Investigation of seismic behaviour of reinforced concrete structures insulated with seismic meta-materials in earthquake engineering

Located on multiple active fault lines, Turkey frequently experiences devastating earthquakes. In recent years, seismic metamaterials have emerged as an innovative isolation technique in earthquake engineering due to their ability to create band gaps that prevent the propagation of seismic waves within specific frequency ranges. Periodic foundations composed of such materials can reduce structural responses by dissipating in seismic energy before it reaches the structure. This study experimentally investigated the damping performance of metamaterial-based periodic foundations. A uniaxial shaking table capable of horizontal motion along the x-axis, driven by a 0.75 kW servo motor, was used as a vibration source. The motor's motion was simulated through Arduino IDE programming. Servo motor control signals with step counts of 5000, 4000, and 3000 representing three different vibration frequency profiles were applied to three test specimens for 20.667 seconds. Accelerometers placed on the top layer of each specimen recorded acceleration responses at 80-millisecond intervals. The recorded data were analyzed in the time domain (acceleration-time) and the frequency domain (via Fast Fourier Transform). The test specimens consisted of: (i) a conventional foundation made of reinforced concrete plates, (ii) a one-dimensional periodic foundation composed of rubber and concrete plates, and (iii) a one-dimensional periodic foundation embedded with piezoelectric sensors. All specimens were scaled to represent soil- layer bonded using a polyurethane-based adhesive. Experimental results revealed that periodic foundations were more effective in suppressing vibration energy than conventional ones. Furthermore, the piezoelectric sensor-integrated foundations exhibited vibration-induced energy harvesting potential, offering multifunctional benefits for structural applications in seismic environments.