AN EQUIVALENT NON-UNIFORM INELASTIC BEAM-LIKE MODEL FOR THE SEISMIC VULNERABILITY ASSESSMENT OF BUILDINGS

The study proposes a non-uniform beam-like model able to reproduce the static and dynamic responses of multistorey buildings. The considered equivalent beam is a step-wise shear-torsional beam and allows to model buildings which do not have uniform stiffness distribution along the height and are characterised by unsymmetrical plans, thus having eccentricity between the Mass Centre and the Stiffness Centre. The equivalent beam has been applied for both the evaluation of the elastic and the inelastic behaviour of buildings using different calibrations of the equivalent beam-like model characterised by linear or non-linear constitutive laws. Numerical results of two benchmark buildings show the comparisons with the results provided by beam-like and FEM models and confirm the ability of the proposed model to reproduce both the linear and non-linear responses of multistorey buildings. The inelastic beam-like model has also been adopted for the seismic vulnerability assessment of new and existing buildings and it turned out to be a low computational tool to be effectively used for a reliable construction of fragility curves. It has been highlighted that the obtained results for the beam-like model provide more accurate vulnerability assessments of new and existing buildings with respect to commonly used index-based assessments methods.