ESTIMATION OF GOVERNING PARAMETERS Of STRUCTURE SUBJECTED TO GROUND MOTION USING TRANSFER FUNCTION APPROACH

Abstract

To carry out the dynamic analysis of structure the engineer have available either the time domain or frequency domain methodologies. Biggest advantage of using frequency domain approach over time domain is the simplicity through which convolution for determining system response is obtained. Frequency domain analysis methods provide insight to the effect on various frequency components of system response i.e. transfer function of system. In this thesis, the governing parameters such as bending moment, shear force and inter storey displacement of a multi-storied reinforced concrete G+8 building subjected to ground motion are estimated using transfer function approach through frequency domain. The transfer functions were determined by finding Fourier Transform of its responses for synchronous noise input. Synchronous noise is a broad band time series, which looks like random noise but has an absolutely flat power spectrum. The comparisons of responses of multi storey building using linear modal time history analysis using commercial software SAP2000 V 11 and frequency domain analysis through transfer function approach for earthquake excitation have made. It is proposed that once we have found the transfer function of the building responses for bending moment, shear force, inter storey drift then if there is earthquake of recorded accelerogram in future then by multiplying the transfer function with the Fourier Transform of - earthquake time history we can obtain responses of that particular element. Thus, if we can archive different transfer functions of the building then we will not require to do detailed modeling of the building for future earthquake. iii