Importance of Rotational Ground Motions on Seismic Response of Tall Buildings

Date: 4/25/2019

Time: 04:45 PM

Room: Pine

Rotational components of earthquake ground motions are currently not accounted for in seismic design codes. However, records from ground stations and instrumented buildings clearly indicate that rotational components of ground shaking can be an important factor in seismic response of buildings, particularly tall buildings.

In this study, we first identify the rotational components of ground motions by analyzing the data from a T-shaped, 22-station short aperture seismic array with station separations varying from 5 to 100 meters. The array is on the grounds of Air Force Academy in Istanbul at a soft soil site near the airport. The records show that the rotational excitations are generated mainly by the displacement gradient of travelling Rayleigh waves.

In order to see the effects of ground rotations on structural response, we have calculated the seismic response of a tall building at that site first by neglecting and then by considering the rotational components of ground accelerations recorded during an M=6.5 earthquake. The results show that rotational components have a significant influence on the response of the building.

Presenting Author: Erdal Safak

Authors