Abstract. The seismic vulnerability of some frame structures, typical of existing Reinforced Concretebuildings designed only to vertical loads, has been evaluated. They are representative of building
buildings designed only to vertical loads, has been evaluated. They are representative of building
types widely present in the Italian building stock of the last 30 years. A simulated design of the
structures has been made with reference to the codes in force, the available handbooks and the
current practice at the time of construction. The seismic response is calculated through non linear
dynamic analyses with artificial and natural accelerograms. Three main types have been examined:
bare frames, regularly infilled frames and pilotis frames. The results show a high vulnerability for the
pilotis buildings: they can be assigned to the class B of the European Macroseismic Scale of 1998
(EMS98). On the contrary, a low vulnerability (class D of EMS98) can be attributed to the regularly
infilled buildings: in this case collapse can be considered unlikely also with strong earthquakes.
An intermediate seismic behavior is shown by buildings without infills, whose vulnerability can be
placed between the classes B and C of EMS98
