Energy-Based Analysis of a Seismically Isolated Structure Considering Simple Soil Effects

An energy-based formulation for vibration mitigation of structures by implementing seismic isolation and considering soil effects is presented in this paper. The utility of the formulation is analyzed for a shear building structure under the effect of earthquake motion by considering the soil-structure interaction. Seismic energy-based comparisons are made between soil-structure interaction and fixed-base cases. Ten sets of earthquakes, including the very devastating and recent Kahramanmaras, Turkey, earthquake in 2023, are used in the seismic performance analysis. Total seismic energy, damping energy, strain energy and kinetic energy distributions of the structure are presented by taking into account the soil effects. The usage of the seismic isolation considering soil-structure interaction is discussed not only by considering energy perspectives but also by the response reduction performance of the seismically isolated building. The energy-based (Formula presented) can be applied to all different types of building structures independent from the number of degrees of freedom in each story such as three-dimensional tier buildings. Numerical simulations under a significant number of earthquakes showed that the energy-based formula considering soil effects does not yield to any stability problems or numerical anomalies. Moreover considering soil effects significantly increases both structural responses and energies. In addition implementation of seismic isolation decreases structural energies and displacements simultaneously.