JP2022134432A - Vibration damper for viscous systems - Google Patents

Abstract

To provide a vibration damper for viscous systems capable of easily and reliably checking whether or not a disconnection pin has been cut with a simple configuration.SOLUTION: The vibration damper for viscous systems includes a disconnection pin 68 that horizontally connects a mounting plate and a viscous damper and has a constricted portion 67 configured so as to, when a certain level of horizontal force is generated on the mounting plate against a bottom wall plate, be broken to release the horizontal connection between the mounting plate and the viscous damper. The vibration damper includes: an accelerometer 111 that is placed in an office building 6 for observing the vibration acceleration acting on the office building as detection means 110 for detecting disconnection of the constricted portion; and Fourier analysis means 112 to which the vibration acceleration observed by the accelerometer is input, and which performs a Fourier analysis of dominant frequencies of the office building.SELECTED DRAWING: Figure 2

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a viscous vibration damping device capable of easily and reliably confirming whether or not a disconnection pin has been cut with a simple configuration.

Conventionally, Patent Document 1 is known as a viscous type vibration damping device used in combination with a seismic isolation device.

A viscous vibration damping device and a base-isolated building having the same in Patent Document 1 includes an upper mounting portion and a lower mounting portion for mounting to an upper structure and a lower structure, respectively, which are relatively vibrated in the horizontal direction. a viscous damper connected to the upper mounting portion and the lower mounting portion for damping horizontal vibration of the upper mounting portion with respect to the lower mounting portion; a release mechanism for releasing the connection of at least one of the upper mounting portion and the lower mounting portion to the viscous damper when a horizontal force is generated, the releasing mechanism configured to release the upper mounting portion and the lower mounting portion from the viscous damper; One of the parts and the viscous damper are connected in the horizontal direction, and when a horizontal force exceeding a certain level is applied to the upper mounting part with respect to the lower mounting part, the upper mounting part and the lower mounting part are cut. a connection release pin having a weakened portion for releasing the horizontal connection between one of the parts and the viscous damper; wherein the bending stress blocking means is disposed about the decoupling pin between one of the upper mounting portion and the lower mounting portion and the viscous damper; a retaining member fixed to one of the upper mounting portion and the lower mounting portion and one of the viscous damper and having the bolts screwed thereon; and a receiving surface fixed to one of the upper mounting portion and the lower mounting portion and the other of the viscous damper and in contact with the expanded head portion of each bolt so as to be movable in the horizontal direction. and a lock nut for adjusting the amount of protrusion of each bolt from the holding member.

Japanese Patent No. 4893061

In the background art described above, by using a disconnection pin that is cut off when a horizontal force exceeding a certain level is generated, the viscous damper is switched between vibration damping and other cases.

With such a configuration, it was necessary to check whether or not the disconnection pin was cut each time an earthquake of considerable scale occurred. In addition, it is necessary for the operator to visually check the installation location of the viscous damper. For this reason, it has been desired to devise a measure that can easily confirm whether or not the disconnection pin has been cut without taking much time.

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned problems in the conventional art. It is an object of the present invention to provide a damping device.

A viscous vibration damping device according to the present invention comprises an upper mounting portion and a lower mounting portion for mounting to an upper structure and a lower structure that are relatively vibrated in a horizontal direction, and the upper mounting portion and the lower mounting portion. a viscous damper for damping horizontal vibration of the upper mounting portion with respect to the lower mounting portion; a release mechanism for releasing the coupling of at least one of the upper mounting portion and the lower mounting portion, the release mechanism connecting one of the upper mounting portion and the lower mounting portion with the viscous damper; are connected in the horizontal direction, and are cut when a horizontal force of a certain level or more is generated in the upper mounting portion with respect to the lower mounting portion, and one of the upper mounting portion and the lower mounting portion and the viscous damper and a bending stress prevention means for preventing bending stress from occurring in the weakened portion of the connection release pin. Means includes a plurality of bolts disposed about the decoupling pin between one of the upper mounting portion and the lower mounting portion and the viscous damper and having an enlarged head. a holding member fixed to one of the upper mounting portion and the lower mounting portion and one of the viscous dampers and to which the bolts are screwed; the upper mounting portion and the lower mounting portion; a pedestal fixed to one of the parts and the other of the viscous dampers and having a receiving surface that contacts the enlarged head of each bolt so as to be movable in the horizontal direction; The viscous vibration damping device comprising a lock nut for adjusting the amount of protrusion from the holding member, further comprising detecting means for detecting cutting of the fragile portion, the detecting means being located on the upper mounting portion side. An accelerometer for observing vibration acceleration acting on the upper structure side, and Fourier analysis means for inputting the vibration acceleration observed by the accelerometer and executing Fourier analysis of dominant frequencies on the upper structure side. and

The detection means further comprises a second accelerometer provided on the side of the lower mounting portion for observing vibration acceleration acting on the side of the lower structure, and the Fourier analysis means comprises the accelerometer and the second accelerometer. Vibration acceleration observed on each side is inputted, and Fourier analysis of dominant frequencies on the upper structure side and the lower structure side is performed.

The Fourier analysis means analyzes the Fourier amplitude ratio between the upper structure side and the lower structure side from the vibration acceleration observed on the upper structure side and the lower structure side respectively. do.

In the viscous vibration damping device according to the present invention, it is possible to easily and reliably confirm whether or not the disconnection pin has been cut, with a simple structure.

FIG. 3 is a cross-sectional explanatory view of the vibration damping device of the example shown in FIG. 2; 1 is a front explanatory view of a preferred example of an embodiment of the present invention; FIG. FIG. 2 is a cross-sectional view of the vibration damping device shown in FIG. 1 taken along line III-III. FIG. 2 is a perspective view of the decoupling pin of the example shown in FIG. 1; FIG. 2 is an operation explanatory diagram of the example shown in FIG. 1; FIG. 2 is an operation explanatory diagram of the example shown in FIG. 1; FIG. 4 is a graph of Fourier spectral ratios as an example of results of Fourier analysis performed by the detection means of the present invention;

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of a viscous vibration damping device according to the present invention will be described in detail below with reference to the accompanying drawings. First, a viscous vibration damping device, which is a premise of the present invention, will be described.

1 to 4, the seismic isolation building 1 of this example includes a concrete foundation 2 fixed to the ground by piles or the like, a seismic isolation device 5 consisting of an isolator 4 containing lead columns 3, and a base isolation device 5. It comprises an office building 6 as a superstructure supported on the foundation 2 via a seismic device 5, and a viscous vibration damping device 7 arranged between the foundation 2 and the office building 6. there is

The superstructure is preferably an office building, apartment house or detached house, particularly preferably a high-rise office building or apartment house, but the invention is not limited to these and other superstructures. It can be a thing.

Further, the upper structure and the lower structure may be the upper layer portion and the lower layer portion of the structure divided by the base isolation layer on which the base isolation device 5 is installed, respectively.

A seismic isolation device 5 that is interposed between the foundation 2 as a substructure and the office building 6 and supports the load in the vertical direction (vertical direction) V of the office building 6 is the horizontal direction H caused by an earthquake. An isolator 4 that performs seismic isolation against vibration, a lead column 3 as an elastic plastic body that attenuates vibration in the horizontal direction H and is embedded in the isolator 4, and fixed to the upper and lower surfaces of the isolator 4. The isolator 4 is provided with upper and lower mounting steel plates 8 and 9 fixed to the office building 6 and the foundation 2 via anchor bolts or the like, respectively. A seismic isolation device 5 made of laminated rubber in which a plurality of elastic layers 11 are alternately laminated in the vertical direction V, and performs seismic isolation against vibration in the horizontal direction H caused by an earthquake and attenuates the vibration. are appropriately distributed on the foundation 2 in order to receive the load of the office building 6 .

The seismic isolation device 5 may be made of laminated rubber in which a rigid layer made of a steel plate or the like and an elastic layer made of a high-damping rubber or the like for effectively damping vibration are alternately laminated. It may be provided with laminated rubber in which layers and elastic layers are alternately laminated, and lead struts that are embedded in the laminated rubber and effectively dampen vibration. Even if there is, it may be a combination of the above as appropriate. ) can be used.

Furthermore, the seismic isolation device 5 may not have a damping function. In that case, a device having a damping function such as a hydraulic damper may be provided in addition to the vibration damping device 7 .

The vibration damping device 7 for damping the vibration in the horizontal direction H of the high-rise office building 6 which is seismically isolated and supported with respect to the vibration in the horizontal direction H with respect to the foundation 2 via the seismic isolation device 5 The bottom wall plate 26 and the mounting plate 66 as the upper mounting portion of the container 25 as the lower mounting portion attached to the base 2 to be vibrated and the office building 6 respectively, and the bottom wall plate 26 and the mounting plate 66 are connected to each other. and the viscous damper 21 damping the vibration of the mounting plate 66 with respect to the bottom plate wall 26 in the horizontal direction H, and At least one of the mounting plate 66 and the bottom wall plate 26 (in this example, the mounting plate 66) is released from the viscous damper 21 when a horizontal force exceeding a certain level is generated.

The viscous damper 21 consists of a container 25 fixed and connected to the foundation 2 by means of anchor bolts or the like via a bottom wall plate 26 as the lower mounting portion, and a bottom wall plate 26 of the container 25 arranged in the container 25. A plurality of annular fixed plates 28 fixed to each other at their outer peripheral edges via mounting mechanisms 27 and arranged with a gap in the vertical direction V, and arranged in the container 25 and arranged in the vertical direction V a plurality of annular movable plates 29 arranged in respective gaps between the fixed plates 28 with gaps from the fixed plates 28 and arranged movably in the horizontal direction H with respect to the fixed plates 28; The viscous body 30 disposed in the gap between the fixed plate 28 and the movable plate 29 and accommodated in the container 25 and the inner peripheral edge of each movable plate 29 are fixed to the flange 32 via the mounting mechanism 31. A cylindrical body 33 with a flange 32 that supports the movable plate 29, and a cylindrical part 34 that is inserted into the cylindrical body 33 so as to be movable in the vertical direction V, and is integrally formed with the cylindrical part 34. A connecting member 36 having a flange 35, a rectangular upper base 39 in which the mounting flange 35 of the connecting member 36 is fixed to a lower surface 38 by a plurality of bolts 37, and an upper surface 40 of the upper base 39. It has four pedestals 42 fixed by a plurality of bolts 41 to the corners of the housing.

The container 25 has a rectangular bottom wall plate 26 fixed to the foundation 2 with anchor bolts or the like, a cylindrical side wall plate 45 fixed to the bottom wall plate 26 via welding or bolts, and a wall plate 45 welded to the side wall plate 45 . and an annular cover plate 48 fixed to the collar plate 46 via welding, bolts or the like and having a circular opening 47 in the center for allowing the connecting member 36 to pass through. and a plurality of reinforcing members 49 fixed to the bottom wall plate 26, the side wall plate 45 and the collar plate 46 by welding or the like.

The bottom wall plate 26 also functions as a lower mounting portion for mounting the vibration damping device 7 to the foundation 2 as the lower structure. It may be a lower mounting plate fixed to the bottom wall plate 26 via welding, bolts or the like and also fixed to the foundation 2 with anchor bolts or the like.

The mounting mechanism 27 includes upper and lower annular plates 51, an annular spacer plate 52 disposed between the outer peripheral edges of the fixed plates 28, and the upper and lower annular plates 51 and the annular spacer plate 52 disposed between the outer peripheral edges of the fixed plates 28. The mounting mechanism 31 includes a plurality of bolts 53 that secure the plate 52 to the bottom wall plate 26, and the mounting mechanism 31 includes an annular plate 54 and an annular spacer plate disposed between the inner peripheral edges of each movable plate 29. 55 , and a plurality of bolts 56 that secure the inner peripheral edge of each movable plate 29 , the annular plate 54 and the annular spacer plate 55 to the flange 32 .

The lower surface 57 of the cylinder 33 is in movably contact with the upper surface 58 of the bottom wall plate 26 in the horizontal direction H, and a space 61 is maintained between the bottom surface 59 of the cylinder 34 and the inner bottom surface 60 of the cylinder 33. Spacers (not shown) are fixed to both surfaces of the movable plate 29 so as to maintain a gap between the fixed plate 28 and the movable plate 29 and to slidably contact the fixed plate 28 . Such spacers may be provided on the fixed plate 28 .

Each of the four cradles 42 has a receiving surface 62 parallel to the horizontal direction H on its upper surface and consisting of a flat sliding surface.

The viscous damper 21 moves the movable plate 29 relative to the fixed plate 28 in the horizontal direction H by causing viscous shear deformation in the viscous body 30 arranged in the gap between the fixed plate 28 and the movable plate 29 . A resistance force due to viscous shear deformation is exerted against the movement of the plate 29 in the horizontal direction H, causing the vibration of the movable plate 29 in the horizontal direction H, and the vibration of the office building 6 in the horizontal direction H via the mounting plate 66. It is designed to dampen vibrations.

The mounting plate 66 is fixed to the lower surface 65 of the office building 6 with bolts or the like.

The release mechanism 22 connects one of the mounting plate 66 as the upper mounting portion and the bottom wall plate 26 as the lower mounting portion (in this example, the mounting plate 66 and the viscous damper 21 in the horizontal direction H). Due to the relative vibration of the building 6 and the foundation 2 in the horizontal direction H, the mounting plate 66 is cut when a horizontal force above a certain level is generated against the bottom wall plate 26, and in this example, the mounting plate is sheared in the horizontal direction H. A connection release pin 68 having a constricted portion 67 as a weakened portion for releasing the connection in the horizontal direction H between 66 and the viscous damper 21, and the connection member 36 vicinity of the connection release pin 68 to the constricted portion 67 is centered. Bending stress preventing means 70 for preventing bending stress from being generated at the constricted portion 67 due to the application of bending moment in the R direction, On the other hand, in this example, a fixing means 72 for fixing to the mounting plate 66 and a fixing means 74 for fixing the other main body 73 of the disconnecting pin 68 to the upper base 39 of the viscous damper 21 are provided.

The connection release pin 68 is fixed to the mounting plate 66 via fixing means 72 and is attached to a cylindrical main body 71 having a screw hole 75 on one end face and an upper base of the viscous damper 21 via fixing means 74 . 39 and integrally provided with a columnar main body 73 having a screw hole 76 on one end face, and a constricted portion 67 as a fragile portion interposed between the main bodies 71 and 73. .

The decoupling pin 68 usually consists of both main bodies 71 and 73 and a fragile portion integrally formed, but the fragile portion may be formed of a material having a mechanical strength lower than that of both main bodies 71 and 73. A material with such low mechanical strength may be used for the constricted portion 67 .

The fixing means 72 consists of a holding member 84 fixed to the lower surface 82 of the mounting plate 66 by a plurality of bolts 81 and having a recess 83 in which the main body 71 is tightly fitted, and a central portion of the holding member 84. The fixing means 74 is fixed to the upper surface 40 of the upper base 39 by a plurality of bolts 86. a retaining member 89 having a recess 88 in which the body 73 is tightly fitted; The lower surface of the holding member 84 and the upper surface of the holding member 89 are opposed to each other with a gap 91 therebetween.

Therefore, the upper base 39 having the cylindrical portion 34 inserted for vibration transmission in the cylindrical body 33 in which the movable plate 29 of the viscous damper 21 is arranged is attached to the upper mounting portion via the connection release pin 68. It is suspended from a mounting plate 66 which is . A space 61 is formed between the bottom surface 59 of the columnar portion 34 and the inner bottom surface 60 of the cylindrical body 33 by hanging by the connection release pin 68 .

The bending stress preventing means 70 is interposed between one of the mounting plate 66 and the bottom wall plate 26 , in this example, between the mounting plate 66 and the viscous damper 21 and between the mounting plate 66 and the viscous damper 21 . Corresponding to at least one, in this example, four bolts 95 (only two are shown) as intervening members that are movable in the horizontal direction H with respect to the viscous damper 21, and the pedestal 42 to hold each bolt 95. Four holding members 98 are secured to the four corners of the lower surface 82 of the mounting plate 66 with a plurality of bolts 96 and have screw holes 97, respectively.

A plurality of bolts 95 as struts arranged around the connection release pin 68 are screwed into screw holes 97 of corresponding holding members 98 and are movable in the horizontal direction H with their enlarged heads. It is in contact with the receiving surface 62 of the corresponding cradle 42 . The amount of screwing of each bolt 95 into the screw hole 97 of the corresponding holding member 98 is fixed by a lock nut 99 screwed onto each bolt 95 . The amount of screwing, in other words, the amount of protrusion of each bolt 95 from the corresponding holding member 98 can be adjusted by loosening the lock nut 99 .

In a preferred example, the bending stress preventing means 70 is interposed between one of the upper mounting portion (mounting plate 66) and the lower mounting portion (bottom wall plate 26) and the viscous damper 21, and An intervening member (bolt 95) is provided which is horizontally movable with respect to one of the mounting portions and/or the viscous damper, such intervening member connecting the upper mounting portion and the lower mounting portion. one of the parts and the viscous damper at one end, or the other of the upper mounting part and the lower mounting part and the viscous damper at the other end. preferably in horizontal movably contact H or in horizontal movably contact with one of the upper mounting portion and the lower mounting portion and the viscous damper at one end and the other; , a plurality, preferably at least three, of struts (bolts 95) arranged around the decoupling pin 68. As shown in FIG.

In the seismic isolation building 1 with the damping function, normally, as shown in FIGS. The head is in contact with the substantially central portion of the receiving surface 62 of the corresponding receiving base 42 in the horizontal direction H. In this state, when a strong wind is generated and the shear deformation of the elastic layer 11 of the seismic isolation device 5 causes the office building 6 to vibrate in the horizontal direction H with respect to the foundation 2, the vibration is caused by the strong wind or the like. If the amplitude is less than the amplitude and the magnitude of the horizontal force that causes the vibration is less than a certain level, the vibration in the horizontal direction H of the office building 6 is transmitted to the upper base 39 without shearing the constricted portion 67 . As a result, in addition to the elasto-plastic deformation of the lead support 3 embedded in the isolator 4 in the horizontal direction H, as shown in FIG. The viscous body 30 in the gap between the movable plate 29 and the fixed plate 28 is viscous shear-deformed by the movement of the movable plate 29 in the horizontal direction H, and the lead column 3 is deformed in the horizontal direction H. In addition to the resistance force due to elasto-plastic deformation, the resistance force due to this viscous shear deformation in the viscous damper 21 damps the vibration of the movable plate 29 in the horizontal direction H, thereby damping the vibration of the office building 6 in the horizontal direction H attenuate the vibration of When the strong wind subsides, the base isolation building 1 is returned to the state shown in FIGS.

When an earthquake occurs and the office building 6 vibrates in the horizontal direction H with respect to the foundation 2 due to the shear deformation of the elastic layer 11 of the seismic isolation device 5, the magnitude of the horizontal force causing the vibration is constant. In the case below, the horizontal direction of the office building 6 is the same as the above. The oscillation of H is damped.

On the other hand, when an earthquake occurs and the office building 6 vibrates in the horizontal direction H with respect to the foundation 2 due to shear deformation of the elastic layer 11 of the seismic isolation device 5, the magnitude of the horizontal force causing the vibration is is greater than a certain value, in other words, when the acceleration of the earthquake is large, as shown in FIG. The connection in the direction H, in other words, the connection in the horizontal direction H between the office building 6 and the viscous damper 21 is released, and the vibration of the office building 6 in the horizontal direction H with respect to the foundation 2 is transmitted to the upper base 39. As a result, the movable plate 29 is stopped at that position and does not perform the damping action, while the movement of the office building 6 in the horizontal direction H sufficiently deforms the lead column 3, resulting in a large horizontal force. The movement of the office building 6 in the horizontal direction H is damped favorably and early due to the elasto-plastic deformation of the lead column 3 .

After the constricted portion 67 is sheared, the upper base 39 is dropped by the space 61 , and as a result, the receiving surfaces 62 of the cradles 42 are separated from the enlarged heads of the corresponding bolts 95 .

By the way, according to the base-isolated building 1, if the magnitude of the horizontal force caused by strong winds or earthquakes applied to the office building 6 is below a certain level, the bolts 95 arranged around the disconnection pin 68 will be expanded. Since the head is in contact with the receiving surface 62 of the corresponding cradle 42 so as to be movable in the horizontal direction H, a bending moment in the R direction around the connecting member 36 is generated due to such strong winds or earthquakes. Even if it occurs in the mounting plate 66 through the office building 6, the application of the bending moment in the R direction to the constricted portion 67 is prevented, and the bending at the constricted portion 67 due to the bending moment in the R direction is prevented. Generation of stress is prevented, mechanical fatigue caused by such stress generation can be avoided, and unintended breakage (cutting) of the constricted portion 67 due to mechanical fatigue can be eliminated.

That is, according to the base-isolated building 1, an office building 6 is supported on a foundation 2 via a base-isolation device 5 that isolates vibration in the horizontal direction H caused by an earthquake and attenuates the vibration. A viscous damper 21 is connected to the office building 6 and the foundation 2 in the horizontal direction H to attenuate the vibration of the office building 6 in the horizontal direction H. is generated, the release mechanism 22 shears the constricted portion 67 to release the connection of the viscous damper 21 to the office building 6. Therefore, it is possible to effectively attenuate minute vibrations due to wind etc. at an early stage and obtain a damping effect during strong winds. Since only the seismic isolation device 5 is operated for vibration damping, it is also necessary to increase the stroke of the viscous damper 21 so that it can be operated against a large vibration caused by a horizontal force exceeding a certain level. As a result, a smaller viscous damper 21 can be used, while the shear release mechanism 22 allows horizontal force to be applied to the constriction 67 of the decoupling pin 68 and shear at the constriction 67. , the bending stress prevention means 70 for preventing the generation of bending stress at the constricted portion 67 due to the application of the bending moment to the constricted portion 67 of the connection release pin 68 in the R direction. Mechanical fatigue of the constricted portion 67 of the connection release pin 68 due to moment can be avoided, and unintended breakage (cutting) of the constricted portion 67 of the connection release pin 68 due to such mechanical fatigue can be eliminated. As long as shear in the horizontal direction H caused by the horizontal force does not occur in the constricted portion 67 of the disconnection pin 68, the viscous damper 21 can effectively damp minute vibrations caused by wind etc. You can get the vibration effect.

As the seismic isolation device, instead of using the lead columns 3, a friction-based seismic isolation device using friction may be used. , instead of releasing the horizontal H connection between the viscous damper 21 and the office building 6 via the mounting plate 66, the horizontal H connection between the viscous damper 21 and the foundation 2 via the bottom wall plate 26 may be released. Alternatively, the space 61 may not be provided so that the upper base 39 does not drop after the constricted portion 67 is sheared. The vertical tensile force based on the load of the upper base 39 and the like may be applied as little as possible. The width of the receiving surface 62 is sufficiently large so as to ensure contact with the bolt 95, and if necessary, a lubricant such as grease is interposed in the contact surface between the receiving surface 62 and the bolt 95, or for example, the receiving surface 62 and the bolt 95, or at least one of interposing a low-friction member between the bolt 95, but avoid applying an unnecessary horizontal shearing force to the constricted portion 67 before shearing. For this purpose, the contact surface between the receiving surface 62 and the bolt 95 may be roughened so as to generate some frictional resistance.

By replacing the decoupling pin 68 sheared at the constricted portion 67 with a new decoupling pin 68 that is not sheared at the constricted portion 67, the releasing mechanism 22 can be used again in the base-isolated building 1.

Next, a preferred embodiment of the viscous system vibration damping device according to the present invention will be described. The viscous vibration damping device of the present embodiment is provided with detection means for detecting cutting of the constricted portion 67 (weak portion) of the disconnection pin 68 .

The sensing means 110 is composed of an accelerometer 111, a second accelerometer 113, and a Fourier analysis means 112 connected to these accelerometers 111 and 113, as shown in FIG.

The accelerometer 111 is attached to the mounting plate 66 side of the viscous damper 21 , for example, the office building 6 , in order to observe the response of the office building 6 to the seismic motion acting on the foundation 2 side, that is, the vibration acceleration acting on the office building 6 . is provided at an appropriate location. The accelerometer 111 is preferably provided on the first floor of the office building 6 .

The second accelerometer 113 is provided on the side of the foundation 2, for example, at an appropriate location on the foundation 2 in order to observe the vibration acceleration of the seismic motion acting on the side of the foundation 2. FIG.

Vibration accelerations observed by the accelerometer 111 and the second accelerometer 113 are individually input to the Fourier analysis means 112, and the Fourier analysis means 112 performs Fourier analysis on these input vibration accelerations.

The Fourier analysis means 112 is composed of, for example, a personal computer loaded with spreadsheet software such as Excel (registered trademark) capable of executing Fourier analysis. In the case of a personal computer, analysis results can be displayed on the screen, printed, and saved. The Fourier analysis means 112 is not limited to the personal computer loaded with the spreadsheet software, and may be of any type.

The Fourier analysis means 112 calculates and outputs the dominant frequency in the office building 6 and the dominant frequency in the foundation 2 from each of the input vibration accelerations as an analysis result.

In this embodiment, the Fourier analysis means 112 further calculates and outputs the Fourier amplitude ratio between the office building 6 and the foundation 2 from the dominant frequencies obtained with respect to the office building 6 and the foundation 2 .

As the analysis result of the Fourier analysis means 112, when considering the Fourier amplitude ratio, compared with individually examining the dominant frequencies in the office building 6 and the foundation 2, it is possible to cut the constricted portion 67 of the disconnecting pin 68. , can be determined more clearly.

For example, when the Fourier amplitude ratio changes by a predetermined value or more between before and after the occurrence of an earthquake, it can be determined that the constricted portion 67 has broken.

A graph of an example of the result of Fourier analysis is shown in FIG. The frequency is displayed on the horizontal axis and the Fourier amplitude ratio is displayed on the vertical axis.

The solid line X represents the case where the viscous damper 21 and the isolator 4 contribute to seismic isolation, and the dashed line Y represents the case where the constricted portion 67 of the viscous damper 21 is broken and only the isolator 4 contributes to seismic isolation. showing.

According to the detection means 110 of the present embodiment, when the constricted portion 67 breaks due to an earthquake, the Fourier spectral ratio changes from the solid line X to the dashed line Y in the time-series records observed by the accelerometer 111 and the second accelerometer 113. transition to At this time, it can be determined that the constricted portion 67 of the disconnection pin 68 has broken due to the change in the dominant frequency.

The acceleration of the ground on the side of the foundation 2 and the acceleration on the side of the office building 6 via the isolator 4 and the viscous damper 21 are in an input/output relationship, and the Fourier spectrum ratio of these two is the same as that of the office building from the foundation 2 side. 6 is the transfer function to the 6 side.

A change in the Fourier spectrum ratio means that the transfer function has changed, and it is determined that there has been a change in the stress transmission mechanism.

Similarly, a change in the Fourier amplitude ratio, for example, a change in which the damping effect is reduced due to an increase in the Fourier amplitude ratio, can also be inferred that there has been a change in the stress transmission mechanism, and the constricted portion 67 of the disconnect pin 68 is It can be determined that it is broken.

However, depending on the vibration characteristics, only one of the Fourier spectrum ratio and the Fourier amplitude ratio may change, and the other may not change. When the Fourier spectrum ratio changes and the Fourier amplitude ratio increases, it can be reliably determined that the constricted portion 67 of the disconnection pin 68 has been cut.

Therefore, if only one of them has changed, it can be used as a guideline to perform "inspection work", and if both have changed, it can be used as a guideline to perform "replacement work" from the beginning.

With respect to changes in the Fourier spectrum ratio and the Fourier amplitude ratio, it is desirable to determine the threshold value for determining that the constricted portion 67 of the disconnection pin 68 has broken in advance by structural analysis or the like.

For example, the example in FIG. 7 is a two-story steel-framed structure with base isolation, a height of 10 m, and a building area of about 1,500 m2. It is determined that the disconnection pin 68 has broken when the amplitude ratio is doubled or more. At this time, it is desirable to compare using the measured values of the vibration acceleration due to microtremors before and after the occurrence of the earthquake.

When the device is restored, it is sufficient to replace it with a new decoupling pin 68, and the accelerometer 111, the second accelerometer 113, and the Fourier analysis means 112, which are the detection means 110, can continue to be used without maintenance.

In this embodiment, it is possible to easily and reliably check at any time whether or not the disconnection pin 68 has been cut, with a simple configuration in which only the accelerometer 111, the second accelerometer 113, and the Fourier analysis means 112 are provided. and suitable use of viscous vibration dampers.

In the above embodiment, the Fourier analysis means 112 analyzes the Fourier amplitude ratio between the office building 6 side and the foundation 2 side from the vibration acceleration observed on the office building 6 side and the foundation 2 side. , but it is sufficient to calculate the dominant frequencies of the office building 6 and the foundation 2 respectively by the Fourier analysis means 112. Even in such a case, based on the dominant frequencies that changed before and after the earthquake, It is possible to determine whether or not the disconnection pin 68 is broken.

Furthermore, in the above embodiment, in addition to the vibration acceleration observed in the office building 6, the vibration acceleration acting on the foundation 2 observed by the second accelerometer 113 is input to the Fourier analysis means 112 for Fourier analysis. However, the second accelerometer 113 is omitted and only the accelerometer 111 is provided, and only the vibration acceleration of the office building 6 observed by this accelerometer 111 is used to calculate the office building by the Fourier analysis means 112. The dominant frequency on the side of office building 6 may be calculated only. can be determined to be broken.

2 Foundation 6 Office Building 21 Viscous Damper 22 Release Mechanism 26 Bottom Wall Plate 33 Cylindrical Body 34 Cylindrical Part 42 Receptacle 61 Space 62 Receiving Surface 66 Mounting Plate 67 Constricted Part 68 Disconnection Pin 70 Bending Stress Preventing Means 71 Main Body 73 Main Body 95 bolt 98 holding member 99 lock nut 110 detection means 111 accelerometer 112 Fourier analysis means 113 second accelerometer

Claims (3)

an upper mounting part and a lower mounting part for mounting to the upper structure and the lower structure, respectively, which are relatively vibrated with respect to the horizontal direction;
a viscous damper coupled to the upper mounting portion and the lower mounting portion for damping horizontal vibration of the upper mounting portion relative to the lower mounting portion;
a releasing mechanism for releasing the connection of at least one of the upper mounting portion and the lower mounting portion to the viscous damper when a horizontal force of a certain level or more is generated in the upper mounting portion with respect to the lower mounting portion; cage,
The release mechanism is
One of the upper mounting portion and the lower mounting portion is connected to the viscous damper in the horizontal direction, and is cut when a horizontal force exceeding a certain level is applied to the upper mounting portion with respect to the lower mounting portion. a decoupling pin having a weakened portion for decoupling the horizontal connection between one of the upper mounting portion and the lower mounting portion and the viscous damper;
bending stress preventing means for preventing bending stress from being generated in the weakened portion of the disconnection pin;
The bending stress blocking means comprises:
a plurality of bolts disposed about the decoupling pin between one of the upper mounting portion and the lower mounting portion and the viscous damper and having an enlarged head;
a holding member fixed to one of the upper mounting portion and the lower mounting portion and one of the viscous damper and to which each of the bolts is screwed;
a receiving surface fixed to one of the upper mounting portion and the lower mounting portion and the other one of the viscous damper and in contact with the expanded head portion of each bolt so as to be movable in the horizontal direction; a cradle;
A viscous vibration damping device comprising a lock nut for adjusting the amount of protrusion of each bolt from the holding member,
Furthermore, a detection means for detecting cutting of the vulnerable portion is provided,
The detection means includes an accelerometer provided on the side of the upper mounting portion for observing vibration acceleration acting on the side of the upper structure, and a vibration acceleration observed by the accelerometer. and Fourier analysis means for performing Fourier analysis of dominant frequencies. The detection means further comprises a second accelerometer provided on the side of the lower mounting portion for observing vibration acceleration acting on the side of the lower structure, and the Fourier analysis means comprises the accelerometer and the second accelerometer. 2. A vibration damping device for a viscous system according to claim 1, wherein the vibration acceleration observed at each of said upper structure side and said lower structure side is subjected to Fourier analysis of dominant frequencies respectively. . The Fourier analysis means analyzes the Fourier amplitude ratio between the upper structure side and the lower structure side from the vibration acceleration observed on the upper structure side and the lower structure side respectively. 3. The viscous system vibration damping device according to claim 2.

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