Performance of geotechnical seismic isolation system using rubber‐soil mixtures in centrifuge testing

Abstract

Geotechnical seismic isolation (GSI) system involves the dynamic interaction between structure and low‐modulus foundation material, such as rubber‐soil mixtures (RSM). Whilst numerical studies have been carried out to demonstrate the potential benefits of GSI‐RSM system, experimental research is indispensable for confirming its isolation mechanism and effectiveness in reducing structural demand. In this regard, centrifuge modelling with an earthquake shaker under an acceleration field of 50 g adopted in this study can mimic the actual nonlinear dynamic response characteristics of RSM and subsoil in a coupled soil‐foundation‐structure system. This is the first time the performance of GSI‐RSM system was examined in a geotechnical centrifuge. It was found that an average of 40‐50% reduction of structural demand can be achieved. The increase in both the horizontal and rotation responses of the foundation was also evidenced. The unique augmented rocking mechanism with reversible foundation rotation was highlighted.

Large‐scale field testing of geotechnical seismic isolation of structures using gravel‐rubber mixtures

“…A similar average decrease was also seen for the same rubber proportion in SRM layers studied as GSI in previous numerical and experimental reports. 38,43 At an operating frequency 9 Hz during this test and at 8 Hz in Experiment 4 (not shown here), we noticed an abrupt and unexpected amplification in the motion for the GRM70/30. The source seems to be related to a sharp increase in the movement's vertical and rocking components.…”

“…Furthermore, another shaking table experimental series highlighted the beneficial effects of the SRM in the vibration isolation of structures 27 . The first centrifuge test on a model structure founded on SRM pronounced increased seismic energy dissipation through sliding and rocking and a resulting structural demand reduction 43 . Relatively fewer field tests concerning the seismic isolation capability of the SRM‐filled sleeve piles and trench barriers have been reported 44 …”

Seismic fragility assessment of geotechnical seismic isolation (GSI) for bridge configuration

“…The study results were presented in terms of the acceleration change due to the use of the GSI. Tsang et al (2021) performed centrifuge studies to examine the efficiency of the GSI system for the case of a building subjected to seismic effect. The case of a building subjected to earthquake effect and resting on GSI with a thickness of 2.0 m was modelled in the centrifuge experiments.…”

Fragility Assessment of Geotechnical Seismic Isolated (GSI) Configurations

“…Tsiavos et al [10] performed direct shear tests and small-scale 1 g shaking table tests. Tsang et al [11] conducted centrifuge tests, while Kaneko et al [12] proposed hybrid simulations. Another typology of verifications consists of numerical simulations, such as in [13][14][15][16][17].…”