An Investigation Study of Effective Use of Magnetic Levitation to Control Horizontal Vibrations for Seismic Isolation of the Structures

Base isolation is the energy dissipating device used in the structure, so that the violent earthquake motions will not be transmitted into the structure. A magnetic levitation type seismic isolation device composed of permanent magnets can theoretically remove horizontal vibration completely. In our case we have focused only on levitation system composed of the PM-PM system created using only permanent magnets and investigation is done for the suitable arrangement of magnets for improving levitation force and obtaining stable levitation. In order to clarify the most suitable permanent magnet arrangement in the PM-PM system and best suitable position for application of loading and for levitation force improvement the repulsive force between permanent magnets will be measured at various sections of the PM-PM system. Rate of loading under static design condition using simple permanent magnet arrangements is examined, for varying loading at different positions. We have developed a magnetic levitation type seismic isolation model. Use of ring type rare earth magnets is the primary focus of this work. The model is expected to remove any horizontal vibrations very effectively. The horizontal vibration characteristics depend upon the air gap between the top and bottom layers, the air gap is also closely related to the load weight distribution. We have conducted testing for inhomogeneous load weight distribution causing the different air gap in each loading case.