The dynamic response of some important structural systems such as 3-dimensional piping systems, freeway bridge structures, and dams to strong earthquake excitations are very much dependent upon all three components of ground motion. A orthogonal set of principal axis is defined for earthquake ground motions along which the component variances have maximum, minimum and intermediate values and the covariances equal zero. Corresponding axes are defined which yield maximum values for the covariances. The orthogonal transformations involved are identical in form to those used in the transformation of stress. Examination of real accelerograms reveals that the major principal axis points in the general direction of the epicenter and the minor principal axis is nearly vertical. It is concluded that artificially generated components of ground motion need not be correlated statistically provided they are directed along a set of principal axes.

  • Corporate Authors:

    Wiley (John) & Sons, Limited

    Baffins Lane
    Chichester, Sussex  England 
  • Authors:
    • Penzien, J
    • Watabe, M
  • Publication Date: 1975-4

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Filing Info

  • Accession Number: 00096223
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jul 15 1975 12:00AM