Vulnerability assessment at large scale requires referring to reliable models which are able to establish a
correlation between hazard and structural damage. Among the different approaches proposed in literature, the
attention is focused on mechanical models based on the displacement-based approach, which describe the
inelastic response of buildings by capacity curves able to provide essential information in terms of stiffness,
overall strength and ultimate displacement capacity. In the paper an extensive sensitivity analysis is carried out
by considering the various expressions proposed in literature for these entities (in order to define the more
reliable ones) and by evaluating how each parameter (e.g. strength and ductility of materials, structural element
dimensions, interstorey heigt, ...), which mechanical models may be founded on, affect the structural response (in
terms of main parameters which define the capacity curve). Particular attention is paid to the model adopted in
Lagomarsino et al. (2010) by proposing some improvements as pointed out from the sensitivity analyses results
