Synthesis of accelerograms compatible with the Chinese GB 50011-2001 design spectrum via harmonic wavelets: artificial and historic records

                                                                     P.D. Spanos¹, A. Giaralis² and Li Jie³

1. Rice University, Houston, TX, 77005-1827, USA
2. Department of Civil and Environmental Engineering, Rice University, Houston, TX, 77005-1827, USA
3. Institute of Civil Engineering, Tongji University, Shanghai 200092, China

Abstract: 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 definition 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 efficient auto-regressive moving-average (ARMA) filtering technique is utilized to generate
ensembles of non-stationary artificial 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 field recorded accelerograms pertaining to the May, 2008 Wenchuan seismic event. In
the process, zero-phase high-pass filtering 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.

Keywords: design spectrum; Chinese aseismic code; artificial accelerograms; evolutionary power spectrum; peak factor;
recorded accelerograms; wavelets




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