Effect of bulk compressibility on the stiffness of cylindrical base isolation bearings

Chalhoub, Michel Soto; Kelly, James M.

doi:10.1016/0020-7683(90)90004-f

Cited by 78 publications

(40 citation statements)

References 2 publications

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“…The steel shims restrain the rubber at the bond interface and the spacing of the shims (or individual rubber layer thickness) controls the bulging around the perimeter and thus the compression modulus of the elastomeric layer [16,17]. For example, the compression modulus for an individual, solid, circular rubber layer, assuming the rubber is incompressible, is:…”

Section: Elastomeric Bearingsmentioning

confidence: 99%

“…Although bulk compressibility was not considered in Equation 2 for simplicity, Chalhoub and Kelly [16] demonstrated that the assumption of incompressibility overestimates the compression stiffness of an elastomeric bearing, where the degree of over-estimation increases with increasing shape factor. Based on their work, Chalhoub and Kelly [16] concluded the effect of bulk compressibility should be considered in the analysis of seismic isolation.…”

Section: Rubber Covermentioning

confidence: 99%

“…Based on their work, Chalhoub and Kelly [16] concluded the effect of bulk compressibility should be considered in the analysis of seismic isolation. The close spacing of steel shim plates, i.e., thin rubber layers, produces a high shape factor that in turn results in a large vertical stiffness:…”

Section: Rubber Covermentioning

confidence: 99%

“…However, according to Equation 5, this range of shape factors results in vertical stiffness that ranges from one to several thousand times greater than the horizontal stiffness. As a result, isolation systems composed of bearings detailed with high shape factors (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) typically have vertical isolation periods ranging from 0.03 to 0.15 second. Consequently, the vertical isolation frequencies can align with the dominant frequencies of the vertical spectrum, leading to significant amplification of the vertical acceleration.…”

Section: Rubber Covermentioning

confidence: 99%

See 3 more Smart Citations

A Review of Seismic Isolation for Buildings: Historical Development and Research Needs

2012

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Seismic isolation is a technique that has been used around the world to protect building structures, nonstructural components and content from the damaging effects of earthquake ground shaking. This paper summarizes current practices, describes widely used seismic isolation hardware, chronicles the history and development of modern seismic isolation through shake table testing of isolated buildings, and reviews past efforts to achieve three-dimensional seismic isolation. The review of current practices and past research are synthesized with recent developments from full-scale shake table testing to highlight areas where research is needed to achieve full seismic damage protection of buildings. The emphasis of this paper is on the application of passive seismic isolation for buildings primarily as practiced in the United States, though systems used in other countries will be discussed.

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Section: Elastomeric Bearingsmentioning

confidence: 99%

Section: Rubber Covermentioning

confidence: 99%

Section: Rubber Covermentioning

confidence: 99%

Section: Rubber Covermentioning

confidence: 99%

See 2 more Smart Citations

A Review of Seismic Isolation for Buildings: Historical Development and Research Needs

2012

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“…The use of an inter-segment made of soft material (D) can lead to a locking of the segments over the whole section. The stiffness of a multilayer structure (a rubber layer between two rigid plates) can be modified by its compression [130]. A solution based on an endoskeleton-like structure is proposed in [131].…”

Section: Structural Interactionsmentioning

confidence: 99%

Flexible Medical Devices: Review of Controllable Stiffness Solutions

2017

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Abstract:In the medical field and in soft robotics, flexible devices are required for safe human interaction, while rigid structures are required to withstand the force application and accuracy in motion. This paper aims at presenting controllable stiffness mechanisms described in the literature for applications with or without shape-locking performances. A classification of the solutions based on their working principle is proposed. The intrinsic properties of these adaptive structures can be modified to change their mechanical characteristics from a geometrical point of view or equivalent elastic properties (with internal mechanisms or with a change in material properties). These solutions are compared quantitatively, based on selected criteria linked to the medical field as the stiffness range, the activation time and the working conditions. Depending on the application and its requirements, the most suitable solution can be selected following the quantitative comparisons. Several applications of these tunable stiffness structures are proposed and illustrated by examples of the literature.

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Improved numerical analysis for ultimate behavior of elastomeric seismic isolation bearings

Ishii

Kikuchi

2018

Earthq Engng Struct Dyn

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Summary Elastomeric isolation bearings consist of multiple rubber layers with their top and bottom surfaces bonded to steel plates to restrict compressive deformation. Deformation constraints result in a variation of elastic modulus over the cross section of the rubber layers. In this paper, we describe a normalized compression modulus distribution on a circular rubber pad. The compressive and bending moduli of the rubber pad can be reproduced by applying the distribution to a series of axial springs. We also present a mechanical model for predicting the behavior of elastomeric seismic isolation bearings subject to large shear deformation and high compressive load. The mechanical model consists of a series of multiple shear springs at midheight and a series of axial springs at the top and bottom interfaces of the bearing. Simulation analyses of bearing tests were conducted to validate the proposed model. The analyses demonstrated that a model for circular lead‐rubber bearings can successfully capture the influence of the axial load magnitude on the bearing shear behavior. The new model can simulate much more realistic behavior than prior models based on a uniform modulus assumption.

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Effect of bulk compressibility on the stiffness of cylindrical base isolation bearings

Cited by 78 publications

References 2 publications

A Review of Seismic Isolation for Buildings: Historical Development and Research Needs

A Review of Seismic Isolation for Buildings: Historical Development and Research Needs

Flexible Medical Devices: Review of Controllable Stiffness Solutions

Improved numerical analysis for ultimate behavior of elastomeric seismic isolation bearings

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