Performance evaluation of a novel low-cost seismic isolation system based on shicras through hybrid simulation

Large-scale shaking table tests provide the most accurate description of a structure’s response under seismic excitation. However, the high costs associated with such campaigns in terms of financial resources, manpower, and time often exceed available constraints. Hybrid simulation where structure is divided into numerical and physical substructures has emerged as an effective and increasingly popular alternative to full-scale shaking table tests, offering significant reductions in cost and complexity. This study investigates the seismic performance of a novel low-cost isolation system inspired by the ancient technology of the Incas in the Andes using hybrid simulation. The Andean region, one of the most seismically active areas in the world, has experienced devastating earthquakes throughout history. Archaeological evidence reveals the significance of shicras (stones encased in fiber bags) in reducing seismic demands. Traditionally used in foundations, shicras have been proposed to act as a natural seismic isolation layer. In this study, the isolation layer composed of shicras of varying sizes, each representing a basket filled with stones, is adopted as the physical substructure, while the superstructure is modeled numerically in OpenSEES. The University of Toronto Hybrid Simulation Framework is employed to conduct hybrid simulation. Through the simulation, the energy dissipation mechanisms and performance of shicras as a base isolation system are examined. The results highlight the rocking and rolling behavior of this ancient isolation system as a key factor in reducing the dynamic response. The findings confirm the effectiveness of shicras under different loading conditions and demonstrate that this ancient concept can be adapted for modern applications to mitigate earthquake impacts cost-effectively. By reviving and optimizing this technology, developing communities can achieve affordable and resilient infrastructure in earthquake-prone regions.