Temporal characteristics of earthquake ground motion and their possible implications on structural damage

In this dissertation, two new temporal characteristic parameters, tangential acceleration and normal acceleration, are studied. In Chapter One, traditional ground motion characteristics and parameters are summarized. In Chapter Two, the mathematical formulations of the two new parameters are derived. Then some features of tangential and normal accelerations are discussed. In Chapter Three, these two parameters are used to examine the Northridge Earthquake (1994) ground motion characteristics and the relationships of tangential and normal acceleration with other parameters are discovered. More comprehensive study is carried out in Chapter Four using tangential and normal accelerations to explore the temporal characteristics of the Chi-Chi Earthquake (1999). The conclusions are drawn based on 10 sets of earthquake ground motions from the Chi-Chi Earthquake and several sets from the Northridge (1994) and the Kobe Earthquakes. It is shown that the temporal characteristics of earthquake ground motions are not unique to any individual earthquake. Each of the temporal characteristics may be explained by using three dynamic models. This is discussed in Chapter Five. In chapter Six, the possible implications of temporal characteristics of earthquake ground motions on structural damage are explored. Based on the recently proposed concept that velocity pulse may be a good parameter to measure the damage potential of earthquake motion, velocity norm and tangential acceleration are used to investigate the damage potentials of earthquake ground motions in Chapter Seven. Chapter Eight deals with conclusions and discussions.