar to vibration-damping truss 2. Furthermore, the main truss 1 or its constituent members can be made into a hybrid structure of steel and wood, as described above.

[0039] Furthermore, the number and location of the vibration-damping trusses 2 are not limited to those shown in Figure 1. As mentioned above, it is desirable to install the vibration-damping trusses 2 in the central part in the span direction of the main truss 1, but two vibration-damping trusses 2 may be placed parallel to each other in the central part, with the midpoint of the main truss 1 in the longitudinal direction in between.

[0040] Furthermore, in the vibration-damping truss frame 10 of this embodiment, the main truss 1 is provided along the short side direction of the building 20's plan, and the vibration-damping truss 2 is provided along the long side direction. However, conversely, the main truss 1 may be provided along the long side direction of the building 20's plan, and the vibration-damping truss 2 may be provided along the short side direction.

[0041] In this embodiment, the plan of the building 20 is rectangular, but the plan shape of the building 20 is not particularly limited and may be square or circular (elliptical or perfect circle). In any case, the main truss 1 and the damping truss 2 are arranged to intersect.

[0042] Furthermore, while the vibration-damping truss frame 10 of this embodiment is installed in a building 20 where the rooftop floor 201 is used as a sports park or event space, it is not limited to this and can be applied to any building 20 where vertical vibrations may occur on the upper floors, and the upper floor is not limited to the rooftop (rooftop floor 201). The vibration-damping truss frame 10 of this embodiment can be applied to sports facilities such as a gymnasium on the upper floor and a heated swimming pool on the lower floor, or to a complex facility such as a hall where rock concerts and other events are held on the upper floor and a conference room on the lower floor.

[0043] Preferred embodiments of the present invention have been described above with reference to the attached drawings, but the present invention is not limited to these examples. It will be obvious to those skilled in the art that various modifications or alterations can be conceived within the scope of the technical idea disclosed herein, and these will naturally also fall within the technical scope of the present invention. [Explanation of symbols]

[0044] 1: Main truss 2: Vibration-damping truss 3: Oil damper 10: Vibration-damping truss frame 11, 21: Upper chord material 12, 22: Lower chord 13, 23: Diagonal material 20: Building 201: Rooftop floor

Claims

1. A vibration-damping truss frame that supports the floor of a building, Multiple first trusses arranged in parallel, A second truss is arranged in a direction intersecting the first truss and is joined to a plurality of the first trusses, A damping member provided on the lower chord of the second truss at the central part of the second truss in the span direction, A vibration-damping truss frame characterized by having the following features.

2. The vibration-damping truss frame according to claim 1, characterized in that the second truss is provided in the central part of the first truss in the span direction.

3. The second truss has triangular corrugated diagonal members that connect the upper chord and the lower chord. The vibration-damping truss frame according to claim 1, characterized in that one damping member is provided on each side of the joint between the diagonal member and the lower chord member.

4. A method for controlling the vibration of a floor structure supported by a vibration-damping truss frame, The aforementioned vibration-damping truss frame is, Multiple first trusses arranged in parallel, A second truss is arranged in a direction intersecting the first truss and is joined to a plurality of the first trusses, A damping member provided on the lower chord of the second truss at the central part of the second truss in the span direction, It is equipped with, A vibration control method characterized by damping the vertical vibration of the floor body using the damping member.

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