Normalized response spectrum proposal for structures built on different soils

In a site where the geotechnical properties are known, evaluation of the changes in strong ground motion in each of the layers from the engineering bedrock to the surface is known as Site Response Analysis. This change can be amplification or deamplification. During the analysis, groups of 6 different soil models whose thicknesses vary from 5m to 30m are formed mean Vs is chosen for the first 30m ranging from 150m/s to 400m/s. Deepsoil program is used for site response analysis and for each soil model, 17 different acceleration spectrum is obtained for San Fernando, Tabas, Landers, Loma Prieta, Northridge, Kobe, Kocaeli, Tottori, Iwate and Duzce earthquakes. The gathered 1332 acceleration spectrum are divided by mean spectrum which are 37 acceleration spectrum recorded at the base rock and normalized to obtain normalized response spectrum for periods for different shear wave velocities and layer thicknesses. In practice, response spectrum at the surface can be determined using the normalized response spectrum proposed in this study. The site's average shear wave velocity likelihood equation, the thickness of the soil, PGA of the maximum are used to select the right normalized response spectrum. Then, using the seismic risk maps determined for Turkey, the rock spectrum for the specific site is selected. The site specific response spectrum is obtained by multiplying the selected normalized response spectrum with the site-specific rock spectrum.