Seismic certification of unanchored components: reliability assessment of the ICC-ES AC156 protocol

The paper presents the preliminary results of a study on the seismic certification of unanchored acceleration-sensitive components by means of shake table testing. The application of the ICC-ES AC156 protocol for seismic assessment of unanchored blocks is preliminarily reviewed. Numerical rigid block analysis of several component geometries is performed considering (a) a wide reference set of real records (ATC63), and (b) artificial inputs generated according to the AC156 protocol. The fragility curves of the components are evaluated considering several damage states, and reliable dimensionless intensity measures. The ATC63 results are compared to the AC156 protocol ones checking whether the protocol records are representative of realistically severe earthquake scenarios. The reliability index related to the protocol is assessed according to the first-order reliability method. The real accelerogram results are considered as a capacity measure, and the protocol ones as demand measure. The criticalities of the AC156 protocol are finally evidenced as well as guidelines for a safe application of the protocol are provided.