Experimental study of metamaterial foundation for seismic wave suppression in buildings

The paper proposes a metamaterial foundation to reduce the damage caused by the seismic waves on the buildings. Metamaterials are periodic structures composed of repeated unit cells of hard core and flexible cladding. Their ability to create low-frequency band gaps due to Bragg reflections and local resonance makes them ideal for seismic isolation. In the present work, a scaled model of the metamaterial foundation (1:80 of the original structure) has been investigated experimentally and computationally. A harmonic excitation is applied to the base of metamaterial foundation during the experiments on a vibration shaker. Frequency response functions (FRF) are measured for the reduction of vibration amplitude from the base to the top layer of metamaterial foundation. Experiments and simulations show that increasing the number of layers provides higher wave attenuation in the band gap region. Further, study of building on such a novel foundation is analysed. A frame is placed on the metamaterial foundation and the response has been studied. The metamaterial foundation is found to be very effective in reducing the vibration on frame/building. Based on the results and effectiveness of the scaled model, it is proposed that the larger metamaterial foundation can attenuate the seismic waves range from 6.6 Hz to 10.7 Hz.