Use of corrected sinusoidal pulses to estimate inelastic demands of elasto-perfectly plastic oscillators subjected to narrow-band motions

Expressions to estimate the maximum displacement of elasto-perfectly plastic oscillators undergoing inelastic response subjected to narrow-band earthquake ground motions are proposed. The ground motions are characterized by sinusoidal pulses, corrected in order to have realistic representations of ground motions due to earthquakes. Based on the results obtained from the corrected pulses, it is shown that, for the type of earthquake ground motions considered, the maximum inelastic demands tend to be independent of ground motion duration, while maximum elastic demands do depend on duration. It is also shown that ground motion duration has a strong influence on strength-reduction factors for narrow-band earthquake ground motions. In view of this fact, caution is warranted when using empirical equations developed with data that have very different durations than the accelerograms expected. Comparisons are made between our analytical solution and results obtained from purely empirical expressions and it is shown that the accuracy of the solution presented is comparable to that of the empirical formulations. The advantage of the expression proposed over expressions obtained from statistical analysis is that it is independent of the elastic strength and displacement spectra.