Estimation of Seismic Demands on Isolators Based on Nonlinear Analysis

Seismic Reliability-Based Design of Inelastic Structures With Different Values of the Post-Yielding Stiffness Isolated by FPS

“…This assumption represents the failure condition assumed within the numerical analyses. The results of the incremental non-linear dynamic analyses (IDAs), taking into account the collapsed systems, have allowed to estimate the superstructure and isolation response parameters, expressed in terms of displacement ductility demand and of maximum displacement of the isolation level with respect to the ground max max , , respectively, adopted as the engineering demand parameters (EDPs) and assumed to follow a lognormal distribution [21], [31], [48], [52]. Knowing the sample lognormal mean ln ( ) EDP and the dispersion ( ) EDP , it is possible to determine the 50 th , 84 th and 16 th percentile of each lognormal distribution [20].…”

“…In the analyses carried out in this study, the damping ratio b is taken equal to zero, consistently with other works which assume that friction is the only source of damping in the isolators [31], [52]. The corresponding IM is hereinafter denoted as…”

Optimal Friction Coefficients for Isolated Structures Depending on the Soil Condition

“…Thus, this system can be assumed as reference case for evaluating the influence of the isolator friction and of the period ratio on the response statistics [17]. In the analyses carried out in this study, the damping ratio b is taken equal to zero, consistently with other works which assume that friction is the only source of damping in the isolators [17], [22], [57]. The corresponding IM is hereinafter denoted to as…”

“…(4) for each set of the 100 ground motion records, a set of samples is obtained for the output variables used to monitor the performance. In this paper, the response parameters are assumed to follow a lognormal distribution [17]- [18], [39], [57]- [58]. The lognormality assumption permits to estimate, with a limited number of samples, the response at different percentile levels, which is very useful for system reliability assessment.…”

“…From a design point of view, it may be of interest to evaluate the values of * ,opt that minimize response percentile others than the 50 th , corresponding to different exceedance probabilities [57]. Therefore, for each soil type, through a multivariate nonlinear regression analysis, a regression expression is obtained for …”