Seismic vulnerability of non-structural components: from traditional solutions to innovative low-damage systems

Non-structural components are typically not designed for seismic loads, nevertheless their response can significantly affect the building functionality after earthquakes, even for low-intensity events. The poor performance of non-structural elements can result in substantial economic losses and business interruption. Consequently, damage of these components has severe impact in the post-earthquake building recovery in addition to the potential risk to life safety. Recent earthquakes have further highlighted these considerations and a substantial research effort has been dedicated to better understand the seismic behavior and damage states of non-structural elements and develop innovative solutions able to mitigate their risk of damage. In order to facilitate the quantification of damage levels as well as the proposal of practical and efficient low-damage solutions, a state-of-the-art overview on the seismic vulnerability and expected performance of alternative systems, either based on traditional construction practice and on innovative systems, is needed. In this paper, a collection of key characteristics of different non-structural components (facades, partitions, ceilings) in terms of seismic response, mechanisms and fragility curves, developed through laboratory testing, earthquake damage data and/or numerical studies available in literature, is presented. Finally, numerical investigations are performed in order to define and compare the fragility functions of traditional and low-damage solutions. Specifically, Incremental Dynamic Analyses are performed for a multi-storey case-study building with alternative precast concrete cladding configurations. Fragility curves are derived and a quantitative risk assessment is developed to highlight the efficiency and benefits related to the application of innovative low-damage technologies.