Slider bearing for seismic isolation using material combination
Abraham, Nijo Alexander
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Seismic isolation is one of the earthquake protective technologies used for buildings, bridges and other structures as well as non-structural components. Among the seismic isolation technologies, the newly developed roller bearing system ensures constant and low acceleration of superstructure and regulates bearing displacement. However, due to the limited contact area, to withstand large vertical force, the size of rollers must be large. To overcome this problem, a special slider will be used in this thesis to replace the roller. This slider bearing will have the identical dynamic behavior as the roller bearing and will support considerably large weight. The sliding surface is combined with two different materials with different friction coefficient, so that the slider bearing can provide a desirable friction coefficient to dissipate seismic energy while minimizing bearing displacement. This thesis comprises both computational and experimental studies to examine the mechanical performance, along with an experimental study to analyze the uni-directional thermo-mechanical performance of this slider bearing system. The experiments are performed using a shaker table in the Structural Engineering and Earthquake Simulation Laboratory (SEESL), University at Buffalo. Four slider bearings are used to support a concrete mass as a superstructure on the table. Selected earthquake records are used as ground excitations. Accelerations of the table and superstructure were measured along with relative displacements between the table and superstructure. Both the theoretical and experimental studies presented here show great potential of this slider bearing system. The dynamic performance of this seismic isolation slider bearing is virtually identical to the roller bearing, ensuring low level of accelerations and minimum relative displacement. Moreover the slider itself can support more vertical loads with limited working areas.