Response spectra for differential motion of columns, paper II: Out-of-plane response

Trifunac, Mihailo and Gicev, Vlado (2006) Response spectra for differential motion of columns, paper II: Out-of-plane response. Soil Dynamics and Earthquake Engineering, 26 (12). pp. 1149-1160.

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It is shown that the common response spectrum method for synchronous ground motion can be extended to make it applicable for earthquake response analyses of extended structures experiencing differential out-of-plane ground motion. A relative displacementspectrum for design of first-story columns SDC (T, TT, z, zT, t, d) is defined. In addition to the natural period of the out-of-plane
response, T, and the corresponding fraction of critical damping, z, this spectrum also depends on the fundamental period of torsional vibrations, TT, and the corresponding fraction of critical damping, zT, on the ‘‘travel time,’’ t (of the waves in the soil over a distance of
about one-half the length of the structure), and on a dimensionless factor d, describing the relative response of the first floor. The new spectrum, SDC, can be estimated by using the empirical scaling equations for relative displacement spectra, SD, and for peak ground velocity, vmax. For recorded strong-motion acceleration, and for symmetric buildings, the new spectrum can be computed from
Duhamel’s integrals of two uncoupled equations for dynamics equilibrium describing translation and rotation of a two-degree-offreedom system. This representation is accurate when the energy of the strong-motion is carried by waves in the ground the wavelengths of which are one order of magnitude or more longer than the characteristic length of the structure.

Item Type: Article
Subjects: Natural sciences > Earth and related environmental sciences
Natural sciences > Matematics
Natural sciences > Physical sciences
Divisions: Faculty of Computer Science
Depositing User: Vlado Gicev
Date Deposited: 05 Nov 2012 12:41
Last Modified: 29 Oct 2013 10:52

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