Structural vibration control devices

Abstract

To provide a vibration control device for a structure allowing vibration control effect to be realized as in the case where initial tension is not introduced as abbreviating a buckling prevention mechanism for a support member through introduction of the initial tension to the support member.SOLUTION: A vibration control device for a structure of the present invention is provided with: a support member 2 connected to a structure B and extending vertically; a mass damper 3 connected to the support member 2 and constituting an additional vibration system A with the support member 2, to exert a rotational inertia mass effect and a viscous-damping effect through conversion of displacement of the structure B transmitted through the support member 2 to rotational motion of a rotational mass 16 when the structure is vibrated; and a tension spring 4 connected to the support member 2 parallel to the mass damper 3 to add initial tension with predetermined strength to the support member 2. Rotational inertia mass mdηd of the mass damper 3 is set at enlarged value in accordance with rigidity of the tension spring 4 for rotational inertia mass mdo set in a condition where the tension spring 4 is not installed.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a vibration control device for a structure, particularly for suppressing vibrations of a high-rise structure. [Background technology]

[0002] A known example of this type of vibration control device is disclosed by the present applicant in Patent Document 1. This vibration control device is intended for structures such as high-rise buildings, and includes a plurality of support members extending in the vertical direction that are connected between the upper end of the structure and its foundation, mass dampers connected in series to the lower ends of each support member, and a buckling prevention mechanism for preventing buckling of the support members.

[0003] The mass damper and support member constitute an additional vibration system for the structure (main system) that is the target of vibration damping. The support member is made up of multiple hollow columns connected with bolts and nuts. The mass damper is, for example, a ball screw type with an inner cylinder, ball screw, and rotating mass, and the inner cylinder is connected to the bottom end of the support member, and the screw shaft of the ball screw is connected to the foundation. Furthermore, the rotational inertia mass of the rotating mass and the rigidity of the support member are set so that the natural frequency of the additional vibration system is in tune with the natural frequency of the structure.

[0004] Multiple buckling prevention mechanisms are placed at predetermined intervals along the length of the support member, and each mechanism consists of a slab that is integral with the structure and a sliding plate attached to the slab. Multiple rectangular restraining holes are formed in the slab, and a support member is inserted into each of the restraining holes. The sliding plate is made of a lubricating material and is attached to the wall surface of the restraining hole in the slab. In addition, abutment plates made of stainless steel or the like are attached to the outer surface of the support member at positions corresponding to the restraining holes.

[0005] In the above configuration, when a structure vibrates during an earthquake or other events, bending deformation exceeds shear deformation, particularly in high-rise structures, causing the upper part of the structure to undergo large lateral reciprocating (swinging) movements. The large displacement caused by this swinging is effectively transmitted to the mass damper via the support member, which slides vertically through the restraint holes in the buckling prevention mechanism, causing the rotating mass to rotate and vibrating the additional vibration system consisting of the support member and mass damper. As a result, the natural frequency of the additional vibration system is synchronized with the natural frequency of the structure, so the vibration energy of the structure is absorbed by the additional vibration system, thereby suppressing the vibration of the structure.

[0006] On the other hand, by inserting the support member into the restraint hole of the buckling prevention mechanism, the horizontal movement of the support member is restrained, and as a result, buckling of the support member when a compressive load is applied is prevented. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 5399540 Summary of the Invention [Problem to be solved by the invention]

[0008] In the conventional vibration control devices described above, the anti-buckling mechanism restricts the horizontal movement of the support members to prevent buckling of the support members, while allowing the support members to move vertically. This allows large displacements of the structure to be effectively transmitted to the mass damper via the support members. The large mass damper movements fully utilize the mass damper's rotational inertia mass effect, resulting in a significant vibration control effect. However, due to their functionality, the anti-buckling mechanisms must be installed at predetermined intervals along the length of the support members. Therefore, as the length of the support members increases with the height of the structure, the number of anti-buckling mechanisms required increases, resulting in a significant increase in costs.

[0009] To resolve this problem, it is conceivable that a tension spring could be installed in parallel with the mass damper, for example, and this tension spring could be used to introduce initial tension into the support member, thereby keeping the support member in a tensioned state and preventing buckling even when the maximum compressive load acts on the support member during an earthquake.

[0010] However, in this case, if a tension spring with a high stiffness and a biasing force greater than the reaction force of the mass damper is used to effectively obtain the initial tension effect, the tension spring will obstruct the movement of the mass damper, suppressing the mass damper's rotational inertia mass effect and preventing the mass damper from achieving an adequate vibration damping effect.In this case, the greater the stiffness of the tension spring, the greater the degree to which it obstructs the movement of the mass damper, and the smaller the vibration damping effect of the mass damper.

[0011] The present invention has been made to solve the above-mentioned problems, and aims to provide a vibration control device for a structure that, by introducing initial tension into a support member, makes it possible to omit a buckling prevention mechanism for preventing buckling of the support member, while still achieving vibration control effects equivalent to those obtained when initial tension is not introduced. [Means for solving the problem]

[0012] In order to achieve the above object, the invention of claim 1 is a vibration control device for a structure for suppressing vibration of a structure erected on the ground, comprising: a support member connected at one end to the structure and extending in the vertical direction; a mass damper connected to the support member and constituting an additional vibration system together with the support member, the mass damper having a rotating mass, and which, when the structure vibrates, converts the displacement of the structure transmitted via the support member into rotational motion of the rotating mass, thereby exhibiting a rotational inertia mass effect and a viscous damping effect; and a tension spring connected to the support member in parallel with the mass damper and applying a predetermined amount of initial tension to the support member, wherein the rotational inertia mass of the mass damper is set to a value increased in accordance with the rigidity of the tension spring relative to the rotational inertia mass that would be set when the tension spring is not installed.

[0013] When a structure vibrates during an earthquake or other event, bending deformation of the structure exceeds shear deformation, particularly if the structure is high-rise, and the structure vibrates (sways) in a manner that causes the upper part of the structure to vibrate (oscillate) in a large lateral reciprocating motion. With a structural vibration control device configured as described above, when the structure sways, the displacement of the structure is transmitted to the mass damper via the support member, causing the additional vibration system consisting of the support member and the mass damper to vibrate, and the displacement of the structure is converted into rotational motion of the rotating mass. This produces a rotational inertia mass effect and a viscous damping effect, thereby suppressing the vibration of the structure.

[0014] Furthermore, because the tension spring applies a predetermined amount of initial tension to the support member, the support member is always kept in tension even when the mass damper alternately applies tensile and compressive loads to the support member during vibration of the structure. This makes it possible to prevent buckling of the support member without the need for a special buckling prevention mechanism as in the past.

[0015] Furthermore, the rotational inertia mass of the mass damper is set to a value that is increased in accordance with the stiffness of the tension spring relative to the rotational inertia mass that would be set when no tension spring is installed. This prevents a decrease in the rotational inertia mass effect of the mass damper that would occur with the introduction of initial tension, and achieves vibration damping effects equivalent to those achieved when no initial tension is installed.

[0016] The invention according to claim 2 is the vibration damping device for a structure according to claim 1, wherein the ratio of the stiffness of the tension spring to the stiffness of the support member is ηd, and the rotational inertia mass mdηd of the mass damper is set so that the natural frequency of the additional vibration system is synchronized with the natural frequency of the structure under the condition that the tension spring is not installed, and the rotational inertia mass mdηd of the mass damper is expressed as mdηd=(1+ηd) 2 ·It is characterized by being set to mdo.

[0017] As will be described later, the rotational inertia mass mdηd of the mass damper is calculated based on the stiffness ratio ηd defined above and the rotational inertia mass mdo when the tension spring is not installed, as follows: mdηd=(1+ηd) 2 When set to mdo (rotational inertia mass mdo (1 + ηd) 2 It has been theoretically proven, and confirmed by the results of simulation analysis, that when the pretension is set at 1 / 2 times, the same vibration control effect as when no pretension is introduced can be obtained. Therefore, with this configuration, it is possible to obtain the same vibration control effect as when pretension is introduced, by synchronizing the natural frequency of the additional vibration system with the natural frequency of the structure.

[0018] The invention according to claim 3 is characterized in that, in the vibration control device for a structure according to claim 1 or 2, the mass damper is configured as a pressure motor-type mass damper that converts the flow of a working fluid generated when the displacement of the structure is transmitted through a support member into rotational motion of a rotating mass.

[0019] With this configuration, the mass damper is a pressure motor type, and generates a rotational inertia mass effect by converting the flow of the working fluid generated when the displacement of the structure is transmitted through the support member into the rotational motion of the rotating mass. Furthermore, unlike ball screw-type mass dampers, pressure motor-type mass dampers generate a torque force simultaneously with the damping force, which does not act on the support member. This allows for the omission of a twist prevention mechanism for the support member, which is required for ball screw-type mass dampers.

[0020] The invention of claim 4 is characterized in that, in the vibration control device for a structure described in claim 1 or 2, the support member extends to the roof of the structure through the inside of a column installed on the periphery of the structure, and the mass damper and tension spring are arranged on the roof of the structure and connected to the support member.

[0021] The roof of a structure has more space than the bottom of the structure. Therefore, with this configuration, the mass damper and tension spring can be placed on the roof with ample space. Furthermore, because the support members are hidden inside the columns and the mass damper and other components are placed on the roof far from the ground, the appearance of the structure can be maintained in a good condition.

[0022] The invention of claim 5 is characterized in that, in the vibration control device for a structure described in claim 4, it further comprises a gate-shaped support frame provided on the roof of the structure to support the mass damper, the upper ends of the support members extend within the premises of the support frame, the mass damper and tension spring are arranged within the premises of the support frame, and an exterior material is attached to the support frame so as to cover the mass damper and tension spring.

[0023] With this configuration, the mass damper and tension spring can be housed compactly within the support structure, and the exterior material attached to the support structure effectively protects the mass damper and other components from exposure to wind and rain. [Brief explanation of the drawings]

[0024] [Figure 1] 1A and 1B are a front view and a plan view, respectively, schematically illustrating a vibration damping device according to the present invention and a structure to which the device is applied. [Figure 2] 1A and 1B are diagrams showing a support member, a mass damper, and a tension spring before and after the application of initial tension, respectively; [Figure 3] FIG. 2 is a cross-sectional view of a mass damper. [Figure 4] FIG. 2 is a front view showing how the structure of FIG. 1 swings. [Figure 5] FIG. 2 is a diagram showing a model of a structure and a vibration damping device. [Figure 6] FIG. 10 is a diagram showing the relationship between the frequency ratio and the displacement response magnification. [Figure 7] FIG. 10 is a diagram showing the relationship between the mass ratio and stiffness ratio and the optimum tuning frequency ratio. [Figure 8]FIG. 10 is a diagram showing the relationship between the mass ratio and stiffness ratio and the displacement response magnification of a fixed point at the optimal tuning frequency ratio. [Figure 9] FIG. 10 is a diagram illustrating an example of the relationship between the stiffness ratio and the equivalent mass increase ratio. [Figure 10] FIG. 10 is a diagram showing the relationship between the mass ratio and stiffness ratio and the optimum damping constant. [Figure 11] 1A and 1B are diagrams showing the relationship between the stiffness ratio and (a) the equivalent mass increase ratio, (b) the stiffness increase ratio, and (c) the damping coefficient increase ratio. [Figure 12] 12A and 12B are diagrams showing examples of (a) equivalent mass increase ratio, (b) stiffness increase ratio, and (c) damping coefficient increase ratio calculated using FIG. 11. [Figure 13] Figure 1 shows the results of simulation analysis (OTM and inter-story deformation angle) when two types of earthquake motions (a) and (b) are input for cases where no tension spring is installed, where a tension spring is installed, and where no mass damper is installed. [Figure 14] FIG. 10 is a diagram showing the results of a simulation analysis (absolute acceleration response magnification) when the stiffness of the support member is set to the optimum value and a value deviated from the optimum value, for (a) a case where a tension spring is not provided, and (b) a case where a tension spring is provided. [Figure 15] 10A and 10B are diagrams illustrating other examples of the arrangement of vibration damping devices relative to a structure. [Figure 16] FIG. 10 is a diagram showing another example of the arrangement of a vibration damping device relative to a structure. [Figure 17] FIG. 10 is a diagram showing yet another example of the arrangement of vibration damping devices relative to a structure. [Figure 18] 3A and 3B are diagrams showing a support member, a mass damper, and a tension spring having a different configuration from that shown in FIG. 2, in a state before initial tension is applied, and in a state after initial tension is applied. [Figure 19] FIG. 1 is a front view schematically showing a vibration control device in which a mass damper or the like is arranged on the roof of a structure. [Figure 20] 20 shows an embodiment of the vibration damping device according to FIG. 19. FIG. [Figure 21]20A and 20B are diagrams showing another embodiment of the vibration damping device based on FIG. 19. [Figure 22] 20A and 20B show yet another embodiment of the vibration damping device according to FIG. 19. DETAILED DESCRIPTION OF THE INVENTION

[0025] A preferred embodiment of the present invention will be described in detail below with reference to the drawings. As shown in Fig. 1, structure B on which vibration control device 1 is installed is a high-rise building, for example 38 stories high, and is erected on foundation F on the ground. Vibration control device 1 includes a plurality of additional vibration systems A each consisting of support members 2 and mass dampers 3, and tension springs 4 for applying initial tension to support members 2. Vibration control device 1 synchronizes the natural frequency of additional vibration system A with the natural frequency of structure B, which vibrates during an earthquake or the like, thereby absorbing the vibration energy of structure B with additional vibration system A and suppressing the vibration of structure B.

[0026] Structure B has a rectangular planar shape, and its dimensions are, for example, long side length L = @7.2m x 7 = 50.4m, short side length D = 12.8 + 9.6 = 22.4m, and height H = @4m x 38 = 152m. Additional vibration systems A are installed between the top of structure B and foundation F, with seven units on each side of the short side of structure B (14 units in total), evenly spaced along the long side.

[0027] The support member 2 is disposed outside the structure B and extends in the vertical direction, with its upper end connected to the top of the structure B and its lower end connected to the mass damper 3. More specifically, the support member 2 is composed of a plurality of steel columns joined and fixed in the vertical direction, and as shown in FIG. 2, a first steel connecting member 5 is integrally provided at the lower end, and the support member 2 is connected in series to one end of the mass damper 3 via the first connecting member 5. The mass damper 3 is disposed in the vertical direction, and its other end is connected to a second steel connecting member 6 provided integrally with the foundation F.

[0028] A pair of threaded rods 7, 7 are fixed to the second connecting member 6 on both sides of the mass damper 3 with fixing nuts 8 or the like. Each threaded rod 7 extends upward from the second connecting member 6, passes through the first connecting member 5, and protrudes upward. The tension spring 4 and adjustment nut 9 are provided on the protruding portion of this threaded rod 7. The tension spring 4 is, for example, a coil spring threaded onto the threaded rod 7, and has a predetermined rigidity (axial rigidity) kd. The adjustment nut 9 is positioned above the tension spring 4, and is screwed onto the threaded rod 7 so that it can move back and forth.

[0029] With the above configuration, as shown in FIG. 2(a), when the adjusting nut 9 is separated from the upper end of the threaded rod 7, the tension spring 4 is in a free state, and no initial tension is applied to the support member 2. From this state, as shown in FIG. 2(b), when the adjusting nut 9 is turned and moved downward, the tension spring 4 is compressed by the adjusting nut 9, pressing the first connecting member 5 downward and thereby applying initial tension to the support member 2. The magnitude of this initial tension can be continuously adjusted by adjusting the amount of compression of the tension spring 4 by the adjusting nut 9. In this embodiment, the initial tension is set to a predetermined value slightly greater than the maximum compressive load of the mass damper 3 expected to act on the support member 2 during an earthquake.

[0030] The mass damper 3 is a gear motor-type viscous mass damper that uses a working fluid HF, and as shown in FIG. 3, includes a cylinder 12 having a peripheral wall 12a and first and second end walls 12b, 12c and filled with the working fluid HF, a piston 13 slidably provided within the cylinder 12 and dividing the interior of the cylinder 12 into first and second fluid chambers 12d, 12e, a communication passage 14 bypassing the piston 13 and communicating with the first and second fluid chambers 12d, 12e, a gear motor 15 disposed within the communication passage 14, a rotating mass 16 connected to the gear motor 15, and first and second piston rods 17a, 17b that are integral with the piston 13, extend on both sides of the piston 13, and protrude from the first and second end walls 12b, 12c, respectively.

[0031] A hollow protrusion 12f is integrally formed on the first end wall 12b of the cylinder 12, and the first piston rod 17a is housed within this protrusion 12f. A first mounting fixture FL1 is attached to the tip of the protrusion 12f via a universal joint BJ, and a second mounting fixture FL2 is attached to the tip of the second piston rod 17b via a universal joint BJ. The working fluid HF is a fluid with appropriate viscosity, such as silicone oil or hydraulic oil.

[0032] The gear motor 15 is, for example, an external gear type, and is housed in a casing 15a that communicates with the communication passage 14. It has an input gear 15b and an output gear 15c that mesh with each other, and an output shaft 15d that is integrally connected to the output gear 15c. A disk-shaped rotating mass 16 is integrally connected to this output shaft 15d. Of course, an internal gear type may also be used as the gear motor 15.

[0033] The piston 13 has a plurality of holes (only two are shown) that penetrate in the axial direction, and these holes are provided with first and second relief valves 18, 19, respectively. The first relief valve 18 is composed of a valve body and a spring that biases the valve body to the valve closing side, and opens when the pressure of the working fluid HF in the first fluid chamber 12d increases and reaches a predetermined relief load as the piston 13 moves leftward in FIG. 3. The second relief valve 19 is similarly configured, and opens when the pressure of the working fluid HF in the second fluid chamber 12e reaches a relief load as the piston 13 moves rightward in FIG. 3.

[0034] As shown in FIG. 2, the mass damper 3 having the above configuration is attached to the upper surface of the second connecting member 6 via a first mounting fixture FL1, and is attached to the lower surface of the first connecting member 5 via a second mounting fixture FL2.

[0035] In this mass damper 3, when the structure B oscillates as shown in Fig. 4 during an earthquake or the like, the displacement of the structure B is transmitted via the support member 2 and the first connecting member 5, causing the piston 13 to reciprocate relative to the cylinder 12. As a result, the working fluid HF in one of the first and second fluid chambers 12d, 12e is pushed out by the piston 13 and flows into the communicating passage 14. This flow of the working fluid HF is converted into rotational motion by the gear motor 15, thereby exerting an inertial mass effect due to the rotation of the rotating mass 16 and an inertial mass effect due to the flow of the working fluid HF. In addition, a viscous damping effect is obtained by the working fluid HF flowing through the communicating passage 14.

[0036] Furthermore, as structure B sways, the compressive load and tensile load of mass damper 3 act alternately and repeatedly on support member 2. As described above, because the initial tension on support member 2 is set to a predetermined value greater than the maximum compressive load of mass damper 3 during an earthquake, support member 2 is always maintained in a tensile state during an earthquake. This makes it possible to prevent buckling of support member 2 without requiring a special buckling prevention mechanism as in the past.

[0037] Furthermore, as structure B oscillates, additional vibration system A, which is made up of support member 2 and mass damper 3, vibrates. As a result, the vibration energy of structure B is absorbed by additional vibration system A, thereby suppressing the vibration of structure B. In this embodiment, even when initial tension is introduced to support member 2 by tension spring 4, the specifications of additional vibration system A (equivalent mass (rotational inertia mass) md and damping coefficient cd of mass damper 3, stiffness kb of support member 2) and stiffness kd of tension spring 4 are set so that the natural frequency of additional vibration system A, taking into account the influence of the stiffness of tension spring 4, is optimally synchronized with the natural frequency of structure B. This setting method will be described in detail below.

[0038] First, the overall system consisting of structure B and vibration control device 1 shown in Figure 1 is modeled as shown in Figure 5. Structure B, the target of vibration control (hereinafter referred to as "main system B"), is represented by a one-mass system model in which an internal spring (k) and internal damping (c) are connected in parallel to one mass (m). An additional vibration system A, which takes into account the effect of the stiffness of the tension spring 4, is modeled in such a way that an inertial connection element (md) consisting of the rotating mass 16 of the mass damper 3 and a viscous element (cd) consisting of the working fluid HF are connected in parallel to a spring element (kb) consisting of the support member 2, and further, a spring element (kd) consisting of the tension spring 4 is connected in parallel to the inertial connection element (md) and the viscous element (cd).

[0039] In the above overall system, the displacement response magnification of the main system B when subjected to ground motion input is analyzed based on fixed point theory, and the optimum tuned frequency ratio between the main system B and the additional vibration system A, which takes into account the effect of the stiffness of the tension spring 4, and the optimum damping constant of the additional vibration system A, which takes into account the effect of the stiffness of the tension spring 4, are determined as follows.

[0040] First, the equations of motion when the main system B receives ground motion input are expressed by the following equations (1) and (2).

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[0041] To solve this equation of motion, the following relational expressions (parameters) are defined.

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[0042] From the above equations (1) to (3), the displacement response magnification x / xo (displacement of the primary system / input displacement) of the primary system B is calculated as shown in the following equation (4): Here, the symbol i in equation (4) represents the imaginary unit √(-1).

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[0043] Furthermore, by substituting the damping constant h=0 of the main system B and the damping constant hd=0 of the additional vibration system A, as well as h=0 and hd=∞ into equation (4), we obtain the following equations (5) and (6) which represent the displacement response magnification |x / xo| when h and hd are under these conditions.

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[0044] Next, based on fixed point theory, by connecting the right-hand sides of equations (5) and (6) with an equation taking into account the signs in the absolute values, the following equation (7) is obtained. By solving equation (7) for the frequency ratio γ, the frequency ratios γ(P) and γ(Q) of the two fixed points P and Q, which are the intersections of the two response magnification curves shown in Figure 6, can be obtained as shown in the following equation (8).

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[0045] Next, the natural circular frequency ratio β when the heights (displacement response magnification) of the fixed points P and Q are equal is calculated as the optimal tuning frequency ratio βopt. Specifically, the displacement response magnifications |x / xo| obtained by substituting the frequency ratios γ(P) and γ(Q) of equation (8) into equation (6) are assumed to be equal to each other, leading to the following equation (9), and by expanding equation (9), the following equation (10) is obtained. Then, the frequency ratio γ of equation (8) is added to equation (10). 2 (P), γ 2 By substituting (Q) and solving for the natural circular frequency ratio β, the optimal tuning frequency ratios βopt(S) and βopt(H) shown in the following equation (11) can be obtained. Note that βopt(S) is a soft spring solution corresponding to the embodiment, and βopt(H) is a hard spring solution.

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[0046] If βopt(S) of the flexible spring solution of this equation (11) is illustrated, it is mapped as shown in Figure 7. Furthermore, if ηd = 0 in equation (11), equation (12) is obtained. This equation (12) is completely consistent with the equation known as the flexible spring solution of the optimal tuning frequency ratio when no tension spring is provided. Furthermore, if equation (11) is rearranged with respect to the flexible spring solution, equation (13) is obtained. The equation in the square root of this equation (13) = (1 + ηd) 2 From the condition -4μ≧0, when the mass ratio μ with respect to the stiffness ratio ηd satisfies the condition of equation (14), a soft spring solution exists.

[0047] Next, the displacement response magnification of the fixed points P and Q at the optimal tuned frequency ratio βopt(S) when the stiffness ratio ηd is taken into consideration (when the tension spring 4 is provided) is calculated. First, the following equation (15) is derived from equation (6). The optimal frequency ratio γ 2 (P)_opt(S), γ 2 By substituting the following equation (16) for (Q)_opt(S) and the above equation (13) for the optimal tuning frequency ratio βopt(S) and rearranging them, the following equation (17) is obtained.

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[0048] On the other hand, when ηd=0 (when tension spring 4 is not provided), the displacement response magnification |x / xo|βopt(S) of fixed points P and Q at the optimal tuning frequency ratio βopt(S) is expressed by the following equation (18) by substituting the optimal tuning frequency ratio βopt(S) of equation (12) and equation (16) into equation (15) and rearranging. The relationship between the mass ratio μ and stiffness ratio ηd and the displacement response magnification |x / xo|βopt(S) of fixed points P and Q at the optimal tuning frequency ratio βopt(S), which is expressed by the above equations (17) and (18), is mapped as shown in Figure 8.

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[0049] Furthermore, by comparing equations (17) and (18), the condition for obtaining the same displacement response magnification when ηd is taken into account as when ηd = 0 at fixed points P and Q at the optimal tuning frequency ratio βopt(S) is expressed by the following equation (19). That is, the mass ratio μηd (equivalent mass mdηd) when ηd is taken into account is calculated by multiplying the mass ratio μo (equivalent mass mdo) when ηd = 0 by (1 + ηd) 2 It can be seen that by setting the stiffness ratio ηd to 0, the same displacement response magnification |x / xo|βopt(S) can be obtained. Therefore, the increase ratio Rmd of the equivalent mass md when considering ηd (hereinafter referred to as "equivalent mass increase ratio") required to obtain the same vibration suppression effect as when the stiffness ratio ηd=0 is expressed as Rmd=mdηd / mdo=(1+ηd) as shown in the following equation (20). 2 It is represented as shown in FIG. 9 and is also mapped as shown in FIG. 11(a).

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[0050] Next, the optimal damping constant hd at the optimal tuning frequency ratio βopt(S) is calculated as the optimal damping constant hd_opt(S). The basic formula is expressed by the following formula (21). The optimal damping constants h(P)_opt(S) and h(Q)_opt(S) under the condition that the response magnification curves become maximum values ​​at fixed points P and Q in formula (21) are given by the following formula (22). Furthermore, the displacement response magnification |x / xo|βopt(S) in formula (22) is calculated by the above formula (17) using the optimal frequency ratio γ 2 (P)_opt(S), γ 2 (Q)_opt(S) is given by the above formula (16), and the optimal tuning frequency ratio βopt(S) is given by the above formula (13). As a result, the optimal damping constant hd_opt(S) becomes a function of the mass ratio μ and stiffness ratio ηd, and although the formula is very complicated and not shown, it can be mapped as shown in Figure 10.

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[0051] Furthermore, if the stiffness ratio ηd = 0 in the function representing this optimal damping constant hd_opt(S), the following equation (23) is obtained. This equation (23) is completely consistent with an equation known as the soft spring solution for the optimal damping constant when no tension spring is provided.

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[0052] The viscosity coefficient cd corresponding to the optimal damping constant hd_opt(S) is expressed by the following equation (24). By substituting the optimal damping constant hd_opt(S) from equation (21) and the optimal tuning frequency ratio βopt(S) from equation (13) into this equation (24), the viscosity coefficient cdηd when ηd is taken into account can be obtained as a function of the mass ratio μ and the stiffness ratio ηd. Furthermore, by substituting the optimal damping constant hd_opt(S) from equation (18) and the optimal tuning frequency ratio βopt(S) from equation (12) into equation (24), the viscosity coefficient cdo when ηd = 0 can be obtained as a function of the mass ratio μ and the stiffness ratio ηd. Therefore, the increase ratio Rcd of the damping coefficient cd when ηd is taken into account (hereinafter referred to as the "damping coefficient increase ratio") required to obtain the same vibration damping effect as when the stiffness ratio ηd = 0 is expressed as Rcd = cdηd / cdo as shown in the following equation (25), and is mapped as shown in Figure 11(c).

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[0053] Furthermore, the stiffness kb of the support member 2 corresponding to the optimal tuning frequency ratio βopt(S) (hereinafter referred to as "support member stiffness") is expressed by the following equation (26). By substituting the optimal tuning frequency ratio βopt(S) from equation (13) into this equation (26), the support member stiffness kbηd when ηd is taken into account can be obtained, and by substituting the optimal tuning frequency ratio βopt(S) from equation (12), the support member stiffness kbo when ηd = 0 can be obtained, both as functions of the mass ratio μ and the stiffness ratio ηd. Therefore, the increase ratio Rkb of the support member stiffness kb when ηd is taken into account (hereinafter referred to as "stiffness increase ratio") required to obtain the same vibration damping effect as when the stiffness ratio ηd = 0 is expressed as Rcd = kbηd / kbo as shown in the following equation (27), and is mapped as shown in FIG. 11(b).

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[0054] Next, we will explain in detail the specific method for setting the parameters of the additional vibration system A (equivalent mass md and damping coefficient cd of the mass damper 3, support member rigidity kb, etc.) when initial tension is introduced to the support member 2 by the tension spring 4 using the setting method described above.

[0055] First, for a high-rise structure B (main system) as shown in Figure 1 (L = 7.2m x 7 = 50.4m, D = 12.8 + 9.6 = 22.4m, H = 4m x 38 = 152m), when the stiffness ratio ηd = 0 (tension spring 4 is not provided), the specifications of each additional vibration system A are set as follows so that the natural frequency of the additional vibration system A is optimally synchronized with the first natural frequency of structure B. ·Equivalent mass mdo=20000ton (mass ratio μo=0.031) Damping coefficient cdo=4.7kNs / mm Support member stiffness kbo=36.4kN / mm Connection node consideration stiffness kbo'=30.7kN / mm The above mass ratio μo was calculated taking into consideration the excitation function in the first mode of the high-rise structure B (main system) model.

[0056] Furthermore, the model set up as above, i.e., the model in which the additional vibration system A (support member 2 and mass damper 3) is provided to the structure B shown in Figure 1, the tension spring 4 is not provided (ηd = 0), and the specifications of the additional vibration system A are set up as above, is called the "ηd = 0 model."

[0057] Next, based on these specifications, when the tension spring 4 is provided, the specifications of the additional vibration system A to obtain the same vibration damping effect as when it is not provided (ηd=0) are set as follows. Here, the stiffness ratio ηd is set to 0.3. First, for the equivalent mass mdηd, use the above formula (19) and substitute the values ​​of the equivalent mass mdo and stiffness ratio ηd when ηd=0 above, and you can get mdηd=(1+ηd) 2 ·mdo =(1+0.3) 2 ×20000 = 33,800 ton (mass ratio μηd = 0.052).

[0058] If the table of FIG. 9 or the map of FIG. 11(a) relating to the equivalent mass increase ratio Rmd is available, these can be used to apply ηd=0.3 to obtain Rmd=approximately 1.7 (see FIG. 12(a)), and then multiply this by the equivalent mass mdo to obtain the equivalent mass mdηd.

[0059] Next, for the damping coefficient cdηd, by applying ηd=0.3 and μ=0.031 to the map in FIG. 11(c), we obtain the damping coefficient increase ratio Rcd=approximately 1.7 as shown in FIG. 12(c). Then, by multiplying this by the damping coefficient cdo when ηd=0, we obtain cdηd=Rcd·cdo = approx. 1.7×4.7 =8.0kNs / mm.

[0060] Next, for the support member stiffness kbηd' taking into account the stiffness of the connection nodes, by applying ηd=0.3 and μ=0.031 to the map in Figure 11(b), we obtain a stiffness increase ratio Rkb=approximately 1.3 as shown in Figure 12(b). Then, by multiplying this by the support member stiffness kbo' taking into account the stiffness of the connection nodes when ηd=0, we obtain kbηd'=Rkb·kbo' = approx. 1.3×30.7 =40.1kN / mm. Here, when the support member stiffness kbηd is calculated after removing the influence of the connection node stiffness, it becomes kbηd=50.5 kN / mm. In addition, the stiffness kd of tension spring 4 is kd=0.3×kbηd' =0.3×40.1 =12.03kN / mm.

[0061] Furthermore, the model set up as above, i.e., the model in which the additional vibration system A and the tension spring 4 are provided to the structure B shown in Figure 1, the specifications of the additional vibration system A are set as above, and the stiffness ratio ηd is set to 0.3, is referred to as the "ηd = 0.3 model."

[0062] Next, a simulation analysis performed to confirm the vibration damping effect of the vibration damping device of this embodiment and the results thereof will be described with reference to Figures 13 and 14. This simulation analysis was a time history response analysis of the response of structure B when a predetermined earthquake motion was input to the foundation F of structure B.

[0063] The conditions for the simulation analysis are as follows: First, the analysis targets were the "ηd=0 model" without the tension spring 4 described above, and the "ηd=0.3 model" with the tension spring 4, and further, for comparison, a "damper-less model" without the additional vibration system A and the tension spring 4 was added.

[0064] Furthermore, the input earthquake motions used were the "Tokyo Meteorological Agency NS" earthquake prediction and the "L2 Hachinohe Phase" earthquake wave.The response acceleration, velocity, and displacement of each floor of Structure B when these earthquake motions were input to the foundation F of Structure B were calculated, and the OTM (overturning moment) and story deformation angle were also calculated.

[0065] The results of the analysis are shown in Figure 13. First, for the OTM, in all earthquake motions, the "ηd=0 model" and "ηd=0.3 model" show a significant reduction compared to the "no damper model." The same is true for the story drift angle. From the above, it can be inferred that the vibration control effect is fully exerted by optimally tuning the natural frequency of additional vibration system A to the primary natural frequency of structure B.

[0066] Furthermore, when comparing the "ηd=0 model" and the "ηd=0.3 model," the OTM and story deformation angle were nearly the same for both earthquake motions, and for this reason, the results for both models are depicted with a single line in Figures 13(a) and (b). This confirms that when tension spring 4 is installed, the same vibration control effect can be obtained as when tension spring 4 is not installed, depending on the settings of the specifications of additional vibration system A described above.

[0067] Furthermore, in order to confirm the effect of the support member stiffness kb on robustness in each of the "ηd=0 model" and "ηd=0.3 model," a time history response analysis was performed on models in which the support member stiffness kb was set to the optimal value (=kbo, kbηd), 1.2 times the optimal value, and 0.8 times the optimal value, and the absolute acceleration response magnification of the top to ground motion was calculated.

[0068] The results of this analysis are shown in Figure 14. When the support member stiffness kb is set to the optimal value, the maximum absolute acceleration response magnification is approximately 8.8 for both the "ηd=0 model" and the "ηd=0.3 model." In contrast, when the support member stiffness kb is deviated from the optimal value by 1.2 or 0.8 times, the maximum acceleration response magnification increases to approximately 16 or 12.5 for the "ηd=0 model," while it increases to a lower value of approximately 14 or 11.5 for the "ηd=0.3 model." In other words, the "ηd=0.3 model," which includes the tension spring 4, is found to have higher robustness against the support member stiffness kb than the "ηd=0 model," which does not include the tension spring 4.

[0069] The present invention is not limited to the embodiment described above and can be embodied in various forms. For example, in the embodiment, as shown in Fig. 1, a plurality of additional vibration systems A are arranged outside the outer periphery of a structure B, each support member 2 is installed so as to extend vertically from the top of the structure B to near the bottom, and a mass damper 3 and a tension spring 4 (hereinafter referred to as "mass damper 3, etc.") are installed at the bottom of the structure B, but the present invention is not limited to this.

[0070] For example, Figures 19 to 22 show several examples in which mass dampers 3 and other components are installed on the roof of structure B. As shown in Figure 19, in these examples, several additional vibration systems A are arranged on the outer periphery of structure B, and each support member 2 extends vertically from the roof of structure B to near the bottom, just like in Figure 1, and mass dampers 3 and tension springs 4 are installed on the roof of structure B, unlike in Figure 1.

[0071] Specifically, in the embodiment of FIG. 20 , support frames 31 are erected integrally at the joints between a plurality of columns PE near the periphery of structure B and beams BU on the rooftop floor, and support beams 32 are provided above support frames 31. For example, columns PE are made of steel columns (steel pipes), and support frames 31 and support beams 32 are made of H-shaped steel. Support members 2 are made of, for example, steel rods and are passed through the interior of columns PE, with their upper ends passing through beams BU, support frames 31, and support beams 32 with some play and extending above support beams 32. Note that if structure B is made of reinforced concrete, sheath pipes may be installed in advance inside the reinforced concrete columns, and support members 2 (steel rods) may be placed inside the sheath pipes.

[0072] The portion of the support member 2 above the support frame 31 is threaded, and two upper and lower adjustment nuts 9, 9 are screwed into this threaded portion so that they can move back and forth. The upper and lower adjustment nuts 9, 9 are arranged above and below the support beam 32, respectively. The tension spring 4 is made up of multiple disc springs with a predetermined rigidity (axial rigidity) kd, and is passed through the threaded portion of the support member 2 and is arranged between the lower adjustment nut 9 and the support frame 31. The mass damper 3 is also arranged in the vertical direction, with its lower end connected to the upper surface of the beam BU and its upper end connected to the underside of the support beam 32.

[0073] With the above configuration, when the lower adjusting nut 9 is tightened and moved downward, the tension spring 4 is compressed, and the reaction force pushes up the support member 2 via the adjusting nut 9, thereby introducing initial tension into the support member 2. The magnitude of the initial tension can be adjusted continuously by adjusting the amount of compression of the tension spring 4 by the adjusting nut 9.

[0074] Furthermore, the roof of structure B has more space than the bottom of structure B, allowing for ample placement of mass dampers 3, tension springs 4, etc. Furthermore, because support members 2 are hidden inside columns PE and mass dampers 3 and other components are placed on the roof far from the ground, the appearance of the building can be maintained in good condition.

[0075] In the embodiment of Figure 21, a support framework 33 is erected integrally at the joints between multiple columns PE near the periphery of structure B and beams BU on the rooftop floor. The support framework 33 is an assembly of multiple H-shaped steel beams, and is formed into a portal shape from left and right vertical sections 33a, 33a and a horizontal section 33b connecting their upper ends. The support members 2 are made of steel rods, which are passed through the interior of the columns PE, penetrate the beams BU on the upper floor with some play, and extend within the premises of the support framework 33.

[0076] The mass damper 3 is arranged vertically within the support frame 33, with its upper end connected to the underside of the horizontal section 33b of the support frame 33 and its lower end connected to the support member 2. A threaded portion is formed on the surface of a first piston rod extending upward from the piston of the mass damper 3, and an adjustment nut 9 is screwed onto this threaded portion so that it can move back and forth. The tension spring 4 is composed of a coil spring, a disc spring, or the like having a predetermined rigidity (axial rigidity) kd, and is arranged between the first piston rod and the convex portion of the cylinder that houses it, and between the first end wall of the cylinder and the adjustment nut 9. A roof and walls (neither of which are shown) are attached to the top and outer periphery of the support frame 33 as exterior materials for covering the mass damper 3.

[0077] 20, when the adjusting nut 9 is tightened and moved downward, the tension spring 4 is compressed, and the resulting reaction force pushes up the support member 2 via the adjusting nut 9, thereby introducing initial tension into the support member 2. The magnitude of the initial tension can be adjusted continuously by the amount of compression of the tension spring 4.

[0078] 20, the mass damper 3, tension spring 4, etc. can be placed with ample space on the roof of structure B, which has a relatively large space, while maintaining a good appearance of the building. Furthermore, the mass damper 3, tension spring 4, etc. can be housed compactly within the premises of the support structure 33, and the roof and walls attached to the support structure 33 can effectively protect the mass damper 3, etc., from exposure to wind and rain. Note that while this embodiment has the advantage of the tension spring 4 being built into the mass damper 3 in a compact manner, it tends to be difficult to ensure the required rigidity of the tension spring 4.

[0079] The embodiment of FIG. 22 is configured to obtain greater rigidity of the tension spring 4. Specifically, as in the case of FIG. 21, a portal-shaped support frame 33 assembled from multiple H-shaped steel beams is erected integrally at the joints between multiple columns PE near the periphery of structure B and beams BU on the roof floor. The support member 2 is made of a steel rod, passes through the interior of the column PE, penetrates the beam BU on the top floor with some play, and extends into the premises of the support frame 33, with a connecting member 34 integrally attached to its upper end. The mass damper 3 is arranged in the vertical direction, with its lower end connected to the upper surface of the connecting member 34 and the other end connected to the underside of the horizontal part of the support frame 33.

[0080] A pair of threaded rods 7, 7 are fixed to the connecting member 34. Each threaded rod 7 is offset from the mass damper 3 in the depth direction of the paper in FIG. 22, extends upward, and penetrates the horizontal portion 33b of the support frame 33 with some play, protruding upward. A tension spring 4 and an adjustment nut 9 are provided on the protruding portion of each threaded rod 7. The tension spring 4 is made up of, for example, multiple disc springs and has a predetermined stiffness (axial stiffness) kd. The adjustment nut 9 is disposed above the tension spring 4 and is threaded onto the threaded rod 7 so as to be able to move back and forth. Furthermore, as in the embodiment of FIG. 21 , a roof and walls (neither of which are shown) are attached to the top and outer periphery of the support frame 33 so as to cover the mass damper 3.

[0081] In the above configuration, when the adjustment nut 9 is tightened and moved downward, the tension spring 4 is compressed, and the reaction force pushes up the support member 2 via the adjustment nut 9, introducing initial tension into the support member 2, the magnitude of which is continuously adjustable by the amount of compression of the tension spring 4.

[0082] Furthermore, the mass damper 3, tension spring 4, etc. can be placed with ample space on the roof of structure B, which has a relatively large space, while maintaining a good appearance of the building. Furthermore, the roof and walls attached to the support frame 33 effectively protect the mass damper 3 from exposure to wind and rain. Also, unlike the embodiment in FIG. 21, two disc springs with high rigidity are used as the tension spring 4, so the required rigidity can be easily ensured.

[0083] Furthermore, in the examples so far, the upper end of the support member 2 is connected to the top of the structure B, but it may also be connected to any intermediate layer, for example. Also, in the examples of Figures 1 and 19, multiple additional vibration systems A are installed on both sides of the periphery of the structure B, but it goes without saying that additional vibration systems A may be placed on only one side of the periphery of the structure B, or may be placed only at any selected column positions.

[0084] Furthermore, as shown in Figure 15(a), a support member 2 may be installed in the shape of a diagonal brace extending vertically using the PS (pipe space) of structure B, and a mass damper 3 may be installed at its lower end. Also, as shown on the right side of Figure 15(a), the upper end of the support member 2 may be connected to any intermediate layer rather than the top of structure B.

[0085] Also, as shown in the left part of Figure 1(b), the support member 2 may be installed in the form of a diagonal brace on the outside of structure B, or as shown in the right part of Figure 1(b), the mass damper 3 and the like may be installed at any intermediate part or upper part of support member 2 rather than at the lower part. Also, as shown in Figure 1(c), when structure B is set back, support member 2 may be installed in the form of a diagonal brace in the empty space within the setback range (right part of Figure 1(c)), and support member 2 may also be installed in the form of a diagonal brace on the outside of the periphery of structure B (left part of Figure 1(c)).

[0086] Furthermore, when support members with a small moment of inertia are installed in the form of diagonal braces as described above, when the initial tension shifts in the decreasing direction due to the damper reaction force, there is a risk that the expected axial rigidity of the support members may not be secured due to the influence of deflection (sag) caused by the support members' own weight.For this reason, when installing long support members in the form of diagonal braces, it is desirable to use support members with a fairly large moment of inertia.

[0087] It is also possible to arrange the additional vibration system A as shown in Figure 16. In this example, the atrium S of structure B is used as the installation space, and a mountain-shaped support member 2 consisting of a pair of rods connected to each other is installed between the 19th and 26th floors, and an inverted mountain-shaped support member 2 consisting of a pair of rods connected to each other is installed symmetrically above and below this between the 28th and 35th floors. In addition, a tension spring 4 consisting of a cable or the like is installed between the 26th and 28th floors, connecting the upper and lower support members 2, 2, and this tension spring 4 introduces an initial vertical tension to the upper and lower support members 2, 2.

[0088] Furthermore, four mass dampers 3 are installed horizontally (horizontally) on each of the 26th and 28th floors (only two are shown on each floor in Figure 16(b)). These four mass dampers 3 are arranged to extend radially from the center of the atrium S, and are connected to the connection c1 between the support member 2 and tension spring 4 and the connection c2 between the column and beam of structure B, respectively. Note that in the example of Figure 16, the mass dampers 3 are installed horizontally (horizontally) between connection c1 and connection c2, but it is of course possible to move the position of connection c2 from the 26th and 28th floors to the 27th floor and install the mass dampers 3 diagonally instead of horizontally.

[0089] With the above configuration, when structure B sways during an earthquake or other event, the displacement of structure B is transmitted as horizontal displacement to mass damper 3 via support member 2, activating mass damper 3 to achieve vibration control. Furthermore, because tension spring 4 applies initial vertical tension to support member 2, buckling of support member 2 can be prevented without the need for a special buckling prevention mechanism. Furthermore, by setting the specifications of additional vibration system A, such as the equivalent mass md of mass damper 3, in the same way as in the previously described embodiment, the same vibration control effect can be achieved as when no initial tension is applied.

[0090] Figure 17 shows another arrangement of the additional vibration system A. In this example, a pair of left and right support members 2, 2 are arranged on the upper and lower sides, respectively, between the left and right columns P, P of the structure B. The upper left support member 2 has one end connected to the left column P and the other end formed into a mountain shape by a pair of rods connected to each other, and the right support member 2 has one end connected to the right column P and the other end formed into a mountain shape by a pair of rods connected to each other, and faces the left support member 2. Tension springs 4 made of cables or the like are connected to these left and right support members 2, 2, and an initial horizontal tension is introduced.

[0091] Meanwhile, the lower left and right support members 2, 2 are configured similarly to the upper left and right support members 2, 2, but are formed with a more acute mountain shape and face each other. Tension springs 4 made of cables or the like are connected to these left and right support members 2, 2, and an initial horizontal tension is introduced. Furthermore, U-shaped connecting members CM made of steel or the like are connected to the connections c3, c3 between the upper left and right support members 2, 2 and the tension springs 4. Mass dampers 3 are installed vertically (vertically) between these connecting members CM and the connections c4, c4 between the lower left and right support members 2, 2 and the tension springs 4, respectively. While the mass dampers 3 are installed vertically (vertically) in the example shown in FIG. 17, it goes without saying that the mass dampers 3 may be installed diagonally by moving the positions of the connections c4, c4, etc.

[0092] With the above configuration, when structure B sways during an earthquake or other event, the displacement of structure B is transmitted as vertical displacement to mass damper 3 via support member 2, activating mass damper 3 to achieve vibration control. Furthermore, as a result of the tension spring 4 introducing initial horizontal tension into support member 2, buckling of support member 2 can be prevented without the need for a special buckling prevention mechanism, and by appropriately setting the specifications of additional vibration system A, the same vibration control effect as when initial tension is not introduced can be obtained, thereby achieving the same effects as those achieved by the vibration control device of the above-mentioned embodiment and the one shown in FIG. 16.

[0093] In the embodiment, a coil spring or a disc spring is used as the tension spring 4 for applying initial tension to the support member 2, but this is not limiting and other appropriate configurations can be used. Figure 18 shows an example of such a tension spring. In this example, tension springs 24 are of the laminated rubber type and are installed on both sides of the mass damper 3 between a first connecting member 5 integrated with the support member 2 and a second connecting member 6 integrated with the foundation F.

[0094] Each tension spring 24 is composed of a laminated body including a central movable plate 24a, rubber plates 24b, 24b on both sides of the movable plate 24a, and fixed plates 24c, 24c on both sides of the movable plate 24a. The movable plate 24a and the fixed plate 24c are made of, for example, steel plates, and the rubber plate 24b is made of natural rubber having a predetermined elasticity (rigidity). The fixed plates 24c, 24c extend upward beyond the rubber plate 24b and are connected at their upper ends to the first connecting member 5. The movable plate 24a extends below the rubber plate 24b, and a horizontal connecting plate 24d is integrally attached to its lower end. A predetermined gap is formed between the connecting plate 24d and the second connecting member 6. A plurality of threaded rods 25 are fixed to the second connecting member 6. Each threaded rod 25 extends upward from the second connecting member 6, penetrates the connecting plate 24d, and protrudes upward. An adjusting nut 26 is screwed onto the protruding portion of this threaded rod 25 so as to be able to move back and forth.

[0095] With the above configuration, as shown in Figure 18(a), when the adjustment nut 26 is located at the upper end side of the threaded rod 25 and is separated from the connecting plate 24d, the tension spring 24 is in a free state and no initial tension is generated in the support member 2.

[0096] From this state, as shown in FIG. 2(b), when the adjustment nut 26 is turned and moved downward, the movable plate 24a is pushed down via the connecting plate 24d pressed by the adjustment nut 26. As a result, the rubber plate 24b is pulled downward and, in an extended state, an initial tension is introduced into the support member 2 via the fixed plate 24c and the first connecting member 5. The magnitude of this initial tension depends on the rigidity of the rubber plate 24b, and can be adjusted continuously by adjusting the amount of extension of the tension spring 24 using the adjustment nut 26. As described above, the tension spring 24 can be used in the same way as the tension spring 4 in FIG. 2.

[0097] In addition, in the embodiment, a steel pillar material is used as the support member 2. As described above, in the present invention, the introduction of initial tension causes the support member to be constantly in tension, so it is sufficient for the support member to have the necessary axial rigidity. Therefore, steel materials with a relatively small moment of inertia, cables, steel rods, etc. can be used as the support member. Of course, a high-strength material may also be used to increase the elastic limit strength of the support member 2. In the above explanation, it is assumed that the initial tension is set to a predetermined value greater than the maximum compressive load of the mass damper 3. However, it is of course possible to set the initial tension to a value smaller than the maximum compressive load of the mass damper 3 as long as the support member does not buckle.

[0098] Furthermore, in the embodiment, the mass damper 3 is a gear motor type that uses the working fluid HF, but a pressure motor other than a gear motor, such as a piston motor, vane motor, or screw motor, may also be used. Also, instead of a pressure motor type mass damper, it is possible to adopt a ball screw type that uses a ball screw to drive a rotating mass. However, in the case of a ball screw type mass damper, a torque force is generated simultaneously with the damping force. Therefore, it is necessary to provide a twist prevention mechanism to prevent twisting of the support member due to the action of this torque force.

[0099] Furthermore, in the embodiment, the natural frequency of the additional vibration system A is set to synchronize with the first natural frequency of the structure B, but this is not limited to this, and it is of course possible to set it to synchronize with the natural frequency of any order of the structure B.

[0100] Furthermore, the structure of structure B is not particularly limited, and any of steel frame construction (S construction), reinforced concrete construction (RC construction), steel framed reinforced concrete construction (SRC construction), concrete filled steel pipe construction (CFT construction), etc. can be used as the vibration control target. The present invention is particularly effective for steel towers and structures with large aspect ratios. In addition, the detailed configuration can be modified as appropriate within the scope of the present invention. [Explanation of symbols]

[0101] 1. Vibration control device 2 Support member 3 Mass damper 4 tension springs 15 Gear motor (pressure motor) 16 Rotating grid 24 tension spring 33 Support frame A Additional vibration system B Structure PE pillar mdηd Equivalent mass of the mass damper (rotational inertia mass) ηd: stiffness ratio between tension spring and support member mdo Equivalent mass (rotational inertia mass) when no tension spring is installed

Claims

1. A vibration control device for a structure for suppressing vibration of a structure erected on the ground, a support member having one end connected to the structure and extending in the vertical direction; a mass damper connected to the support member, constituting an additional vibration system together with the support member, having a rotating mass, and exhibiting a rotational inertia mass effect and a viscous damping effect by converting the displacement of the structure transmitted via the support member into rotational motion of the rotating mass when the structure vibrates; a tension spring connected to the support member in parallel with the mass damper and applying an initial tension of a predetermined magnitude to the support member, a rotational inertia mass of the mass damper set to a value that is increased in accordance with the rigidity of the tension spring relative to the rotational inertia mass that would be set under conditions in which the tension spring is not installed;

2. When the ratio of the stiffness of the tension spring to the stiffness of the support member is ηd and the rotational inertia mass is mdo, which is set so that the natural frequency of the additional vibration system is synchronized with the natural frequency of the structure when the tension spring is not installed, the rotational inertia mass mdηd of the mass damper is expressed as mdηd=(1+ηd) ２ 2. The vibration damping device for a structure according to claim 1, wherein the vibration damping device is set to mdo.

3. 3. The vibration control device for a structure according to claim 1, wherein the mass damper is a pressure motor-type mass damper that converts a flow of a working fluid generated when a displacement of the structure is transmitted through the support member into a rotational motion of the rotating mass.

4. 3. The vibration control device for a structure according to claim 1, wherein the support member extends to the roof of the structure through the inside of a column installed on the outer periphery of the structure, and the mass damper and the tension spring are disposed on the roof of the structure and connected to the support member.

5. a gate-shaped support frame provided on a roof of the structure to support the mass damper, an upper end of the support member extends within the support frame, and the mass damper and the tension spring are disposed within the support frame; 5. The vibration damping device for a structure according to claim 4, wherein an exterior material is attached to the support frame so as to cover the mass damper and the tension spring.

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