analysis on response of dynamic systems to pulse sequences excitation

near-fault ground motions with long-period pulses can place severe demands on structures near an active fault. these pulse-type ground motions can be represented by pulse sequences with simple shapes. half-sinusoidal pulse sequences are used to approximate recorded ground motions and dynamic responses of sdof system under the excitation of these pulse sequences are studied. four cases are considered: (1) variation in duration of successor sub-pulse; (2) variation in duration of predecessor sub-pulse; (3) variation in amplitude of successor sub-pulse; and (4) variation in amplitude of predecessor sub-pulse. the corresponding acceleration, velocity and displacement response spectra of these pulse sequences are studied. the analysis on sdof system shows that in some cases the responses are strongly affected by the changes of duration and/or amplitude of the sub-pulse. the study can be useful to understand the influences of sub-pulse in the near-fault pulse-type ground motions.