Reliability based assessment of the effectiveness of metallic dampers in buildings under seismic excitations

Both for purposes of seismic retrofitting and in new designs of building frames, external energy dissipation systems may be advantageously used. In this paper, the improvement of the system reliability achieved through use of external passive metallic or viscous dampers is assessed by simulation. The effect of the dissipation system is numerically evaluated using the properties of a prototype lead-rings damper developed at LDEC, UFRGS in conjunction with methods for nonlinear structural dynamic analysis. To obtain robust estimators of the reliability, a database including acceleration records with markedly different characteristics was used in the simulation study. On the premise that the efficiency of a dampers system can best be assessed on a reliability basis, full reliability analyses of typical steel and reinforced concrete frame buildings are performed, showing that a five-fold reduction in the probability of failure may be achieved by introducing external metallic or similar dampers systems.