Large-scale engineered meta-barriers for attenuation of seismic surface waves

Abstract

This study evaluates the performance of large-scale meta-barriers in attenuating seismic surface waves and transportation-induced vibrations in the most disastrous frequency range of 0–30 Hz. By developing analytical and three-dimensional numerical models, it evaluates the properties of the proposed meta-barrier and presents their effects on the attenuation range. Moreover, it discusses a simplified mass-spring-mass model of the meta-barrier, demonstrating that the attenuation range of a unit cell can be approximated using this model. The proposed design consists of three-dimensional two-layers (3D-2C) unit cells arranged periodically with different configurations to be placed between the wave source and structure. Specifically, the meta-barriers can be arranged gradually (periodic spacing along the length), widening the attenuation range to block nearly 85% of the most devastating waves using typically arranged stacked unit cells and triangular-like arrangement (double wedge). The results show that a typical stacked unit cells reflect the incoming waves towards the source, while using the double wedge design, the surface wave can be converted to bulk wave, thereby reducing the risk to the surroundings. Moreover, the study validates the attenuation range using three-dimensional time history analysis subjected to an artificial wavelet (Ormsby wavelet) and three actual seismic records (1975 Oroville, 1984 Bishop, and 2001 Anza time histories).