JPH0833082B2 - Laminated rubber seismic isolation device - Google Patents

Description

Description: [Industrial field of application] The present invention relates to a seismic isolation device for laminated rubber that is installed on the bottom of a pillar or the like of a building.

[Conventional technology]

In the so-called seismic isolation structure, the natural period of the building is extended by seismic isolation support such as laminated rubber, avoiding the resonance phenomenon due to the coincidence of the predominant period of the earthquake motion and the natural period, and reducing the seismic force acting on the building. Damping devices such as elasto-plastic dampers absorb vibration energy to reduce seismic input and suppress response displacement.

When using such a laminated rubber seismic isolation device, first install the lower foundation beam under the seismic isolation device, then set the laminated rubber seismic isolation device and construct the upper foundation beam and the columns and superstructures above it. Is going.

[Problems to be Solved by the Invention]

When constructing the seismic isolation device and its superstructure as described above, the following points should be noted.

It is necessary to make the axial deformation of the laminated rubber due to the load of the superstructure as uniform as possible to prevent uneven settlement of the columns.

The ultimate yield strength of the laminated rubber is affected by the axial force received by the rubber, particularly the tensile stress, and if the tensile stress increases, the ultimate yield strength of the rubber decreases, so this point must be taken into consideration in the design.

Further, a fail-safe mechanism, which is a preliminary support structure, is required so that the entire building will not collapse even if a force greater than the yield strength of the laminated rubber should occur.

In addition to laminated rubber, a seismic isolation device requires a damper to absorb seismic energy.

In addition, as a means for solving the problem of,
There is a seismic isolation device described in Japanese Patent No. 66334, which discloses a structure in which one or more wire strands are attached to the inside or outside of a laminated rubber bearing to resist tensile force.

SUMMARY OF THE INVENTION The present invention has an object to provide a laminated rubber seismic isolation device capable of easily addressing the above problems.

[Means for solving the problem]

The present invention, in a laminated rubber seismic isolation device having plates for installation at both ends of the laminated rubber, a plurality of steel rods connecting both plates are arranged outside the laminated rubber so as to surround the laminated rubber, and Prestress was introduced into the steel rod to apply initial pressure to the laminated rubber.

[Work]

According to the present invention, the deformation of the laminated rubber due to the axial force is reduced, and the laminated rubber does not generate a tensile force even if an unexpected large earthquake is received. It becomes a fail safe mechanism.

〔Example〕

 Hereinafter, the illustrated embodiment will be described.

FIG. 1 and FIG. 2 show an embodiment of the present invention, in which a plurality of steel rods 2 (usually 6 to 12) and a laminated rubber 1 are surrounded around a normally used laminated rubber 1. Thus, the tensile force which is a prestressing force is introduced into this steel rod 2. Due to this prestressing force, an initial compression force is introduced into the laminated rubber 1. In the figure, 7 is an upper foundation beam, 8 is a lower foundation beam, and 9 is a building pillar.

With this mechanism, compared to the case of a single laminated rubber,
It is possible to reduce the rubber deformation due to the column axial force applied to the laminated rubber 1. Therefore, the absolute value of the differential settlement between the pillars 9 can be reduced.

When an unexpected large earthquake occurs and a tensile force is generated on the laminated rubber 1 due to the overturning moment of the entire building, the upper nut 3 and plate 4 of the anchor portion of the steel rod 2 cause the steel rod 2 to pull. Therefore, no tensile force is generated in the laminated rubber 1.

As a fail-safe mechanism in an abnormal situation where the rubber of the laminated rubber 1 is damaged, a stopper such as a lower nut 5 is provided below the plate 4 at a predetermined interval so that the axial force of the pillar can be prevented when the rubber is damaged. Is transmitted from the lower nut 5 to the steel rod 2. The horizontal steelness of the steel rod 2 depends on the fixed portion 6 below the steel rod 2. (However, the structure that follows a large deformation of rubber and supports the axial force as a fail-safe is not always simple, and it may be rational to install a normal fail-safe mechanism).

The steel rod 2 can also be used as a damper at the same time.
That is, it is possible to absorb the seismic energy by the bending resistance of the steel rod 2 when it is horizontally deformed in conjunction with the laminated rubber 1 during an earthquake.

〔The invention's effect〕

As described above, the laminated rubber seismic isolation device of the present invention is one in which a steel rod is arranged around the laminated rubber and a prestressing force is introduced into it, thereby reducing the differential settlement of the building due to rubber deformation. , It is possible to prevent the ultimate yield strength of the rubber from decreasing due to the tensile stress generated in the laminated rubber due to the overturning moment at the time of earthquake, and at the same time to use this steel rod as a damper or a fail-safe mechanism, thereby rationalizing the seismic isolation mechanism.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an example of an installed state of the seismic isolation device of the present invention, and FIG. 2 is a plan view thereof. 1 ... laminated rubber, 2 ... steel rod, 3 ... upper nut, 4 ...
Plate, 5 ... Lower nut, 6 ... Fixed part, 7 ... Upper foundation beam, 8 ... Lower foundation beam, 9 ... Pillar

Claims (1)

[Claims] 1. A laminated rubber seismic isolation device having plates for installation at both ends of the laminated rubber, wherein a plurality of steel rods connecting the plates are arranged outside the laminated rubber so as to surround the laminated rubber. A laminated rubber seismic isolation device in which prestress is introduced into the steel rod.