Long-periodpulsesinnear-fieldearthquakesleadtolargedisplacementsinthebaseofisolatedstructures.Todissipateenergyinisolatedstructuresusingsemi-activecontrol,piezoelectricfrictiondampers(PFD)canbeemployed.TheperformanceofaPFDishighlydependentonthestrategyappliedtoadjustitscontactforce.Inthispaper,theseismiccontrolofabenchmarkisolatedbuildingequippedwithPFDusingPD/PIDcontrollersisdeveloped.Usinggeneticalgorithms,thesecontrollersareoptimizedtocreateabalancebetweentheperformanceandrobustnessoftheclosed-loopstructuralsystem.Oneadvantageofthistechniqueisthatthecontrollerforcescaneasilybeestimated.Inaddition,thestructureisequippedwithonlyasinglesensoratthebasefloortomeasurethebasedisplacement.Consideringsevenpairsofearthquakesandnineperformanceindices,theperformanceoftheclosed-loopsystemisevaluated.Then,theresultsarecomparedwiththosegivenbytwowell-knownmethods:themaximumpossiveoperationofpiezoelectricfrictiondampersandLQGcontrollers.Thesimulationresultsshowthattheproposedcontrollersperformbetterthantheothersintermsofsimultaneousreductionofflooraccelerationandmaximumdisplacementoftheisolator.Moreover,theyareabletoreducethedisplacementoftheisolatorsystemsfordifferentearthquakeswithoutlosingtheadvantagesofisolation.
