Risk-based evaluation of economic feasibility for strengthening of low-code RC structures

In this study, the economic feasibility of strengthening several types of low-code RC structures in Bucharest is analyzed. Using recently compiled information regarding the characteristics of the residential building stock of Bucharest built in the period 1963-1977, an updated seismic risk assessment is performed. Moreover, analytical fragility functions are obtained for each structural system by employing the same approach that relies on the pushover curve. Subsequently, a logic-tree approach involving previously derived fragility functions is employed for seismic risk computations. Three economic loss models and two casualty loss models were implemented in the risk assessment procedure. The smallest mean annual loss is obtained for the medium-rise large panels structures that had very good behavior during the Vrancea 1977 earthquake. The analysis of the economic feasibility of strengthening shows that the RC soft-story structures appear as the most feasible to be strengthened because the range of costs of the strengthening works is the largest in this case. Correspondingly, the RC dual structures appear as the least feasible for strengthening works among the considered structural systems.