Structural robustness has emerged as a fundamental property in the design of structures in modern days, reflecting the need for system-level design approach against unforeseen and accidental actions. In fact, traditional design approaches based on member-level checks, mainly for strength and stability, have proven to be not sufficient in some occurrences, in particular in case of local damages. Despite its recognized importance, structural engineers and the research world around it are still struggling in assessing robustness in a quantitative way. This thesis aims thus to try filling that gap, by calibrating and developing a new quantitative metric based on connectivity for assessing robustness of frame structures, starting from the Resilience Index proposed by Chiaia et Al.