Seismic reliability of steel structures isolated by fps

This paper evaluates the seismic reliability of steel structures, isolated using friction pendulum system, subjected to artificial earthquake ground motions. The behaviour of the steel superstructure is assumed linear whereas the FPS devices are described by adopting a velocity-dependent model. Both the seismic input, modelled as a non stationary random processes, and the friction coefficient at large velocity are considered as random variables through appropriate probability density functions. Incremental dynamic analyses are developed and then the fragility curves related to both superstructure and isolation level are evaluated. Finally, considering the seismic hazard curve related to a site near Sant’Angelo dei Lombardi (Italy), the seismic reliability of the overall steel system is evaluated.