Seismic vulnerability of existing precast buildings with frictional beam-to-column connections, including treatment of epistemic uncertainty

Italian reinforced concrete precast industrial buildings featuring frictional beam-to-column connections suffered from severe losses following recent earthquakes. Despite the relevance of this topic, the current literature includes only few works investigating the seismic behaviour of these buildings, the influence of vertical records on their modelled dynamic response, as well as the sensitivity of their seismic fragility to the friction type implemented in-situ. The above considerations imparted momentum to this research. First, a sensitivity analysis was conducted considering both concrete-to-concrete and neoprene-to-concrete friction types, as well as the presence or absence of vertical records in the vulnerability analyses. Within a multiple-stripe analysis framework, a number of nonlinear dynamic analyses were carried out on two precast building models created in OpenSees and assumed to be located in three Italian cities subjected to different hazard levels. Fragility curves related to the limit states of Serviceability Preventing Damage and Life Safety were derived. Then, epistemic uncertainty in the friction type and the influence of vertical records on the fragility curve was treated by employing a logic tree framework, allowing for the derivation of weighted average fragility curves, one per city. While the latter are structure-specific and site-dependent, they may be considered as generic or typological fragility curves, for use by researchers or practitioners who are interested in carrying out a fragility analysis on a reinforced concrete precast industrial building but are not confident on the friction type implemented in-situ and the influence of vertical records for the site and structure at hand.