P.D. Spanos, A. Giaralis, Li Jie
Earthquake Engineering and Engineering Vibration
Analysis of earthquake disaster
design spectrum; Chinese aseismic code; artifi cial accelerograms; evolutionary power spectrum; peak factor; recorded accelerograms; wavelets
A versatile approach is employed to generate artificial accelerograms which satisfy the compatibility criteria prescribed by the Chinese aseismic code provisions GB 50011-2001. In particular, a frequency dependent peak factor derived by means of appropriate Monte Carlo analyses is introduced to relate the GB 50011-2001 design spectrum to a parametrically defined evolutionary power spectrum (EPS). Special attention is given to the defi nition of the frequency content of the EPS in order to accommodate the mathematical form of the aforementioned design spectrum. Further, a one-to-one relationship is established between the parameter controlling the time-varying intensity of the EPS and the effective strong ground motion duration. Subsequently, an effi cient auto-regressive moving-average (ARMA) fi ltering technique is utilized to generate ensembles of non-stationary artifi cial accelerograms whose average response spectrum is in a close agreement with the considered design spectrum. Furthermore, a harmonic wavelet based iterative scheme is adopted to modify these artificial signals so that a close matching of the signals’ response spectra with the GB 50011-2001 design spectrum is achieved on an individual basis. This is also done for fi eld recorded accelerograms pertaining to the May, 2008 Wenchuan seismic event. In the process, zero-phase high-pass fi ltering is performed to accomplish proper baseline correction of the acquired spectrum compatible artificial and field accelerograms. Numerical results are given in a tabulated format to expedite their use in practice.