SEISMIC RELIABILITY ASSESSMENT OF NONLINEAR STOCHASTIC STRUCTURES

Seismic reliability assessment of nonlinear stochastic structures is a challenging problem in that there have been only preliminary investigations on response analysis of stochastic structures involving nonlinearity. In recent a class of probability density evolution method (PDEM), in which the probability density evolution equation governing the response of nonlinear structures is derived, has been proposed by the authors. Based on the newly developed PDEM, a seismic reliability assessment method for nonlinear stochastic structures is put forward. In the method, dynamic reliability for a first passage problem can be obtained by imposing an absorbing boundary condition corresponding to the failure criterion on the probability density evolution equation and integrating over the safe domain. The proposed method is performed through a numerical algorithm combining the time integration method and the difference method with TVD schemes. In the proposed method, the computation of mean crossing rate is not needed, neither the assumption about the crossing process such as Poisson or Markovian suppose. A frame subject to seismic excitation is studied to assess the reliability and the results are compared with those obtained by the Monte Carlo method. The investigation shows that the proposed method is of high accuracy and time saving