A parametric study on the effect of rotational ground motions on building structural responses

The characteristics of the rotational components of strong earthquake ground motion and their effects on structural response are rarely considered. A reduced order parametric model is used to investigate the effects of the rotational ground motions upon buildings, which includes the influence of Soil-Structure Interaction. An indirect method of extracting rotational ground components using a multi-station procedure is employed. Ground accelerogram data recorded from the SMART-1 array in Taiwan for three different events are used. Over 3 million system/ground motion cases are analysed in this extensive parametric study. The results show that the rotational ground motion can significantly affect the displacement and acceleration responses of certain structures. The impact of the rotational ground motion depends principally on the amplitude ratio of the rotational to horizontal ground motion and the phase difference content at the structural system's frequencies.