JPH0262670B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention has durability and reliability against repeated deformation, has a simple structure, and has an economical ability to absorb earthquake energy. This relates to seismic isolation devices for structures.

[Problems to be solved by this invention]

In seismic isolation construction methods that support structures with laminated rubber bearings, it is generally proposed to use some kind of energy absorbing device, that is, a damper, in order to suppress the large relative horizontal displacement that occurs between the structure and the ground during an earthquake. There is. An example of this is JP-A-59-
As shown in Japanese Patent No. 210166, a structure in which a cantilever-shaped damper is provided at the foundation has been proposed.

This damper is used by connecting one end to the structure and the other end to the foundation on the ground side. Although this damper utilizes energy absorption during plastic deformation of metal, that is, hysteresis damping, the maximum curvature occurs at the fixed end, and there is a risk that damage will be concentrated.

In other words, since seismic isolation dampers are subjected to large deformations and repeated loads many times, it is necessary to avoid local concentration of strain due to the formation of plastic hinges and to increase fatigue strength and deformability by averaging strain as much as possible.

This invention is an improvement on the known example in order to meet the above demand.

[Means for solving problems]

The gist of this invention is that a laminated rubber bearing and a damper are arranged between the ground side foundation and the building foundation, and the damper is made of a ductile metal such as mild steel, lead, or superplastic metal. It consists of a circular plate part whose periphery is fixed on one side, and a cantilevered beam part with a circular cross section that stands vertically at the center of this circular plate part and connects the end to the foundation on the other side. When the foundation undergoes relative displacement, the disk portion is plastically deformed, and horizontal displacement during an earthquake is transmitted from the cantilever portion to the disk portion, thereby avoiding local concentration of strain. It is something.

〔Example〕

The present invention will be described below based on illustrated embodiments.

As shown in FIG. 1, a laminated rubber bearing 1 and a hysteretic damper 2 are arranged between a ground side foundation A and a building foundation B.

The damper 2 consists of a disc part 3 made of a ductile metal material such as mild steel, lead, or a superplastic metal, and a cantilever part 4 made of steel or the like that stands vertically at the center of the disc part 3 and perpendicular to the disc surface. Become.

The upper end of the cantilever portion 4 is formed with a disc-shaped or spherical projection 5. The drawings show a case where the protrusion 5 is disc-shaped and the outer periphery of the disc is spherical.

A steel gripping jig 6 into which the protrusion 5 is fitted is fixed to one of the foundations, a building foundation B in the drawing, with an anchor bolt 7.

The disk portion 3 is fixed to the ground side foundation A at its periphery with anchor bolts 10 via a spacer 9 such as a nut to ensure a certain clearance 8 between it and the ground side foundation A.

In the above configuration, when a relative horizontal displacement occurs between the structure and the ground during an earthquake, the cantilever section 4
Rotation occurs at the lower end of the disk, that is, at the portion fixed to the disk portion 3, and the disk portion 3 undergoes bending and torsion deformation, exceeding elastic deformation and reaching plastic deformation depending on the amount of deformation.

If the vertical cross-sectional shape of the disk portion 3 is tapered so as to be thick at the center as shown in FIG. 6, the plastic region will further expand around the disk. Note that the cantilever portion 4 has a diameter to obtain sufficient rigidity, and its lower end is designed so as not to yield.

During an earthquake, the disk portion 3 undergoes repeated plastic deformation and absorbs the energy at that time, providing an effective vibration damping effect to the structure.

The mechanical characteristics of a seismic isolation system using such a damper and laminated rubber are shown in Figure 8. The displacement-load relationship of the laminated rubber is roughly elastic deformation with some hysteresis as shown in Figure 8, and the displacement-load relationship of the damper is elastic-plastic, with a hysteresis loop as shown in Figure 8 against repeated displacement. Therefore, the displacement-load relationship of the seismic isolation system is the sum of these, and a hysteresis loop as shown in Fig. 8 is drawn. The area of this hysteresis loop provided by the damper then represents energy absorption and provides a vibration damping effect.

It is preferable that the disc portion 3 and the cantilever portion 4 are fitted into each other through a fitting hole 11 as shown in FIG.

〔Effect of the invention〕

Since the present invention has the above configuration, it has the following effects.

7 The disc part of the damper begins to yield along the circumference of the lower end of the cantilevered part, and the plastic region expands toward the periphery of the disc (see Figure 9).
Local concentration of strain is avoided, the deformability is large, there is little property deterioration even after large deformations are repeated many times, and it has good fatigue properties and sufficient energy absorption performance.

8. Simple structure, inexpensive materials, and therefore low cost.

9. Since ductile metal materials such as mild steel and lead are used, the restoring force characteristics (displacement-load relationship) of the damper are close to perfect elastic-plastic, making modeling and design easy.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the arrangement of the seismic isolation device according to the present invention, and FIGS. 2, 3, 4, and 5 are perspective, front, longitudinal, and cross-sectional views of the damper. ,
Fig. 6 is a longitudinal sectional view showing another example of the damper shape, Fig. 7 is a longitudinal sectional view showing yet another example of the damper, Figs. It is a schematic diagram showing a deflection state. A... Ground side foundation, B... Building foundation, 1... Laminated rubber bearing, 2... Hysteretic damper, 3
...disc part, 4...cantilever part, 5...protrusion, 6...gripping jig, 7...anchor bolt,
8...Clearance, 9...Spacer, 10...
...Anchor bolt, 11...Fitting hole.

Claims (1)

[Claims] 1. A laminated rubber support and a damper are arranged between the ground side foundation and the building foundation, and the damper consists of a circular plate part made of ductile metal whose periphery is fixed to either one of the foundations, and this circular It consists of a cantilever beam part with a circular cross section that stands vertically at the center of the plate part and connects the end to the other foundation, and when the ground side foundation and the building foundation are displaced relative to each other, the disc part deforms plastically. A seismic isolation device for a structure, characterized in that: