Torsional displacement ratio of frame-tube structure under expected rare earthquake

摘要

Columns in frame-tube structures may be damaged easily because of the torsional response, therefore, torsional displacement ratio was defined by national codes for spectrum analysis under frequent earthquake. For analysis of time-history under expected rare earthquakes, different from displacement angle, it isn't essential for the checking of torsional displacement. Numerical simulation indicates that torsional response cannot be embodied by displacement angle in nonlinear time-history analysis. As columns in a frame-tube structure may be damaged earlier than being expected by the transfinite torsional displacement ratio, and then the performance of double fortification lines for earthquake may be decreased, the structural torsional response should be considered together with the displacement angle.