ABSTRACT
For the purpose of this study the term „effective” (in connection with design parameters) is restricted to the analysis of strong motion data, i.e. to the problem on seismic action or impact side. The paper can be regarded as an attempt to discuss concepts which may be suited to define seismic action in terms of effective ground motion parameters. Therefore, the widely and in different approaches recommended use of effective peak ground acceleration is extended to earthquake response spectra. The applied procedure follows with slight modifications a method proposed by Kawashima and Aizawa (1986) taking account of the number of response cycles of linear oscillators with a single degree of freedom subjected to ground motion (SDOF-systems). Response spectra are determined for number of response cycles N between N = 1 (representing the maximum responses leading to elastic spectra) and an arbitrary selected upper number of N = 50. Strong motion data from recent damaging earthquakes are considered for illustrating the period-dependent deamplification of response amplitudes which can be interpreted (with caution) as an indicator of inherent damage potential. Using samples of north Italian strong motion data statistical investigations are performed for three intensity and three subsoil classes (nine groups). The selection of ground motion data is related to previous studies being carried to define realistic load parameters for central European seismic regions (Hosser et al. 1986, Schwarz et al. 1992).
