JPH11326113A - Method for testing performance of vibration-immune device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple performance testing method wherein vibration- immune performance is obtained with precision, by simulating a condition where actual earthquake takes place for testing. SOLUTION: With a work of art 1 placed on a vibration-immune device 3 provided on a floor F, the work of art is forcedly applied with initial displacement for free oscillation. The time history displacement of a stage 2 for the work of art 1 is measured with a laser displacement gauge 5 to generate a time history displacement curve. Based on the time history displacement curve, intrinsic cycle and damping constant of the vibration-immune device 3 on which the work of art is placed are obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a test method for knowing the performance of a small-scale seismic isolation device for protecting articles such as works of art from earthquakes.

[0002]

2. Description of the Related Art Conventionally, when examining the performance of small-scale seismic isolation devices such as works of art, conventionally, a seismic isolation device is mounted on a shaking table, and an article such as art is mounted on the seismic isolation device. We are conducting a vibration experiment.

However, important cultural properties such as Buddha statues cannot be moved, and their installation locations are very limited, such as inside a temple, so that large-scale test equipment cannot be used. . For this reason, the actual situation is that the performance after assembly is predicted from the performance of the seismic isolation rubber alone constituting the seismic isolation device.

[0004]

However, it is not possible to accurately grasp the seismic isolation performance in the event of an actual earthquake simply by predicting the performance after assembly from the performance of the seismic isolation rubber alone.

The present invention provides a simple performance test method capable of accurately grasping seismic isolation performance by performing a test by simulating a state when an earthquake actually occurs in consideration of the above circumstances. The purpose is to do.

[0006]

According to the first aspect of the present invention, there is provided a method of testing the performance of a seismic isolation device which is interposed between an article to be isolated and a floor and absorbs vibration transmitted from the floor to the article. hand,
A time-history displacement curve is obtained by placing an article on the seismic isolation device placed on the floor, forcibly giving the initial displacement to the article and causing it to vibrate freely, and measuring the time-history displacement of the article with a displacement measuring instrument. And the characteristic period and the damping constant of the seismic isolation device on which the article is placed are obtained from the time history displacement curve.

According to a second aspect of the present invention, in the first aspect, after the article is subjected to an initial displacement from a first direction in a horizontal plane to determine the natural period and the damping constant, the first direction in the horizontal plane is determined. An initial displacement is given to the article from a second direction orthogonal to the above, the natural period and the damping constant are obtained, and their average values are used as the final natural period and the damping constant.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. In practicing the present invention,
First, as shown in FIG. 1A, a seismic isolation device 3 to be actually used is installed on a floor F, and an art object (article) 1 such as a Buddhist image is placed thereon. 2 is a pedestal of art. The seismic isolation device 3 in this case has a structure in which annular seismic isolation rubbers and annular steel plates are alternately laminated so that the vibration absorbing function can be equally exerted in all directions in the horizontal plane. It is hidden behind.

Next, at a position facing the outer peripheral surface of the base 2,
A laser displacement meter (displacement measuring device) 5 for measuring a horizontal vibration displacement of the pedestal 2 is installed and connected to a computer 6. In this case, the laser displacement meter 5
As shown in FIG. 2B, the laser light is emitted toward the center 2a of the circular pedestal 2, and the reflector 4 is attached to a position on the pedestal 2 where the laser light is applied. The measurement of the vibration displacement is performed by using a laser displacement meter 5 and a reflecting plate 4 attached to the base 2.
Is irradiated with a laser beam, and the distance is calculated from the time required for the reflection.

Next, with respect to the pedestal 2, the center 2a of the pedestal 2
A forced initial displacement N is given in a direction parallel to a line connecting the laser displacement meter 5 and the laser displacement meter 5, and thereafter, free oscillation is performed as indicated by an arrow P. Then, a time history displacement curve S as shown in FIG. 2 is created by measuring the time history displacement of the pedestal 2 of the artwork 1 with the laser displacement meter 5, and the artwork 1 is obtained from the time history displacement curve S. The natural period T1 and the damping constant h of the seismic isolation device 3 in the actual use state mounted thereon are obtained.

The natural period T1 in this case is obtained from the distance between adjacent vertices Xn and Xn + 1 in the time history displacement curve S. The damping constant h is calculated by the following equation. h = (1 / 2π) ln (Xn / Xn + 1)

When an initial displacement is applied to the pedestal 2 from a first direction (horizontal direction in the drawing) in a horizontal plane to obtain a natural period and a damping constant, then, from a second direction (front-back direction) orthogonal to the natural direction. An initial displacement is applied to the pedestal 2 to determine a natural period and a damping constant. In that case, the laser displacement meter 5 and the reflector 4
Is changed according to the direction in which the displacement is given.

When the measurement data is obtained several times in different directions, the average value of the data is obtained, and the average value is used as the final natural period and attenuation constant.

As described above, it is examined whether or not the performance as designed can be exhibited by simulating free vibration in an actual situation and performing a test. Then, when it is confirmed that the expected performance can be obtained, the test is completed.

The articles placed on the seismic isolation device 3 are as follows:
It is not particularly limited to works of art. Further, the type of the seismic isolation device 3 is not limited to the type using the seismic isolation rubber.

[0016]

As described above, according to the first aspect of the invention, the article is forcibly free-vibrated while the article is actually placed on the seismic isolation device, and the time history displacement of the article is measured by the displacement measuring device. , A time history displacement curve is created, and the natural period and damping constant of the seismic isolation device are determined from the time history displacement curve, so that the seismic isolation device has the performance as designed in actual use. It can be easily and accurately checked. In addition, since only a time history curve is obtained from the data of the displacement measuring device, the test can be performed with a simple device, and the movement of the object and a large-scale device are not required.
Fewer test personnel and less cost.

According to the second aspect of the present invention, the natural period and the damping constant are obtained by averaging the data in two directions orthogonal to each other in the horizontal plane, so that the performance with respect to an actual earthquake can be grasped more accurately.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a test method according to an embodiment of the present invention, (a) is a front view showing a state in which a test is being performed,
(B) is the same top view.

FIG. 2 is a characteristic diagram showing a time history displacement curve obtained by free vibration in the test of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Art work (article) 2 Pedestal 3 Seismic isolation device 5 Laser displacement meter (displacement measuring instrument) S Time history curve T1 Natural period

Claims (2)

[Claims] Claims: 1. An article is interposed between an article to be seismically isolated and a floor,
A method for testing the performance of a seismic isolation device that absorbs vibration transmitted from a floor to an article, wherein the initial displacement is forcibly applied to the article while the article is placed on the seismic isolation apparatus arranged on the floor. Create a time history displacement curve by freely vibrating and measuring the time history displacement of the article with a displacement measuring instrument, and find the natural period and damping constant of the seismic isolation device on which the article is loaded from the time history displacement curve A method for testing the performance of seismic isolation devices characterized by the following. 2. An article is given an initial displacement from a first direction in a horizontal plane to determine the natural period and the damping constant. Then, the article is applied to the article from a second direction orthogonal to the first direction in the horizontal plane. 2. The performance test method of the seismic isolation device according to claim 1, wherein the natural period and the damping constant are obtained by giving an initial displacement, and an average value thereof is used as a final natural period and a damping constant.