RESEARCH ON TORSIONAL VIBRATION CONTROL OF TALL BUILDING STRUCTURES

The provisions in Technical Specification for Concrete Structures of Tall Building on torsional irregularity are problematic and the specified measures for torsional vibration control need to be revisited. The ratio of torsion-controlled first period to translation-controlled first period (i.e. the coupled period ratio), combined with the drift ratio, is incorporated in the specification to exclude tall structures with severe torsional irregularity, and its limits should be satisfied in seismic design. By changing the magnitudes of the parameters (i.e. eccentricity, torsional stiffness, and lateral stiffness), the analysis of the difference between the coupled period ratio and uncoupled period ratio shows that the provisions cannot guarantee torsional vibration control in certain situations. In this respect, the coupled-period-ratio index is not well-founded and the ratio of lateral energy to torsional energy is proposed as an alternative.