ABSTRACT
One of the most active research areas in earthquake engineering is the inelastic torsional response of non symmetric, irregular buildings. Code provisions for designing such buildings have often been questioned (Chopra & Goel 1991, De la Colina 2003, Stathopoulos & Anagnostopoulos 2003, 2005) while torsion has frequently been identified as a main cause of irregular building failures during catastrophic earthquakes (e.g., Chandler 1986). Key factors that make this problem difficult are: various accidental eccentricities that cannot be predicted when the structure is designed, torsional components of ground motion normally ignored in design, coupling of translational and torsional modes that can lead to non-symmetric yielding in a building, thus causing additional stiffness eccentricities etc.
