Reducing earthquake amplitude by optimizing seismic metamaterials created using concrete piles

The destructiveness of earthquakes is an unavoidable reality. Many of the world's accepted risk reduction strategies regarding seismic effects aim to isolate the structure by using devices integrated into the structure instead of preventing seismic waves from reaching the structure. It is important to dampen seismic surface waves in the low frequency range, which can spread over large areas and have a very destructive effect, because these waves can have dangerous consequences if they resonate with the structures to be protected. In this thesis, it is aimed to provide remote seismic isolation of structures by using seismic metamaterials. Seismic metamaterials formed using concrete piles were analyzed in four different mesh structures: square mesh, triangular mesh, circular mesh and sinusoidal mesh. Analyzes were carried out both numerically and experimentally. Numerical analysis was carried out with the Finite Element Method (FEM) based simulation program. The data obtained as a result of the soil tests were used in the numerical analysis. First of all, unit cell structures were analyzed for each lattice structure and band diagram was drawn, and then studies were carried out in both frequency and time domains. Experimental analysis was carried out on a one-to-one scale using optimum dimensions obtained by numerical analysis. Surface waves were created with the harmonic vibration device placed in the experimental area and these waves were applied to the fields. After the measurements of the areas where seismic metamaterials were not applied were recorded with accelerometers, field measurements were carried out again by applying concrete piles to the fields in each mesh structure. These data obtained in the time domain have been converted to the frequency domain and their seismic mapping has been made. The areas where seismic metamaterial is not applied and applied are compared with each other and displacement rates of seismic surface waves are obtained. Numerical studies have been confirmed by experimental studies. As a result of numerical and experimental studies, it has been seen that there are transmission losses for each lattice structure, the total displacements of seismic surface waves are reduced, and as a result of torsion, seismic surface waves can be damped in the low frequency range.