Finite locally resonant Metafoundations for the seismic protection of fuel storage tanks

Abstract

Summary This paper introduces a novel seismic isolation system based on metamaterial concepts for the reduction of ground motion‐induced vibrations in fuel storage tanks. In recent years, the advance of seismic metamaterials has led to various new concepts for the attenuation of seismic waves. Of particular interest for the present work is the concept of locally resonant materials, which are able to attenuate seismic waves at wavelengths much greater than the dimensions of their unit cells. Based on this concept, we propose a finite locally resonant Metafoundation, the so‐called Metafoundation, which is able to shield fuel storage tanks from earthquakes. To crystallize the ideas, the Metafoundation is designed according to the Italian standards with conservatism and optimized under the consideration of its interaction with both superstructure and ground. To accomplish this, we developed two optimization procedures that are able to compute the response of the coupled foundation‐tank system subjected to site‐specific ground motion spectra. They are carried out in the frequency domain, and both the optimal damping and the frequency parameters of the Metafoundation‐embedded resonators are evaluated. As case studies for the superstructure, we consider one slender and one broad tank characterized by different geometries and eigenproperties. Furthermore, the expected site‐specific ground motion is taken into account with filtered Gaussian white noise processes modeled with a modified Kanai‐Tajimi filter. Both the effectiveness of the optimization procedures and the resulting systems are evaluated through time history analyses with two sets of natural accelerograms corresponding to operating basis and safe shutdown earthquakes, respectively.

A Review of Research on Seismic Metamaterials

“…[60] La Salandra et al constructed a 3D three-component periodic foundation using the two commonly used basic building materials, concrete and rubber, for isolation of the fuel storage tank system in 2017. [61] They further optimized the periodic metafoundation in 2019, [62] as shown in Figure 7. In 2018, Witarto et al applied alternating materials layer periodic foundation to the seismic protection of the small modular reactor and conducted a large-scale shake table test, [63] as shown in Figure 8.…”

“…Reproduced with permission. [62] Copyright 2019, John Wiley and Sons Ltd. Reproduced with permission. [63] Copyright 2018, American Institute of Physics.…”

“…In recent years, significant research has introduced the local resonance mechanism in the construction of SMs. [6][7][8]14,[21][22][23][24][25][26][27][30][31][32][33][34][35][36]38,39,41,[47][48][49]55,56,61,62,64] The local resonance bandgap is the result of coupling between the long traveling wave property and the resonance characteristic of the periodic local oscillator in the matrix. The existence of coupling is the key factor to determine whether the bandgap is generated.…”

“…[21,22] Yan et al, Casablanca et al, La Salandra et al, and Shi and Huang used classical three-component local resonance metamaterials as periodic isolation foundations to attenuate seismic waves in the bandgaps. [55,56,61,62,64] Du et al also studied a three-component resonance structure and pointed out that the scatterer can be regarded as an oscillating rigid body and the connector as a spring between adjacent scatterers. [39] Du et al, Zeng et al, and Muhammad et al studied the inhibition of seismic wave propagation by the local resonance of H-shaped, I-shaped, and built-up structural steel pillars with periodic arrangements, respectively.…”

On the Use of Meta-Foundations for Seismic Isolation: A Practical Application for Conventional Buildings

“…The potential advantage of metafoundations against conventional base isolation is in reducing the large displacement demand by reflecting the incoming energy on the interfaces and/or by dissipating energy through local resonance. Since the pioneering works on phononic crystals and metamaterials [7,8,9], a lot of recent interesting studies in the framework of metafoundations have been published [5,6,10,11,12,13,14,15,16]. The crucial challenge is the realisation of a sufficient band gap, targeting the main frequency content of the earthquake excitation and the characteristic frequencies of the isolated structure (normally between 0.5-10 Hz), while maintaining the dimensions of the foundation in a realistic range.…”