Static structures (e.g. – buildings) – Means compensating earth-transmitted force – Relative motion means between a structure and its foundation
Patent
1996-08-08
1998-08-25
Friedman, Carl D.
Static structures (e.g., buildings)
Means compensating earth-transmitted force
Relative motion means between a structure and its foundation
521678, 521671, 527413, 248638, 248632, E04B 198
Patent
active
057972281
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates, generally, to seismic isolation bearings and, more particularly, to bearings which employ a rubber bearing body in conjunction with steel pin yielders.
BACKGROUND OF THE INVENTION
Seismic bearings, sometimes referred to as isolation bearings, are generally characterized by their bearing, conservative, and dissipative capacity.
More particularly, isolation bearings of the type typically used with bridges, buildings, machines, and other structures potentially subject to seismic phenomena are typically configured to support a bearing load, i.e., the weight of the structure being supported. In this regard, it is desirable that a particular seismic isolation bearing be configured to support a prescribed maximum vertical gravity loading at every lateral displacement position.
The conservative character of a seismic isolation bearing may be described in terms of the bearing's ability to restore displacement caused by seismic activity or other external applied forces. In this regard, a rubber bearing body, leaf spring, coil spring, or the like may be employed to urge the bearing back to its original, nominal position following a lateral displacement caused by an externally applied force. In this context, the bearing "conserves" lateral vector forces by storing a substantial portion of the applied energy in its spring, rubber volume, or the like, and releases this applied energy upon cessation of the externally applied force to pull or otherwise urge the bearing back to its nominal design position.
The dissipative character of an isolation bearing surrounds the bearing's ability to dissipate a substantial portion of an applied force, for example an applied force due to seismic activity. Typical dissipative modalities include the use of mating frictional surfaces, as well as the use of lead or steel members designed to plastically deform (yield) in response to the application of external forces. Ideally, the yielding members dissipate a portion of the applied energy, and are thereafter urged back to their original position through the action of the bearing's restoring (i.e., conservative) mechanism.
Presently known isolation bearings often employ a laminated rubber bearing body, reinforced with steel plates. More particularly, thin steel plates are interposed between relatively thick rubber plates, to produce an alternating steel/rubber laminated bearing body. The use of a thin steel plate between each rubber plate in the stack helps prevent the rubber from bulging outwardly at its perimeter in response to applied vertical bearing stresses. This arrangement permits the bearing body to support vertical forces much greater than would otherwise be supportable by an equal volume of rubber without the use of steel plates.
The aforementioned steel/rubber laminate bearing body is particularly useful in the context of bridges, buildings, and other large structures.
Steel coil springs combined with snubbers (i.e., shock absorbers) are often used in the context of machines to vertically support the weight of the machine. Coil springs are generally preferable to steel/rubber laminates in applications where the structure to be supported (e.g., machine) may undergo an upward vertical force, which might otherwise tend to separate the steel/rubber laminate.
Rubber bearings are typically constructed of high damping rubber, or are otherwise supplemented with lead or steel yielders useful in dissipating applied energy. Presently known metallic yielders, however, are disadvantageous in that they inhibit or even prevent effective vertical isolation, particularly in assemblies wherein the metallic yielder is connected to both the upper bearing plate and the oppositely disposed lower bearing plate within which the rubber bearing body is sandwiched.
Presently known seismic isolation bearings are further disadvantageous inasmuch as it is difficult to separate the viscous and hysteretic damping characteristics of a high damping rubber bearing; a seismic isolation bearing is thus needed whic
REFERENCES:
patent: 2660386 (1953-11-01), Munro
patent: 3245646 (1966-04-01), Bratoff
patent: 3430901 (1969-03-01), Cauvin
patent: 4065082 (1977-12-01), Oota
patent: 4117737 (1978-10-01), Robinson
patent: 4463753 (1984-08-01), Gustilo
patent: 4605106 (1986-08-01), Fyfe et al.
patent: 4633628 (1987-01-01), Mostaghel
patent: 4644714 (1987-02-01), Zayas
patent: 4713917 (1987-12-01), Buckle et al.
patent: 4718206 (1988-01-01), Fyfe et al.
patent: 4727695 (1988-03-01), Kemeny
patent: 4744539 (1988-05-01), Stimeling
patent: 4823522 (1989-04-01), White
patent: 4887788 (1989-12-01), Fischert et al.
patent: 4910930 (1990-03-01), Way
patent: 4942703 (1990-07-01), Nicolai
patent: 5215382 (1993-06-01), Kemeny
patent: 5242147 (1993-09-01), Kemeny
patent: 5339580 (1994-08-01), Koshika et al.
FIP Industrial (Italy Catalog).
Friedman Carl D.
Tekton
Yip Winnie S.
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