Enhancing seismic resilience of precast RC structures with BRFD technology: A case study from Northern Italy

Precast reinforced concrete (RC) structures have been widely used in Italy over the past seventy years, particularly for industrial and commercial buildings. Many of these buildings exhibit vulnerabilities such as weak element connections, low shear strength, and limited column ductility. Originally, most were designed only for gravity loads, as earlier regulations did not require consideration of seismic actions. Recent earthquakes, notably the 2012 Emilia events, exposed the high seismic vulnerability of these structures, causing fatalities, injuries, and major socio-economic disruptions. A primary collapse mechanism involves beams resting on frictional bearings without mechanical restraints, where near-fault vertical ground motions can compromise horizontal resistance. Therefore, effective retrofitting is essential not only for human safety but also to protect assets and enhance community resilience. This application introduces the Bidirectional Rotation Friction Damper (BRFD) as an innovative and sustainable retrofit solution for precast RC structures. Its application is demonstrated on a real industrial warehouse in Forlì, Italy, designed to store 14-meter-high vats. BRFDs improve seismic performance by providing additional damping and limiting displacements. The paper details the simple measures used during the on-site installation process. The effectiveness of BRFDs was evaluated through Nonlinear Time History Analyses (NLTHA), focusing on near-fault seismic effects. Results show the retrofit significantly enhances the building’s seismic behaviour, preventing structural damage while remaining cost-effective. Compared to conventional techniques, BRFDs offer clear advantages: their bidirectional action reduces the number of devices and steel connections needed, and importantly, avoids foundation retrofitting. This yields considerable economic savings and supports sustainable seismic upgrading of vulnerable precast RC buildings. In conclusion, BRFDs provide a practical, efficient, and sustainable solution to improve the seismic resilience of existing precast RC structures, addressing both safety and economic concerns while minimizing intrusive interventions.