Abstract:
This thesis presents a unique research, on what will be the effect on ground motion due to Rayleigh wave generated during the earthquake and to find out what will be the effect on free field ground motion due to the interaction of the Rayleigh wave with structure of the city. And to also find out whether the structure of the city act as a meta-structure for the Rayleigh wave response.
Response of structure constructed on the soft soil is larger and longer duration as compared to structure constructed on stiff rock. Response of free field ground motion is different to that if structure is present on ground due to interaction of structure of city with surrounding earth during seismic event. This thesis presents a study on the effect of Rayleigh wave on response of building and ground motion after crossing the city. Also what will be the role of impedance contrast in site city interaction are studied and to find out weather, structure falling in the path of Rayleigh wave are acting as meta-structure or not. Meta-structure absorbs the energy of Rayleigh wave corresponding to different modes of vibration of building and delays release of energy causing drops in spectra corresponding to different modes of vibration and acting as insulator for the structure falling ahead. For this study, a fourth order accurate viscoelastic FD staggered grid program is used to find out the response of Rayleigh wave for different considered city model of RC and steel building. From this study it is concluded that building types and impedance effect the ground motion and building acting as meta-structure falling in the path of Rayleigh wave and meta-material effect increases with the decrease of impedance contrast. This property helps in designing building in order to have minimum damage during the earthquake.
