DYNAMIC CHARACTERIZATION OF POLYURETHANE GEL FOR GEOTECHNICAL SEISMIC ISOLATION APPLICATIONS

This study presents the dynamic characterization of a polyurethane gel intended for use as a material in geotechnical seismic isolation systems. Resonant column and cyclic torsional shear tests were conducted to evaluate the material properties, including shear modulus and damping ratio, over a wide range of shear strain levels. The polyurethane gel used in this study demonstrated promising characteristics, with a very low shear modulus of approximately 300 kPa and a less pronounced decrease in shear modulus compared to soils. It also exhibited a very high damping ratio, even at low shear strain levels, which is advantageous for dissipating seismic energy. The tests indicated that the gel's mechanical response is not particularly dependent on shear strain and is almost unaffected by confinement pressure, while showing significant energy dissipation over a wide range of strain levels, making it a promising candidate for seismic isolation. The gel's unique viscoelastic behavior suggests it could effectively reduce seismic loads transmitted to overlying structures. This dynamic characterization provides a fundamental understanding of the material's suitability for mitigating earthquake-induced vibrations in geotechnical applications, contributing to safer and more resilient infrastructure designs.