A stochastic approach for generating spectrum compatible fully nonstationary earthquakes

Abstract

Simulation of artificial earthquakes in agreement with the provision of international seismic codes is addressed. Due to the importance of nonstationary frequency content on the seismic assessment of structures, in this paper a new method for generating spectrum compatible fully nonstationary earthquakes is proposed. The method assumes that the ground motion is modeled by the superposition of two contributions: the first one is a fully nonstationary counterpart modeled by a recorded earthquake; the second one is a corrective random process adjusting the recorded earthquake in order to make it spectrum compatible. Several examples show the accuracy of the proposed method.

Derivation of response spectrum compatible non-stationary stochastic processes relying on Monte Carlo-based peak factor estimation

“…In fact, it can accommodate any analytically defined "fully non-stationary" (i.e., non-separable) EPS to be used to model the evolutionary attributes observed in recorded strong ground motions. For instance, the non-separable EPS used in Spanos and Vargas Loli (1985) and more recently adopted by Conte and Peng (1997) could have been assumed (see also Cacciola 2010). This EPS is defined by a weighted sum of Kanai-Tajimi uniformly modulated processes and may potentially involve tens of parameters to be determined.…”

“…Then, stationary time-histories compatible with the initially obtained power spectrum are generated and treated deterministically on an individual basis to assign certain nonstationary attributes similar to those observed in field recorded accelerograms. Alternatively, Cacciola (2010) has considered fitting the sum of two contributing processes to the UHS, namely a stationary power spectrum and a scaled time-frequency energy distribution of a single recorded seismic accelerogram using the spectral estimation method of Conte and Peng (1997). The aforementioned studies are useful in deriving small suites of design spectrum compatible accelerograms.…”

A Novel Analytical Model of Power Spectral Density Function Coherent With Earthquake Response Spectra

“…Equation (6) allows to obtain an accurate numerical PSD function compatible with assigned RS. It should be stressed that the effectiveness of this procedure does not depend on the shape of RS and it can be also used for the non-smooth RS obtained in the case of natural earthquake ground motion time histories [19].…”

Anti-symmetric mode excitation and seismic response of base-isolated bridges under asynchronous input motion

“…To overcome these weaknesses, Shields [26] recently presented a method that updates the evolutionary PSD through random functional perturbations. In addition, the method of Cacciola [27] for the simulation of fully non-stationary, spectrum-compatible earthquake motions at a single point, was extended for the purposes of multi-variate simulation by Cacciola & Deodatis [28]. In this method, spectrum compatibility is satisfied through the superposition of an appropriate corrective quasi-stationary process to a "known" fully non-stationary process that represents the seismological properties of the region.…”