JP2000074132A - Fixing structure of building provided with base isolation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fix a building to a ground while enduring external disturbance other than inertia force without deteriorating a primary function of a base isolation device by breaking a supporting member mounted on the building provided with the base isolation device against external force by an oscillator vibrated by vibration external disturbance of the ground. SOLUTION: In the case where a load is acted on an orthogonal direction in a figure space on a building by external force such as wind, the building is fixed to a ground while a concrete block 2 resists thereto in order to prevent a displacement from generating. In this case, as an oscillator 3 is not vibrated by external force other than inertia force such as wind, the concrete block 2 is not broken without colliding with the oscillator 3. In the case where external disturbance of ground vibration such as an earthquake acts on the building, an oscillating motion of the oscillator 3 is started, the oscillator 3 is resonated with the external disturbance of vibration, and thereby, a crack is generated on the concrete block 2 by a hammer 3a of the oscillator 3, rigidity is remarkably reduced, and the concrete block 2 is broken. As it becomes a condition in which the building is not really fixed, vibration can be absorbed by a base isolation device 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology related to a seismic isolation device for improving the seismic performance of a building, and more particularly, to a technology that makes the seismic isolation device resistant to inertial force due to external force other than an earthquake that is difficult to withstand. The present invention relates to a fixed structure of a building having a seismic isolation device for fixing the building to the ground.

[0002]

2. Description of the Related Art As one of the techniques for improving the seismic performance of an existing building, a technique of installing a seismic isolation device having seismic isolation laminated rubber on a pillar or the like of the building has been proposed. In this method, a part of a pillar of a building (usually near the ground) is deleted, and a seismic isolation device is inserted there. When a vibration disturbance acts on the building, the vibration is absorbed by the seismic isolation device.

[0003]

On the other hand, the seismic isolation device is deformed even when an external force other than a vibration disturbance such as an earthquake, for example, an external force other than an inertial force such as a wind acts on a building. In such a case, it may remain deformed in one direction, causing the destruction of the seismic isolation device or the tilting or swinging of the building, reducing the livability and causing the so-called pull-out or breakage of the seismic isolation laminated rubber. It is a factor to make it. In particular, in the case of a light-weight building such as a single-family house, or a plate-shaped apartment or the like having a large tower-to-ratio or side-to-side ratio, this tendency becomes even stronger. In order to avoid this, it has been proposed to install a wind shield door that can be freely opened and closed, and to additionally install a reinforcing member that can only withstand external forces other than inertial force. It is difficult to carry out, and the latter is likely to prevent the seismic isolation device from exerting its seismic isolation function because it works to fix the building to the ground even if vibration disturbance such as an earthquake acts on the building There is.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a seismic isolation device capable of fixing a building to the ground with durability against disturbances other than inertial force without impairing the original function of the seismic isolation device. An object of the present invention is to provide a fixed structure of a building provided with a device.

[0005]

According to the present invention, a support member attached to a building provided with a seismic isolation device so as to resist an external force against the building is provided. A structure for fixing a building provided with a seismic isolation device including a vibrator for breaking a support member is provided. According to this means, when an external force other than an inertial force such as a wind acts on the building, the support member resists the external force, so that the building is prevented from tilting or the like. on the other hand,
When a vibration disturbance such as an earthquake acts on a building, the vibrator vibrates due to the vibration disturbance and collides with the support member to destroy it. As a result, the support member does not fix the building, the seismic isolation function of the seismic isolation device is sufficiently exerted, and the building is protected from an earthquake or the like. Therefore, the fixing structure of the present invention has an effect that the original function of the seismic isolation device provided in the building is not impaired, the structure is durable to external forces other than the inertial force, and the building can be fixed to the ground.

In the present invention, as a material of the supporting member, solid concrete or concrete block, porcelain, cast iron or the like is used from the viewpoint that the building is sufficiently fixed and at the same time is easily broken by the vibrator. Are preferred. It is preferable that the vibrator is designed by setting its natural frequency based on the predominant period of the ground on which the building is constructed. Due to this, the vibrator vibrates greatly for a small ground acceleration before the main motion such as an earthquake,
The support member can be destroyed immediately. In general, external force refers to a force applied to a building, and disturbance refers to a dynamic (accompanying vibration) force among external forces, and inertial force refers to a force applied to a building during an earthquake.

[0007]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic view showing a fixing structure 1 of the present invention. The fixed structure 1 includes a seismic isolation device 4
And a concrete block 2 (supporting member) and a vibrator 3.

The concrete block 2 is arranged so as to be adapted to the direction of an external force such as wind acting on the building (preferably, the direction of the external force is the longitudinal direction). FIG.
In this example, one concrete block 2 is arranged on both sides of the vibrator 3, but any one of them may be used as long as it can resist disturbance acting on the building. In addition, the shape of the concrete block 2 can be freely selected in a range where the concrete block 2 is destroyed by the vibrator 3. For example, the concrete block 2 is formed in a circular or square cylindrical shape installed so as to surround the vibrator 3. It is good. Vibrator 3
Is composed of a hammer 3a and a spring steel rod 3b, and is designed such that the natural frequency specified by the mass of the hammer 3a and the spring constant of the spring steel rod 3b is synchronized with the dominant period of the ground. It is.

The operation of the fixing structure 1 having the above configuration will be described. When a load is applied to the building by an external force such as wind, for example, in a direction perpendicular to the plane of the drawing, the concrete block 2 resists the fixing, fixes the building to the ground, and hardly causes displacement or the like. At this time, the vibrator 3 does not vibrate with an external force other than the inertial force such as wind, so that the vibrator 3 does not collide with the concrete block 2 and break it. On the other hand, when a ground vibration disturbance such as an earthquake acts on the building (see the arrow in FIG. 2), the vibrator 3 starts to shake and resonates with the vibration disturbance. Then, the hammer 3a of the vibrator 3 collides with the concrete block 2 and breaks it, or at least cracks the concrete block 2 and significantly lowers its strength. As a result, the concrete block 2 collapses due to the collision of the hammer 3a and the vibration of the building, and the building is not fixed at all (FIG. 2), the seismic isolation device 4 absorbs the vibration, and the building is protected from the vibration disturbance. Will be done. In a normal earthquake, it has similar properties in two horizontal directions. Therefore, if the design for installing the fixing structure 1 in which the fixing direction is changed is performed, there is an effect in two horizontal directions.

Next, another embodiment of the present invention will be described. The fixed structure 1 ′ in FIG. 3 is obtained by mounting the vibrator 3 ′ on the building side, and the other configuration is the same as the above-described fixed structure 1.

In this configuration, the vibrator 3 'vibrates according to the shaking of the building, but no higher-order vibration of the building is excited by an external force other than an inertial force such as wind. Therefore, by designing the period of the vibrator to be synchronized with the higher natural period of the building, it is possible to resonate against an earthquake or the like.

FIG. 4 shows a state in which the fixing structure 1 is installed on a steel plate 5a erected on a table 5b. In general, seismic isolation rubber causes vertical deformation of about several mm in several decades due to long-term creep (subsidence). Therefore, when the fixing structure 1 is installed substantially horizontally on the seismic isolation device 4 as shown in the example of the figure, the force acts in the vertical direction due to the sinking of the seismic isolation device 4, and the fixing structure 1 is destroyed. Become. In the example of FIG. 4, in order to prevent this, the fixing structure 1 is installed on a steel plate 5 a erected on a table 5 b, and the steel plate can be bent vertically downward, so that the seismic isolation device 4 sinks. Fixed structure 1 according to
Is adapted to translate vertically downward.

FIG. 5 is a view showing another embodiment of the concrete block 2 in FIG. In FIG. 5A, a groove 2′a is formed in the concrete block 2 ′. When the above described concrete block 2 collides with the hammer 3a, the concrete block 2 may be in an upright state with a crack. In this case, the concrete block 2 is not strong enough to fix the building, but may resist swinging of the building with respect to the ground due to friction between the cracked surfaces. As a result, a situation may occur in which the seismic isolation function of the seismic isolation device 4 is not sufficiently exerted. In the concrete block 2 ', when the hammer 3a collides with the concrete block 2' due to the presence of the groove 2'a, it is immediately crushed into at least three pieces, and such a situation does not occur.

FIG. 5 (b) shows a concrete block 2 "provided with a groove 2" a, a lower end of the concrete block 2 "being slightly lifted to form a hinge 2" b for the same reason as in the case of FIG. 5 (a). It is fixed to the ground side via According to this structure, the concrete block 2 "is connected to the hammer 3
If a collides with a, it is broken at the groove 2 "b and the lower half thereof tilts around the hinge 2" b, so that the above situation can be solved. In this case, if the concrete block is previously inclined slightly counterclockwise in the figure, this effect is further enhanced.

FIG. 5 (c) realizes the same operation as that of FIG. 5 (b) by another configuration, and the concrete block 2 ″ has left and right fixing jigs 6 with its lower end slightly raised. Since the right and left fixing jigs 6 are arranged so that the direction of the fixing force is shifted up and down, a counterclockwise moment always acts on the lower half of the concrete block 2 ". I have. Therefore, when the concrete block 2 "breaks at the groove 2" a, the lower half thereof falls down according to the moment, and the above situation can be solved.

FIG. 5D shows the seismic isolation device 4 described with reference to FIG.
It is a fixing structure of the concrete block 2 corresponding to the sinking of the concrete block. In FIG. 5D, the concrete block 2 is sandwiched between the L-shaped angles 8 via the rubber sheet 7 by being pressed by the plate 9a and the bolt 9b with a small gap 2b from the ground side. . According to this fixing structure, the concrete block 2 can slide vertically between the L-shaped angles 8 due to the shearing deformation of the rubber sheet 7 and move in a vertical downward direction. be able to. The method of fixing the concrete block 2 in FIGS. 5C and 5D may be upside down.

FIG. 6 is a view showing another embodiment of the vibrator 3. The vibrator 3 ′ includes a hammer 3a ′ and a hammer 3
and a bar 3b 'connected to a' via a hinge 3c '. The bar 3b' is withdrawn and connected to the building via the hinge 3c '. In this vibrator 3 ′, unlike the above-described vibrator 3, the rod 3 b ′ may not be made of a spring material, and its natural frequency is determined by the mass of the hammer 3 a ′ and the rod 3 b ′.
It is set by the length of b 'and the like.

Finally, an example of the design of the concrete block 2 and the vibrator 3 in the fixed structure as shown in FIG. 1 will be described. It is assumed that a wind load Qw = 0.2 × W1 is applied to the building weight W1 above the seismic isolation device 4. When the concrete block 2 is made of unreinforced mortar, the cross section required for the concrete block 2 is calculated as follows. The compressive strength of concrete block 2 is defined as Fc, and the shear strength is
If Fs (= 1/10 × Fc), in order not to break down to Qw,
Shear cross section As = Qw / Fs is required. Therefore, in the case of the structure shown in FIG. 1, since there are two concrete blocks 2, if the sectional area of each block 2 satisfies approximately As / 2, the building is fixed (non-seismic) against the wind load.

On the other hand, the force P required to break one of the concrete blocks 2 is calculated as follows.
The moment M required for fracture is M = σt × Z (σt: tensile yield stress of the block, Z: quadratic modulus of the section of the block),
If the distance L between the fulcrums of the concrete block 2 is supported by both ends of the pin, M = 1 / 4P × L. Therefore, P = 4
× σt × Z / L.

Next, the vibrator 3 is moved to the concrete block 2.
The vibration conditions for destroying and the weight of the hammer 3a are calculated as follows. Assuming that the ground acceleration at the time of the seismic isolation response of the building is Ag and the response magnification is x, the response Ap of the vibrator 3 is Ap = Ag × x. Here, hammer 3
Assuming that the impact coefficient (the ratio between the static force and the impact force) when α collides with the concrete block 2 is α and the gravitational acceleration is G, the weight mp of the hammer 3a is mp = P × G / (Ap × α).

Next, the length Lp of the spring steel bar 3b is calculated as follows. Assuming that the spring steel rod 3b is roller-supported on the hammer 3a side and pin-supported on the ground side, and the period of the vibrator 3 is Tp, the rigidity Kp is Kp = 4 × π ² × mp / G / Tp ² . Also, from the relationship between the deflection of the cantilever and the force, Kp = mp / δ = 3 × E
× I / Lp ³ (δ: deflection of spring steel bar, E: Young's modulus of spring steel bar, I: second moment of area of spring steel bar), Lp ³ = 3
× E × I / Kp, and Lp is determined. The spring steel rod 3
The buckling load Pcr of b is Pcr = π ² if the buckling length Lk = 2Lp
It does not buckle if it meets × E × I / Lk ² > mp × G.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a fixing structure 1 of the present invention.

FIG. 2 is a view showing a mode in which a concrete block 2 is broken by a vibrator 3;

FIG. 3 is a schematic view showing another fixing structure 1 ′ of the present invention.

FIG. 4 is a schematic diagram showing another installation structure of the fixing structure 1 of the present invention.

FIG. 5A is a view showing another concrete block 2 ′. (B) It is a figure which shows another concrete block 2 ". (C) It is a figure which shows another installation structure of another concrete block 2". (D) is a diagram showing another installation structure of the concrete block 2.

FIG. 6 is a schematic view of another vibrator 3 '.

[Explanation of symbols]

 Reference Signs List 1 fixed structure 2 concrete block 3 oscillator 4 seismic isolation device

Claims (1)

[Claims] 1. A support member attached to a building provided with a seismic isolation device so as to resist external force against the building, and a vibrator that vibrates due to vibration disturbance of the ground and destroys the support member. Fixed structure of building equipped with seismic isolation device.