Fernando Fraternali

This work illustrates a novel two-layer version of the sliding–stretching isolator recently proposed in the literature to protect buildings and infrastructure from seismic waves. Such a device has a biomimetic character and is formed by rigid members mimicking the role played by human arms and legs when walking or running, and deformable membranes referred to as tendons. It tunes the elongation and contraction of the tendons to recenter the system and to safely avoid resonance of the system with earthquake frequencies. The paper illustrates how is possible to generalize the mechanical model of the one-layer isolator (SSI1) formulated in previous studies to account for the presence of the second layer (SSI2 system). The two-layer device doubles the lateral displacement capacity of the system, while keeping the footprint of the device fixed. Shake-table tests on reduced-scaled SSI2 prototypes are employed to derive the constitutive parameters of the proposed mechanical model and to experimentally validate it. The given results demonstrate that SSI2 systems pave the way to real-life applications of sliding–stretching isolators in multistory buildings.