JP3800339B2 - Seismic isolation structure of building - Google Patents

Description

  The present invention relates to a seismic isolation structure for a building that reduces vibrations of the building during an earthquake by rolling support of boulder gravel.

  In conventional seismic isolation technology, as an isolator (vibration isolation device) for immobilizing the building against earthquakes (vibration isolation device), between the foundation of the building and the support part (base) provided at the bottom, Laminated rubber bearings constructed by alternately laminating steel plates and rubber plates, sliding bearings using sliding members such as polyfilm, rolling bearings using rolling functions such as steel balls, elastic material bearings using elastic members such as rubber (Technology) is used, but there is also one that uses a damper as a damping and restoring device.

  The rolling bearings related to the present invention include the following documents that are implemented using ball gravel and steel balls (steel balls).

    Utility Model Registration No. 3036572     Japanese Patent Laid-Open No. 11-303456     Japanese Patent Publication No. 5-14062     Japanese Patent No. 3172765

  Among the above-mentioned prior arts, Patent Document 1 can be interpreted from the specification and drawings that the gravel is laid in a large amount and in multiple layers. However, with a large amount of multi-layered gravel, rolling is impossible in the event of an earthquake, so seismic isolation is hardly established.

  In addition, the seismic isolation structures in Patent Documents 2, 3 and 4 that require seismic isolation for rolling bearings with steel balls have a high rolling function and excellent seismic isolation, but on the other hand, a damper for damping and restoration is required. In addition, there is a drawback that the building swings due to wind pressure in strong winds. For this reason, the windy day makes the residents uneasy. In addition, some of the above documents have acquired seismic isolation using electric power, but this does not function if there is a power outage or failure.

  The present invention, which attempts to acquire seismic isolation by the rolling bearing described above, does not use a steel ball (steel ball) with a high rolling function or a poly film with a high sliding function as a material, and has a rolling function. We decided to seek a way to inferior jade gravel. In other words, with a roughly equal grain of gravel (with no overlap), a solid foundation (a foundation on which the lower part of the building on which the building is placed is a single plate) and a base (a single board that supports the solid foundation) ) And laid between them to establish seismic isolation and prevent the building from swinging due to wind pressure. As a result, seismic gravel rolls only in the case of medium and strong earthquakes and does not deal with weak earthquakes, and seismic isolation is established. Moreover, in this invention, it is an advantage that the rolling function of the gravel is inferior, it can endure the wind pressure at the time of a strong wind, and does not lead to rocking | fluctuation of a building.

  However, the function of the shingle gravel laid and interposed in one layer is inferior in restoring ability, and the position of the building may be shifted after the earthquake. In order to prevent this, in the present invention, a required number of dampers are installed in relation to the solid foundation and the base. The restoring force is obtained from the elasticity (stretching force) of the elastic member provided in the damper, and the displacement of the building due to the earthquake is minimized.

  In the present invention, the seismic isolation function is entrusted to the rolling support of the gravel layer and the damper function that are further spread as described above, and the rolling function is intentionally inferior. Although the seismic function does not work, it has the advantage of functioning effectively for seismic isolation of medium and strong earthquakes and for rocking buildings due to strong winds.

In addition, since the restoring force in the present invention is formed by a synergistic effect of medium and strong seismic intensity and the elasticity (stretching force) of the damper, the building will not be greatly displaced in the event of an earthquake.
Further, since elastic members (coil springs) are arranged radially between the inner frame and the outer frame of the damper, there is an advantage that a restoring force corresponding to vibrations (swings) in all directions can be obtained.

  The configuration of the present invention is simple, and the work process is also simple. In addition, since the materials are inexpensive, construction has the advantage of low cost. Moreover, it is a big advantage that this invention is a mechanism which does not require electric power. Therefore, the present invention does not cause problems such as malfunction due to failure or power failure.

1 and 2 are diagrams showing an outline of the configuration of the present invention.
A crusher 9 is formed on the bottom of a recess formed by excavating a construction site of a building, and a concrete base 6 is formed on the crusher 9. The base 6 has a built-in reinforcing bar, which is not shown in the figure. The thickness of the base 6 is about 200 mm, and its upper surface is configured to be horizontal and smooth. In addition, a support shaft 7 that serves as a shaft for installing a damper 2a, which will be described later, is erected at a required portion of the base 6, but the lower part is embedded in the base 6, the crusher 9, and the ground. The support shaft 7 is a steel cylinder having an outer diameter of approximately 200 mm (when six coil springs are used), and is erected at a rate of about one per 10 m ² of the base 6 in a general wooden building. Further, the protruding portion (height) of the support shaft 7 is slightly larger than the thickness of the pace portion of the solid base 1.

  The damper 2a is involved in the attenuation and restoration of the vibration of the building in the event of an earthquake. The inner frame 3a fitted on the support shaft 7 is provided at the center thereof, and the outer frame 4a is provided outside thereof. The six coil springs 5 are arranged radially at equal angles as elastic members in the meantime and are not shown in the figure, but their ends are welded or screwed to the inner frame 3a and the outer frame 4a. It sticks with etc. However, the number of coil springs 5 is not limited to the above, and other numbers may be used.

  The inner frame 3 has an inner diameter that can be fitted to the support shaft 7, and the outer frame 4a has a diameter of approximately 800 to 900 mm. Both the inner frame 3a and the outer frame 4a have a hollow cylindrical shape, and the height of the outer frame 4a is slightly larger than the thickness of the base portion of the solid base 1.

Next, formation of the solid foundation 1 on which the building is placed will be described.
On the upper surface of the base 6, approximately equal grains of gravel 8 are laid in a non-overlapping layer. The gravel 8 has an appropriate diameter in the range of 20 to 30 mm in view of its functionality, and selects and uses a substantially equiparticulate one from that range.

  After laying the ball gravel 8, the inner frame 3a of the damper 2a is fitted to the support shaft 7, and the damper 2a is installed at a required position. At this time, the inner frame 3a and the support shaft 7 are fixed by a rotation preventing member 13 such as a screw or a pin, welding or the like. Next, the iron plate 12 that has pierced the damper 2a portion is laid on the gravel 8 without any gaps by welding or the like. The iron plate 12 may have a thickness of 1 mm or less, but it is preferable to attach a protrusion on the upper surface of the iron plate 12 so as to be integrated with the solid base 1 after laying. Instead of the iron plate 12, a veneer plate (thickness of about 3 mm) or the like can be used.

  After laying the iron plate 12 (not shown in the figure), the formwork that forms the solid foundation 1 and the two-level reinforcing bars are assembled on this, and concrete is placed here to form the base portion of the solid foundation 1 At the same time, a rising portion 11 on which the foundation of the building is placed is formed of reinforced concrete.

Next, the function (action) of the present invention will be described.
The present invention seeks a seismic isolation structure for rolling bearings, and uses gravel with a low rolling function as its rolling member, replacing intense and rapid seismic motion with slow swinging with a small swing width, and seismic isolation of the building. I am trying. Accordingly, the present invention is not intended to deal with weak earthquakes or the like with small shaking, but is intended to deal with earthquakes that are greater than the middle earthquake.

  In addition, the present invention takes into consideration not only seismic isolation but also swinging of the building due to strong winds caused by the seismic isolation structure by using gravel with a low rolling function. In other words, the present invention is able to withstand strong winds with a wind speed of 40 m / sec because it faces strong winds within the range of static grazing force of the gravel.

  However, with the seismic isolation structure using boulders, the position of the building may be shifted due to a large earthquake or strong wind. As a countermeasure, a damper 2a provided with a coil spring 5 having elasticity (stretching force) commensurate with (confronting) the rolling grazing force of the gravel is engaged with both the solid base 1 and the base 6 as shown in FIG. Install.

Finally, basic numerical values related to the establishment of the present invention are shown.
In the present invention, it is obtained from an experiment that the static glazing force (average value) of the gravel 8 is about one-fourth of the building weight including the solid foundation 1, and the seismic isolation structure is constructed based on this. Yes. In addition, it has been confirmed that the seismic isolation structure of the present invention can withstand strong winds of 40 m / sec or more without swinging due to strong winds because of the relationship between wind speed and wind pressure. Furthermore, if the function of the damper is also taken into consideration, it is possible to withstand wind speeds of 50 m / sec.
Even if the wind is 50 m / sec or higher, the range of movement of the building is within the reduction limit of the coil spring 5, so that it does not move greatly. In addition, about 300 kg per piece may be sufficient as the required maximum expansion-contraction force of the coil spring 5 of the damper 2a in this invention in the case of a general wooden building.

  The damper in the above description is the cylindrical damper 2a. However, the present invention is not limited to this, and as shown in FIG. 4, both the inner frame and the outer frame may be prismatic. FIG. 4 shows a hexagonal prism shape as an example. Thereby, the coil spring 5 can be effectively fixed to the inner frame 3b and the outer frame 4b. Fixing is performed by welding or screwing. Further, as shown in FIG. 5, the support shaft 7 fitted in the inner frame 3 b is provided with strip-like projections at equal intervals to prevent the damper from rotating. Further, as shown in FIGS. 3 and 4, hook projections 15 for fixing the outer frame to the solid base 1 are provided outside the outer frames 4 a and 4 b. However, the projection is not limited to the hook projection 15 but may be a projection having a sphere at the tip.

  The present invention can be applied not only to a seismic isolation structure of a building but also to a seismic isolation structure unique to a structure (such as a display shelf or an important structure).

  It is a partially broken perspective view showing an outline of the present invention.   It is a partially broken sectional view which shows the principal part side surface of this invention.   It is a top view which shows the damper of this invention.   It is a top view which shows the other example of the damper of this invention. (Example)   FIG. 5 is a plan view of a support shaft assembled with the damper of FIG. 4. (Example)

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solid foundation 2a, 2b Damper 3a, 3b Inner frame 4a, 4b Outer frame 5 Coil spring 6 Base 7 Support shaft 8 Gravel 9 Crusher 10 Ground surface 11 Stand-up 12 Iron plate 13 Anti-rotation member 14 Band-shaped projection 15 鉤 projection

Claims (1)

  A damper having a radially arranged elastic member between the inner frame and the outer frame is incorporated in a required portion of the solid base having a flat lower surface, and the upper surface is a flat surface below the solid base, and A base-isolated structure for a building having a structure in which a support shaft to be fitted into an inner frame of a damper is formed, and substantially equal grain gravel is further laid between the base and the solid base.

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