Geotechnical Seismic Isolation Method Using Rubber-Soil Mixtures

Abstract

Seismic isolation is a method of protecting buildings from earthquake-induced deformations by using isolators and devices under the superstructure. The purpose of the seismic isolation method is to reduce the earthquake forces transferred from the ground to the structure by placing energy-absorbing elements between the foundation and superstructure. Especially in developing countries, the "Geotechnical Seismic Isolation (GSI)" system has been proposed as an isolation method to reduce earthquake-induced damages on buildings. This study, it is aimed to reduce the effects of earthquakes in a multi-story building with an isolation layer formed by a rubbersand mixture (RSM). For this purpose, a 10-story reinforced concrete building was numerically modeled. Beneath the foundation of the building model, a seismic energy absorbent RSM layer was placed and its contact with the natural soil was interrupted by using geosynthetic liners. The model was subjected to the 1992 Erzincan (EW) Earthquake motion and its performance has been evaluated in terms of lateral displacements and accelerations. The numerical studies indicated a substantial improvement due to the use of the RSM layer. The accelerations measured by the superstructure decreased up to 48% by employing the isolation layer. The numerical analysis was carried out using the dynamic module of the PLAXIS 2D finite element analysis program.