Seismic Response and Design of Setback Buildings

Effects of setbacks on the earthquake response of multistory building structures are evaluated. As part of the study, measured responses to simulated earthquakes of a ductile moment‐resisting reinforced concrete test structure are examined. The test structure is a one‐quarter scale model of a six‐story, two‐bay by two‐bay building having a 50% setback at midheight. Experimental observations are supplemented with a series of analytical studies. Guidelines are established by which to detect configurations for which concentrations of damage in tower members are likely. A static lateral‐load design method to improve performance is proposed.