Urban-scale risk assessment: Does it change if we include SSI and site effects?
Seismic risk assessment is still performed at an urban scale, assuming all structures and the man-made environment are fixed on the soil. Intuitively, one could argue that this is the case if only the ground is rock hard. To tackle this shortcoming, in an ongoing effort, we developed, applied, and tested a new framework to include soil-foundation-structure interaction (SSI) and site effects in the vulnerability assessment of structures at an urban scale. We argue that soil-structure interaction and, especially, local site-effects, should not be neglected in urban-scale risk assessment. Our framework uses state-of-the art open-source software (like OpenSees, OpenQuake, and Q-GIS), bound together using Python. Our results reveal the soil-related effects on the vulnerability of buildings. We apply our framework to the city of Thessaloniki in Greece, and we highlight the differences from the typical vulnerability assessment of fixed-base structures because of SSI and site effects