Analytical design models for geotechnical seismic isolation systems

Abstract

Geotechnical Seismic Isolation (GSI) can be defined as a new category of seismic isolation techniques that involve the dynamic interaction between the structural system and geo-materials. Whilst the mechanism of various GSI systems and their performance have already been demonstrated through different research methods, there is a missing link between fundamental research and engineering practice. This paper aims to initiate the development in this direction. A new suite of equivalent-linear foundation stiffness and damping models under the same framework is proposed for four GSI configurations, one of which is a novel combination of two existing ones. The exact solutions for the equivalent dynamic properties of flexible-base systems have also been derived that explicitly include the foundation inertia and the strain-dependent equivalent damping of foundation materials, which are both significant for GSI systems. The application of the proposed analytical design models has been illustrated through response history analyses and a detailed hand-calculation design procedure has also been outlined and demonstrated.

Experimental study on sand-tire chip mixture foundations acting as a soil liquefaction countermeasure

“…The research conducted on the area of seismic isolation, has shown that the inclusion of rubber underneath a structure can work efficiently to protect structures against earthquakes, mainly through activating some efficient detuning-type mechanism. This is an outcome from numerical and analytical results (Tsang et al 2008(Tsang et al , 2009(Tsang et al , 2012(Tsang et al , 2019(Tsang et al , 2022Xu et al 2009;Pitilakis et al 2015;Brunet et al 2016). The results from numerical studies are backed up by physical testing, including shaking table tests (Xiong et al 2011;Xiong and Li 2013;Kaneko et al 2013;Nikitas et al 2014Nikitas et al , 2016Bandyopadhyay et al 2015;Tsiavos et al 2019;Yin et al 2022) and centrifuge tests (Tsang et al 2021).…”

Preface for the special issue on geotechnical seismic isolation (GSI)

“…Dynamic soil-foundation-structure interaction and its favourable effects can be facilitated in a controlled manner by modifying the foundation soils to lengthen the natural period of the system and dissipate seismic wave energy without causing undesirable permanent ground deformations. Half of the articles in this special issue focus on GSI systems that are based on this mechanism (Aloisio et al 2022;Bernal-Sanchez et al 2023;Chiaro et al 2022;Dhanya et al 2023;Edinçliler and Yildiz 2023;Tsang 2022;Vratsikidis and Pitilakis 2022). 2.…”

“…Amongst these, rubber-soil mixtures have been the most researched materials (Bernal-Sanchez et al 2023;Chiaro et al 2022;Dhanya et al 2023; Forcellini and Alzabeebee 2022; Nikitas and Bhattacharya 2023; Vratsikidis and Pitilakis 2022), whilst there is a case study with the use of whole waste tyres (Hazarika et al 2023). Meanwhile, other materials have also been investigated, including EPS beads (Edinçliler and Yildiz 2023), geosynthetics (Banović et al 2022;Dhanya et al 2023), stone pebbles (Banović et al 2022), sand, timber and PVC (Tsiavos et al 2022), polyurethane (Gatto et al 2022), super absorbent polymers (SAP) (Somma and Flora 2023), as well as various high-damping (Aloisio et al 2022) and low-modulus materials (Tsang 2022).…”

“…On the other hand, investigation of GSI involves utilising a wide range of research tools and skills. This includes analytical and numerical modelling of soil-foundation-structure systems (Aloisio et al 2022;Chiaro et al 2022;Forcellini and Alzabeebee 2022;Gatto et al 2022;Hazarika et al 2023;Somma and Flora 2023;Tsang 2022). Laboratory testing of material samples has also been carried out (Dhanya et al 2023;Gatto et al 2022;Hazarika et al 2023;Nikitas and Bhattacharya 2023;Somma and Flora 2023), along with characterising geomaterials at the particle scale (Bernal-Sanchez et al 2023).…”

“…Shaking table testing (Banović et al 2022;Dhanya et al 2023;Edinçliler and Yildiz 2023;Nikitas and Bhattacharya 2023;Tsiavos et al 2022) and field measurements (Hazarika et al 2023;Vratsikidis and Pitilakis 2022) have been conducted as well. In addition, practical design models and parameters have been proposed for designing GSI systems (Aloisio et al 2022;Somma and Flora 2023;Tsang 2022).…”