Rocking-type seismic isolation base for protecting structure against earthquake
A rocking-type seismic isolation base for protecting structure against earthquake includes a body having a configuration similar to a generally recognized flying saucer. The base serves as a buffer when a structure is horizontally displaced relative to a supporting foundation of the structure, and largely reduces the vertical displacement of the structure. The rocking-type seismic isolation base also allows the displaced structure to automatically return to its original position. The base is provided at a bottom with a space for an anti-slipping lock to mount and freely move therein, so as to prevent the rocking-type base from horizontally slipping in a condition exceeded the designed seismic vibration. The rocking-type base may be cooperatively used with a saucer spring to further mitigate the vertical vibration.
The present invention relates to a seismic isolation device applicable to the fields of civil engineering, construction, and mechanical engineering; and more particularly to a rocking-type seismic isolation base having a configuration similar to a generally recognized flying saucer and provided with a bottom space for mounting an anti-slipping lock therein.
BACKGROUND OF THE INVENTIONThe currently available seismic isolation products for protecting a structure against earthquake mainly include lead rubber isolation bearings, friction-type isolation bases, etc. While the present invention and these conventional seismic isolation products employ similar principles for the same purpose of seismic isolation, the present invention is quite different from the conventional products in terms of its shape and mounting technique. According to a major seismic isolation principle, a seismic isolation product generally utilizes various kinds of components to enable a structure to have a swing period longer than the vibration period of a seismic origin, so as to achieve the object of seismic isolation.
It is known in general mechanical and seismic fields that when a relatively swinging component has different radiuses of swinging, the component may have an extended swinging period.
SUMMARY OF THE INVENTIONA primary object of the present invention is to provide a seismic isolation device to mitigate the influences of earthquake on a structure.
To achieve the above and other objects, the seismic isolation device according to the present invention is a rocking-type seismic isolation base including a body having a configuration similar to a generally recognized flying saucer. In a preferred embodiment of the present invention, the rocking-type seismic isolation base has a concave spherical upper surface having a relatively small rolling radius and a convex spherical lower surface having a relatively large rolling radius. The base so designed may have a swinging period larger than that of a seismic origin to achieve the effect of seismic isolation.
The rocking-type seismic isolation base serves as a buffer when a structure is horizontally displaced relative to a supporting foundation of the structure, and largely reduces the vertical displacement of the structure. The rocking-type seismic isolation base also allows the displaced structure to automatically return to its original position.
The rocking-type seismic isolation base is provided at a bottom with a space for an anti-slipping lock to mount and freely move therein, so as to prevent the rocking-type base from horizontally slipping in a condition exceeded the designed seismic vibration.
The rocking-type seismic isolation base may be cooperatively used with a saucer spring and/or a plunger piston to further mitigate the vertical vibration.
BRIEF DESCRIPTION OF THE DRAWINGSThe structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein
Please refer to
As shown, the rocking-type seismic isolation base 1 of the present invention has a configuration similar to a generally recognized flying saucer, and includes a concave spherical upper surface 5 allowing a correspondingly shaped member to rotate and slide thereon, and a convex spherical lower surface 6 allowing the base 1 to rotate and roll or rock on a foundation surface 2. The concave spherical upper surface 5 has a radius smaller than that of the convex spherical lower surface 6. The concave spherical upper surface 5 is in tight and firm contact with a contact surface of the same radius pre-provided on the structure, while the convex spherical lower surface 6 is in point contact with the foundation surface 2.
When rolling or rocking, the base 1 moves horizontally relative to the foundation surface 2. Since the rocking-type base 1 rolls or rocks to move, a friction between the convex spherical lower surface 6 and the foundation surface 2 is relatively small to allow the base 1 to easily move horizontally. On the other hand, a friction between a sliding article and a supporting surface is relatively large. Therefore, the condition of horizontal sliding would not occur under generally relatively small seismic vibration.
With the concave spherical upper surface 5 having a relatively small rolling radius and the convex spherical lower surface 6 having a relatively large rolling radius, the base 1 so designed may have a swinging period larger than that of a seismic origin to achieve the effect of seismic isolation. Meanwhile, as shown in
From a comparison between the shifted center of sphere 8 and the original center of sphere 7 of the concave spherical upper surface 5 of the rocking-type seismic isolation base 1, it can be seen from
While it is ensured the rocking-type seismic isolation base 1 would not slide to displace within the designed seismic vibration condition, any possible special condition exceeded the seismic vibration design condition must still be taken into consideration. For this purpose, the base 1 is provided at the convex spherical lower surface 6 with a bottom space 4 for an anti-slipping lock 3 to mount thereto, so as to enhance the safety in using the rocking-type seismic isolation base 1 of the present invention. From an observation of a geometrically positional relation between the bottom space 4 and the anti-slipping lock 3, it is found the bottom space 4 preferably has a curved inner surface to provide an optimal moving condition for the anti-slipping lock 3.
Generally, when a seismic isolation device is cooperatively used with a damping device, it is possible to provide the whole structure with an enhanced earthquake-resistant condition. Therefore, it is strongly recommended that a structure should be designed to allow direct mounting of a vertical earthquake vibration cushion spring thereto, so as to cooperate with an overall earthquake resisting solution.
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Claims
1. A rocking-type seismic isolation base for protecting a structure against earthquake, comprising a body having a configuration similar to a generally recognized flying saucer, and including a spherical upper surface allowing a member having correspondingly shaped matching surface to rotate and slide thereon, and a convex spherical lower surface allowing the base to rotate, roll, or rock on a foundation surface; wherein said spherical upper surface has a small radius relative to said spherical lower surface.
2. The rocking-type seismic isolation base for protecting a structure against earthquake as claimed in claim 1, wherein said body is provided at said convex spherical lower surface with a bottom space having a curved inner surface for an anti-slipping lock device to mount and freely rotate and move in said bottom space.
Type: Application
Filed: May 15, 2006
Publication Date: Nov 23, 2006
Inventor: Wei Lee (Keelung City)
Application Number: 11/433,447
International Classification: E04H 9/02 (20060101);