Vibration damping structure and design method for vibration damping structure

Abstract

To provide a vibration control structure allowing stress created through temperature change and vibration upon an earthquake to be reduced.SOLUTION: A vibration control structure comprises: a lower structure 2; a roof part 3 connected to the lower structure 2 and supported with the lower structure 2; a first vibration control device 5 provided on a connection part 4 between the lower structure 2 and the roof part 3; a spring device 6 provided on the connection part 4 between the lower structure 2 and the roof part 3; and a second vibration control device 7 provided on the lower structure 2.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a vibration damping structure and design methods for vibration-damping structures and pertains to it.

Background Art

[0002] Buildings that construct large spaces such as stadiums, arenas, and halls where various sports and events are held, and whose lower structures support roofs with large spans, are known (for example, see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a roof supported by a large span expands and contracts due to temperature changes, there is a problem that large stresses occur in the columns and beams of the lower structure. In addition, since a roof supported by a large span has a smaller weight compared to the lower structure, when an earthquake occurs, it displaces more than the lower structure. As a result, the response acceleration and response shear force of the roof increase, and a large force acts on the lower structure. In order to improve seismic resistance, it is conceivable to install a large number of vibration damping devices in the lower structure. However, buildings such as stadiums construct large spaces and have few spans, so the locations where vibration damping devices can be installed are limited. Furthermore, if a large number of vibration damping devices are installed in the lower structure, there is a problem that it hinders traffic flow planning and the like. [[ID=4I]]<U

[0005] and design methods for vibration damping structures Therefore, an object of the present invention is to provide a vibration damping structure that can reduce the stress caused by temperature changes and the vibrations during an earthquake.

Means for Solving the Problems

[0006] To achieve the above objective, the vibration damping structure according to the present invention comprises a substructure, a roof connected to and supported by the substructure, a first vibration damping device provided at the connection between the substructure and the roof, a spring device provided at the connection between the substructure and the roof, and a second vibration damping device provided on the substructure.

[0007] In this invention, a spring device is provided at the connection between the substructure and the roof, allowing the spring device to absorb deformation caused by expansion and contraction of the roof due to temperature changes. Therefore, the stress generated in the columns and beams of the substructure due to the contraction of the roof due to temperature changes can be reduced. In this invention, the first vibration damping device, spring device, and roof section function as mass dampers, and the first vibration damping device, spring device, and second vibration damping device are set to synchronize with the substructure and roof section based on the fixed-point theory. As a result, the response of the entire building, including the substructure and roof section, and vibrations during earthquakes can be reduced. Consequently, seismic resistance can be improved without installing a large number of vibration damping devices in the substructure. Compared to conventional vibration damping structures, the same level of required seismic resistance can be ensured even when the number of vibration damping devices installed in the substructure 2 is reduced.

[0008] Furthermore, in the vibration damping structure according to the present invention, the lower structure may have a plurality of layers, some of the layers of the plurality of layers may be made more flexible than the other layers, and the second vibration damping device may be provided on the some of the layers.

[0009] This configuration concentrates earthquake-induced deformation on a portion of the substructure, allowing the second vibration control device installed on that portion of the substructure to efficiently absorb the earthquake energy. [Effects of the Invention]

[0010] According to the present invention, stress caused by temperature changes and vibrations during earthquakes can be reduced. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic diagram showing an example of a vibration damping structure according to an embodiment of the present invention. [Figure 2] This is a diagram showing the analysis model. [Figure 3] This figure shows the input seismic motion. [Figure 4] This is a graph showing the analysis results. [Modes for carrying out the invention]

[0012] The vibration damping structure according to an embodiment of the present invention will be described below with reference to Figure 1. The vibration damping structure 1 according to this embodiment shown in Figure 1 is used in buildings 11 that construct large spaces such as stadiums, halls, and arenas with roofs. The vibration damping structure 1 includes a substructure 2, a roof 3, a first vibration damping device 5 provided at the connection 4 between the substructure 2 and the roof 3, a spring device 6 provided at the connection 4 between the substructure 2 and the roof 3, and a second vibration damping device 7 provided on the substructure 2.

[0013] The substructure 2 is supported by the ground. The substructure 2 has columns and beams. The substructure 2 has multiple floors (levels). If the building 11 is a stadium, seating for spectators is provided in the substructure 2. The second vibration control device 7 is composed of, for example, oil dampers arranged in a bracing type, shear link type, or intermediate column type, or viscous walls, etc. The substructure 2 of this embodiment is a so-called first-story concentrated seismic damping structure, in which the first floor is made more flexible than the floors above the second floor, and a second seismic damping device 7 is installed on the first floor. The first-story concentrated seismic damping structure is a structure that concentrates deformation caused by earthquakes on a specific floor and absorbs seismic energy on that floor. The building 11 shown in Figure 1 has four floors.

[0014] The roof section 3 has its edges connected to the upper end of the substructure 2 when viewed from above or below. The roof section 3 is supported by the substructure 2 over a large span. The first vibration damping device 5 is, for example, an oil damper. The spring device 6 is configured by appropriately combining a disc spring, a coil spring, a laminated rubber bearing, or the like. For example, the spring device 6 uses a horizontal spring capable of supporting a vertical load, such as a laminated rubber bearing, or a spring that only expects a horizontal restoring force, such as a disc spring or a coil spring, in combination with a bearing (a sliding bearing or a rolling bearing) that supports a vertical load. The first vibration damping device 5 and the spring device 6 are provided in parallel at the connecting portion 4 between the lower structure portion 2 and the roof portion 3. Further, in order to prevent the roof portion 3 from constantly swaying during strong winds that occur several times a year, a wind resistance locking device or a sliding bearing having a friction coefficient such that the sliding load is greater than the wind load may be installed in parallel with the spring device 6 and the first vibration damping device 5. The first vibration damping device 5, the spring device 6, and the second vibration damping device 7 are set so that the lower structure portion 2 and the roof portion 3 are synchronized based on the fixed point theory.

[0015] Next, the operation and effects of the vibration damping structure according to the present embodiment will be described. In the vibration damping structure 1 according to the present embodiment, since the spring device 6 is provided at the connecting portion 4 between the lower structure portion 2 and the roof portion 3, the spring device 6 can absorb the deformation when the roof portion 3 expands and contracts due to temperature changes. Therefore, the stress generated in the columns and beams of the lower structure portion 2 due to the contraction of the roof portion 3 due to temperature changes can be reduced. In the vibration damping structure according to the present embodiment, the first vibration damping device 5, the spring device 6, and the roof portion 3 function as a mass damper, and the first vibration damping device 5, the spring device 6, and the second vibration damping device 7 are set so that the lower structure portion 2 and the roof portion 3 are synchronized based on the fixed point theory. As a result, the response of the entire building 11 including the lower structure portion 2 and the roof portion 3 can be reduced. Therefore, the seismic resistance can be improved without installing a large number of vibration damping devices in the lower structure portion 2. Even when the number of vibration damping devices installed in the lower structure portion 2 is reduced compared to the conventional vibration damping structure, the necessary seismic resistance equivalent to the conventional one can be ensured.

[0016] By means of the second vibration damping device 7 provided in the lower structure part 2, it is possible to attenuate and reduce the response even for a period band in which the lower structure part 2 and the roof part 3 are not synchronized, such as a high-order mode, and to impart robustness to the building 11.

[0017] In the vibration damping structure 1 according to the present embodiment, the first floor of the lower structure part 2 is made to have a softer structure than the floors above the second floor, and the second vibration damping device 7 is provided on the first floor, which is a so-called first-layer concentrated vibration damping structure. With such a configuration, the deformation due to an earthquake is concentrated on the first floor of the lower structure part 2, and the earthquake energy can be efficiently absorbed by the second vibration damping device 7 provided on the first floor of the lower structure part 2.

[0018] A time history response analysis of a building adopting the vibration damping structure 1 of the present embodiment was carried out. The analysis is carried out under the following conditions. In the analysis, a building having an opening / closing roof is assumed. The opening / closing roof is supported by a fixed roof provided at the upper end part of the lower structure part 2. The opening / closing roof is connected to the fixed roof via the first vibration damping device 5 and the spring device 6. The opening / closing roof corresponds to the roof part 3 of the above embodiment, and the fixed roof is included in the lower structure part 2.

[0019] (Assumed weight) The weight of the roof part 3 is about 2650 t. The weight of the lower structure part 2 (from the first-floor rise to the fixed roof) is about 52300 t. The lower structure part 2 (from the first-floor rise to the fixed roof) does not include the part from the foundation to the first-floor slab in the lower structure part 2. The second vibration damping device 7 is provided in the lower structure part 2 (from the first-floor rise to the fixed roof).

[0020] (Mass ratio) The mass ratio of the primary equivalent mass normalized at the fixed roof position of the lower structure part 2 (from the first-floor rise to the fixed roof) to the weight of the roof part 3 (opening / closing roof) is approximately 15% (= 2650 / (52300 × 0.35)).

[0021] (Optimal spring) Based on the fixed-point theory, the horizontal spring stiffness at optimal tuning for the substructure 2 (from the first-floor riser to the fixed roof), with a mass ratio of 15%, is approximately Kd = 150,000 kN / m, assuming a primary natural period of approximately 0.7 seconds.

[0022] The analysis results are as follows: (Time history response analysis results) In a two-mass equivalent shear model with optimal damping based on fixed-point theory, the maximum response deformation of the spring obtained by inputting the Hachinohe phase of a Level 2 earthquake motion into a time-history response analysis is approximately 200 mm. On the other hand, when damping five times that of the optimal damping is applied to suppress the deformation, the response deformation is approximately 80 mm.

[0023] (Additional damping effect) For a mass ratio of 15%, the additional attenuation at optimal tuning according to the fixed-point theory is approximately 9%, and even when five times the optimal attenuation is applied, an additional attenuation of about 2% can be obtained.

[0024] (Response reduction effect) Based on the additional damping, the expected reduction in response story shear force in the substructure 2 (from the first floor rise to the fixed roof) is approximately 10-20%.

[0025] Using an analytical model that captures a portion of a stadium employing the vibration-damping structure of the present invention, we conducted a verification analysis of the seismic response reduction effect. Figure 2 shows the analysis model used. The numbers in the figure represent the mass of each node. A sliding support is provided at the lower end of the diagonal member on the first floor. In the figure, the numbers at the position of the sliding support indicate the mass of the upper node of the sliding support at the top and the mass of the lower node at the bottom. The analysis model assumes a building with one basement floor, five above-ground floors, and a rooftop floor. In the drawings and below, "roof vibration control" refers to the first vibration control device 5 and spring device 6 (see Figure 1) of the vibration control structure 1 of the above embodiment, and "stand vibration control" refers to the second vibration control device 7 (see Figure 1) of the vibration control structure 1 of the above embodiment. "With roof vibration control and with stand vibration control" refers to the vibration control structure 1 of the above embodiment, and is also referred to as "dual vibration control".

[0026] On the left side of the stand, a first vibration damping device 5 using an oil damper with a damping coefficient of 0.223 kNsec / mm and a spring device 6 with a spring stiffness of 4.25 kN / mm are installed in parallel as roof vibration damping. On the right side of the stand, a first vibration damping device 5 using an oil damper with a damping coefficient of 0.186 kNsec / mm and a spring device 6 with a spring stiffness of 3.54 kN / mm are installed in parallel as roof vibration damping. Both the left and right stands have a stand vibration control system on the first floor. 2 Vibration damping device 7 As a result, a 200-ton oil damper was installed.

[0027] The primary natural period for both the right-side stand and the left-side stand individually is 0.84 seconds. The input seismic motion is a surface wave with a wave level of 2 (Hachinohe phase) as shown in Figure 3 (maximum acceleration 326 cm / sec). For comparison, we also created analysis models for the following scenarios: no roof damping, with stand damping (a model with very high spring stiffness in the roof's spring mechanism), with roof damping, but no stand damping, and no roof damping, but no stand damping.

[0028] As shown in Figure 4, the response analysis results indicate that the vibration control structure of this embodiment (dual vibration control) has the highest response reduction effect, and in particular, the maximum inter-story drift angle on the first floor can be reduced by 55% compared to the model without roof vibration control and without stand vibration control. The maximum deformation of the spring device is 102 mm, and the maximum load is 368 kN. Both are design-feasible values.

[0029] Although embodiments of the vibration damping structure according to the present invention have been described above, the present invention is not limited to the above embodiments and can be modified as appropriate without departing from the spirit of the invention. For example, in the above embodiment, the substructure 2 is a first-story concentrated vibration damping structure, and the second vibration damping device 7 is provided on the first floor, which has a more flexible structure than the other floors. However, the configuration does not have to be this way. For example, the second vibration damping device 7 may be provided on a floor other than the first floor, or on multiple floors. If the second vibration damping device 7 is provided on multiple floors, it may be provided on multiple consecutive floors, or on multiple non-contiguous floors, such as on the first and third floors. The floor on which the second vibration damping device 7 is provided does not have to be more flexible than the floor on which it is not provided. The roof section 3 may be a retractable roof or a non-retractable roof.

[0030] The Sustainable Development Goals (SDGs) are among the 17 international goals adopted at the UN Summit in September 2015. The vibration-damping structure according to this embodiment can contribute to achieving some of these 17 SDGs, such as Goal 11, "Make cities and human settlements inclusive, safe, resilient and sustainable." [Explanation of Symbols]

[0031] 1. Vibration damping structure 2. Substructure 3. Roof section 4 Connecting part 5. First vibration control device 6. Spring device 7. Second vibration control device

Claims

1. The lower structure and A roof section connected to and supported by the aforementioned substructure, A first vibration damping device is provided at the connection between the lower structure and the roof, A spring device is provided at the connection between the lower structure and the roof, It has a second vibration damping device provided in the lower structure, A vibration damping structure in which the first vibration damping device, the spring device, and the roof section function as mass dampers, and the first vibration damping device, the spring device, and the second vibration damping device are set to synchronize the lower structure section and the roof section based on the fixed-point theory.

2. The lower structure and A roof section connected to and supported by the aforementioned substructure, A first vibration damping device is provided at the connection between the lower structure and the roof, A spring device is provided at the connection between the lower structure and the roof, It has a second vibration damping device provided in the lower structure, The aforementioned substructure has multiple layers, A vibration damping structure in which some of the layers of the aforementioned plurality of layers have a more flexible structure than the other layers, and the second vibration damping device is provided in the aforementioned some of the layers.

3. The lower structure and A roof section connected to and supported by the aforementioned substructure, A first vibration damping device is provided at the connection between the lower structure and the roof, A spring device is provided at the connection between the lower structure and the roof, It has a second vibration damping device provided in the lower structure, The first vibration damping device, the spring device, and the roof section function as mass dampers, and the first vibration damping device, the spring device, and the second vibration damping device are set to synchronize with the lower structure and the roof section based on the fixed-point theory. A method for designing a vibration-damping structure in a building comprising the aforementioned substructure and roof, without assuming a rigid floor for the building.

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