Seismic Isolation

  • James M. Kelly


Before discussing the dynamics of base-isolated structures, it is useful to review the dynamics of the conventional structure and define some terms that will be used in the subsequent analysis. Consider first a single-degree-of-freedom (1-DOF) model of a structure, as shown in Fig. 3-1, with mass, m, supported on top of a weightless frame with linear stiffness, k, and linear damping constant, c. The absolute displacement of the mass of an inertial frame is denoted by u(t) and that of the ground by u g (t). The rate of change of the absolute momentum of the structure, mü (t), is produced by the negative of the reactive force of the structure
$${R_F} = c\left( {\dot u - {{\dot u}_g}} \right) + k\left( {u - {u_g}} \right)$$
(where the superposed dot denotes differentiation with respect to time).


Ground Motion Response Spectrum Isolation System Base Shear Design Spectrum 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag London Limited 1997

Authors and Affiliations

  • James M. Kelly
    • 1
  1. 1.Earthquake Engineering Research CentreNational Information Service for Earthquake EngineeringRichmondUSA

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