Simplified methodologies for seismic vulnerability assessment of building stocks are of fundamental importance for the development of earthquake loss models. These models are needed to support the decision process in disaster prevention and emergency management, as far as seismic risk is concerned. In this paper, a simplified method is presented for Reinforced Concrete (RC) buildings, employing a simulated design procedure to evaluate the building structural characteristics based on few data such as number of storeys, global dimensions and type of design, and on the assumption of a Shear Type behaviour to evaluate in closed form the non-linear static response. The presence of infill elements is also taken into account when evaluating the structural response. The approximation in the evaluation of seismic capacity due to a Shear Type assumption is illustrated for a case study structure. Hence, the assessment of the seismic capacity is evaluated within the framework of the N2 method. Fragility curves are obtained by assuming some input parameters as random variables and, finally, the failure probability in given time windows and for given Limit States can be calculated. The steps of the simplified procedure are described, together with some example applications.

A more simplified method is also proposed, requiring an even lower detail level of input data and providing fundamental parameters of building response based on further simplifying hypotheses. In this case, fragility curves are obtained by assuming pre-determined variability values depending on the considered Limit State and the type of building, according to a procedure similar to HAZUS approach.

Results obtained from the two methods are compared with each other, both in terms of capacity and fragility curves, for different example buildings.