Vibration suppression device for structures

Abstract

To provide a structure vibration suppression device capable of making a vibration suppression effect for an upward vibration and a downward vibration almost the same, and thereby suppressing the vibration in a vertical direction appropriately when vibration in the vertical direction occurs in a structure.SOLUTION: A structure vibration suppression device for suppressing vibration of a structure includes: an outer wall body 4 formed like a box opening upward, an inner wall body 5 inserted into the outer wall body 4 from above which is formed into a plate shape, and a viscous body 6 put in the inside of the outer wall body 4. When force by shearing resistance of the viscous body 6 that acts on the inner wall body 5 is represented as viscous force Fv, and force for compressing the viscous body 6 is represented as compression force Fc when the inner wall body 5 moves downward accompanying vibration of the structure, the width W, the thickness t in a lower end surface of the inner wall body 5, and a distance h between the lower end of the inner wall body 5 and an internal bottom face of the outer wall body 4 are set so that the ratio of the compression force Fc to the viscous force Fv is a predetermined ratio or less.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention is applicable to structures such as large facilities that can accommodate a large number of spectators, such as concert halls and sports facilities, and relates to a vibration suppression device for a structure for suppressing vertical vibrations generated when spectators move in a so-called vertical rhythm.

Background Art

[0002] Conventionally, as this type of vibration suppression device, a damping damper such as an oil damper or a viscous wall is used, and an architectural structure (vibration prevention structure) that prevents vertical vibrations by installing the damping damper under the floor of a large facility is described in, for example, Patent Document 1. This architectural structure includes a beam material that supports the floor surface, has a long span and a small beam formation, a support material that simply supports both ends of the beam material, a damping damper installed between the beam material and the lower floor surface at the central portion in the length direction of the beam material, and a weight body appropriately suspended below the beam material.

[0003] By using an H-shaped steel with a long span of 20 to 60 m as the above-mentioned beam material, a floor having a relatively small natural vibration frequency is configured. Further, the above-mentioned damping damper is provided to exert a resistance against the downward deflection of the beam material and to absorb vibrations. Furthermore, the above-mentioned weight body is provided to adjust the natural vibration frequency of the beam material to a target value and to reduce the response acceleration of the floor surface.

[0004] Furthermore, as a viscous wall that utilizes a viscous material to dampen buildings, for example, the seismic damping wall described in Patent Document 2 is known. This seismic damping wall is installed between an upper beam (a beam on the upper floor) and a lower beam (a beam on the lower floor), and comprises a box-shaped container fixed to the lower beam and open upwards, a resistance plate fixed to the upper beam and hanging down, and inserted into the container from above, and a viscous material filled inside the container. When the upper and lower beams are displaced relative to each other, the resistance plate moves within the container, and shear resistance from the viscous material acts on the resistance plate according to the speed of movement, suppressing the movement of the resistance plate and thereby suppressing the relative displacement between the upper and lower beams. By applying such a seismic damping wall to the damping damper described above, it is possible to absorb and suppress vertical vibrations of beam members in the aforementioned building structure. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2019-90180 [Patent Document 2] Japanese Patent Application Publication No. 11-71935 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, since the aforementioned seismic damping walls primarily suppress the relative horizontal displacement between the upper and lower beams, the following problems arise when trying to suppress vertical vibrations.

[0007] In other words, when vertical vibrations act on a damping wall, when the resistance plate moves downward, it acts to compress the viscous material between itself and the bottom surface of the container, while when the resistance plate moves upward, it acts to be pulled outward from the container. In this case, when the viscous material is compressed by the resistance plate, the reaction force that the resistance plate receives from the viscous material becomes large, and as a result, the resistance force against vertical displacement during compression becomes larger than that during tension.

[0008] Furthermore, during compression by the resistance plate, the shear area of ​​the resistance plate relative to the viscous material increases, while during tension by the resistance plate, the shear area decreases. As a result, a difference in damping force occurs between compression and tension by the resistance plate. Thus, if a difference in damping force occurs in a seismic damping wall when the resistance plate moves in opposite directions, upward and downward, there is a risk that vibrations in the structure to which the seismic damping wall is applied may not be adequately suppressed.

[0009] The present invention was made to solve the above-mentioned problems, and aims to provide a vibration suppression device for structures that can make the vibration suppression effect in the upward and downward directions substantially the same when vertical vibration occurs in a structure, thereby effectively suppressing vertical vibration. [Means for solving the problem]

[0010] To achieve the above objective, the invention according to claim 1 is a vibration suppression device for a structure, provided between an upper structural member and a lower structural member arranged at a predetermined distance from each other in the vertical direction in a structure, for suppressing vibrations of the structure, comprising: an outer wall body formed in the shape of a box opening upward and having its lower end connected to the lower structural member; an inner wall body formed in the shape of a plate, having its upper end connected to the upper structural member, and inserted into the outer wall body from above and positioned at a predetermined distance from the inner surface of the outer wall body; and a viscous body filled inside the outer wall body and existing between the inner surface of the outer wall body and the inner wall body, wherein, when the inner wall body moves downward due to vibrations of the structure, the width and thickness of the lower end surface of the inner wall body, and the distance between the lower end of the inner wall body and the inner bottom surface of the outer wall body are set such that the compressive force acts on the inner wall body as a predetermined ratio or less to the viscous force when the force due to the shear resistance of the viscous body is defined as a viscous force and the force compressing the viscous body is defined as a compressive force, wherein the width and thickness of the lower end surface of the inner wall body, and the distance between the lower end of the inner wall body and the inner bottom surface of the outer wall body are set.

[0011] In this configuration, when the inner wall moves downward due to vibration of the structure, the width and thickness of the lower end surface of the inner wall, as well as the distance between the lower end of the inner wall and the inner bottom surface of the outer wall, are set so that the compressive force is less than or equal to a predetermined ratio of the viscous force. In this case, by setting the width and thickness of the inner wall and the distance so that the compressive force is relatively small compared to the viscous force, the reaction force received from the viscous material compressed by the downward movement of the inner wall can be suppressed. As a result, the difference in damping force of the vibration suppression device between compression due to downward movement of the inner wall and tension due to upward movement of the inner wall can be reduced. Therefore, according to the present invention, when vertical vibration occurs in a structure, the vibration suppression effect for upward and downward directions can be made almost the same, thereby effectively suppressing vertical vibration.

[0012] The invention according to claim 2 is a vibration suppression device for a structure as described in claim 1, characterized in that, when the inner wall moves downward due to vibration of the structure, the shear resistance force acting on the front of the inner wall is defined as the first shear resistance force, and the shear resistance force acting on the side surface of the inner wall is defined as the second shear resistance force, the distance between one end on both the left and right sides of the inner wall and the side surface on the interior of the outer wall that is opposite to it is set such that the second shear resistance force is less than or equal to a predetermined ratio with respect to the first shear resistance force.

[0013] In this configuration, when the inner wall moves downward, the distance between one end on both the left and right sides of the inner wall and the opposing inner side of the outer wall is set such that the second shear resistance force acting on the side of the inner wall is less than or equal to a predetermined ratio of the first shear resistance force acting on the front of the inner wall. In this case, by setting the distance between one end on both the left and right sides of the inner wall and the opposing inner side of the outer wall so that the second shear resistance force is relatively small compared to the first shear resistance force, the shear resistance force of the viscous material acting on the entire inner wall can be suppressed during compression when the inner wall moves downward. As a result, the same effects as those described in claim 1 can be achieved, namely, the difference in damping force of the vibration suppression device between compression due to downward movement of the inner wall and tension due to upward movement of the inner wall can be reduced.

[0014] The invention according to claim 3 is a vibration suppression device for a structure according to claim 1, characterized in that when the compressive force is Fc, the compressive force Fc is set by the following formula. Fc = (W·t)·{K·(δ / h)-C} W: Width of the interior wall t: Thickness of the inner wall K: Bulk modulus of a viscous material δ : Maximum vertical amplitude of the inner wall h: Distance between the bottom edge of the inner wall and the inner bottom surface of the outer wall. C: Initial constant of viscous material before compression

[0015] According to this configuration, the compressive force Fc that compresses the viscous material when the inner wall moves downward is determined by the above equation. As is clear from the above equation, the compressive force is proportional to the width W and thickness t of the inner wall, while being inversely proportional to the distance h between the lower end of the inner wall and the inner bottom surface of the outer wall. Therefore, reducing the compressive force Fc can be easily achieved by reducing the width W and thickness t or by increasing the distance h.

[0016] The invention according to claim 4 is a vibration suppression device for a structure according to any one of claims 1 to 3, further comprising a cover provided to cover an opening at the upper end of an outer wall body, wherein the inner wall body has a main body portion having a predetermined width in the vertical direction, and a cover mounting portion provided at the upper end of the main body portion to which the cover is attached.

[0017] In this configuration, the inner wall has the main body and a cover mounting portion at its upper end, and the opening at the upper end of the outer wall is covered by the cover attached to the cover mounting portion. This prevents foreign matter such as sand and dust or liquids such as rainwater from entering the interior of the outer wall of a vibration damping device installed on a structure, and prevents the viscous material from deteriorating as a result, thus maintaining the viscous material in good condition for a long period of time. Furthermore, since the cover is attached to the cover mounting portion of the inner wall, it can move vertically together with the inner wall when the inner wall moves vertically.

[0018] The invention according to claim 5 is a vibration suppression device for a structure as described in claim 4, characterized in that the cover mounting portion is formed to have a width dimension larger than the predetermined width of the main body portion, and the distance between the lower end of the cover mounting portion and the upper surface of the viscous body is set to be greater than the predetermined distance.

[0019] With this configuration, the cover mounting portion of the inner wall is formed to have a width larger than the predetermined width of the main body. By attaching the cover to the cover mounting portion, which has a relatively large mounting area, the cover can be securely attached to the inner wall. Furthermore, by setting the distance between the lower end of the cover mounting portion and the upper surface of the viscous material to be greater than a predetermined distance (for example, the maximum displacement distance expected in an inner wall that displaces in the vertical direction), it is possible to prevent the cover mounting portion from coming into contact with the upper surface of the viscous material.

[0020] The invention according to claim 6 is a vibration suppression device for a structure according to any one of claims 1 to 3, wherein the inner wall body is formed in a plate shape, and includes a main inner wall body that moves vertically in unison with the upper structural member along with the vibration of the structure, and a sub-inner wall body that is formed in a plate shape and is arranged such that its lower part is immersed in the viscous body in a state of overlapping the main inner wall body in the thickness direction. The invention further includes a sub-inner wall body support mechanism that supports the upper end portion of the sub-inner wall body, and the sub-inner wall body support mechanism is configured to hold the sub-inner wall body stationary when the main inner wall body moves downward, and to allow upward movement when the main inner wall body moves upward.

[0021] According to this configuration, the inner wall body has the main inner wall body and the sub-inner wall body as described above. When the inner wall body moves downward, that is, when the main inner wall body moves downward, the sub-inner wall body is held stationary by the sub-inner wall body support mechanism. As a result, when the inner wall body moves downward, the resistance force acting on the main inner wall body can be obtained as the damping force of the vibration suppression device. On the other hand, when the inner wall body moves upward, in addition to the main inner wall body, the sub-inner wall body, which is arranged such that its lower part is immersed in the viscous body, also moves upward. That is, in addition to the resistance force when only the main inner wall body moves upward, the resistance force when the sub-inner wall body moves upward can be obtained as the damping force of the vibration suppression device. As a result, the resistance force that originally decreases when the inner wall body moves upward can be compensated for by the sub-inner wall body, thereby reducing the difference in the damping force of the vibration suppression device when the inner wall body moves downward and when the inner wall body moves upward.

[0022] The invention according to claim 7 is a vibration suppression device for a structure according to any one of claims 1 to 3, wherein in a state where the inner wall body is located at a steady position, an opening that penetrates in the front-rear direction is provided on the inner wall body immediately above the liquid surface of the viscous body, and the opening is provided to suppress an increase in the cross-sectional area of the inner wall body when the inner wall body moves downward.

[0023] According to this configuration, since the above-mentioned opening is provided at a predetermined position of the inner wall body, when the inner wall body moves downward, an increase in the shear cross-sectional area of the inner wall body is suppressed. Thereby, an increase in the shear resistance force when the inner wall body moves downward can be suppressed. On the other hand, when the inner wall body moves upward, the area of the inner wall body in contact with the viscous body gradually decreases, and accordingly, the shear resistance force acting on the inner wall body decreases. As described above, by providing the above-mentioned opening in the inner wall body, an increase in the shear resistance force when the inner wall body moves downward can be suppressed as compared with the case where there is no such opening. As a result, the difference in the damping force of the vibration suppression device when the inner wall body moves downward and when the inner wall body moves upward can be reduced.

[0024] The invention according to claim 8 is characterized in that, in the vibration suppression device for a structure according to any one of claims 1 to 3, a tapered portion having a side surface shape formed in a tapered shape downward is provided at the lower end portion of the inner wall body.

[0025] According to this configuration, since the above-mentioned tapered portion is provided at the lower end portion of the inner wall body, while ensuring the shear resistance force when the inner wall body moves in the vertical direction, the compressive force by which the inner wall body compresses the viscous body can be significantly reduced. Thereby, in the vibration suppression device, while ensuring a desired damping force, the influence caused by the inner wall body compressing the viscous body can be significantly reduced.

Brief Description of the Drawings

[0026] [Figure 1] FIG. schematically shows a seismic isolation wall as a vibration suppression device according to an embodiment of the present invention together with a part of the structural materials of a building to which this is applied. [Figure 2] (a) is a front view of the seismic isolation wall of FIG. 1, and (b) is a longitudinal sectional view taken along line A-A of (a). [Figure 3] FIG. schematically shows the hysteresis characteristics of the seismic isolation wall. [Figure 4] FIG. shows a model of the seismic isolation wall, where (a) is a model diagram when no compressive force acts, and (b) is a model diagram when a compressive force acts. [Figure 5] (a) and (b) correspond to Figures 2(a) and (b), respectively, and are a front view and a longitudinal cross-section of the seismic isolation wall. [Figure 6] This diagram shows, in three dimensions, the viscous material within the outer wall structure, specifically the material between the inner wall of the inner wall and the bottom plate of the outer wall. [Figure 7] (a) to (d) show hysteresis loops where the input amplitudes are different from each other. [Figure 8] For experiments No. 1 to 5, the experimental results are plotted with the volume change rate ΔV / V on the horizontal axis and the compressive force per unit area Fc / Ac on the vertical axis, and regression lines based on these experimental results are also shown. [Figure 9] The graph shows the calculated changes in viscous force, restoring force, and compressive force with respect to the displacement of the inner wall, as well as the total resistance force, which is the sum of these forces. (a) shows the case where there is a compressive force, and (b) shows the case where there is almost no compressive force. [Figure 10] (a) and (b) are a front view and a longitudinal cross-section of a seismic isolation wall, similar to those in Figures 5(a) and (b), respectively. [Figure 11] This figure shows the first modified example of a seismic damping wall. [Figure 12] This figure shows a second modified example of a seismic damping wall. [Figure 13] This figure shows a third modified example of a seismic damping wall. [Figure 14] This is a diagram illustrating the operation of the seismic isolation wall in the third modified example. [Figure 15] This figure shows a fourth modified example of a seismic isolation wall. [Figure 16] This diagram illustrates the operation of the seismic isolation wall in the fourth modified example (during compression), with (a) showing the state before compression and (b) showing the state during compression. [Figure 17] This diagram illustrates the operation of the seismic damping wall in the fourth modified example (under tension), with (a) showing the state before tension and (b) showing the state under tension. [Figure 18] This figure shows a modified example of the inner wall structure in a seismic damping wall. [Modes for carrying out the invention]

[0027] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. Figure 1 schematically shows a seismic damping wall as a vibration suppression device according to one embodiment of the present invention, along with some structural members of a building to which it is applied.

[0028] The above-mentioned building is a large facility capable of accommodating a large number of spectators, such as a concert hall, and a seismic damping wall 1 is installed in the underfloor structure that constitutes the floor beneath the spectator seating. Specifically, the above-mentioned underfloor structure comprises an upper structural member 2 and a lower structural member 3 that are arranged at a predetermined distance from each other in the vertical direction, and the seismic damping wall 1 is installed between these upper structural member 2 and lower structural member 3. The upper structural member 2 and lower structural member 3 are made of, for example, H-shaped steel and are arranged to extend horizontally and parallel to each other, with flooring material placed above the upper structural member 2.

[0029] Figure 2 shows the seismic damping wall 1, where (a) is a front view and (b) is a cross-sectional view along line AA in (a). As shown in both figures, the seismic damping wall 1 is formed in a box shape with an opening at the top and comprises an outer wall body 4 having a rectangular front shape, an inner wall body 5 formed in a plate shape and inserted into the outer wall body 4 from above and positioned at a predetermined distance from the inner surface of the outer wall body 4, and a viscous body 6 that is filled inside the outer wall body 4 and exists between the inner surface of the outer wall body 4 and the inner wall body. For convenience of illustration, the viscous body 6 is shown in grayscale.

[0030] The exterior wall 4 is formed in a box shape that opens upwards by welding together a bottom plate 11, a front plate 12, a rear plate 13, and left and right side plates 14, 14, all of which are made of steel plates and formed to a predetermined shape and size. The outer surfaces of the front plate 12 and the rear plate 13 are provided with reinforcing ribs 15, 15 extending between the left and right side plates 14, 14, near the center of their vertical direction.

[0031] The inner wall body 5 is made of steel plate and comprises an inner wall 17 with a vertically elongated rectangular front shape and a top plate 18 integrally provided at the upper end of the inner wall 17 and extending horizontally for a predetermined length. In addition, spacers 19, 19 are provided at predetermined positions on the front and rear surfaces of the inner wall 17, protruding for a predetermined length in the front-rear direction.

[0032] The viscous body 6 consists of a fluid of a predetermined material with relatively high viscosity (for example, polyisobutylene or silicone oil) and is filled to a predetermined height within the outer wall body 4.

[0033] As shown in Figure 1, the seismic damping wall 1, constructed as described above, has its bottom plate 11 of the outer wall body 4 fixed to the lower structural member 3, and its top plate 18 of the inner wall body 5 fixed to the upper structural member 2 by multiple bolts (not shown).

[0034] Here, we will explain the resistance force (damping force) provided by seismic damping wall 1. The total resistance force F provided by seismic damping wall 1 is expressed by the following equation. F = Fv + Fk + Fc Fv: Viscous force due to shear resistance of viscous material 6 Fk: Restoring force due to the internal rigidity of the viscous material 6 Fc: Compressive force that causes a volume change in the viscous material 6 during compression In the following explanation, Fv, Fk, and Fc will be referred to as "viscous force Fv," "restoring force Fk," and "compressive force Fc," respectively.

[0035] Furthermore, the viscous force Fv, restoring force Fk, and compressive force Fc mentioned above are expressed by the following equations, respectively. Fv = η(Vs, t) · Vs · As η(Vs,t): Apparent viscosity of viscous material 6 Vs: Shear strain rate of inner wall 5 As: Shear area of ​​inner wall 5 t: Thickness of the inner wall 17 of the inner wall body 5 Fk=Ki·δ Ki: Internal rigidity of viscous material 6 δ: Vertical displacement of the inner wall 5 Fc = Kc·δ Kc: Compressive stiffness of viscous material 6

[0036] Furthermore, Figure 3 schematically shows the hysteresis characteristics due to seismic damping wall 1, and Figure 4 shows a model of seismic damping wall 1. More specifically, the hysteresis characteristics shown in Figure 3 form a clockwise loop, Figure 4(a) is a model diagram when no compressive force acts on seismic damping wall 1, and Figure 4(b) is a model diagram when compressive force acts.

[0037] As shown in the model diagram in Figure 4(a), when no compressive force acts on the damping wall 1, only viscous force and restoring force act on the damping wall 1, resulting in the hysteresis characteristics shown by the solid line in Figure 3, specifically, point-symmetric and nearly elliptical hysteresis characteristics centered at the origin.

[0038] On the other hand, as shown in the model diagram of Figure 4(b), when a compressive force acts on the damping wall 1 in addition to viscous force and restoring force, the hysteresis characteristics shown by the solid line in Figure 3 are obtained in the region where the vertical displacement is negative (the left half of Figure 3) and the load F is negative (the lower half of Figure 3), while the hysteresis characteristics shown by the dashed line in Figure 3 are obtained in the region where the vertical displacement and load F are positive.

[0039] As described above, when a compressive force acts on the seismic damping wall 1 in addition to the viscous force and restoring force, that is, when the inner wall body 5 moves downward in the seismic damping wall 1, a compressive force acts on the inner wall body 5 as a reaction force due to the compression of the viscous material 6, the load F increases by the amount of that compressive force.

[0040] As described above, when the inner wall 5 moves downward in the seismic damping wall 1, a compressive force acts on the inner wall 5, but when the inner wall 5 moves upward, no compressive force acts on the inner wall 5. Therefore, when vertical vibrations act on the seismic damping wall 1, the total resistance force F by the seismic damping wall 1 differs depending on whether the inner wall 5 moves downward or upward, which may result in the inability to obtain an appropriate vibration suppression effect from the seismic damping wall 1.

[0041] Therefore, in this embodiment, the damping wall 1 is configured to be hardly affected by the compressive force. That is, in the total resistance force F provided by the damping wall 1, the compressive force Fc is significantly reduced compared to the viscous force Fv. Specifically, as shown in Figure 5, the thickness t and width W of the inner wall 17 in the inner wall body 5, and the distance h between the lower end of the inner wall 17 and the inner bottom surface of the outer wall body 4 are set so that the compressive force Fc in the damping wall 1 is less than or equal to a predetermined ratio (for example, 10%) of the viscous force Fv. The following equation shows that the compressive force Fc is 10% or less of the viscous force Fv. Fc ≤ 0.1 · Fv

[0042] Generally, the compressive force Fc, which is the resistance force of the viscous material 6 due to pressure, is expressed by the following formula. Fc = Ac·(P + ΔP) Ac: Area of ​​the bottom surface of the inner wall 17 P: Initial pressure (however, its value is 0 before pressure is applied) ΔP: Change in pressure

[0043] Furthermore, the change in pressure ΔP mentioned above is expressed by the following equation. ΔP = K·(ΔV / V) K: Bulk modulus of viscous material 6 V: Volume of the viscous material 6 compressed when the inner wall 5 moves downward. ΔV: Change in the volume of the viscous material 6 compressed when the inner wall 5 moves downward.

[0044] Here, we will describe an experiment and its results when vertical vibration was applied to the damping wall 1 under the following conditions. Figure 6 shows, in grayscale, the viscous body 6 within the outer wall body 4, specifically the viscous body between the inner wall 17 of the inner wall body 5 and the bottom plate 11 of the outer wall body 4 (hereinafter referred to as "compressible viscous body 6P" as appropriate), in three dimensions. The dashed line shows the compressed state as the inner wall 17 moves downward, as indicated by the white arrow. The figure also shows the values ​​of height h, width W, thickness t, volume V, compression area Ac, and input amplitude δ of the compressible viscous body 6P before compression. Furthermore, as the viscous body 6, a material: polyisobutylene, viscosity: 10000 poise, temperature: 20℃ was used, and vertical vibration with a frequency of 2 Hz and an input amplitude δ of 0.5 to 4 mm was applied to the damping wall 1.

[0045] Figure 7 shows hysteresis loops with different input amplitudes δ, with figures (a), (b), (c), and (d) representing the hysteresis loops when the input amplitudes δ are 0.5, 1.0, 2.0, and 4.0 mm, respectively. As shown in figures (a) to (d), the hysteresis loops for each input amplitude δ are, overall, elliptical in shape with a slight upward slope to the right. Also, as shown in figures (a) and (b), when the input amplitudes δ are 0.5 and 1.0 mm, the shape of the hysteresis loop is almost point-symmetric with respect to the origin, indicating that there is almost no difference in load between compression (when the inner wall 5 moves downward) and tension (when the inner wall 5 moves upward). On the other hand, as shown in figures (c) and (d), when the input amplitudes δ are 2.0 and 4.0 mm, the upper right portion of the hysteresis loop's shape is raised, indicating that the load during compression by the inner wall 5 is greater than during tension.

[0046] Table 1 below shows the volume displaced (volume change) ΔV and the volume of the compressible viscous material 6P before compression, when the compression is performed with a frequency of 2 Hz and input amplitude δ of 0.5, 1.0, 2.0, 3.0, and 4.0 mm. 3This shows the volume change rate ΔV / V for ).In the following explanation, the experiments conducted with input amplitudes δ of 0.5, 1.0, 2.0, 3.0, and 4.0 mm in Table 1 will be referred to as Experiment No. 1, 2, 3, 4, and 5, respectively. [Table 1]

[0047] As shown in Table 1, the volume change rate ΔV / V of the compressible viscous material 6P is 0.83 to 6.67% when the input amplitude δ is 0.5 to 4.0 mm. As shown in Figure 7 above, the difference in load between compression and tension due to the inner wall 5 appears in the outer shape of the hysteresis loop when the input amplitude δ is 2 mm or more. From this, as shown in Table 1, it can be seen that the resistance force of the compressible viscous material 6P due to compression becomes large when the volume change rate ΔV / V of the compressible viscous material 6P exceeds approximately 3%, i.e., when it exceeds Experiment No. 3.

[0048] Table 2 below shows the experimental results corresponding to Experiments No. 1 to 5 in Table 1. [Table 2]

[0049] Figure 8 shows the results of experiments No. 1 to 5, based on Tables 1 and 2 described above. The horizontal axis represents the rate of volume change ΔV / V, and the vertical axis represents the compressive force per unit area Fc / Ac. The results are plotted, and a regression line based on these experimental results is also shown.

[0050] The regression line shown above is represented by the following equation. Fc / Ac = 8501 · (ΔV / V) - 101

[0051] Furthermore, from the above equation, the compressive force Fc is expressed by the following equation. Fc = Ac · {8501 · (ΔV / V) - 101} In the above formula, the value of "8501" (unit: kN / m 2) corresponds to the bulk modulus of the viscous material 6, and the value of "101" is the initial constant of the viscous material 6 before compression. Substituting ΔV=δ·W·t and V=t·W·h into the above equation, and setting 8501 to K and 101 to C, the compressive force Fc of the viscous material 6 is expressed by the following equation. Fc = (W·t)·{K·(δ / h)-C}

[0052] In the above equation representing the compressive force Fc, K=8501 is an example where the material of the viscous body 6 is polyisobutylene, the viscosity is 10,000 poise, the temperature is 20°C, and the frequency is 2 Hz. Therefore, an appropriate value for K should be used in the above equation depending on the material, viscosity, temperature, and frequency of the viscous body 6.

[0053] Based on the above, it is clear that in the seismic damping wall 1, when the inner wall 17 of the inner wall body 5 compresses the compressible viscous material 6P, the inner wall body 5 should be determined such that the inner wall body 5 is hardly affected by the compressive force Fc due to the viscous material 6, that is, the compressive force Fc is reduced to a predetermined ratio or less compared to the viscous force Fv, by determining the thickness t and width W of the inner wall 17, as well as the distance h between the lower end of the inner wall 17 and the inner bottom surface of the outer wall body 4.

[0054] Here, using the formula for the compressive force Fc described above, an example of calculating the distance h in the seismic damping wall 1 will be explained with reference to Figures 5 and 9 mentioned earlier. The dimensions of the seismic damping wall 1 and the characteristics of the viscous material 6 shown in Figure 5 are as follows, and the input amplitude δ K and C were set as follows. Interior wall 17, width W: 205 mm, thickness t: 6 mm, Viscosity of viscous material 6: 10,000 poise, temperature 20°C Input amplitude δ :10mm K:8501, C:101

[0055] Under the above conditions, if the distance h between the lower end of the inner wall 17 and the inner bottom surface of the outer wall 4 is 60 mm, then according to the above formula, the compressive force Fc is 1.62 kN.

[0056] Figure 9(a) shows the calculated changes in the viscous force Fv, restoring force Fk, and compressive force Fc with respect to the displacement of the inner wall 17 in the seismic damping wall 1 under the above conditions, as well as the total resistance force F, which is the sum of these forces.

[0057] On the other hand, Figure 9(b) shows the calculated changes in viscous force Fv, restoring force Fk, and compressive force Fc with respect to the displacement of the inner wall 17, as well as the total resistive force F, in the seismic damping wall 1 when the distance h is set such that the compressive force Fc is less than or equal to a predetermined ratio (for example, 10% at maximum amplitude), similar to Figure 9(a). Specifically, in the seismic damping wall 1 of Figure 9(b), the distance h is set to 300 mm so that the compressive force Fc is 0.22 kN.

[0058] Comparing Figures 9(a) and (b), although the viscous force Fv and restoring force Fk are the same in both cases, at the maximum displacement of 10 mm, the compressive force Fc in (b) is significantly smaller than that in (a). As a result, when the viscous body 6 is compressed due to the downward movement of the inner wall 17, the total resistance force F in (a) increases due to the larger compressive force Fc, while the increase in the total resistance force F in (b) is suppressed due to the smaller compressive force Fc.

[0059] As described above, by setting the above-mentioned distance h, etc., in the seismic damping wall 1, the reaction force received from the viscous body 6, which is compressed as the inner wall body 5 moves downward, can be suppressed. As a result, the difference in damping force of the seismic damping wall 1 between the time of compression due to the downward movement of the inner wall body 5 and the time of tension due to the upward movement of the inner wall body 5 can be reduced. Therefore, according to the seismic damping wall 1 of this embodiment, when vertical vibrations occur in a building, the vibration suppression effect in the upward and downward directions can be made almost the same, thereby effectively suppressing vertical vibrations.

[0060] In the above, we have described a method for calculating the distance h between the lower end of the inner wall 17 of the inner wall body 5 and the inner bottom surface of the outer wall body 4. However, when the inner wall body 5 is compressed and moves downward, even if the compressed viscous body 6 expands laterally, it is preferable to ensure a sufficient distance between the inner wall 17 and the left and right side walls 14, 14 of the outer wall body 4 so that the inner wall body 5 is not affected.

[0061] Furthermore, in the seismic damping wall 1, when the inner wall body 5 moves downward due to compression, the distance (J in Figure 10(a)) between one end on either side of the inner wall 17 and the opposite side of the outer wall body 4 that is inside the outer wall body 4 may be set according to the first shear resistance force F1 acting on the front of the inner wall 17 and the second shear resistance force F2 acting on the left and right sides of the inner wall 17.

[0062] Here, with reference to Figure 10, the method for calculating distance J will be briefly explained. In general, the shear resistance force acting on the inner wall 17 is proportional to the shear area and inversely proportional to the gap with the opposing surface. Therefore, the shear resistance force F1 on the front of the inner wall 17 and the shear resistance force F2 on the side can be expressed as follows, where W is the width of the inner wall 17, B is the height of the inner wall 17 immersed in the viscous material 6, y is the gap between the inner wall 17 and the front plate 12 or rear plate 13, t is the thickness of the inner wall 17, and J is the distance between the side of the inner wall 17 and the inner side of the opposing outer wall 4. F1∝W·B / y F2∝B·t / J

[0063] The distance J is set such that the second shear resistance force F2 is less than or equal to a predetermined percentage (for example, 10%) of the first shear resistance force F1. The following equation shows that the second shear resistance force F2 is 10% or less of the first shear resistance force F1. F2 ≤ 0.1 · F1

[0064] From the above equations representing F1 and F2, and the relationship between them, the above distance J can be expressed as follows. J≧t·y / (0.1·W)

[0065] Therefore, from the above equation, the minimum value of the distance J can be easily calculated using the thickness t and width W of the inner wall 17, as well as the gap y.

[0066] As described above, by calculating and setting the above distance J in the seismic damping wall 1, the shear resistance force of the viscous body 6 acting on the entire inner wall 17 can be suppressed during compression when the inner wall body 5 moves downward. As a result, the difference in damping force of the seismic damping wall 1 between compression due to the downward movement of the inner wall body 5 and tension due to the upward movement of the inner wall body 5 can be reduced.

[0067] Next, a modified version of the seismic damping wall 1 will be described with reference to Figures 11 to 18. In the following description, the same reference numerals will be used for components that are the same as those of the seismic damping wall 1 described above and other modified versions, and their detailed explanations will be omitted. Also, in Figures 11 to 18, (a) is a front view and (b) is a longitudinal section view.

[0068] Figure 11 shows a first modified example of a seismic damping wall 1A. The seismic damping wall 1A shown in this figure differs from the aforementioned seismic damping wall 1 mainly in that a liquid reservoir 21 is provided at the top of the outer wall body 4, and a cover 22 is provided to cover the opening 4a that opens to the top of the outer wall body 4. The liquid reservoir 21 is formed so that the upper part of the front plate 12 protrudes forward (to the left in Figure 11(b)), while the upper part of the rear plate 13 protrudes backward (to the right in Figure 11(b)), thereby widening the front-to-back dimension at the top of the outer wall body 4.

[0069] On the other hand, the cover 22 is composed of a front cover 22A and a rear cover 22B, which are made of metal plates such as stainless steel and formed into predetermined shapes, and these are fixed to the inner wall 17 of the inner wall body 5. Specifically, the front cover 22A has a predetermined side shape such that its upper end is located at the upper end of the front surface of the inner wall 17 and its lower half is located in front of the liquid reservoir 21. On the other hand, the rear cover 22B has a predetermined side shape such that its upper end is located at the upper end of the rear surface of the inner wall 17 and its lower half is located behind the liquid reservoir 21. These front cover 22A and rear cover 22B are fixed to the inner wall 17 by a plurality of bolts 23 and nuts 24, with their upper ends sandwiching the upper end of the inner wall 17 from the front and rear.

[0070] In the seismic damping wall 1A, where the cover 22 is fixed to the inner wall 17, the cover 22 moves integrally with the inner wall body 5. In this way, the provision of the cover 22 in the seismic damping wall 1A prevents foreign matter such as sand and dust or liquids such as rainwater from entering the interior of the outer wall body 4 from the outside, and prevents the viscous material 6 from deteriorating as a result, thereby maintaining the viscous material 6 in good condition for a long period of time.

[0071] Figure 12 shows a second modified seismic damping wall 1B. The seismic damping wall 1B shown in this figure differs from the first modified seismic damping wall 1A described above in that the front shape of the inner wall 17 in the inner wall body 5 is formed in a T shape. Specifically, the upper part 17b (cover attachment part) of the inner wall 17 has the same width dimension as the inner wall 17 of the seismic damping wall 1A, while the inner wall main body 17a (main body) that hangs down for a predetermined length from the upper part 17b of the inner wall has a smaller width dimension than that of the upper part 17b of the inner wall.

[0072] Furthermore, in the inner wall 17 of this seismic damping wall 1B, the distance L between the liquid surface (upper surface) of the viscous body 6 and the lower end of the upper part 17b of the inner wall is set to a length greater than the vertical displacement of the inner wall body 5 that is assumed in the seismic damping wall 1B. As a result, when the inner wall body 5 moves downward in the seismic damping wall 1B, the upper part 17b of the inner wall is prevented from coming into contact with the liquid surface of the viscous body 6, and the upper part 17b of the inner wall is not affected by the compression of the viscous body 6.

[0073] Figure 13 shows a third modified example of a seismic damping wall 1C. The seismic damping wall 1C shown in this figure differs from the seismic damping wall 1 described above in the structure of the inner wall body 5, and is configured to reduce the difference between the damping force when the inner wall body 5 moves downward (during compression) and the damping force when the inner wall body 5 moves upward (during tension). In this seismic damping wall 1C, a box-shaped inner wall support part 31 (sub-inner wall body support mechanism) is provided on the underside of the top plate 18. The interior of this inner wall support part 31 has a predetermined height dimension, and the bottom plate 31a has a slit 31b that penetrates in the vertical direction and a plurality of guide holes 31c. The slit 31b extends in the left-right direction and has a predetermined width, and each of the guide holes 31c has a predetermined diameter.

[0074] In the inner wall support section 31 described above, an inner wall 32 (main inner wall body) having a predetermined length in the vertical direction is fixed to the bottom plate 31a at its upper end, and an auxiliary inner wall 33 (sub-inner wall body) having a predetermined length shorter in the vertical direction than the inner wall 32 is supported at its upper end so as to be movable in the vertical direction. More specifically, the inner wall 32 is constructed in substantially the same way as the inner wall 17 of the seismic damping wall 1 described above, and is inserted into the outer wall body 4 from above, with the lower half or more immersed in the viscous material 6. On the other hand, the auxiliary inner wall 33 has a guide plate 33a that is integrated with the auxiliary inner wall 33 at its upper end within the inner wall support section 31. This guide plate 33a is formed to be larger than the slit 31b of the inner wall support section 31, and has a plurality of guide pins 34 that extend in the vertical direction and are loosely inserted into each guide hole 31c fixed to it.

[0075] Figure 14 shows the operation of the seismic damping wall 1C. The dashed lines in the figure indicate the position of the inner wall 5 before operation (hereinafter referred to as the "steady position" as appropriate), with the upper dashed line indicating the upper end position of the top plate 18 of the inner wall 5, and the lower dashed line indicating the lower end position of the inner wall 32 of the inner wall 5. The double dashed line in the figure indicates the lower end position of the auxiliary inner wall 33 of the inner wall 5 in the steady position.

[0076] As shown in Figure 14(a), during compression when the inner wall 5 moves downward, the inner wall support 31 and the inner wall 32 move downward together, while the auxiliary inner wall 33 remains in its steady position. As a result, in the seismic damping wall 1C, during compression, a shear resistance force corresponding to the shear area of ​​the inner wall 32 is exerted as a damping force.

[0077] On the other hand, as shown in Figure 14(b), when the inner wall 5 moves upward in tension, the inner wall support 31 and the inner wall 32 move upward together. In addition, the vertical gap between the bottom plate 31a of the inner wall support 31 and the guide plate 33a of the auxiliary inner wall 33 disappears, and when the bottom plate 31a contacts the guide plate 33a from below, the auxiliary inner wall 33 also moves upward together with the inner wall support 31 and the inner wall 32. As a result, in the seismic damping wall 1C, when in tension, a shear resistance force corresponding to the shear area of ​​the inner wall 32 and the shear area of ​​the auxiliary inner wall 33 is exerted as a damping force. Thus, in the seismic damping wall 1C, the shear resistance force that would normally decrease when the inner wall 5 moves upward can be compensated for by the auxiliary inner wall 33. This makes it possible to reduce the difference in damping force of the seismic damping wall 1C between when the inner wall 5 moves downward in compression and when the inner wall 5 moves upward in tension.

[0078] Although not shown in the diagram, in the seismic damping wall 1C, a biasing member (for example, a coil spring) that biases the guide plate 33a of the auxiliary inner wall 33 downward may be provided within the inner wall support portion 31. By providing such a biasing member, the auxiliary inner wall 33 can be quickly returned to its initial set position.

[0079] Figure 15 shows a fourth modified example of a seismic damping wall 1D. The seismic damping wall 1D shown in this figure differs from the aforementioned seismic damping wall 1 in that its inner wall 36 has an opening 36a that penetrates in the front-to-back direction. This seismic damping wall 1D has an inner wall 36 that is almost identical to the inner wall 17 of the aforementioned seismic damping wall 1, and this inner wall 36 has an opening 36a formed in it that has a horizontally elongated rectangular shape and penetrates in the front-to-back direction. In addition, in the seismic damping wall 1D, when the inner wall body 5 is in a steady position, the opening 36a is located just above the liquid surface of the viscous material 6.

[0080] Figures 16 and 17 show the operation of the inner wall body 5 in the seismic damping wall 1D during compression and tension, respectively. Figure 16(a) shows the inner wall body 5 in a steady position, while Figure 16(b) shows the inner wall body 5 in a compressed state where it has moved downward. In the following explanation, in order to explain the difference due to the presence or absence of the opening 36a, the inner wall 36 having the opening 36a will be appropriately referred to as "inner wall with opening 36", and the inner wall without an opening 36a will be appropriately referred to as "inner wall without opening". Furthermore, in the inner wall body 5 in a steady position, the shear area of ​​the inner wall 36 immersed in the viscous material 6 will be denoted as A, and the shear area that increases or decreases during compression and tension of the inner wall body 5 having an inner wall without an opening will be denoted as ΔA.

[0081] In Figure 16(a), when the inner wall body 5 with an inner wall without an opening moves downward from the steady-state position, the shear area becomes A + ΔA (see the dashed line in Figure 16(b)). In contrast, as shown in Figure 16(b), when the inner wall body 5 with an inner wall 36 with an opening moves downward, the increased shear area (ΔA) is offset by the area suppressed by the opening 36a. As a result, when the inner wall body 5 with an inner wall 36 with an opening is compressed, the shear area of ​​the inner wall 36 at maximum displacement is maintained at approximately A (= A + ΔA - ΔA).

[0082] On the other hand, when the inner wall body 5, which has an inner wall without an opening, moves upward from the steady position shown in Figure 17(a) under tension, the shear area becomes A-ΔA. This is also true for the inner wall 36 with an opening, as shown in Figure 17(b). In other words, regardless of the presence or absence of the opening 36a, when the inner wall body 5 moves upward under tension, the shear area of ​​the inner wall 36 at the maximum displacement becomes A-ΔA.

[0083] From the above, in the seismic damping wall 1D, because the opening 36a is formed in the inner wall 36, the ratio of the shear areas at maximum displacement in the inner wall 36 becomes A / (A-ΔA). This is smaller than the ratio of the shear areas at maximum displacement in an inner wall without an opening [(A+ΔA) / (A-ΔA)]. Therefore, in the seismic damping wall 1D, by providing an opening 36a in the inner wall 36, the difference between the damping force during compression when the inner wall body 5 moves downward and the damping force during tension when the inner wall body 5 moves upward can be reduced.

[0084] It should be noted that the present invention is not limited to the embodiments described above and can be implemented in various forms. Figure 18 shows a modified example of the inner wall body 5 in the seismic damping wall 1. As shown in the figure, this inner wall body 5 has a tapered portion 17c at the lower end of the inner wall 17, the side shape of which is tapered downwards. As a result, the area of ​​the bottom surface of the inner wall 17 is made very small, and as a result, the reaction force that the inner wall body 5 receives from the viscous material 6 when the inner wall body 5 moves downwards during compression can be greatly reduced.

[0085] Furthermore, the detailed configurations of the seismic damping walls 1, 1A to 1D shown in the embodiments are merely illustrative examples and can be modified as appropriate within the scope of the present invention. [Explanation of symbols]

[0086] 1. Seismic damping wall (vibration suppression device) 1A Seismic isolation wall of the first modified form 1B Second modified seismic isolation wall 1C Third modified example of seismic isolation wall 1D Fourth modified seismic isolation wall 2 Upper structural material 3 Lower structural material 4. Exterior wall 4a Openings in the exterior wall 5. Inner wall 6 Viscous body 6P Compressible Viscous Material 11. Base plate of the exterior wall 12 Front panel of the exterior wall 13. Rear panel of the exterior wall 14. Left and right side panels of the exterior wall 17 Inner wall 17a Inner wall main body 17b Upper part of the interior wall 17c Lower end of inner wall (tapered section) 18. Top plate of the inner wall 21 Liquid reservoir 22 Cover 22A Front Cover 22B Rear Cover 31. Inner wall support section (sub-inner wall support mechanism) 31a Bottom plate 31b Slit 31c Guide hole 32. Inner wall (main inner wall body) of the seismic isolation wall in the fourth modified example. 33. Auxiliary interior wall (sub-interior wall body) 33a Guide plate for auxiliary inner wall 34 Guide pins 36. Inner wall of the seismic isolation wall in the fourth modified example. 36a opening Fv viscous force Fk restorative force Fc Compression Force t: Thickness of the inner wall, thickness of the compressible viscous material W: width of the inner wall, width of the compressible viscous material h Distance between the lower end of the inner wall and the inner bottom surface of the outer wall V Volume of the compressible viscous material Ac inner wall bottom area, compression area δ Input amplitude L is the distance between the liquid surface of the viscous material and the lower end of the upper part of the inner wall.

Claims

1. A vibration suppression device for a structure, provided between an upper structural member and a lower structural member arranged at a predetermined distance from each other in the vertical direction, for suppressing vibrations of the structure, An outer wall body formed in a box shape with an upward opening, and whose lower end is connected to the lower structural member, An inner wall body formed in a plate shape, with its upper end connected to the upper structural member, inserted into the outer wall body from above, and positioned at a predetermined distance from the inner surface of the outer wall body, A viscous body is filled inside the outer wall body and exists between the inner surface of the outer wall body and the inner wall body, Equipped with, A vibration suppression device for a structure, characterized in that, when the inner wall moves downward due to vibration of the structure, the width and thickness of the lower end surface of the inner wall, and the distance between the lower end of the inner wall and the inner bottom surface of the outer wall are set such that, when the force acting on the inner wall due to the shear resistance of the viscous material is defined as a viscous force and the force compressing the viscous material is defined as a compressive force, the compressive force is defined as being less than or equal to a predetermined ratio to the viscous force.

2. The vibration suppression device for a structure according to claim 1, characterized in that, when the inner wall moves downward due to vibration of the structure, the distance between one end on both the left and right sides of the inner wall and the side surface on the interior of the outer wall, which is opposite to the second shear resistance force, is set such that the second shear resistance force is less than or equal to a predetermined ratio with respect to the first shear resistance force, when the inner wall moves downward due to vibration of the structure, the shear resistance force acting on the front of the inner wall is defined as the first shear resistance force, and the shear resistance force acting on the side surface of the inner wall is defined as the second shear resistance force.

3. The vibration suppression device for a structure according to claim 1, characterized in that when the compressive force Fc is set by the following formula, the compressive force Fc is set by the following formula. Fc=(W・t)・{K・(δ / h)−C} W: Width of the interior wall t: Thickness of the inner wall K: Bulk modulus of a viscous material δ: Maximum vertical amplitude of the inner wall h: Distance between the lower end of the inner wall and the inner bottom surface of the outer wall. C: Initial constant of a viscous material before compression

4. The exterior wall body is further provided with a cover that covers the opening at the upper end, The aforementioned inner wall body is A main body having a predetermined width in the vertical direction, A cover mounting portion is provided at the upper end of this main body, to which the cover is attached, A vibration suppression device for a structure according to any one of claims 1 to 3, characterized by having the following features.

5. The cover mounting portion is formed to have a width dimension larger than the predetermined width of the main body portion. The vibration suppression device for a structure according to claim 4, characterized in that the distance between the lower end of the cover mounting portion and the upper surface of the viscous body is set to be greater than a predetermined distance.

6. The aforementioned inner wall body is A main inner wall body formed in a plate shape, which moves vertically in conjunction with the upper structural member in response to vibrations of the structure, A sub-inner wall body is formed in a plate shape and is arranged so as to overlap the main inner wall body in the thickness direction, with its lower part immersed in the viscous material, It has, The system further includes a sub-inner wall support mechanism that supports the upper end of the aforementioned sub-inner wall, The vibration suppression device for a structure according to any one of claims 1 to 3, characterized in that the sub-inner wall support mechanism is configured to hold the sub-inner wall immovably when the main inner wall moves downward, and to allow upward movement when the main inner wall moves upward.

7. The vibration suppression device for a structure according to any one of 1 to 3, characterized in that when the inner wall is in a steady position, the inner wall is provided with an opening that penetrates in the front-rear direction just above the liquid surface of the viscous material, and which suppresses the increase in the shear area of ​​the inner wall when the inner wall moves downward.

8. The vibration suppression device for a structure according to any one of claims 1 to 3, characterized in that a tapered portion is provided at the lower end of the inner wall body, the side shape of which is tapered downwards.

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