CHARACTERISTICS OF TORSIONAL VIBRATION OF 1-STORY LINEAR SYSTEM WITH UNIAXIAL ECCENTRICITY

Abstract

This paper studies theoretically on basic characteristics of torsional vibration of 1-story linear system with uniaxial eccentricity subjected to translational ground motions. Basic characteristics mainly of the torsional component is made clear by deriving mathematical expressions for participation vectors and acceleration magnification factors. Based on these magnitudes of vectors and factors new indices for the dynamic torsional effect are proposed. Proposed simple indices are effective for torsional vibration not only in the ordinary case of large eccentricity but also in the extraordinary case of small eccentricity. These indices also show good agreement with damages of structures in past earthquakes.