JPH01268937A - Controller for displacement of earthquake-isolated structure - Google Patents

Abstract

PURPOSE:To reduce the cost of manufacture and simplify the structure of a displacement controller by a method in which a strand whose both ends are fixed to a structure and the foundation is set between a structure to be isolated from earthquake and the foundation. CONSTITUTION:A structure 1 to be isolated from earthquake is supported by a laminated rubber supporter or slippery supporter on the foundation 2. Elastic or elastic and plastic springs 4 are set between the structure 1 and the foundation 2, and both ends of a strand 11 are fixed to the structure 1 and the foundation 2 through fixing parts 12 to make up a displacement controller P.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application) The present invention relates to a displacement control device for flexible structures such as seismic isolation structures.

(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 material are arranged on the opposing 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 interfere with the seismic isolation effect, and therefore do not have sufficient strength during large displacements and are weak in tension.

11) Elasto-plastic springs yield and become plastic at a certain displacement, so they do not have sufficient yield strength at large displacements and are weak in tension.

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

The present invention was proposed 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. Displacement control of seismic isolation structures with simple configuration and low manufacturing cost! The point is that it provides a J location.

(Means for Solving the Problems) In order to achieve the above-mentioned object, a displacement control device for a seismically isolated structure according to the present invention is provided between a seismically isolated structure and a foundation, with both ends connected to the structure. and a strand material fixed to the foundation.

Further, in order to control the region where the initial stiffness takes O or an extremely small value where the displacement control device does not work effectively, the present invention provides a slack in the middle of the strand material.

(Function) Since the present invention is configured as described above, when a structure undergoes minute displacement during an earthquake, etc., the initial rigidity of the displacement control device by the strand material interposed between the structure and the foundation is reduced. 0 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 strand material exerts a resistance force by tension, creating a stone with sufficient strength, and as the deformation of the structure progresses, the horizontal rigidity increases. The displacement of the structure as a whole is greatly suppressed.

Furthermore, the strands have a large yield point and ultimate strength, and serve as a stopper to suppress excessive displacement of the structure.

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

Figure 2 shows a basic insulation type seismic isolation device, in which the structure to be seismically isolated (+1 is supported on the foundation (2) by a support (3) such as a laminated rubber support or a sliding support; An elastic spring or an elastic-plastic spring (4) is interposed between the structure (+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)
) on the periphery of the stopper (5) made of fender material, etc.
is installed.

Furthermore, a displacement control device (P) is interposed between the structure (+1) and the foundation (2).

Fig. 1 shows an example of the same displacement control system ffl (P), in which both ends of the strand material (11) are fixed to the structure (0 and foundation (2)) via the fixing material θ. ing.

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

In the illustrated example, the strand material (11) has a slack in the middle to increase the play area, but the structure 0) and the base FjI (2) are directly connected without having any slack. Good too. Further, by adjusting the degree of slack of the strand material (11), the area of play can be controlled.

In the section B, the horizontal displacement of the structure (+1) progresses, the strand material (11) is fit by the tensile force; it is in the linear region where the displacement control device (P) exerts its effect In this case, 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 point B, the strand material (11) becomes desirable, and therefore the displacement control device (P
) also softens, and finally reaches the breaking point C.

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

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

11) 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.

iii) The strand material has a large yield point and ultimate yield 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 displacement control device for a seismic isolation structure by interposing a strand material having both ends fixed to the structure and the foundation, respectively, between the structure and the foundation. Since we have configured
Since the structure does not exert any resistance force when the structure undergoes a small displacement, but exhibits a large resistance force when the structure undergoes a large displacement, the seismic isolation effect is less inhibited and displacement can be suppressed effectively. In addition, since the strand material that constitutes the main body of the displacement control i11 device exerts resistance force by tension, it is possible to develop sufficient proof strength, and the members can be used effectively.
There is no waste.

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

Further, the device of the present invention has a simple configuration and the production cost is as low as a paper storage.

According to the second aspect of the invention, since the strand material interposed between the structure and the foundation has slack in the intermediate portion, by adjusting the degree of slack, the rigidity of the displacement control device can be reduced to zero. , or a very small area of illumination and vibration, and the timing of the operation of the control device can be controlled.

[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) - Strand material Zero fixed material agent Patent attorney Shige Okamoto 2 outsiders Figure 1

Claims (2)

[Claims] (1) A displacement control device for a seismically isolated structure, characterized in that a strand material is interposed between the seismically isolated structure and the foundation, the ends of which are fixed to the structure and the foundation, respectively. (2) The displacement control device for a seismic isolation structure according to claim 1, wherein the strand material has a slack portion in the middle.