Mechanical vs empirical models for models in-plane response of infilledframes: Reliability comparison and validation of a new data-driven model

The paper proposes a new quadri-linear empirical force-displacement relationship to model the inelastic response of infill equivalent struts. The definition of the model is based on a data-driven approach rather than a mechanical one, therefore parameters defining the force-displacement curve are analytically evaluable by means of empirical correlations. The latter link the force-displacement parameters regulating the axial response to the geometrical and mechanical features of an infilled frame. The analytical correlations are obtained from an experimental data-set enlarged with data from refined finite element simulations. Blind validation tests of the proposed modelling procedure are carried out against experimental results different from those used to build the data-set. A reliability comparison between mechanics-based models and empirical models is finally presented and discussed.