Static structures (e.g. – buildings) – Means compensating earth-transmitted force – Relative motion means between a structure and its foundation
Reexamination Certificate
1999-11-24
2001-12-04
Friedman, Carl D. (Department: 3635)
Static structures (e.g., buildings)
Means compensating earth-transmitted force
Relative motion means between a structure and its foundation
C052S167700, C052S167900
Reexamination Certificate
active
06324795
ABSTRACT:
CROSS REFERENCES TO RELATED APPLICATIONS
(none)
STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT
(none)
BACKGROUND OF THE INVENTION
This invention relates generally to seismic isolation bearings, and more particularly to a seismic isolation device providing an articulating joint.
Many inhabited areas are subject to earthquakes and other seismic activity. Building designs have been developed to limit the property damage, injury, and death due to earthquakes. One approach is to make buildings in seismic areas strong enough to withstand the greatest anticipated strain. Unfortunately, this approach can greatly increase both the material cost and construction cost of the building, and result in a very heavy building. A heavy building can further complicate matters if the building must be placed on a soft or meta-stable ground, like mud or fill. While such ground provides adequate support for the building during normal times, the meta-stable ground may provide reduced support during an earthquake, resulting in the foundation or a portion of the foundation sinking or tilting.
Other approaches have focused on isolating the building (structure) from the foundation and underlying soil that the building rests on. For example, techniques have been developed to allow a structure to slide relative to its foundation. Some devices include a joint with a sliding foot that allows a building to remain vertical as the foot slides. Unfortunately, while a sliding joint may avoid catastrophic failure of the building superstructure, after an earthquake the building may no longer be on its foundation, or the foundation may no longer be level. Other techniques provide an elastomeric bearing that allows some degree of elastic movement between the structure and the foundation. Elastomeric techniques typically focus on allowing shear deformation, that is, the relative movement of the building and foundation in a horizontal plane in response to an earthquake.
One approach to using elastic bearings provides a laminated structure of elastomeric material, such as rubber, interleaved with metal shims. The laminate structure confines the elastomer layers to limit horizontal expansion due to vertical load stresses while allowing shear deformation of the laminate stack in the result of an earthquake. Such laminates do not provide significant compliance for vertical strain, such as may accompany surface waves or tilting, and generally require a high degree of shear deformation, which generally means using an elastomeric material with a high degree of elasticity and/or many laminations.
Therefore, it is desirable to provide seismic isolation between a building and a foundation with improved compliance, including compliance in the vertical plane and tilting. It is further desirable that the seismic isolation be compatible with buildings built on meta-stable ground.
SUMMARY OF THE INVENTION
An apparatus for joining a building superstructure to a foundation has a joint allowing the foundation to tilt relative to the building superstructure. In a further embodiment, the apparatus includes an elastic element coupled to the joint to further facilitate accommodation of shear strain and other strains resulting from a seismic event. The joint is, for example, a ball and socket joint, and the elastic element is a block of elastomeric material allowing deformation along at least two orthogonal axis. The tilting of the building relative to the foundation allowed by the joint works in conjunction with deformation of the elastic element to accommodate both vertical motion and horizontal (shear) motion of the foundation. By tilting, the joint reduces the shear deformation in the elastomeric element that is required in response to a seismic event or other movement of the foundation relative to the building superstructure.
REFERENCES:
patent: 1158932 (1915-11-01), Kohl
patent: 2597800 (1952-05-01), Hussman
patent: 3347002 (1967-10-01), Penkuhn
patent: 4188681 (1980-02-01), Tada et al.
patent: 4320549 (1982-03-01), Greb
patent: 4503710 (1985-03-01), Oertle et al.
patent: 4644714 (1987-02-01), Zayas
patent: 4962668 (1990-10-01), Preston et al.
patent: 5014474 (1991-05-01), Fyfe et al.
patent: 5071261 (1991-12-01), Stuve
patent: 5156494 (1992-10-01), Owens et al.
patent: 5452548 (1995-09-01), Kwon
patent: 5456047 (1995-10-01), Dorka
patent: 5568705 (1996-10-01), Bellavista
patent: 5904010 (1999-05-01), Javid et al.
patent: 5970666 (1999-10-01), Kurabayashi et al.
patent: 19836763 A1 (1999-07-01), None
patent: 0894900 A1 (1999-02-01), None
patent: 1260137 (1989-10-01), None
patent: 3013637 (1991-01-01), None
patent: WO 99/09278 (1999-02-01), None
Pedersen Knud B.
Shukla Shyam N.
Stiles Harold L.
Ever-Level Foundation Systems, Inc.
Friedman Carl D.
Hewett Scott W.
Slack N.
LandOfFree
Seismic isolation system between floor and foundation... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Seismic isolation system between floor and foundation..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Seismic isolation system between floor and foundation... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2601061