Influence of earthquake source parameters and damping on elastic response spectra for Iranian earthquakes

In this paper the influence of effective duration of strong motion, soil condition, magnitude and shape of accelerogram time history on the elastic response spectra has been investigated. A total of 106 of Iran's horizontal acceleration components of strong motion records are selected. These accelerograms are categorized based on their earthquake parameters and soil condition of recording station and the influence of different soil conditions are plotted in graphs. The influence of damping ratio on the response spectra is also investigated. Analytical results show that the influence of soil condition is significant for the shape of response spectra. The influence of effective duration of strong motion has been studied by definition based on the energy of the accelerogram. It can be seen that an increase in effective duration causes a reduction in the slope of response spectra in the long period part and increases the spectral values. The effect of damping on response spectra is represented by a special coefficient which depends on the period and damping of the structure and soil condition.