非平稳地震作用下的结构随机响应及动力可靠性研究

IThe evolutionary power spectrum which can reflect the earthquake energy contribution characteristics on time-frequency plane is estimated by the Hilbert-Huang Transform (HHT), and with reference to the experiential statistical method, an evolutionary spectrum prediction model for given earthquake magnitude and distance is established based on the 121 near-source acceleration records at rock surface with large magnitude from the ground motion database of western U S. The pseudo excitation method is adopted to acquire the solution for linear structural random response under specific non-stationary seismic excitation and structural dynamic reliability is discussed based on the first-excursion failure criterion. The results demonstrate that the non-stationary contents included in seismic excitation will enlarge greatly the random response and failure probability of structure in comparison with strength non-strationary excitation.