MODELING OF NONSTATIONARY GROUND MOTION AND ANALYSIS OF INELASTIC STRUCTURAL RESPONSE

A new stochastic model of ground excitation is proposed in which both intensity and frequency content are functions of time, and corresponding methods for estimating the model parameters based on actual earthquake records are also given. The proposed ground motion model can be efficiently applied in simulations as well as random vibration vibration and reliability studies of inelastic structures. Responses of single-mass inelastic systems and three-story space frames, with or without deterioration under the nonstationary biaxial ground excitation are investigated via the equivalent linearization method and Monte Carlo simulations. The results show that the time-varying frequency content the dominant frequencies of ground excitation are close to the structural natural frequency. Also biaxial and torsional response may become significant in an unsymmetric structure. © 1990.