Periodic structure as seismic barriers

Abstract

Some seismic barriers are periodic structures with the characteristic of frequency band gaps (BGs) similar to sonic crystals, which can protect buildings from damage caused by earthquakes. Their working idea is to arrange periodic structures in the foundation around the buildings you want to protect, and the seismic wave is blocked outside the buildings when the frequencies of seismic waves exactly fall in the frequency BGs of the seismic barriers. Based on sonic crystal, a periodic structure is first presented here, which not only can be utilised as seismic barriers but also has a large internal space to provide the possibility for other functions such as civil air defence construction, line access, etc. The frequency BGs of the presented structure are determined by the spectral element method, and the influence of geometrical parameters and the number of unit cells on the frequency BGs is analysed. Numerical calculation confirms that the proposed structure can effectively isolate some seismic waves.