Territorial seismic protection of the critically important structures

A seismic protecting vertical barrier made of metamaterials with the desired acoustical properties and allowing to trap energy of the incident seismic Rayleigh or Rayleigh – Lamb waves, is analyzed. The considered metamaterials resemble phononic or sonic crystals with a broad frequency band gap in respect of the deviatoric wave components.

Numerical experiments reveal that the considered seismic protecting vertical barriers allow much better seismic protection in terms of larger shadow zones and higher reduction ratios in respect of displacements and accelerations comparing with more traditional barriers made of homogeneous elastic materials.

The corresponding equations of state for the considered metamaterials are discussed. Hyperelastic models with the modified Arruda - Boyce potentials, allowing to account hysteresis loops, are introduced.

Due to better reduction ratios and larger shadow zones, the proposed seismic barriers can be used for seismic protection against Rayleigh and Rayleigh – Lamb waves of the critically important structures, along with constructions with large footprint and stretch constructions like airport runways and taxiways.  

            For the case of bulk S-waves the seismic pads made of similar metamaterials installed beneath foundation slabs, are considered. Similarly to seismic barriers, the seismic pad allow to trap energy of S-waves, thus, considerably reducing structural vibrations caused by arrival of seismic S-waves.