JPH01268939A - Controller for displacement of earthquake-isolated structure - Google Patents

Abstract

PURPOSE:To avoid the development of resistance during fine-displacing period by a method in which a viscous damper 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 ends of upper and lower rods 11 are fixed to a structure 1 and the foundation 2 through fixing parts 12, and a piston 11a provided to the ends facing each other of the rods 11 is slidably inserted into the cylinder 13 of a viscous damper (a) and a viscous material 14 is packed into the cylinder 13. When the displacement of the structure 1 is fine during earthquake, the rods 11 do not work effectively and no resistance occurs. As the deformation of the structure 1 proceeds, the viscous material 14 is compressed between the piston 11a and the cylinder 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 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 has been lengthened to create a flexible structure to reduce earthquake input.

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.

In addition, to suppress excessive displacement, fenders made of rubber are required.
& It is placed on the opposite side of a rigid structure such as a foundation that gets hot.

However, the above method has the following problems.

i) Elastic springs are given low rigidity so as not to have a seismic isolation effect, and therefore do not have sufficient strength when subjected to 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.

iii) Since the fender generates resistance force due to compressive deformation, its shape becomes complicated and the manufacturing cost increases. A seismic isolation protrusion that is simple in structure and low in production cost, does not sometimes exhibit resistance, but exhibits large resistance during large displacements, and effectively suppresses displacement without interfering with the seismic isolation effect. The present invention provides a displacement control device.

(Means for Solving the Problems) 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 that connects a base end to the structure and the foundation, respectively. and are connected via a pair of upper and lower rods with a viscous damper interposed in the middle.

(Function) Since the present invention is configured as described above, II! !
When a structure mounted during an earthquake undergoes a minute displacement, the initial stiffness of the displacement control device, which consists of a rod interposed between the structure and the foundation and with a viscous damper interposed in the middle, is set to 01 or extremely small. value, and without affecting the characteristics of the structure during minute deformation, the rod exerts resistance force by tension as the structure deforms, thereby realizing sufficient proof stress. As the deformation of the structure progresses, the horizontal rigidity increases, and a large displacement suppressing effect is exerted on 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, since a portion of the viscous damper does not have rigidity but has viscous damping, a damping effect can be expected against fast movements.

(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 the structure to be seismically isolated (1) is supported by a base (2), a support (3) such as a laminated rubber support or a sliding support, Further, 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), a stopper (made of fender material, etc.) is installed around the periphery of the foundation (2).
5) is provided.

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

Fig. 1 shows an embodiment of the displacement control device (P), in which the proximal ends of the two lower rods (11) are connected to the structure (1) and the foundation (2) through fixing materials 02). a piston portion (Ila) fixed and provided at the opposite end of each said rod (11);
are slidably fitted into the cylinder 03) of the viscous damper (a), and a viscous body 04) is provided as a shield in the cylinder 0ω, and thus the pair of upper and lower rods (
10 are viscoelastically connected via the viscous damper (a).

Note that the viscous damper (a) part does not have rigidity,
Since it has viscous damping, it is expected to have a damping effect against fast movements.

Figure 3 shows the above displacement! l, lI Indicates the mechanical properties of the control device, and the section 0^ where the displacement of the structure during an earthquake etc. is minute.
is a range in which the rod 00 does not work effectively, and is a "play" region.

As the deformation of the structure (1) progresses, the viscous body θ is compressed between the piston portion (lla) of each rod (11) and the cylinder surface, and each rod (11) receives a tensile force. This leads to the development of resistance.

In the section AB, the deformation of the structure (1) progresses and the rod θ
I) exerts a resistance force by tensile force, and the displacement control device 1
When ffi(P) is in the linear region where it is effective,
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 further progresses and exceeds point B, the rod (11) becomes plastic, and therefore the rigidity of the displacement control device CP) also softens, and finally reaches 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.

'1) 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.

111) The yield point and ultimate strength of the rod are large,
It functions as a stopper and prevents excessive deformation of the structure.

(Effects of the Invention) As described above, the present invention provides an upper and lower pair of dampers between a structure and a foundation, each of which has both ends fixed to the structure and foundation, respectively, and a viscous damper interposed in the middle. Since the displacement control device for the seismic isolation structure is interposed between the structure and the foundation by connecting the structure with a rod, the displacement control device does not exert resistance force when the structure is subjected to minute displacements, but when large displacements occur. Because they sometimes exhibit a large resistance force, they rarely impede the seismic isolation effect and can effectively suppress displacement. 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, a viscous damper provided in the intermediate portion of the rod imparts a viscous damping effect, making it possible to retain the damping effect against rapid movement during an earthquake or the like.

Furthermore, the device of the present invention has a simple configuration and is low in 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) - One structure (2) - Foundation (lI) -
- Rod a3) - Housing 0411-m
- Viscous body (a) - Viscous body damper agent
Patent attorney: Shige Okamoto (2 persons) Figure 2

Claims (1)

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