Masonry Constitutive Model Selection based on Best-Fit Moment-Curvature Diagrams

Macroscopic constitutive models are typically used to simulate mechanical behaviour of masonry as equivalent homogeneous material. A significant number of empirical constitutive models is available in the literature for masonry in compression. Nonetheless, a comprehensive analysis of the effects of such models on theoretical mechanical models for unreinforced masonry (URM) cross sections and walls still needs to be carried out. In this paper, the findings of nonlinear moment-curvature analysis for rectangular URM cross sections are presented, exploring the influence of different macroscopic constitutive models. Uniaxial stress-strain models with different features in terms of mechanical behaviour were selected from the literature and considered in the analysis. Based on numerical integration of sectional equations, moment-curvature diagrams were derived to simulate nonlinear behaviour under eccentric compression. Moment-curvature response was assessed by keeping constant the load eccentricity level in order to compare theoretical results with experimental data provided by past eccentric compression tests. Theoretical-experimental comparisons were performed either by considering the whole data set or by disaggregating data in terms of masonry type. The output of this study is the identification of the constitutive models that allow the best simulation of the experimental moment-curvature behaviour