JPH01268938A - Controller for displacement of earthquake-isolated structure - Google Patents

Abstract

PURPOSE:To control the development of resistance during small-displacing period by a method in which a spring device is connected through upper and lower rods whose basal ends are fixed to a structure and the foundation between the structure and the foundation. CONSTITUTION:The basal ends of upper and lower rods 11 are fixed to a structure 1 and the foundation 2 through fixing parts 12, and the ends facing each other of the rods 11 are slidably inserted into the housing 13 of a spring device (a). A spring 14 is interposed between the top and bottom walls of the housing 13 and the tip collar 11a of the rods 11. In case where the displacement of the structure 1 during earthquake is very small, the rods 11 do not work effectively and no resistance occurs. When the deformation of the structure 1 proceeds, the spring 14 is compressed between the collar 11a and the housing 13 and resistance is exhibited by tension in the rods 11.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a displacement control device for flexible structures such as non-masking products.

(Prior technology) Seismic isolation structure methods for reducing horizontal seismic force include basic insulation type methods and suspension type methods, but most of them reduce the horizontal rigidity of the structure to reduce the natural period. The structure is designed to extend the length of the structure and create a flexible structure to reduce the amount of human effort required during an earthquake.

For this reason, while the acceleration response value is reduced, the displacement response value increases, and depending on the characteristics of the seismic motion, it may become excessive beyond the allowable limit.

As a method to suppress displacement response, in addition to elastic springs that utilize shear deformation of rubber, tension and compression deformation of coil springs, and elastoplastic springs that utilize bending deformation of steel materials, etc. are interposed between the structure and the foundation. equipped.

Further, in order to suppress excessive displacement, fenders made of rubber are placed on the opposite surface of the structure in a rigid body such as a foundation.

(Problem to be solved by the invention) However, the above method has the following problems.

i) Elastic springs are given low rigidity so as not to impair their seismic isolation effect, and therefore do not have sufficient proof strength during large displacements and are weak in tension.

il) An elastoplastic spring yields at a certain displacement and becomes plastic.
Therefore, sufficient yield strength cannot be obtained during large displacements, and it is weak against tension.

iii) Since the fender generates a resistance force due to compressive deformation, its shape becomes complicated and the manufacturing cost increases.

The present invention was developed in view of the problems of the prior art, and it does not exhibit resistance force during minute displacements, but exhibits large resistance force during large displacements, and is effective without impairing the seismic isolation effect. An object of the present invention is to provide a displacement control device for a seismic isolation structure, which is simple in structure, inexpensive to manufacture, and which suppresses displacement.

(Means for Solving the Problem) In order to achieve the above-mentioned object, a displacement control device for a seismic isolation structure according to the present invention provides a displacement control device for a seismic isolation structure in which a base end is connected between a structure and a foundation, respectively. The upper and lower rods are connected via a pair of upper and lower rods with a spring device interposed in the middle.

(Function) Since the present invention is configured as described above, when a structure undergoes minute displacement during an earthquake, etc., the upper and lower parts are interposed between the structure and the foundation, and a spring device is interposed in between. The initial stiffness of the displacement control device consisting of a pair of rods is O
l or an extremely small value, and has no effect on the characteristics of the structure during minute deformation.

As the deformation of the structure progresses, the rods exert a resistance force by tension, and sufficient strength can be achieved, and as the deformation of the structure progresses, the horizontal rigidity increases. , a large displacement suppression effect is exhibited for the entire structure.

Furthermore, the rod has a large yield point and ultimate strength, and serves as a stopper to suppress excessive displacement of the structure.

Furthermore, by adjusting the stiffness of the spring device, the stiffness of the displacement control device can be adjusted as desired.

(Example) The present invention will be described below with reference to the illustrated embodiments.

Figure 2 shows a base isolation type seismic isolation device in which a structure to be isolated (1) is supported on a foundation (2) by a support (3) such as a laminated rubber support or a sliding support, and the structure thing(
An elastic spring or an elastic-plastic spring (4) is interposed between the base (1) and the foundation (2) to connect the two with a weak spring. Furthermore, in order to prevent excessive displacement of the structure (1), the foundation (2)
A stopper (5) made of fender material or the like is disposed at the peripheral edge of the vessel.

Furthermore, a displacement@control device (P) is interposed between the structure (1) and the base vJ (2).

Fig. 1 shows an embodiment of the displacement control device (P), in which the base ends of the upper and lower rods (II) are respectively fixed to the structure (1) and the foundation (2) via the fixing material. The opposing ends of each rod (11) are slidably fitted into the housing side of the spring device (a), and the top and bottom walls of the housing surface and the tip of each rod (11) Tsuba (lla)
), and the upper and lower pairs of rods 01) are thus elastically connected via the spring 04.

Therefore, by adjusting the rigidity of the spring 010, it is possible to arbitrarily adjust the rigidity of the displacement control device f(P).

FIG. 3 shows the mechanical properties of the displacement control device, and shows that the section OA where the displacement of the structure during an earthquake or the like is minute is the range in which the rod (11) does not act effectively, and the "play
This is the area of

The deformation of the structure (1) progresses, and each of the rods 01
The spring (b) is compressed between the flange (lla) of ) and the housing surface, and each rod 01) exerts a resistance force due to the tensile force.

Section AH is the case where the structure (+1 deformation progresses), the rod (11) exerts resistance force due to the tensile force, and the displacement control device (P) is in the linear region where it exerts its effect.
As the deformation angle of the structure increases, its horizontal rigidity increases, exhibiting so-called hard spring type restoring force characteristics.

When the horizontal displacement of the structure progresses further and exceeds 8 points, the rod θ1) becomes plastic, and therefore the rigidity of the displacement control device (P) also softens, finally reaching the breaking point C.

As is clear from FIG. 3, the displacement control device (P) shown in the illustrated embodiment has the following mechanical characteristics.

i) The initial stiffness can take 0 or an extremely small value, and has no effect on the characteristics of the seismically isolated structure during minute deformations.

ii) As the deformation of the structure progresses, the rigidity of the displacement control device increases, so the displacement suppression effect of the entire structure increases.

ii) The rod has a large yield point and ultimate strength, and functions as a stopper to prevent excessive deformation of the structure.

(Effects of the Invention) As described above, the present invention provides a pair of upper and lower rods that are connected between a structure and a foundation, each of which has both ends fixed to the structure and the foundation, respectively, and has a spring device interposed in the middle. Since the displacement control device for the seismic isolation structure is interposed between the structure and the foundation, the displacement control device does not exert resistance force when the structure is slightly displaced, but when the structure is subjected to large displacements, it does not exert resistance force. Since it exhibits a large resistance force, the seismic isolation effect is less inhibited and displacement can be suppressed effectively. In addition, since the rod that constitutes the main body of the displacement control device exerts resistance force by tension, it is possible to develop sufficient strength, and the members are effectively utilized, so that there is no waste.

Furthermore, the rod has a large ultimate strength and yield point, and functions as a stopper to prevent excessive deformation of the structure.

Furthermore, by adjusting the rigidity of the spring device, it is possible to arbitrarily adjust the rigidity of the displacement control device.

Furthermore, the device of the present invention has a simple configuration and low manufacturing cost.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the displacement control device for a seismic isolation structure according to the present invention, FIG. 2 is a longitudinal sectional view showing a seismic isolation structure equipped with the same control device, and FIG. It is a chart showing the mechanical properties of the displacement control device. (1)--Structure (2)-Foundation (11)-
Rod 0 - Housing A4 - Spring Ca) - Spring device agent Patent attorney Shige Okamoto 2 people Fig. 1 Fig. 2

Claims (1)

[Claims] The structure and the foundation are connected through a pair of upper and lower rods whose proximal ends are fixed to the structure and the foundation, respectively, and a spring device is interposed in the middle part. Displacement control device for seismic structures.