Seismic Response of Steel SMFs Subjected to Vertical Components of Far- and Near-Field Earthquakes with Forward Directivity Effects

Abstract

Inthenear-fieldearthquake,forwarddirectivityeffectscauselong-periodpulsewithashorteffectivetimeandalargedomaininthe velocitytimehistory.Thisissueincreasestheductilityneedsofstructures,andinrecentdecades,thedestructiveeffectsofthesekinds of records have been evaluated in comparison with far-field earthquakes. This brings about the necessity to compare a structure’s behavior subjected to vertical components of near-field (NF) earthquakes, including forward directivity effects vs. the effects of vertical components offar-field (FF) earthquakes. Thepresent study investigated 3-,5-,8-, and20-story steelmoment frameswith specialductility(SMF)throughwhichmodelingeffectsofpanelzonehavebeenapplied,subjectedtoverticalcomponentofnear-field (NF)earthquakeswithforwarddirectivityandtheverticalcomponentoffar-fieldearthquakes.Byinvestigatingtheresults,itcanbe clearlyseenthattheaveragevaluesofthemaximumdisplacement,shearforceofthestories,andthevelocityofeachstoryunderthe impact of the near-field earthquake are greater than the amount of that under the effect of a far-field earthquake. However, this comparison is not valid for the amount of acceleration, axial force, and moments in the columns of the structures accurately.