SEISMIC PERFORMANCE OF SUSPENDED PIPING RESTRAINT INSTALLATIONS

The damage observed during past earthquakes repeatedly showed the vulnerability of non-structural elements and their importance in the functionality of critical facilities, such as hospitals. Performance-based seismic design (PBSD) implies the harmonization of performances between structural and non-structural elements. To this aim, performance parameters for non-structural elements need to be evaluated through experimental and numerical studies. Among the multitude of non-structural typologies, the seismic performance of piping systems is of paramount importance in order to guarantee the immediate post-event functionality of critical facilities. Few research studies available in the literature have attempted to evaluate the performance parameters required to enable PBSD of piping systems and more specifically of suspended piping restraint installations. This paper summarizes the results of an experimental and numerical research project dealing with the evaluation of the seismic behaviour of suspended piping restraint installations. Four typologies of suspended trapeze piping restraint subassemblies with channel and rod bracing systems were tested under monotonic and cyclic loading to determine their hysteretic responses and failure modes. The results of the subassembly tests were used to calibrate simplified nonlinear numerical models useful to assess the seismic response of full-scale suspended piping layouts subjected to floor acceleration time-histories.