A Framework to Evaluate the Benefit of Seismic Upgrading

The framework to evaluate the benefit of seismic upgrading of Galanis et al. (2018) is compared to that present in the Swiss seismic code for existing buildings since 2004, updated in 2017. To illustrate the comparison, the example building of Galanis et al. (2018) in Zurich is analyzed following the Swiss code. It is shown that the concept of Degree of Seismic Upgrade is not relevant for practical applications. More generally, the approach of Galanis et al. (2018) would be more suited to a risk-based framework (like the Swiss code) than to a performancebased framework like the one they followed. For existing buildings, we claim that it is appropriate to define the retrofitting strategy based on the absolute level of risk, whereas targeting the safety level of the design code is rarely cost-efficient.