Site-Specific Ground Response Analysis of Some Typical Sites in Amaravati Region, Andhra Pradesh, India

The influence of local geological and geotechnical characteristics on the scale of ground shaking during the earthquake has been well known for a long time. Typical characteristics of strong ground motion like amplitude, frequency and duration will subject to modify due to the influence of local soil conditions. The continuous modifications in the soil deposits lead to amplify or de-amplify the site. The amplification is one of the major key parameters which is significantly used to account the site effects and considered to design the earthquake-resistant structures. The shear wave velocity (Vs) is one of the most important dynamic properties of the soil and is used to represent the stiffness of the soil deposits. The Vs is significantly used to characterize the ground motion either by simplified site classification method or by prices site-specific ground response analysis (GRA). In this study, an attempt was made to estimate the site response of the Amaravati region, Andhra Pradesh, India. The selected capital region is comes under seismic zone III as per the Bureau of Indian standard code BIS: 1893-2016, with a maximum peak horizontal acceleration value of 0.16 g. To assess the penetration resistance (N) number in the selected region, a total of 65 boreholes have been conducted using standard penetration test (SPT) and the Vs of all the profiles determined using the appropriate existing correlation between Vs and SPT-N. Based on the estimated Vs, the seismic site classification is done according to the national earthquake hazard reduction program and Eurocode 08. To conduct the GRA, a total of nine representative sites have been selected and response analysis is conducted for all selected sites using DEEPSOIL software through the one-dimensional equivalent linear approach. The results from the response analysis of all selected boreholes locations have been presented in terms of acceleration time histories at the surface, variation of peak ground acceleration, site amplification along with the depth of the soil column, response spectra for 5% damping and Fourier amplitude ratio against frequency. © 2021, Indian Geotechnical Society.