Novel metamaterial foundation with multi low-frequency bandgaps for isolating earthquakes and train vibrations

The impacts induced by earthquake and traffic loading on engineering structures and human life have become more serious. Thus, a novel metamaterial foundation (NMF) with multi bandgaps is proposed to effectively isolate the seismic waves and train vibrations. The dispersion relationship and vibration modes at starting and ending frequencies of each bandgap are investigated based on multi-spring-mass (MSM) model and finite element (FE) method. And the effects of damping ratio of coating layer on the imaginary wave vector, effective mass, effective damping, and transmission features are fully analyzed. Besides, the shielding performances for seismic waves and train vibrations are evaluated by using the 2D and 3D FE model. The results demonstrate that the NMF has multi bandgaps, of which ranges are the 9.3–11.3 Hz, 26.8–29.7 Hz, 34.5–38.8 Hz, and 43.9–53.3 Hz. The peak values of imaginary wave vector, effective mass, and transmission curve decrease, but the attenuation zone gradually increases with the increase of the damping ratio of coating layer. And the peak accelerations of the RC building with NMF can be reduced by 41% and 56.8% under the seismic wave and train vibration, respectively, which demonstrates the broad application prospects in engineering practice.