Abstract
In general, Live load on structures is not distributed uniformly. The rotational degree of freedom on a plane in the structure is existed and the torsional vibration is occurred. Many examples of damage by the torsional vibration on the past earthquake are reported. This paper presents the vibration modes and the twist responses of multi storied structures to having translational and torsional degrees of freedom on the planes. At first, it is divided each vibration modes into the translational modes and the rotational ones. Next, the relationships of their modes are indicated with transfer function. And the effects on their modes are examined for earthquake responses.
