JP2014114837A - Base isolation structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a base isolation structure capable of effectively and efficiently preventing a superstructure from being damaged even on the occurrence of a large earthquake with seismic intensity exceeding assumed seismic intensity of a seismic bearing.SOLUTION: In addition to a seismic bearing 9 placed between a superstructure 1 and a substructure 2, a base isolation structure B has a large displacement damper device 10 which: activates when a relative displacement between the superstructure 1 and the substructure 2 through the seismic bearing 9 reaches a predetermined amount d1; and applies damping force corresponding to an excess of the relative displacement xp over the predetermined amount d1.

Description

  The present invention relates to a base isolation structure having a base isolation support interposed between an upper layer side structure portion and a lower layer side structure portion.

  This type of seismic isolation structure is designed to increase the period of the vibration transmitted to the upper structure part during an earthquake by the seismic isolation bearing interposed between the upper structure part and the lower structure part. Various technologies have been developed, such as combining multiple types of seismic isolation devices to reduce seismic input to the structure.

  For example, a viscoelastic damper (base isolation device) that performs seismic isolation against small deformations during small earthquakes at the lower end of a metal damper (an example of a base isolation device) that performs base isolation against deformation during medium and large earthquakes In some cases, the seismic isolation bearing is formed by assembling (see Patent Document 1 below).

  In other words, this conventional seismic isolation structure allows viscoelastic dampers to act on small deformations during small earthquakes, and metal dampers to act on deformations larger than that, Make the base-isolated bearings exhibit seismic isolation action against a wide range of earthquakes from small earthquakes to large earthquakes.

JP 2002-242479 A

  However, in all of the conventional seismic isolation structures described above, the relative displacement between the upper layer structure and the lower layer structure becomes too large when a large earthquake exceeding the assumed seismic intensity of the seismic isolation bearing occurs. Thus, there is a possibility that a serious problem may occur in which the upper layer side structural portion collides with an adjacent object (for example, an adjacent object such as a peripheral wall or a retaining wall of the seismic isolation pit) and the upper layer side structural portion or the adjacent object is damaged.

  The present invention has been made in view of the above circumstances, and the main problem is that even if a large earthquake exceeding the assumed seismic intensity of the seismic isolation bearing occurs due to rational improvement, the upper-layer structure portion or the like. The point is to provide a seismic isolation structure that can effectively and efficiently prevent damage to adjacent objects.

The first characteristic configuration of the present invention is a seismic isolation structure having a seismic isolation support interposed between an upper layer side structure portion and a lower layer side structure portion,
A large displacement that operates when the relative displacement of the upper layer side structure portion and the lower layer side structure portion via the seismic isolation bearing reaches a predetermined amount and applies a damping force to the relative displacement portion exceeding the predetermined amount. It is in the point that the damper device for equipment is additionally equipped.

  According to the above configuration, the seismic isolation between the upper structure and the lower structure through the seismic isolation bearing is less than the specified amount (that is, the earthquake within the assumption of the seismic isolation bearing). The seismic support can reliably exhibit the desired seismic isolation effect.

  If an earthquake in which the relative displacement between the upper structure and the lower structure through the base isolation bearing exceeds a specified amount (that is, a large earthquake that is not expected from the base isolation bearing) occurs, a large displacement damper Since the damping force is applied to the relative displacement exceeding the predetermined amount by the operation of the device, the relative displacement amount of the upper layer side structure portion and the lower layer side structure portion becomes too large due to the damping action by the large displacement damper device. Can be deterred.

  Therefore, when an earthquake within the assumption of seismic isolation bearing occurs, it is possible to effectively prevent the upper structure from being damaged by the expected seismic isolation effect of the seismic isolation bearing, but the seismic isolation bearing Even when an unexpected large earthquake occurs, it is possible to prevent damage to the upper structure portion and its adjacent objects due to the damping action of the large displacement damper device.

  In addition, since the operation of the large displacement damper device is limited only when a large earthquake that is not expected from the seismic isolation bearing occurs, the number of operations of the large displacement damper device can be reduced accordingly, and the running cost can be reduced. Inexpensive can also be achieved.

The second characteristic configuration of the present invention is to constitute the large displacement damper device.
One end of the damper is fixed to one of the lower part of the upper structure part and the upper part of the lower structure part, and the relative displacement is applied to the other of the lower part of the upper structure part and the upper part of the lower structure part. Provided with a contact portion that abuts from the lateral side to the other end side that is the free end side of the damper when a fixed amount is reached, and that exerts a damping force on the damper for a relative displacement exceeding the predetermined amount There is a point.

  According to the above configuration, it is possible to equip the large displacement damper device using the seismic isolation bearing installation layer. For example, in order to equip the large displacement damper device by providing a dedicated installation layer separately. Compared to the building space, it can be used effectively.

  A third characteristic configuration of the present invention is that the damper is a displacement proportional type damper in which a damping force increases in proportion to the amount of displacement.

  In other words, in a large displacement region in a large earthquake that is not assumed to be a seismic isolation bearing, the speed is considered to be slow, so the damping force increases in proportion to the speed as the damper that constitutes the large displacement damper device. In the case of providing a speed proportional damper, there is a possibility that a damping force cannot be effectively applied in a large displacement region.

  On the other hand, according to the above configuration, since the displacement proportional damper whose damping force increases in proportion to the amount of displacement is provided as the damper constituting the large displacement damper device, A damping force can be effectively applied, and thereby it is possible to further prevent the upper layer side structural portion and its adjacent objects from being damaged during a large earthquake.

Perspective view showing main parts of seismic isolation structure Plan view showing main parts of seismic isolation structure Longitudinal section showing the main part of the seismic isolation structure (A) Explanatory diagram schematically showing operation during earthquake (small to medium displacement), (b) Explanatory diagram schematically showing operation during earthquake (large displacement) Longitudinal sectional view showing the main part of the seismic isolation structure of another embodiment Longitudinal sectional view showing the main part of the seismic isolation structure of another embodiment Longitudinal sectional view showing the main part of the seismic isolation structure of another embodiment Longitudinal sectional view showing the main part of the seismic isolation structure of another embodiment

  1 to 3 show a reinforced concrete seismic isolation structure B having a seismic isolation layer 3 between an upper layer side structure unit 1 and a lower layer side structure unit 2, and the upper layer side structure unit 1 is a building part on the ground side. The lower layer side structural portion 2 is composed of a seismic isolation pit.

  On the lower end side of the upper layer side structure portion 1, a large beam 7 is extended between lower end sides of adjacent columns 6, and a small beam 8 is extended between intermediate portions in the length direction of the arranged large beams 7. The floor slab 4 (see FIG. 3) is integrally supported by the large beam 7 and the small beam 8.

  The seismic isolation layer 3 of the seismic isolation structure B is configured by interposing a base isolation bearing 9 in accordance with the position of the column 6 of the upper layer side structure portion 1 between the upper layer side structure portion 1 and the lower layer side structure portion 2. It is.

  In addition, in this seismic isolation layer 3, according to the position of an intersection (an example of an intermediate part of the span) between the small beams 8 of the upper layer side structure portion 1 between the upper layer side structure portion 1 and the lower layer side structure portion 2. Further, a large-displacement damper device 10 is additionally provided for imparting a damping force to a large roll generated during an unexpected large earthquake of the seismic isolation bearing 9.

  The seismic isolation bearing 9 is a laminated rubber seismic isolation having a deformed portion 9D formed by alternately laminating a plurality of metal thin plates and rubber thin plates between a pair of upper and lower fixed plates 9A, 9B. It consists of a device. Although not shown, a cylindrical metal plug (an example of a damper) is provided at the center of the deformation portion 9D of the seismic isolation bearing 9.

  The seismic isolation bearing 9 fixes the upper fixing plate 9A to the lower surface of the upper layer side structure portion 1 with fixing means such as bolts, and the lower fixing plate 9B to the upper surface of the lower layer side structure portion 2 with bolts. It is interposed between the upper layer side structure portion 1 and the lower layer side structure portion 2 by being fixed by a fixing means such as.

  That is, the seismic isolation bearing 9 exhibits seismic isolation action by deformation of the deformation portion 9D due to the relative movement of the thin plates in the lateral direction with respect to rolls during an earthquake or the like, and the deformation of the deformation portion 9D. The seismic energy is attenuated by plastic deformation of the built-in metal plug.

  As shown in FIGS. 1 to 3 and 4, the large displacement damper device 10 has an upper end side fixed to a lower surface of the upper layer side structure portion 1 by a fixing means such as a bolt, and the lower layer side structure portion 2. A displacement-proportional metal damper (an example of a damper) 11 supported on the upper surface so as to be movable in the horizontal direction, and the free movement of the metal damper 11 when the relative displacement x reaches a predetermined amount d1 (see FIG. 4). The abutting portion 12 is integrally formed on the upper surface of the lower layer side structural portion 2 so as to abut on the lower end side as an end side from the horizontal direction (an example of the lateral side).

  The metal damper 11 has a lateral U that can be plastically deformed along a horizontal direction between a fixing plate 11A made of metal or the like for the upper layer side structure portion 1 and a cylindrical base 11B supported by the lower layer side structure portion 2. A deformable portion 11D composed of a plurality of character-shaped steel materials 11a is provided.

  In addition, the deformation portion 11D is provided with the steel material 7a along the extending direction of four (an example of a plurality of) small beams 8 having a pitch of about 90 degrees (an example of a predetermined angle pitch), thereby forming a horizontal plane. A damping force due to plastic deformation of the steel material 11a can be effectively applied to each direction along the direction.

  As shown in FIG. 3, the abutting portion 12 has an outer peripheral surface of a disc-shaped base 11b provided at the lower end of the base 11B with the cylindrical base 11B of the metal damper 11 placed at the center C. Is formed of an annular protrusion 12a that protrudes upward with an inner diameter dimension larger than the outer diameter of the base 11b by a predetermined amount d1 so as to form a gap A having the same dimension as the predetermined amount d1. is there.

  In other words, the large displacement damper device 10 regulates the relative movement of the metal damper 11 in each direction along the horizontal plane of the base 11A by the annular protrusion 12a within the range of the predetermined amount d1. ), The deformation portion 11A of the metal damper 11 is deformed with respect to the relative displacement xp exceeding the predetermined amount d1 of the upper layer side structure portion 1 and the lower layer side structure portion 2, and the damping is greater than that of the base isolation bearing 9. A force and a braking force are applied.

  In addition, as shown in FIG. 3, the lower surface of the base 11b of the metal damper 11 is provided with a sliding body 11d coated with a resin material that reduces sliding resistance, and on the upper surface of the lower layer side structure portion 2 facing this. A substantially entire area of the inner surface portion of the annular protrusion 12a is configured as a sliding bearing surface 13 coated with a resin material, thereby allowing the metal damper 11 to function also as a sliding bearing and in the lower portion of the upper layer side structural portion 1. The intermediate portion of the span is supported.

  Further, on the tip end side of the annular protrusion 12a of the contact portion 12, an annular shape that prevents the lower end portion from moving over from the state in which the lower end portion of the metal damper 11 is in contact with the inner peripheral surface of the annular protrusion 12a. Is formed so as to protrude inward.

  As shown in FIG. 4A, the seismic isolation structure B configured in this way is assumed to have a relative displacement x between the upper layer side structure portion 1 and the lower layer side structure portion 2 that is equal to or less than a predetermined amount d1. With respect to rolls, the desired seismic isolation and damping effects of the seismic isolation bearing 9 alone are reliably exhibited in a state where the relative displacement x of the predetermined amount d1 or less is allowed by the seismic isolation bearing 9. It effectively suppresses the seismic isolation structure B from being damaged.

  Nevertheless, for a roll with an unexpected magnitude in which the relative displacement x between the upper layer side structure portion 1 and the lower layer side structure portion 2 exceeds a predetermined amount d1, as shown in FIG. Due to the operation of the damper device 10, a damping force and a braking force larger than the seismic isolation bearing 9 are applied to the relative displacement xp exceeding the predetermined amount d 1, and the upper layer side structure portion 1 is positioned laterally thereof. The seismic isolation structure B and other objects are prevented from being damaged due to collision with another object (for example, an adjacent object such as a peripheral wall portion of the seismic isolation pit).

[Another embodiment]
(1) In the above-described embodiment, the case where the damper 11 is supported on the upper surface of the lower layer side structural portion 2 so as to be horizontally movable is shown as an example to constitute the large displacement damper device 10. As shown in FIG. 2, the metal damper 11 is suspended in a suspended state so that a gap having a dimension equal to or smaller than the height of the contact portion 12 is formed between the damper 11 and the upper surface of the lower layer side structure portion 2. You may arrange in.

(2) In the above-described embodiment, when the damper device 10 for large displacement is configured, the damper 11 is provided at the lower part of the upper layer side structural unit 1 and the contact part 12 is provided at the upper part of the lower layer side structural unit 2. Although shown in the example, for example, as shown in FIG. 6, conversely, the contact portion 12 may be provided at the lower portion of the upper layer side structure portion 1 and the damper 11 may be provided at the upper portion of the lower layer side structure portion 2. Good.

(3) The specific configuration of the damper 11 is not limited to the configuration shown in the above-described embodiment, and various configuration changes are possible. For example, as shown in FIG. You may comprise from the steel material 14 grade | etc.,.

(4) In the above-described embodiment, the large displacement damper device 10 includes the damper 11 that can be attached to the upper layer side structure portion 1 and the contact portion 12 that is integrally formed on the upper portion of the lower layer side structure portion 2. 8, for example, as shown in FIG. 8, a damper 11 for mounting the displacement damper device 10 on the upper layer side structure portion 1, a fixed portion 15 a such as a bolt hole, and a contact portion 12. You may comprise as an apparatus unit from the contact members 15 made from metal etc. which have the sliding receiving surface 13. FIG. This makes it possible to easily equip existing structures and the like.

(5) In the above-described embodiment, the case where the damper device 10 for large displacement is installed below the upper layer side structure unit 1 is shown as an example. However, with the retaining wall formed on the lateral side of the upper layer side structure unit 1 You may equip to the lateral side of the upper layer side structure part 1, such as between.

(6) The damper 11 constituting the large-displacement damper device 10 is not limited to the displacement proportional damper, but may be various dampers such as a speed proportional damper. Or a combination of these.

(7) The seismic isolation bearing 9 is not limited to the laminated rubber seismic isolation apparatus described in the previous embodiment, and may be various seismic isolation apparatuses such as a sliding bearing isolation system and a rolling isolation system, A combination thereof may be used.

DESCRIPTION OF SYMBOLS 1 Upper layer side structure part 2 Lower layer side structure part 9 Seismic isolation bearing 10 Large displacement damper apparatus 11 Damper 12 Contact part x Relative displacement d1 Predetermined amount xp Relative displacement exceeding predetermined amount

Claims (3)

A seismic isolation structure having a seismic isolation bearing interposed between the upper layer side structure part and the lower layer side structure part,
A large displacement that operates when the relative displacement of the upper layer side structure portion and the lower layer side structure portion via the seismic isolation bearing reaches a predetermined amount and applies a damping force to the relative displacement portion exceeding the predetermined amount. Seismic isolation structure with additional damper device. To configure the large displacement damper device,
One end of the damper is fixed to one of the lower part of the upper structure part and the upper part of the lower structure part, and the relative displacement is applied to the other of the lower part of the upper structure part and the upper part of the lower structure part. Provided with a contact portion that abuts from the lateral side to the other end side that is the free end side of the damper when a fixed amount is reached, and that exerts a damping force on the damper for a relative displacement exceeding the predetermined amount The seismic isolation structure according to claim 1.   The seismic isolation structure according to claim 2, wherein the damper is a displacement proportional type damper in which a damping force increases in proportion to a displacement amount.

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