JP6785630B2 - Seismic isolation structure - Google Patents

Description

The present invention relates to a seismic isolation structure whose seismic isolation performance can be appropriately changed.

For example, as seen in Patent Document 1 below, in order to ensure the safety of a building against an earthquake, a seismic isolation layer is formed on the foundation of the building via a seismic isolation device using laminated rubber or a sliding support. In addition to alleviating the vibration that tends to propagate from the foundation side to the building during an earthquake, various passive seismic isolation systems that positively dampen the above vibration by interposing an oil damper or the like between the building and the foundation. The system is adopted.

By the way, a seismic isolated building having the above structure has a characteristic that the deformation of the seismic isolation layer suddenly increases when a seismic force exceeding the assumption is applied. Therefore, a seismic motion that greatly exceeds the initial assumption such as a huge earthquake occurs. If it acts, the building may collide with the retaining wall or the seismic isolation device may be damaged.

However, in order to avoid this, if the damping force of the damper is increased, it is possible to suppress the deformation of the seismic isolation layer in the event of a huge earthquake that exceeds expectations and ensure safety, but small and medium-sized earthquakes and seismic motion at the beginning of design There is a problem that the response acceleration of the building at the level (corresponding to level 2) increases and the seismic isolation performance deteriorates.

Therefore, the present inventors have previously described in Patent Document 2 below that, in normal times, they exhibit seismic isolation performance corresponding to small and medium-sized earthquakes, and the relative displacement that occurs between the upper and lower structures when an earthquake occurs exceeds the set value. In such a case, we proposed a hydraulic damper that can increase the damping force and suppress excessive deformation.

According to the above-mentioned hydraulic damper, by keeping the damping coefficient of the hydraulic damper at a small value in normal times, the desired seismic isolation performance can be obtained against small and medium-sized earthquakes and earthquakes at the seismic motion level at the beginning of design. It can be exerted and the response acceleration of the building can be reduced, and when an excessive displacement occurs in the seismic isolation layer due to an earthquake that exceeds expectations during a large earthquake, it switches to the high damping mode and the seismic isolation layer is switched to by a large damping force. By suppressing the displacement of the seismic isolation device, it is possible to prevent collision with surrounding structures such as a retaining wall and damage to the seismic isolation device.

On the other hand, as shown in FIG. 10, when a heavy object 61 is present in the central portion at the time of designing the building 60 and the oil damper 63 is arranged symmetrically in the center of the seismic isolation layer 62, for example. As shown in FIG. 11, when the heavy object 61 moves to the corner corner side of the building 60 depending on the usage situation, eccentricity occurs and the corner corner portion tends to shake during an earthquake. Therefore, for the oil damper 63a arranged below the heavy object 61, it is necessary to increase the damping force with a displacement amount smaller than the displacement amount at the time of design and suppress the shaking.

However, conventionally, when trying to change the damping performance of the seismic isolation layer 62, there is no other way but to replace, add or remove the oil dampers 63 and 63a, and oil is applied to the space of the seismic isolation layer 62. Due to the large size of the damper 63, the above-mentioned replacement and removal work was large-scale, and the actual situation was that it was hardly carried out.

Japanese Unexamined Patent Publication No. 2006-144346 Japanese Unexamined Patent Publication No. 2014-159850

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a seismic isolation structure capable of easily changing the switching displacement amount of the damping force in the displacement switching type oil damper according to the change of the situation. It is something to do.

In order to solve the above problem, the invention according to claim 1 is a seismic isolation structure in which a displacement switching type oil damper is interposed between the upper and lower structure, and the cylinder of the displacement switching type oil damper has the upper and lower structure. A piston rod fixed to one of the cylinders and integrated with a piston movably provided in the cylinder and extending from the cylinder is connected to the other of the upper and lower structures and on the piston rod side. A detection unit having a step portion whose height changes at intervals in the horizontal direction is attached so that the length dimension between the step portions can be changed, and the detection portion engages with the cylinder side. At the same time, a shut-off valve for switching the damping force before and after the step portion is provided so as to be freely displaceable in the vertical direction.

The invention according to claim 2 is the invention according to claim 1, wherein the detection unit comprises a plurality of detection plates having different length dimensions between the step portions, and these detection plates can be exchanged with each other. It is characterized in that it is detachably attached to the piston rod side.

The invention according to claim 3 is the invention according to claim 1, wherein the detection portion has a step portion extending from the low portion to the high portion at a horizontal interval while forming a low portion in the central portion. It is characterized in that it is composed of a base portion on which a base portion is formed and a plurality of adjustment blocks that are detachably provided on a low portion adjacent to the step portion and whose upper surface is continuous with the high portion.

The invention according to claim 4 is the step portion from the low portion to the high portion in the invention according to claim 1, wherein the detection portion has a low portion formed in the central portion and is spaced horizontally. It is characterized in that it is composed of a base portion on which the base portion is formed and a slide plate which is movably provided on the lower portion of the base portion and whose upper surface is continuous with the high portion.

The invention according to claim 5 is the invention according to claim 1, wherein the detection unit is formed in a columnar shape and is rotatably provided on the piston rod side around the axis, and is provided on the outer peripheral surface in the axial direction. A first detection unit is provided with the above-mentioned stepped portion formed at intervals, and a position at a distance from the first detection unit in the circumferential direction, in the axial direction from the first detection unit. It is characterized in that the second detection unit in which the step portion is formed is provided at different intervals.

According to the invention according to any one of claims 1 to 5, the length dimension between the steps formed in the detection unit, that is, the amount of displacement between the upper and lower structures for which the damping force is switched by the shut-off valve is changed. Therefore, the switching displacement amount of the damping force in the displacement switching type oil damper can be easily changed according to the change of the situation without requiring a large-scale replacement or removal work.

It is a front view in the vertical sectional view for demonstrating the 1st Embodiment of this invention. It is a schematic block diagram in the vertical sectional view which shows the displacement switching type passive oil damper of FIG. 2 is a view showing the tip shape of the shut-off valve of FIG. 2, where FIG. 2A is a perspective view and FIG. 2B is a side view thereof. FIG. 2 is a schematic configuration diagram in a vertical cross-sectional view showing an operating state of the displacement switching type passive oil damper of FIG. 2 at the time of a large earthquake. 2 is a vertical cross-sectional view showing the detection plates of FIGS. 2 and 4. It is a vertical sectional view which shows the detection part in the 2nd Embodiment of this invention. A detection unit according to a third embodiment of the present invention is shown, where (a) is a vertical sectional view and (b) is a plan view. It is a front view which shows the detection part in 4th Embodiment of this invention. It is a front view which shows the detection part in 5th Embodiment of this invention. (A) is a plan view of the ground floor of a conventional seismic isolated building, and (b) is a plan view of the seismic isolated layer as well. A plan view of the ground floor of the seismic isolated building of FIG. 10, which has undergone renovation after completion, and FIG. 10B is a plan view of the seismic isolated layer.

(First Embodiment)
1 to 4 show a first embodiment of the seismic isolation structure according to the present invention, in which the seismic isolation structure includes laminated rubber or sliding on the foundation (lower structure) 4 of the building (upper structure) 1. A seismic isolation layer 3 is formed by interposing a seismic isolation device (a laminated rubber bearing is shown in the figure) 2 by a bearing to alleviate the vibration that tends to propagate from the foundation 4 side to the building 1 due to an earthquake or the like, and further to the building. A passive seismic isolation structure is provided between 1 and the foundation 4 by interposing a displacement switching type oil damper 6 in addition to a general-purpose oil damper 5 to positively dampen the vibration.

The displacement switching type oil damper 6 is set to a low damping mode having a small damping coefficient in normal times, and switches to a high damping mode having a large damping coefficient when a preset displacement occurs in the seismic isolation layer 3. is there.

FIGS. 2 to 4 show the displacement switching type oil damper 6, and the displacement switching type passive oil damper 6 is provided in a cylinder 7 filled with hydraulic oil and movable in the cylinder 7. It is roughly composed of a piston 8 and a piston rod 9 integrated with the piston 8 and extending outward from the cylinder 7.

Then, the displacement detection rod 10 is integrated in parallel with the piston rod 9. Then, the piston rod 9 is connected to the foundation 4 side, and the cylinder 7 is fixed to the building 1 side.

Further, the piston 8 is formed with a piston flow path 12 in which cylinder chambers 7a and 7b before and after the piston 8 are communicated with each other and a damping valve 11 for a high damping mode is interposed. Further, an external flow path 13 for communicating the cylinder chambers 7a and 7b is provided outside the cylinder chambers 7a and 7b, and the external flow path 13 is provided with a damping valve 14 for a low damping mode and the external flow path 13. A shut-off valve 15 for opening and closing the cylinder is provided.

On the other hand, a detection plate (detection portion) 16a is detachably provided on the upper surface of the detection rod 10 facing the tip end portion of the shut-off valve 15. Here, a displacement detection groove 17 is formed in the detection plate 16a, and step portions 17a are formed at both ends in the horizontal direction of the displacement switching groove 17.

Then, in normal times, the shut-off valve 15 is arranged in the displacement detection groove 17. Further, in the upper part of the shut-off valve 15, as shown in FIG. 3, a through hole 15a for communicating the external flow path 13 interposed with the damping valve 14 in a state of being arranged in the displacement detection groove 17. 15b is bored and other parts are formed in a solid columnar shape.

As a result, in the displacement switching type passive oil damper 6, in normal times, the shutoff valve 15 is arranged in the displacement detection groove 17 as shown in FIG. 2, and the external flow path 13 is held in an open state and operates. The low damping coefficient is set by the oil flowing through the damping valve 11 in the piston 8 and the damping valve 14 in the external flow path 13.

Further, the seismic isolation layer 3 is displaced more than expected, and as shown in FIG. 4, the shut-off valve 15 rides on the upper surface of the detection plate 16a from the stepped portions 17a at both ends of the displacement detection groove 17, and rises to the outside. By closing the flow path 13, the hydraulic oil flows only through the damping valve 11 in the piston 8 to switch to a high damping coefficient.

Further, in this seismic isolation structure, in addition to the detection plate 16a, a detection plate 16b that can be replaced with the detection plate 16a is provided. Here, the detection plate 16b is formed so that the length dimension L of the displacement detection groove 17, that is, the distance between the step portions 17a in the horizontal direction is shorter than that of the detection plate 16a. Instead of the detection plates 16a and 16b, a plurality of detection rods 10 having different lengths of the displacement detection grooves 17 may be provided.

In the seismic isolation structure having the above configuration, in normal times, the shut-off valve 15 is positioned between the step portions 17a in the displacement detection groove 17, so that the damping coefficient is kept at a small value and small and medium-sized earthquakes occur. In response to an earthquake with a seismic motion level at the initial design, the seismic isolation performance of the seismic isolated building 1 can be exhibited and the response acceleration of the building 1 can be reduced.

Further, when a large earthquake occurs and the seismic isolation layer 3 is excessively displaced, the shut-off valve 15 switches to the high damping mode by riding on the upper surface of the detection plate 16a from the step portion of the displacement detection groove 17. By suppressing the displacement of the seismic isolation layer 3 with a large damping force, it is possible to prevent collision with surrounding structures such as a retaining wall and damage to the seismic isolation device.

Furthermore, in this seismic isolation structure, changes in building eccentricity due to changes in building usage, changes in building aging, changes in owners' demands for building safety, revisions to laws, or new possible major earthquakes. When it becomes desirable to change the seismic isolation performance by estimation or the like, the detection plate 16a is replaced with the detection plate 16b or the like, and the displacement detection groove 17 has a length dimension L, that is, a damping force by the shutoff valve 15. By changing the displacement amount for switching the displacement, the switching displacement amount of the damping force in the displacement switching type oil damper 6 can be easily changed without requiring a large-scale replacement or removal work.

(Second Embodiment)
FIG. 6 shows a second embodiment of the present invention, and the same components as those shown in FIGS. 1 to 4 are designated by the same reference numerals to simplify the description.
In this seismic isolation structure, a low portion 21 is formed in the central portion on the upper surface of the detection rod 10, and a step portion 21a extending from the low portion 21 to the upper surface (high portion) is formed at intervals in the horizontal direction. The base portion 20 is formed.

A plurality of adjusting blocks 22 having an upper surface continuous with the upper surface of the base portion 20 are detachably attached on the lower portion 21 adjacent to the step portions 21a. As a result, the base portion 20 and the adjusting block 22 form a displacement amount detecting portion of the shutoff valve 15.

Therefore, in the seismic isolation structure, the displacement amount for switching the damping force by the shut-off valve 15 is adjusted by adjusting the length dimension L of the displacement detection groove formed between the adjustment blocks 22 by attaching and detaching the adjustment block 22. It can be easily changed. As a result, the same action and effect as those shown in the first embodiment can be obtained.

(Third Embodiment)
FIG. 7 shows a third embodiment of the present invention. Similarly, the same components as those shown in FIGS. 1 to 4 will be described with reference to the same reference numerals.
In this seismic isolation structure, on the upper surface of the detection rod 10, a low portion 31 is formed in the central portion of the upper surface, and a step portion leading to the upper surface (high portion) is formed at intervals in the horizontal direction. The base 30 is formed.

Guides 32 having a predetermined length dimension from the stepped portion toward the center are provided on both sides of the lower portion 31 of the base portion 30, and a slide plate 33 is provided between the guides 32. It is provided so as to be movable along the lower portion 31.

The slide plate 33 is a flat plate member whose upper surface is continuous with the upper surface of the base portion 30, and an inclined surface inclined from the lower portion 31 side toward the upper surface side is formed at the tip portion on the central portion side. As a result, the displacement detection portion of the shut-off valve 15 is configured between the lower portion 31 of the base portion 30 and the tip portion of the slide plate 33.

In the seismic isolation structure having the above configuration, the damping force is switched by the shut-off valve 15 by moving the slide plate 33 and adjusting the length dimension L of the displacement detection grooves formed between the tips of the slide plates 33. The amount of displacement can be easily changed, and thus the same effect as that shown in the first embodiment can be obtained.

(Fourth Embodiment)
FIG. 8 shows a fourth embodiment of the present invention, and similarly, the same components as those shown in FIGS. 1 to 4 will be described with reference to the same reference numerals.
In this seismic isolation structure, a detection unit 40 rotatably provided around the axis is formed at least in a portion of the detection rod 10 facing the shut-off valve 15.

Then, on the outer peripheral surface of the detection unit 40, a first displacement detection groove (first detection unit) 41 in which step portions 41a are formed at intervals in the axial direction is formed.

Further, on the outer peripheral surface of the detection unit 40, on the side opposite to the first displacement detection groove 41 in the radial direction, a second displacement detection portion 42a is formed at intervals in the axial direction. A groove (second detection unit) 42 is formed. Here, the length L ₁ between the stepped portion 42a of the second displacement detecting groove 42 is set smaller than the length L between the stepped portion 41a of the first displacement detection groove 41.

Therefore, according to the seismic isolation structure having the above configuration, the detection unit 40 is rotated about the axis, and the first displacement detection groove 41 is exposed on the upper surface of the detection rod 10 and the shutoff valve 15 is engaged. By switching to the second displacement detection groove 42, the displacement amount for switching the damping force by the shut-off valve 15 can be easily changed from L to L ₁ , and thus the one shown in the first embodiment. The same effect as the above can be obtained.

(Fifth Embodiment)
FIG. 9 shows a fifth embodiment of the present invention, and this seismic isolation structure is such that the detection unit 40 shown in the fourth embodiment is automatically switched.
That is, in this seismic isolation structure, in addition to the detection unit 40, a seismograph 50 installed close to the building 1 and a P wave of seismic motion detected by the seismograph 50 are used to perform a distance attenuation formula or the like. A PC (personal computer) 51 equipped with a program for predicting the maximum seismic intensity (acceleration) using it, and a detection unit when the seismic intensity (acceleration) predicted by the above program of the PC 51 exceeds a preset seismic intensity (acceleration). A motor 52 for rotationally driving the 40 is provided. The output shaft 52a of the motor 52 is coaxially connected to the end face of the columnar detection unit 40.

According to the seismic isolation structure having the above configuration, when an earthquake occurs, the maximum seismic intensity (acceleration) of the main dynamic S wave is predicted in the PC 51 from the P wave observed by the seismograph 50, and when this exceeds the set value, The detection unit 40 is rotated by 180 ° by the motor 52, and the first displacement detection groove 41 with which the shutoff valve 15 is engaged is switched to the second displacement detection groove 42.

As a result, it automatically switches to the high damping mode with a smaller amount of displacement, and suppresses the displacement of the seismic isolation layer with a large damping force, resulting in collision with surrounding structures such as retaining walls and damage to the seismic isolation device. Can be prevented.

1 Building (superstructure)
4 Foundation (substructure)
6 Displacement switching type oil damper 7 Cylinder 8 Piston 9 Piston rod 15 Shut-off valve 16a, 16b Detection plate (detection unit)
17a, 21a, 41a, 42a Steps 20, 30 Bases 21, 31 Low 22 Adjustment block 33 Slide plate 40 Detection 41 First displacement detection groove (first detection)
42 Second displacement detection groove (second detection unit)

Claims (5)

In a seismic isolation structure in which a displacement switching type oil damper is interposed between the upper and lower structures
The cylinder of the displacement switching type oil damper is fixed to one of the upper and lower parts structures, and the piston rod that is integrated with the piston movably provided in the cylinder and extends from the cylinder is the upper and lower parts. As well as being connected to the other side of the structure
A detection unit having stepped portions whose height changes at intervals in the horizontal direction is formed on the piston rod side so that the length dimension between the stepped portions can be changed, and the detection portion is mounted on the cylinder side. A seismic isolation structure characterized in that a shut-off valve that engages with the portion and switches the damping force before and after the step portion is provided so as to be freely displaceable in the vertical direction. The detection unit is composed of a plurality of detection plates having different length dimensions between the step portions, and these detection plates are detachably attached to the piston rod side so as to be interchangeable with each other. The seismic isolation structure according to item 1. The detection unit has a base portion in which a low portion is formed in the central portion and a step portion from the low portion to the high portion is formed at intervals in the horizontal direction, and a lower portion adjacent to the step portion. The seismic isolation structure according to claim 1, wherein the seismic isolation structure is detachably provided on the surface and the upper surface thereof is composed of a plurality of adjusting blocks continuous with the high portion. The detection unit includes a base portion in which a low portion is formed in the central portion and a step portion from the low portion to the high portion is formed at intervals in the horizontal direction, and above the low portion of the base portion. The seismic isolation structure according to claim 1, wherein the seismic isolation structure is provided so as to be movable and the upper surface thereof is a slide plate continuous with the high portion. The detection unit is formed in a columnar shape, and is provided on the piston rod side so as to be rotatable around the axis, and the first detection unit is formed on the outer peripheral surface at intervals in the axial direction. The second detection unit is provided at a position spaced from the first detection unit in the circumferential direction, and the step portion is formed at a distance different from that of the first detection unit in the axial direction. The seismic isolation structure according to claim 1, wherein the seismic isolation structure is provided.