###### Abstract  
The paper compares several simplified methods proposed in the literature for assessing the seismic vulnerability of existing buildings. Type and number of input and output data, limitations of use for different structural typologies, and complexity of use are examined for each methodology to identify the most suitable for assessing the vulnerability of a given class of buildings, based on the available data, the computational effort, and the type of vulnerability judgment. The selected methods were applied to a sample of school buildings located in the province of Naples (Italy). Data were available due to a digital platform and were used to verify the possibility of providing reliable large scale vulnerability judgments based on a reduced set of information, without carrying out additional surveys. The most simplified methods were applied to a sample of about a thousand of buildings, while more detailed methods, needing more information, were applied to a smaller sample. The comparison between the results obtained from different methods allows highlighting advantages and weaknesses of each, so as to identify the convenience in their use according to the specific available information and the objectives of the analysis, finally to evaluate which is more or less safe. seismic vulnerability; territorial seismic risk; approximate methods +
Footnote †: journal: Applied  
seismic vulnerability of buildings are often adopted in the literature in order to provide vulnerability judgments with different levels of detail and reliability [5; 6; 7; 8; 9; 10; 11; 12; 13; 14; 15; 16; 17; 18]. Most simplified analyses are generally carried out for classes of homogeneous buildings, especially in the case of a 'large-scale' vulnerability assessment: the seismic vulnerability is, indeed, evaluated starting from a limited number of geometric and physical-mechanical parameters, which are supposed to be a low variable within the buildings of the same class. The quantification of the seismic vulnerability of buildings has been a topic of study for over thirty years, during which the problem was examined with different approaches and approximation levels. The methodologies available in the literature for assessing the seismic vulnerability of buildings can be synthetically grouped into mechanical and macroseismic ones. The mechanical approaches are usually based on the capacity spectrum method, which provides a 'capacity curve' for the building through a nonlinear static pushover analysis aimed to represent the relationship between the lateral load resistance and the displacement of a control point of the examined building. The capacity curve is then converted in terms of spectral acceleration in order to compare it with the demand spectrum, obtain the performance point in terms of displacement, and carry out the verification according to the chosen design limit state. When such a procedure is applied to a single building, an accurate level of knowledge is needed so as to achieve reliable results from the nonlinear analyses. However, the mechanical methods have evolved also to be able to evaluate the vulnerability of whole classes of buildings, although by means of simplified approaches for obtaining the capacity curves [10; 12; 19; 20]. HAZUS [19] is a methodology developed specifically for U.S. buildings, which refer to 36 typological classes: for each class of buildings the parameters for defining the capacity curves in a simplified way are provided. The LM2 approach proposed by the RiskUE methodology [14; 20] is substantially based on the same capacity spectrum-based procedure adopted by the HAZUS method, since for each building class, the capacity curve of an equivalent single-degree-of-freedom (SDOF) system is defined in a simplified way by the means of four parameters corresponding to two typical control points of the capacity spectrum (i.e., yield and ultimate capacity in terms of spectral displacement and acceleration) or of the capacity curve expressed in terms of base shear and roof displacement [12; 14; 20].