INVESTIGATION OF SEISMIC BEHAVIOR OF REINFORCED CONCRETE STRUCTURES INSULATED WITH SEISMIC META-MATERIALS IN EARTHQUAKE ENGINEERING

Turkey is located in an active seismic zone surrounded by fault lines and frequently experiences destructive earthquakes. In recent years, seismic meta-materials have emerged as an innovative isolation technique in earthquake engineering due to their ability to create frequency band gaps that block the propagation of seismic waves. In this study, the damping performance of periodic foundations incorporating meta-materials was experimentally investigated. A shaking table driven by a 0.75 kW servo motor capable of 7.5 cm horizontal displacement was used as the vibration source. The motion was controlled using Arduino IDE software. Three vibration profiles with step counts of 3000, 4000, and 5000 were applied to the test specimens, each for a duration of 20.667 seconds. Three types of foundations were tested: (i) a conventional foundation made of reinforced concrete plates, (ii) a onedimensional periodic foundation composed of alternating rubber and concrete plates, and (iii) a piezoelectric sensor-integrated periodic foundation. Accelerometers placed on the upper surfaces of the specimens recorded acceleration data at 80-millisecond intervals. The recorded data were analyzed in both time (acceleration-time) and frequency (via Fourier Transform) domains. Experimental results revealed that the periodic foundations containing metamaterials significantly reduced vibration energy compared to the conventional system. Moreover, the piezo-supported system produced an electrical output of up to 1.64 V during vibration, indicating energy harvesting capability. These findings suggest that such systems can serve as multifunctional seismic isolation solutions and provide enhanced performance, particularly under low-frequency ground motions.