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MULTI-level framework to enhance seismic RESilience of RC buildings

Periodic Reporting for period 1 - MULTIRES (MULTI-level framework to enhance seismic RESilience of RC buildings)

Reporting period: 2019-11-01 to 2021-10-31

Among all natural hazards, earthquakes lead to the highest number of fatalities and, after severe storms, cause the second highest annual economic losses. This is not only true worldwide, but also for Europe. Although there is increasing earthquake risk awareness among the public and policy-makers in many European countries, there is a dire need to develop holistic strategies for mitigating and managing seismic risk. Among European construction types built from 1960s onwards, RC buildings represent the highest share for both residential and commercial occupancy.
A seismic-resilient community is one which is leading comprehensive efforts towards mitigation and pre-disaster preparedness to recover quickly after major earthquakes. Common metrics related to seismic resilience refer to earthquake consequences on the built environment in terms of casualties/injuries, direct economic losses due to repairs/reconstruction, and indirect losses due to downtime related to the lost functionality (the so-called three Ds: Deaths, Dollars, Downtime).
Seismic resilience can be increased, for instance, by implementing structural retrofit strategies that reduce seismic vulnerability/expected damage to buildings (‘hard’ solutions) or, for instance, by transferring the risk to the (re)insurance market (‘soft’ solutions). This requires assessing the site-specific earthquake-induced ground shaking (seismic hazard), quantifying building response, estimating earthquake consequences (loss), designing and comparing different resilience-enhancing strategies.
The ambitious main objective of MULTIRES is the development of a multi-level, harmonised, innovative, seismic risk assessment framework for existing RC buildings (individual or portfolios) and the design, selection and implementation of practice-oriented, cost-effective, resilience-enhancing solutions.
The proposal combined analytical and numerical work, together with probability/statistics and software development, to deal with mathematical, behavioural, and societal aspects of risk and uncertainty. The project focused on several areas of structural and earthquake engineering such as: probabilistic seismic hazard analysis, seismic design/assessment/retrofit of RC structures, simplified to highly-refined numerical structural analyses, seismic loss assessment. Moreover, the field of multi-criteria analysis/optimisation is involved, also considering economics models. Thus, the project allowed the integration and combination of different and complementary expertise provided by the Experienced Researcher, the Supervisor, and the Host Institution. The proposed framework produced results that are of interest to researchers/consultants involved in other research areas such as assessment for windstorms, flooding or other extreme natural and man-made hazards, since analogous frameworks for such hazards might be designed in a similar way.

The project resulted in 13 published journal papers (gold/green open access) in leading international journals such as Earthquake Engineering & Structural Dynamics, Computer-Aided Civil and Infrastructure Engineering, Earthquake Spectra, Structural Safety, Engineering Structures, Soil Dynamics and Earthquake Engineering, Bulletin of Earthquake Engineering, and Journal of Structural Engineering. Six more journal papers related to this project are under review or in preparation at the time of end of the action. The project also resulted in ten international conference presentations. Such results overwhelmingly exceed the targets at the time of the proposal writing (three journal papers and three conference presentations). Social media posts have been constantly used to disseminate the results to the public, and give constant updates on the status of the project.

Through research, international collaboration, transfer of knowledge, dissemination, and communication, the Fellowship allowed the Experienced Researcher working towards a scientific and professional maturity, and therefore to an independent research and academic position. Before the end of the action, the Experienced Researcher was offered a full academic position as an assistant professor (lecturer).
The Experienced Researcher investigated and developed a multi-level seismic risk assessment method for buildings, which is capable of combining hard solutions (such as structural retrofit) and soft solutions (such as insurance). Based on a set of alternatives, the optimal solution can be selected based on measurable goals, e.g. cost-effectiveness, lifecycle cost, targeted reduction of risk and/or consequences. This framework can accommodate the trade-off between simplicity of the methods and accuracy of the results, that different stakeholders generally tolerate. Private owners likely need a detailed analysis concerning single buildings or small portfolios of buildings, while government agencies or (re)insurance companies might look at large portfolios requiring a lower refinement level and accepting higher uncertainties.

The application of this methodology directly responds to the societal demand for earthquake resilience and will help households, structural engineers, and government agencies worldwide. This will allow significant reduction of socio-economic losses associated with strong earthquakes.
MULTIRES framework