Loss of operation or devastating damage to buildings and industrial structures, as well as equipment housed in them, has been observed due to earthquakeinduced vibrations. A common source of operational downtime is due to the performance reduction of vital equipment, which are sensitive to the total transmitted acceleration. A wellknown method of protecting such equipment is seismic isolation of the equipment itself (or a group of equipment), as opposed to the entire structure due to the lower cost of implementation. The first objective of this dissertation is assessing a rolling isolation system (RIS) based on existing design guidelines for telecommunications equipment. A discrepancy is observed between the required response spectrum (RRS) and the one and only accelerogram recommended in the guideline. Several filters are developed to generate synthetic accelerograms that are compatible with the RRS. The generated accelerograms are used for probabilistic assessment of a RIS that is acceptable per the guideline. This assessment reveals large failure probability due to displacement demands in excess of the displacement capacity of the RIS. When the displacement demands on an isolation system are in excess of its capacity, impacts result in spikes in transmitted acceleration. Therefore, the second objective of this dissertation ismore »
A Geometric Approach to Inelastic Collapse
We show how to interpret logarithmic spiral tilings as onedimensional particle systems undergoing inelastic collapse. By deforming the spirals appropriately, we can simulate collisions among particles with distinct or varying coefficients of restitution. Our geometric constructions provide a strikingly simple illustration of a widely studied phenomenon in the
physics of dissipative gases: the collapse of inelastic particles.
 Award ID(s):
 2006125
 Publication Date:
 NSFPAR ID:
 10320712
 Journal Name:
 37th European Workshop on Computational Geometry (EuroCG)
 Sponsoring Org:
 National Science Foundation
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