Towards a Database of Fragility Functions for Retrofitted RC Buildings for regional analysis

According to the recently released European exposure model, the majority of the reinforced concrete structures were designed while code regulations with insufficient seismic provisions were in force. This generates the need for risk mitigation actions applied to this vulnerable building stock. Seismic Retrofitting is an efficient risk mitigation strategy for RC structures, fast growing in the past decades in the area of Europe. This study aims at investigating the characteristics of European reinforced concrete structures built without modern seismic provisions and developing fragility function for two retrofitting methods. The retrofitting methods of interest are the Reinforce Concrete Jacketing and FRP Jacketing due to their large applicability and feasibility in the hazardous sites of Europe. Adopting the Seismic Vulnerability Assessment Framework 2022 developed by SERA, a 3D numerical modelling and design procedure is followed for the assessment of a series of realizations that represent diverse possible building scenarios within a specific building class. The retrofit design is being optimized using risk objectives, and specifically using the Average Annual Probability of Collapse being equal for multihazardous sites of Europe. These numerical models are used to derive sets of fragility functions, using the open source framework VMTK (Vulnerability Modeler Toolkit). These functions will be incorporated within the European vulnerability database, thus enabling the wider scientific community to perform large-scale seismic risk analyses, and consequently to explore the benefits of structural retrofitting.