investigating the effect of soil type on non-linear response spectrum using wavelet theory

In this paper, using wavelet denoising theory (wdt), the non-linear response spectrum (nrs) of single degree of freedom (sdof) was plotted for different soil types, as well as different ductility for earthquake record. employing the wdt, the ground wave frequencies were filtered in three stages. the wavelet denoising theory was used to smoothen the diffraction in the acceleration and noise spectrum. the nrs of the sdof was computed for the main earthquake record (mer) and the wave was obtained in the third stage of wdt. in the third wavelet stage, the high frequencies of the mer were separated three times; in the first phase, the largest wave frequencies were eliminated. the results revealed that the third-phase spectrum had an average difference of less than 10% when compared with the original earthquake spectrum. the highest difference was observed in soil type 4 and the lowest difference was seen in soil type 1. in addition, shearing base force of sdof structure was calculated for each of the four soil types employing the nrs of acceleration.