Seismic risk assessment of an old RC frame-wall building in Lisbon

This study investigates the structural vulnerability of an old reinforced concrete dual wall-frame building structure, in Lisbon, Portugal. The building presents non-ductile behaviour and detailing typical of buildings designed before the introduction of modern seismic codes (pre– 1980). An analytical methodology is adopted in which multiple stripe analysis are performed on a three- dimensional model of the building. Fragility and vulnerability functions are developed for this structure, representative of a typology of old RC buildings. The fragility is derived taking into account the brittle shear failures of RC vertical members, i.e. columns and shear walls. The nonlinear dynamic analyses clearly indicate that these failure modes have a critical influence on the seismic performance of the structure. The results of this study can be used for seismic loss assessment and for the identification of appropriate mitigation strategies for this typology of existing RC buildings.