JPH10184089A - Vibration isolation structure of structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To relax an impulse working to a structure and display vibration- isolation performance excellently even to a small earthquake in the vibration isolation structure of the structure. SOLUTION: The vibration isolation structure of the structure has a roller bearing means 6 being interposed between a foundation 2 and a building 4 and movably supporting the building 4 in the horizontal direction. The roller bearing means 6 consists of a lower-side support plate 8 being fixed on the foundation 2 side and having approximately cone-shaped inclined planes 8a and a ball 12 rolled on the inclined planes 8a of the lower-side support plate 8 when the foundation 2 and the building 4 are displaced relatively in the horizontal direction at that time, and the inclined planes 8a are inclined by stages so that angles are increased towards the outside in the radial direction from the center of the lower-side support plate 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a seismic isolation structure for a structure.

[0002]

2. Description of the Related Art Conventionally, seismic isolation structures for buildings using rolling bearing means have been known. The rolling bearing means is fixed to the foundation or the building and has a support plate having a substantially mortar-shaped slope, and rolls the slope of the support plate when the base and the building are relatively displaced in the horizontal direction. The ball is mainly composed of a ball and the ball is rolled on the slope to obtain a restoring force. The angle θ of the slope is set to about 4 (°) when the rolling friction coefficient μ is 0.07, for example.

[0003]

In the process of raising the ball on the slope, the load shared by the rolling bearing means (the load obtained by dividing the weight of the building by the number of the rolling bearing means).
Is W, the rolling friction coefficient is μ, and the angle of the slope is θ,
As shown in FIG. 3, the ball a has the sum of the force overcoming the frictional force and the force overcoming the drag (μ · W · cos ² θ + W).
・ Sinθ ・ cosθ) acts in the horizontal direction, and this force acts as a horizontal force on the building. This horizontal force is θ = 4
(°), μ = 0.07, W = 5 (ton), μ · W · c
os ² θ + W · sin θ · cos θ = 0.7 (ton) Therefore, since the slope b has a constant angle, the building has a disadvantage that the ball a receives an impact of 0.7 (ton) at the moment when the ball a starts to rise. Also, the horizontal force of 0.7 (ton) is
This corresponds to a ground motion with an acceleration of 137 (Gal) received by a non-seismic building (980 (Gal) / 5 (ton) x 0.7 (ton) = 13
7 (Gal)). Therefore, in the conventional rolling bearing, 137 (Gal)
There is a problem that it cannot respond to the following earthquakes.

[0004] The present invention has been made in view of the above-mentioned conventional problems, and has been made in consideration of the above-mentioned problems, and has an object to mitigate an impact acting on a structure,
An object of the present invention is to provide a seismic isolation structure for a structure that exhibits good seismic isolation performance even for a small earthquake.

[0005]

The present invention has the following configuration to achieve the above object. In other words, the invention according to claim 1 is a seismic isolation structure for a structure having rolling support means interposed between a foundation and a structure for movably supporting the structure in a horizontal direction. The support member is fixed to the foundation or structure and has a substantially mortar-shaped slope, and a ball that rolls on the slope of the support member when the foundation and the structure are relatively displaced in the horizontal direction. Mainly, a seismic isolation structure for a structure, characterized in that the slope is inclined stepwise so that the angle becomes larger toward the outside in the radial direction from the center of the support member.

According to the present invention, the slope is formed in a stepwise manner so that the angle increases radially outward from the center of the support member, so that the horizontal force applied to the building during the ball lifting process is reduced. The size gradually increases, and the impact applied to the building can be reduced.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The seismic isolation structure according to the present embodiment is an example in which the present invention is applied to a building for a general house. As shown in FIG. 1, between the foundation 2 and the building 4, for example, at each of the four corners of the building 4, rolling bearing means 6 that supports the building 4 movably in the horizontal direction is interposed. Have been. The rolling bearing means 6 includes a lower support plate (corresponding to a support member) 8 provided on the foundation 2 side, an upper support plate 10 fixed to the base of the building 4 so as to face the lower support plate 8, The upper support plate 10 and the lower support plate 8 are disposed between the upper support plate 10 and the lower support plate 8, respectively, when the foundation 2 and the building 4 are relatively displaced in the horizontal direction. Ball 12 that rolls.

[0008] The upper support plate 10 has a lower surface 1 along a horizontal plane.
It is substantially circular in plan view having 0a. The lower support plate 8 has a substantially circular shape in plan view and is fixed to the foundation 2. The lower support plate 8 has a substantially mortar-shaped slope 8a approaching the base of the building 4 from the center to the outside.

The slope 8a is formed such that the angle gradually increases from the center of the lower support plate 8 toward the outside in the radial direction. That is, the slope 8a includes an inner slope 8a1 having an outer diameter of D1 and an outer slope 8a2 having a truncated cone shape having an inner diameter of D1 and an outer diameter of D2. , 8a2 are both formed in a straight line in longitudinal section.

FIG. 2 is a graph showing the restoring force characteristics of the seismic isolation structure of the present embodiment. The angle of the inner slope 8a1 is 1 (°), and the angle of the outer slope 8a2 is 4 (°). 4 shows the restoring force characteristics when set to. In FIG. 2, the right side of the vertical axis indicating the horizontal force applied to the building 4 (first,
The fourth quadrant shows the characteristic that the ball 12 rises rightward on the slope 8a and descends leftward, and the left side (second and third quadrants).
Shows a characteristic in which the ball 12 rises leftward on the slope 8a and descends rightward. In this case, the rolling bearing means 6
Has a shared load of 5 (ton) and a rolling friction coefficient of 0.07.

As shown in the first quadrant of FIG. 2, when an earthquake occurs, the ball 12 at the center of the lower support plate 8 first starts climbing a gentle 1 (°) slope 8a1.
Then, the slope 8a2 of 4 (°) is ascended. In this process, the horizontal force applied to the building 4 is 0.44 (ton) when the ball 12 rises slowly on the slope 8a1 of 1 (°).
In the case of the slope 8a2 of 4 (°), the normal value is 0.7 (ton). The magnitude of this horizontal force is the same when the ball 12 rises to the left as shown in the third quadrant (however, in this case, the horizontal force is given a negative sign). The impact force when moving from the slope 8a1 of 1 (°) to the slope 8a2 of 4 (°) is as follows.
0.26 (to) obtained by subtracting 0.44 (ton) from 0.7 (ton)
n).

According to the seismic isolation structure of the present embodiment as described above, the impact force applied to the building 4 in the step of lifting the ball 12 is 0.44 (ton) at the beginning of rolling, and the ball 12 When transitioning from 8a1 to the slope 8a2, it is 0.26 (ton). Therefore, a large impact of 0.7 (ton) is not applied to the building 4 at a time, and the impact can be reduced. The equivalent damping constant in this case is 32 (%)
This also satisfies the conditions generally required for the seismic isolation structure (the equivalent damping constant is in the range of 20 to 40 (%)).

The acceleration of an earthquake when a horizontal force of 0.44 (ton) acts is 980 (Gal) / 5 (ton) × 0.44 (t)
on) = 86 (Gal), and in the present embodiment, seismic isolation starts from a small-scale earthquake of about 86 (Gal). In the case of a small earthquake, the displacement of the ball 12 is also small, so it is possible to deal with only the gentle slope 8a1.

The present embodiment is a preferred embodiment of the present invention, and the technical scope of the present invention is not limited to this embodiment. For example, in the present embodiment, the present invention is applied to the rolling bearing means 6 for rolling the ball 12 on both the upper support plate 10 and the lower support plate 8, but the present invention is not limited to this, and the present invention is not limited to this. A ball is rotatably held on one of the objects and a support member is provided only on the other,
The present invention is also applicable to a rolling bearing means (for example, a so-called free-bearing type bearing means) for rolling a ball only by the other supporting member. Further, the slope according to the present invention may be provided on the upper support plate 10 or on both the upper support plate 10 and the lower support plate 8.

[0015]

As described above, according to the present invention, in a seismic isolation structure for a structure, the impact applied to the structure is reduced, and the seismic isolation performance is excellent even for a small earthquake. be able to.

[Brief description of the drawings]

FIG. 1 is a side view of a rolling bearing according to the present embodiment.

FIG. 2 is a diagram showing restoring force characteristics according to the embodiment.

FIG. 3 is a side view of a rolling bearing means showing a force acting on a ball in a conventional seismic isolation structure.

[Explanation of symbols]

 2 Foundation 4 Building (example of structure) 6 Rolling bearing means 8 Lower support plate (corresponding to support member) 8a Slope 8a1 Inner slope 8a2 Outer slope 12 Ball

Claims (1)

[Claims] 1. A seismic isolation structure for a structure having rolling bearing means interposed between a foundation and a structure for movably supporting the structure in a horizontal direction, wherein the rolling bearing means comprises a foundation or A support member fixed to the structure and having a substantially mortar-shaped slope, mainly comprising a ball rolling on the slope of the support member when the foundation and the structure are relatively displaced in the horizontal direction, A seismic isolation structure for a structure, wherein the slope is inclined stepwise so that the angle becomes larger toward the outside in the radial direction from the center of the support member.