Probabilistic analysis of structures equipped with FVDs accounting for their brittle failure

Anti-seismic devices should be designed with proper safety margins against their failure. Seismic standards generally prescribe safety factors (reliability factors) in order to reach a target safety level. In the case of Fluid Viscous Dampers (FVDs), these factors are applied to the stroke and velocity, and their values are not homogenous among seismic codes. This paper investigates the influence of the values of the safety factors for FVDs on the reliability of the devices and of the structural systems equipped with them. An advanced FVD model is employed to account for the impact forces arising when the dampers reach the end-stroke and the brittle failure due to the attainment of the maximum force capacity. The effect of damper failure on the seismic risk of the structural system is investigated by performing multiple-stripe analysis and monitoring different global and local demand parameters. A parametric study has been carried out, considering a case study consisting of a low-rise steel building, coupled with a dissipative system with linear and nonlinear properties and studying the consequences of different values of safety factors for stroke and forces.