JP7451448B2 - Viscous vibration damping device - Google Patents

Description

The present invention relates to a viscous vibration damping device that has a simple configuration and is capable of easily and reliably confirming whether or not a connection release pin has been disconnected.

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

The "viscous vibration damping device and seismically isolated building equipped with the same" in Patent Document 1 includes an upper mounting part and a lower mounting part for mounting on an upper structure and a lower structure, respectively, which are subjected to relative vibration in the horizontal direction. , a viscous damper connected to the upper mounting part and the lower mounting part to damp horizontal vibration of the upper mounting part with respect to the lower mounting part; a release mechanism that releases 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; One of the parts and the viscous damper are connected in the horizontal direction, and when a horizontal force of more than 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 disconnected. a decoupling pin having a weakened portion that disconnects one of the portions from the viscous damper in the horizontal direction; and a bending stress prevention means that prevents bending stress from occurring at the weakened portion of the decoupling pin. , the bending stress blocking means being disposed around 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 plurality of bolts having a section, and a holding member fixed to one of the upper mounting part and the lower mounting part and one of the viscous damper, and to which each of the bolts is screwed. and a receiving surface which is fixed to one of the upper mounting part and the lower mounting part and the other of the viscous damper, and which contacts the enlarged head of each of the bolts in a horizontally movable manner. and a lock nut for adjusting the amount of protrusion of each of the bolts from the holding member.

Patent No. 4893061

In the above-mentioned background art, by using a disconnection pin that is disconnected when a horizontal force of a certain level or more is generated, the viscous damper is switched between a case where vibration is damped and a case where vibration is not damped.

With such a configuration, it was necessary to check whether the disconnection pin was disconnected every time an earthquake of a considerable scale occurred. In addition, it was necessary for the operator to visually check the viscous damper at the location where the viscous damper was installed. For this reason, it has been desired to devise a method that can easily and easily confirm whether or not the connection release pin has been disconnected.

The present invention has been devised in view of the above-mentioned conventional problems, and has a simple structure that uses viscous vibration to easily and reliably confirm whether or not the uncoupling pin has been disconnected. The purpose is to provide a damping device.

A viscous vibration damping device according to the present invention includes an upper mounting part and a lower mounting part for mounting on an upper structure and a lower structure, respectively, which are relatively vibrated in the horizontal direction, and the upper mounting part and the lower mounting part. a viscous damper connected to the viscous damper to damp horizontal vibration of the upper mounting part relative to the lower mounting part; a release mechanism that releases the connection of at least one of the upper mounting part and the lower mounting part, and the release mechanism connects one of the upper mounting part and the lower mounting part to the viscous damper. are connected in the horizontal direction, and when a horizontal force above a certain level is applied to the upper mounting part relative to the lower mounting part, the viscous damper is disconnected and one of the upper mounting part and the lower mounting part is connected to the viscous damper. a connection release pin having a weakened portion for releasing the connection in the horizontal direction; and bending stress prevention means for preventing generation of bending stress at the weakened portion of the connection release pin, the bending stress prevention means The means includes a plurality of bolts disposed around the decoupling pin and having enlarged heads between one of the upper mounting portion and the lower mounting portion and the viscous damper. , a holding member fixed to one of the upper mounting part and the lower mounting part and one of the viscous damper and having each of the bolts threaded thereon; and the upper mounting part and the lower mounting part. a pedestal fixed to one of the parts and the other of the viscous damper and having a receiving surface movably in contact with the enlarged head of each of the bolts in a horizontal direction; The viscous vibration damping device includes a lock nut that adjusts the amount of protrusion from the holding member, further comprising a detection means for detecting cutting of the fragile portion, and the detection means is located on the upper mounting portion side. an accelerometer for observing the vibration acceleration acting on the upper structure side; and a Fourier analysis means for receiving the vibration acceleration observed by the accelerometer and performing a Fourier analysis of the dominant frequency on the upper structure side. It is characterized by having the following.

The detection means further includes a second accelerometer that is provided on the lower mounting part side and observes vibration acceleration acting on the lower structure side, and the Fourier analysis means includes a second accelerometer that is installed on the lower mounting part side and that observes vibration acceleration acting on the lower structure side. The method is characterized in that the vibration accelerations observed in each are input, and Fourier analysis of the dominant frequencies of the upper structure side and the lower structure side is executed.

The Fourier analysis means executes an analysis of the Fourier amplitude ratio between the upper structure side and the lower structure side based on the vibration acceleration observed on the upper structure side and the lower structure side, respectively. do.

With the viscous vibration damping device according to the present invention, it is possible to easily and reliably confirm whether or not the connection release pin has been disconnected, despite having a simple configuration.

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

Hereinafter, preferred embodiments of the viscous vibration damping device according to the present invention will be described in detail with reference to the accompanying drawings. First, a viscous vibration damping device, which is the premise of the present invention, will be explained.

1 to 4, the seismic isolation building 1 of this example includes a concrete foundation 2 fixed to the ground with piles etc., a seismic isolation device 5 consisting of an isolator 4 containing a lead support 3, and It is equipped with an office building 6 as a superstructure supported on the foundation 2 via a vibration 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, an apartment building, or a single-family house, and particularly preferably a high-rise office building or an apartment building, but the present invention is not limited thereto, and may be applied to other superstructures. It may be a thing.

Further, the upper structure and the lower structure may be an upper part and a lower part of a structure separated by a seismic isolation layer in which the seismic isolation device 5 is installed, respectively.

The seismic isolation device 5, which is interposed between the foundation 2 as a lower structure and the office building 6 and supports the load in the vertical direction (V) of the office building 6, is designed to protect against the load in the horizontal direction H due to an earthquake. An isolator 4 that performs seismic isolation against vibrations, a lead column 3 as an elastoplastic body that damps vibrations in the horizontal direction H and is embedded in the isolator 4, and is fixed to the upper and lower surfaces of the isolator 4, respectively. 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, and the isolator 4 includes a plurality of rigid layers 10 made of steel plates or the like and a rubber plate. The seismic isolation device 5 is made of laminated rubber in which a plurality of elastic layers 11 are alternately laminated in the vertical direction V, and acts as a seismic isolation device against vibrations in the horizontal direction H caused by an earthquake and attenuates the vibrations. A plurality of these are appropriately distributed and arranged on the foundation 2 in order to bear the load of the office building 6.

The seismic isolation device 5 may be made of laminated rubber in which rigid layers made of steel plates etc. and elastic layers made of high damping rubber etc. that effectively damp vibrations are laminated alternately. It may be equipped with a laminated rubber layer in which layers and elastic layers are alternately laminated, and a lead support that is embedded in the laminated rubber layer and effectively damps vibrations.Furthermore, it may be one that uses sliding friction. Even if there is, it may be a combination of the above as appropriate.In short, it acts as a seismic isolator against vibrations in the horizontal direction H due to earthquakes (exhibits an isolator function) and attenuates the vibrations (attenuates the vibrations). It is acceptable as long as it exhibits the following.

Furthermore, the seismic isolation device 5 may not have a damping function, and in that case, a device with a damping function such as a hydraulic damper may be provided separately from the vibration damping device 7.

A vibration damping device 7 that damps vibrations in the horizontal direction H of a high-rise office building 6 that is seismically supported with respect to vibrations in the horizontal direction H with respect to the foundation 2 via the seismic isolation device 5 is configured to The bottom wall plate 26 of the container 25 as a lower attachment part and the attachment plate 66 as an upper attachment part are attached to the foundation 2 and the office building 6 to be vibrated, respectively, and are connected to the bottom wall plate 26 and the attachment plate 66. The viscous damper 21 damps vibrations of the mounting plate 66 in the horizontal direction H relative to the bottom wall 26, and the mounting plate 66 damps the vibrations of the mounting plate 66 relative to the bottom wall 26 due to relative vibrations in the horizontal direction H of the office building 6 and the foundation 2. It has a release mechanism 22 that releases the connection of at least one of the mounting plate 66 and the bottom wall plate 26, in this example the mounting plate 66, to the viscous damper 21 when a horizontal force of a certain level or more is generated.

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

The container 25 includes a rectangular bottom wall plate 26 fixed to the foundation 2 with anchor bolts, etc., a cylindrical side wall plate 45 fixed to the bottom wall plate 26 by welding, bolts, etc., and a cylindrical side wall plate 45 welded to the side wall plate 45. An annular flange plate 46 fixed to the flange plate 46 via welding, bolts, etc., and an annular lid plate 48 having a circular opening 47 in the center through which the connecting member 36 passes. and a plurality of reinforcing members 49 fixed to each of the bottom wall plate 26, side wall plate 45, and collar plate 46 through welding or the like.

The bottom wall plate 26 also functions as a lower attachment part for attaching the vibration damping device 7 to the foundation 2 as a lower structure. It may be a lower mounting plate that is fixed to the bottom wall plate 26 via welding, bolts, etc., 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 periphery of each fixing plate 28, and the upper and lower annular plates 51 and the annular spacer together with the outer periphery of each fixing plate 28. The mounting mechanism 31 includes a plurality of bolts 53 for fixing the plate 52 to the bottom wall plate 26, and the mounting mechanism 31 includes an annular spacer plate disposed between the annular plate 54 and the inner peripheral edge of each movable plate 29. 55, and a plurality of bolts 56 for fixing the annular plate 54 and the annular spacer plate 55 to the collar portion 32 together with the inner peripheral edge of each movable plate 29.

The lower surface 57 of the cylindrical body 33 is movably in 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 cylindrical portion 34 and the inner bottom surface 60 of the cylindrical body 33. Spacers (not shown) are fixed to both surfaces of the movable plate 29 to maintain a gap between the fixed plate 28 and the movable plate 29 and to slidably contact the fixed plate 28. Such a spacer may be provided on the fixed plate 28.

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

The viscous damper 21 is movable by causing viscous shear deformation in the viscous body 30 disposed in the gap between the fixed plate 28 and the movable plate 29 when the movable plate 29 moves in the horizontal direction H relative to the fixed plate 28. A resistance force due to viscous shear deformation is applied to the movement of the plate 29 in the horizontal direction H, causing vibrations in the horizontal direction H of the movable plate 29 and, in turn, vibrations in the horizontal direction H of the office building 6 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 an upper mounting portion and the bottom wall plate 26 as a lower mounting portion, in this example, the mounting plate 66 and the viscous damper 21 in the horizontal direction H, and When a horizontal force of more than a certain level is applied to the mounting plate 66 against the bottom wall plate 26 due to the relative vibration of the building 6 and the foundation 2 in the horizontal direction H, it breaks, and in this example, it is sheared in the horizontal direction H and the mounting plate 66 and the viscous damper 21 in the horizontal direction H, and centering on the connection release pin 68 having a constriction 67 as a weak part to release the connection in the horizontal direction H, and the connection member 36 of the connection release pin 68 to the constriction 67. A bending stress prevention means 70 that prevents the generation of bending stress in the constricted portion 67 due to the addition of a bending moment in the R direction, and one main body 71 of the connection release pin 68 are attached to one of the mounting plate 66 and the bottom wall plate 26. On the other hand, this example includes 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 decoupling pin 68 to the upper base 39 of the viscous damper 21.

The connection release pin 68 is connected to a cylindrical main body 71 which is fixed to the mounting plate 66 via a fixing means 72 and has a screw hole 75 on one end surface, and to the upper base of the viscous damper 21 via a fixing means 74. 39 and integrally includes a cylindrical main body 73 having a screw hole 76 on one end surface, and a constricted part 67 as a weak part interposed between the two main bodies 71 and 73. .

The uncoupling pin 68 usually consists of both bodies 71 and 73 and a weakened part formed integrally, but the weakened part may be made of a material with lower mechanical strength than both bodies 71 and 73, Such a material with low mechanical strength may be used for the constricted portion 67.

The fixing means 72 includes a holding member 84 that is fixed to the lower surface 82 of the mounting plate 66 by a plurality of bolts 81 and has a recess 83 into 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 holding member 89 having a recess 88 into which the main body 73 is tightly fitted, and a bolt 90 passing through the center of the holding member 89 and screwed into the screw hole 76 of the main body 73. The lower surface of the holding member 84 and the upper surface of the holding member 89 face each other with a gap 91 between them, and the constricted portion 67 is arranged at the position of the gap 91.

Therefore, the upper base 39, which includes the cylindrical part 34 fitted for vibration transmission into the cylindrical body 33 on which the movable plate 29 of the viscous damper 21 is disposed, is connected to the upper mounting part through the connection release pin 68. It is suspended from a mounting plate 66. A space 61 is formed between the bottom surface 59 of the columnar part 34 and the inner bottom surface 60 of the cylindrical body 33 due to the suspension by the connection release pin 68 .

The bending stress prevention 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 also between the mounting plate 66 and the viscous damper 21. At least one of the four bolts 95 (only two are shown) as an intervening member that is movable in the horizontal direction H with respect to the viscous damper 21 in this example, and a pedestal 42 to hold each bolt 95. The mounting plate 66 is provided with four holding members 98 fixed to each of the four corners of the lower surface 82 by a plurality of bolts 96 and each having a screw hole 97.

Each of the bolts 95 serving as a plurality of supports arranged around the connection release pin 68 is screwed into a screw hole 97 of a corresponding holding member 98, and is movable in the horizontal direction H with its enlarged head. It is in contact with the receiving surface 62 of the corresponding pedestal 42. The amount by which each bolt 95 is screwed 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, 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 prevention means 70 is interposed between the viscous damper 21 and one of the upper mounting portion (mounting plate 66) and the lower mounting portion (bottom wall plate 26), and An intervening member (bolt 95) is provided that is movable in the horizontal direction H with respect to one of the mounting parts and at least one of the viscous damper, and the intervening member is connected to the upper mounting part and the lower mounting part. contacting one of the parts and the viscous damper at one end so as to be movable in the horizontal direction H, or contacting one of the upper mounting part and the lower mounting part and the other of the viscous damper at the other end. It is preferable that the damper is in contact with the viscous damper so as to be movable in the horizontal direction H, or in contact with one of the upper mounting part and the lower mounting part and the viscous damper in a movable manner in the horizontal direction H, and , may consist of a plurality of, preferably at least three, struts (bolts 95) arranged around the decoupling pin 68.

In the above-described seismic isolation building 1 with a vibration damping function, as shown in FIGS. The head is in contact with approximately the center of the receiving surface 62 of the corresponding pedestal 42 in the horizontal direction H. In this state, when a strong wind occurs and the office building 6 is vibrated 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 vibration is caused by, for example, a predetermined amount of If the amplitude is below the amplitude and the magnitude of the horizontal force that causes the vibration is below a certain level, the vibration in the horizontal direction H of the office building 6 will be transmitted to the upper base 39 without shearing the constricted portion 67. As a result, in addition to the elastic-plastic deformation of the lead column 3 buried in the isolator 4 in the horizontal direction H, the movable plate 29 also deforms as the office building 6 moves in the horizontal direction H, as shown in FIG. When the movable plate 29 is moved in the horizontal direction H, the viscous body 30 in the gap between the movable plate 29 and the fixed plate 28 is deformed by viscous shearing, and the lead column 3 is moved in the horizontal direction H. In addition to the resistance force caused by elastoplastic deformation, the resistance force caused by this viscous shear deformation in the viscous damper 21 damps the vibration of the movable plate 29 in the horizontal direction H, thereby causing the horizontal direction H of the office building 6 to Attenuates vibrations. When the strong wind subsides, the seismic isolation building 1 is returned to the state shown in FIGS. 1 and 2 by the origin return function of the elastic layer 11 of the seismic isolation device 5.

When an earthquake occurs and the office building 6 is vibrated in the horizontal direction H relative 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 that causes the vibration is constant. The case below is also the same as above, and the resistance force due to the elastic-plastic deformation in the horizontal direction H of the lead column 3 and the resistance force due to the viscous shear deformation in the viscous damper 21 are combined in the horizontal direction of the office building 6. The vibrations of H are damped.

On the other hand, when an earthquake occurs and the office building 6 is vibrated in the horizontal direction H relative 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 that causes the vibration is is above a certain level, in other words, when the acceleration of the earthquake is large, the constricted portion 67 is sheared in the horizontal direction H, and the mounting plate 66 and the viscous damper 21 become horizontal, 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 relative 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 any damping operation, while the lead column 3 is sufficiently deformed due to the movement of the office building 6 in the horizontal direction H, resulting in a large horizontal force. The movement of the office building 6 in the horizontal direction H is preferably attenuated quickly by the elastic-plastic deformation of the lead column 3.

After the constricted portion 67 is sheared, the upper base 39 falls by the space 61, so that each receiving surface 62 of the pedestal 42 is separated from the enlarged head of the corresponding bolt 95.

By the way, according to the seismic isolation building 1, when 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 connection release pin 68 are Since the head is movable in the horizontal direction H and in contact with the receiving surface 62 of the corresponding pedestal 42, a bending moment in the R direction centered around the connecting member 36 due to such strong winds or earthquakes is generated. Even if the bending moment occurs on the mounting plate 66 through the office building 6, the bending moment in the R direction is prevented from being applied to the constriction part 67, and the bending moment at the constriction part 67 due to the bending moment in the R direction is prevented. Generation of stress is prevented, mechanical fatigue due to 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 seismic isolation building 1 in which an office building 6 is supported on the foundation 2 via a seismic isolation device 5 that performs seismic isolation against vibrations in the horizontal direction H due to an earthquake and attenuates the vibrations. The viscous damper 21 is connected to the office building 6 and the foundation 2 in the horizontal direction H to damp vibrations of the office building 6 in the horizontal direction H. When a horizontal force of As a result, small vibrations caused by wind, etc. can be effectively damped at an early stage, and a damping effect can be obtained during strong winds.Furthermore, the office building 6 can be effectively damped against large vibrations caused by earthquakes that generate horizontal forces above a certain level. Since only the seismic isolation device 5 is activated for vibration damping, it is also necessary to make the stroke of the viscous damper 21 long so that it can be activated even in response to large vibrations caused by horizontal forces above a certain level. As a result, a small viscous damper 21 can be used, and the shear release mechanism 22 allows horizontal force to be applied to the constriction 67 of the decoupling pin 68 while allowing shear at the constriction 67. , is provided with a bending stress prevention means 70 that prevents the generation of bending stress in the constricted portion 67 due to the application of a bending moment in the R direction to the constricted portion 67 of the connection release pin 68. Mechanical fatigue of the constricted portion 67 of the decoupling pin 68 due to moment can be avoided, and unintended breakage (cutting) of the constricted portion 67 of the decoupling pin 68 due to such mechanical fatigue can be avoided. As long as shear in the horizontal direction H due to horizontal force does not occur in the constricted portion 67 of the connection release pin 68, the viscous damper 21 can effectively dampen minute vibrations caused by wind, etc., and is effective in controlling strong winds. You can get a shaking effect.

As the seismic isolation device, instead of using the lead columns 3, a friction type seismic isolation device using friction may be used. occurs, instead of releasing the connection in the horizontal direction H between the viscous damper 21 and the office building 6 via the mounting plate 66, the connection in the horizontal direction H between the viscous damper 21 and the foundation 2 via the bottom wall plate 26 may be canceled. Alternatively, the space 61 may not be provided to prevent the upper base 39 from falling after the constricted portion 67 is sheared. Furthermore, an elastic body may be provided in the space 61 to prevent the upper base 39 from falling after the constricted portion 67 of the connection release pin 68 is sheared. The vertical tensile force based on the load on the upper base 39 etc. may be avoided as much as possible, and if the upper base 39 is to be prevented from falling after shearing, the bearing surface 62 and bolts 95 may be applied even after shearing. The width of the receiving surface 62 is made sufficiently large to ensure contact with the bolt 95, and if necessary, a lubricant such as grease is interposed on the contact surface between the receiving surface 62 and the bolt 95. Although at least one of the methods of interposing a low-friction member between the bolt 95 and the bolt 95 may be applied, it is necessary to prevent unnecessary shearing force in the horizontal direction H from being applied to the constricted portion 67 before shearing. In order to achieve this, the contact surface between the receiving surface 62 and the bolt 95 may be made rough so as to generate some frictional resistance.

Note that by replacing the disconnection pin 68 that has been sheared at the constricted portion 67 with a new disconnection pin 68 that has not been sheared at the constricted portion 67, it can be used again as the release mechanism 22 in the seismically isolated building 1.

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

As shown in FIG. 2, the detection 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.

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

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

The 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 equipped with spreadsheet software such as Excel (registered trademark) that can perform Fourier analysis. If you use a computer, you can display the analysis results on the screen, print them, or save them. The Fourier analysis means 112 is not limited to a personal computer equipped with the spreadsheet software described above, 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 the Fourier amplitude ratio between the office building 6 and the foundation 2 from the dominant frequencies obtained regarding the office building 6 and the foundation 2, and outputs it.

As an analysis result of the Fourier analysis means 112, compared to examining the dominant frequencies of the office building 6 and the foundation 2 individually, if the Fourier amplitude ratio is examined, it is possible to cut the constricted portion 67 of the disconnecting pin 68. , can be judged 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 results of Fourier analysis is shown in FIG. Frequency is displayed on the horizontal axis, and Fourier amplitude ratio is displayed on the vertical axis.

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

According to the detection means 110 of the present embodiment, when the constricted portion 67 is ruptured due to an earthquake, the Fourier spectrum ratio changes from the solid line to move to. At this time, it can be determined that the constricted portion 67 of the connection release pin 68 has broken due to the change in the dominant frequency.

The acceleration of the ground on the foundation 2 side and the acceleration on the office building 6 side via the isolator 4 and viscous damper 21 have an input/output relationship, and the Fourier spectrum ratio of these two is This is the transfer function to the 6th side.

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

Similarly, a change in the Fourier amplitude ratio, such as a change in which the Fourier amplitude ratio increases and the damping effect decreases, can also be inferred to indicate a change in the stress transmission mechanism, and the constriction 67 of the decoupling pin 68 It can be determined that it has been broken.

However, depending on the characteristics of the vibration, there may be cases where only one of the Fourier spectrum ratio and the Fourier amplitude ratio changes while the other does not change. If there is a change in the Fourier spectrum ratio and the Fourier amplitude ratio becomes larger, it can be reliably determined that the constricted portion 67 of the disconnecting pin 68 has been disconnected.

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.

Regarding the 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 disconnecting pin 68 has broken by performing a structural analysis or the like in advance.

For example, the example shown in Fig. 7 is a two-story steel frame structure with base isolation, a height of 10 m, and a building area of about 1,500 m2, and the Fourier spectral ratio decreases by 0.1 Hz or more, and the Fourier spectrum ratio decreases by 0.1 Hz or more. When the amplitude ratio becomes twice or more, it is determined that the disconnection pin 68 is broken. At this time, it is desirable to compare the measured values of vibration acceleration due to constant microtremors before and after the earthquake.

When restoring the device, it is only necessary to replace the disconnection pin 68 with a new one, and the accelerometer 111, which is the detection means 110, the second accelerometer 113, and the Fourier analysis means 112 can continue to be used without maintenance.

In this embodiment, with a simple configuration that only includes an accelerometer 111, a second accelerometer 113, and a Fourier analysis means 112, it is possible to easily and reliably confirm whether or not the connection release pin 68 is disconnected at any time. Therefore, a viscous vibration damping device can be used appropriately.

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 based on the vibration acceleration observed on the office building 6 side and the foundation 2 side, respectively. As explained above, it is sufficient to simply calculate the dominant frequencies of the office building 6 and the foundation 2 through analysis by the Fourier analysis means 112, and even in such a case, it is sufficient to calculate the dominant frequencies of the office building 6 and the foundation 2, respectively, based on the dominant frequencies that changed before and after the occurrence of the earthquake. It is possible to determine whether or not the connection release pin 68 has 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 to perform Fourier analysis. However, the second accelerometer 113 is omitted and only the accelerometer 111 is provided, and the office building is analyzed by the Fourier analysis means 112 using only the vibration acceleration of the office building 6 observed by this accelerometer 111. It is also possible to simply calculate the predominant frequency on the office building 6 side. Even in such a case, the predominant frequency on the office building 6 side has changed by more than a predetermined value before and after the occurrence of the earthquake. can be determined to have broken.

2 Foundation 6 Office building 21 Viscous damper 22 Release mechanism 26 Bottom wall plate 33 Cylindrical body 34 Cylindrical part 42 Rest 61 Space 62 Receiving surface 66 Mounting plate 67 Constriction 68 Uncoupling pin 70 Bending stress prevention 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 on the upper structure and the lower structure, respectively, which are subjected to relative vibration in the horizontal direction;
a viscous damper connected to the upper mounting part and the lower mounting part to damp horizontal vibration of the upper mounting part with respect to the lower mounting part;
a release mechanism that releases the connection of at least one of the upper mounting part and the lower mounting part to the viscous damper when a horizontal force of a certain level or more is generated on the upper mounting part with respect to the lower mounting part; Ori,
The release mechanism is
One of the upper mounting part and the lower mounting part is connected to the viscous damper in the horizontal direction, and is disconnected when a horizontal force of more than a certain level is applied to the upper mounting part with respect to the lower mounting part. a connection release pin having a weakened portion that releases the connection in the horizontal direction between one of the upper attachment portion and the lower attachment portion and the viscous damper;
and a bending stress prevention means for preventing the generation of bending stress at the weakened portion of the connection release pin,
The bending stress blocking means includes:
a plurality of bolts disposed around the decoupling pin and having enlarged heads between one of the upper mounting part and the lower mounting part and the viscous damper;
a holding member that is fixed to one of the upper mounting part and the lower mounting part and to one of the viscous damper and to which each of the bolts is screwed;
The receiving surface is fixed to one of the upper mounting part and the lower mounting part and the other of the viscous damper, and has a receiving surface movably in contact with the enlarged head of each of the bolts in a horizontal direction. A pedestal and
A viscous vibration damping device comprising a lock nut that adjusts the amount of protrusion of each of the bolts from the holding member,
Furthermore, it includes a detection means for detecting cutting of the vulnerable part,
The detection means includes an accelerometer that is provided on the upper mounting part side and that observes the vibration acceleration acting on the upper structure side, and the vibration acceleration observed by the accelerometer is inputted to detect the vibration acceleration on the upper structure side. 1. A vibration damping device for a viscous system, comprising: Fourier analysis means for performing Fourier analysis of a dominant frequency. The detection means further includes a second accelerometer that is provided on the lower mounting part side and observes vibration acceleration acting on the lower structure side, and the Fourier analysis means includes a second accelerometer that is installed on the lower mounting part side and that observes vibration acceleration acting on the lower structure side. The vibration damping device for a viscous system according to claim 1, wherein the vibration accelerations observed in each are inputted to perform Fourier analysis of the dominant frequencies of the upper structure side and the lower structure side, respectively. . The Fourier analysis means executes an analysis of the Fourier amplitude ratio between the upper structure side and the lower structure side based on the vibration acceleration observed on the upper structure side and the lower structure side, respectively. The viscous vibration damping device according to claim 2.

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