Equivalent-Linear and Nonlinear Seismic Ground Response Analysis of Important Sites in Amaravati Capital Region, Andhra Pradesh, India

Abstract

The characteristics of bedrock motion are examined using seismic ground response analysis to determine the impact of the regional soil layers overlaying the bedrock, with the use of two programs, DEEPSOIL and SHAKE. The diversity in the seismic ground response is investigated for a variety of input parameters, including soil geometry, the use of various shear moduli, damping curves, and analytical techniques. The present study attempted to study the local site effects for important towns like Amaravati, Velagapudi, Nekkallu, and Abburaju Palem in the Amaravati capital region by adopting both the equivalent linear and non-linear approaches. The ground responses are observed for the synthetic accelerograms obtained from 2001 Bhuj earthquake motion as seed accelerogram and results are presented in the form of response spectrum, acceleration time histories, and Amplification ratio. The peak ground acceleration and amplification factor for the Velagapudi soil site are found to be the highest among the four soil sites with a value of 0.149g.  The maximum surface acceleration obtained for Amaravati, Nekkallu, and Abburaju Palem is 0.09g, 0.084g, and 0.128g respectively for a given input motion. The amplification ratio for maximum acceleration is found to be 4 at a frequency of 2.5 Hz for Velagapudi, 3.5 at a frequency of 5.5 Hz for Abburaju Palem, 3.4 at a frequency of 3.5 for Amaravati and 3.85 at a frequency of 10 Hz for Nekkallu town respectively. The mean spectral values obtained by equivalent linear analysis are found to be higher than that of the non-linear analysis