Seismic Reliability-Based Design of Elastic and Inelastic Structural Systems Equipped with Seismic Devices

Abstract

The scope of this chapter is to illustrate the seismic reliability-based design (SRBD) as an effective methodology to design both linear and nonlinear structures isolated with seismic devices such as FPS (friction pendulum system) isolators. In order to model the isolated structures, an equivalent two-degree-of-freedom model has been used taking into account the superstructure elastic or nonlinear response, whereas a widespread nonlinear velocity-dependent model has been adopted for the FP device. By considering natural or artificial seismic records and assuming the seismic input characteristics together with the friction coefficient as the main aleatory uncertainties, incremental dynamic analyses are developed to derive the seismic fragility curves. The convolution integral permits to derive the seismic reliability curves by integrating the seismic hazard with the seismic fragility curves. Particularly, SRBD expressions between the displacement ductility demand and the strength reduction factors for the inelastic superstructure as well as abacuses useful for the FPS device design are derived.