A probabilistic strong floor motion duration model for seismic performance assessment of non-structural building elements

Non-structural elements (NSEs) are not designed to be part of the structural load-bearing system of a building but are subjected to the same dynamic environment as the supporting structure during an earthquake. Non-structural damage and ensuing losses have exceeded structural damage and losses in many buildings during recent earthquakes that have occurred in urban regions around the world. Damage to NSEs is strongly influenced by the amplitude, the frequency content and the duration of floor motions. Although the effects of amplitude and frequency content of floor motions are well captured by floor response spectra, little attention has been given on the characterisation of floor motion duration and how it can impact damage to NSEs, particularly for those responding in the inelastic range. To contribute to a better understanding of these issues, this paper develops a probabilistic strong floor motion duration model through multiple stripes non-linear time-history analyses of a population of 100 code-compliant reinforced concrete frame building models designed for a medium-to-high seismicity site in Italy. The resulting probabilistic model can be used when selecting historical or generating synthetic floor motions for the seismic response assessment of NSEs or when generating shake-table test records for the seismic qualification of NSEs.