This dissertation presents a probabilistic fragility assessment for piping systems to mitigate the seismic hazards. The percentage of construction cost for nonstructural components such as mechanical and electrical equipments, medical equipments, and piping systems is over 80% of the total cost in critical facilities. This research is conducted under the NEES Grand Challenge Project "Simulation of the Seismic Performance of Nonstructural Systems". It focuses on characterizing the seismic performance of threaded Tee-joints in actual piping system and incorporating the experimentally observed behavior in a system level piping analysis with the purpose of evaluating piping fragilities. A key step in this process is analyze the experimentally observed moment-rotation relationship of threaded Tee-joints and use it to characterize the appropriate limit-state. A nonlinear finite element model for the threaded Tee-joint, validated against the experimental results, is then incorporated in the complete piping system model in order to facilitate system level piping analysis and fragility assessment. More specifically, the research presented in this dissertation focuses on evaluating fragility for the limit-state characterized to represent "First-Leakage" failure at the threaded Tee-joint. Finally, the effect of building performance on the piping fragility is also evaluated by considering a high rise 20-story and a low rise 5-story building. Differences in piping fragility are evaluated for piping located in buildings that remain linear as well as that exhibit significant nonlinear behavior. Variation in fragility due to location of piping at different floor levels is also explored.
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