Reliability-based optimum design of passive friction dampers in buildings in seismic regions

This paper describes an approach to design friction damper systems for installation in buildings located in seismic regions using a novel optimization technique: the Search Group Algorithm (SGA). The method aims at reducing the probability of failure of typical concrete buildings and is illustrated with a case study for Cucuta, Colombia. To characterize seismic risk, records of ground acceleration during seismic events are used to determine the expected value of the peak ground acceleration (PGA) annual exceedance rate for the site of interest. Seismic risk was estimated by fitting probability distribution functions of the PGA for periods of one and fifty years, with the objective of evaluating, through numerical simulation, the reliability of a concrete structure. It is confirmed that a significant increase of the system reliability may be achieved through the use of an optimized passive friction dampers system. Robust estimators of the reliability are determined with a database of seismic records with markedly different characteristics. The results highlight the efficiency of passive friction dampers to reduce the probability of failure in structures located in regions with high seismic activity.