ACCELEROGRAM-BASED DURATION AND ENGINEERING DURATION OF GROUND MOTION
Xie Lili , Zhang Xiaozhi (Institute of Engineering Mechanics, State Seismological Bureau)
In this paper, the existing definition oi strong ground motion duration is reviewed and re-classified into two different categories:record-based duration which was directly defined upon ground motion accelerograms and response-based duration which was defined upon the structure response subjected to ground acceleration. A conception and definition of engineering duration of earthquake ground motion is proposed, and its predicting equations are deduced. The engineering duration is clear in conception, simple in calculation, easy in establishing the relations with other existing record-based durations, and convenient in formulating the predicting equation by fully using the existing ones. Because the defined engineering duration is related directly to both seismic and structural parameters, it can much better reflect both the characteristics of earthquake ground motion and its effects en the seismic damage of structure than any definition presented ever before.