Design and experimental validation of composite materials with low environmental and energetic impact for seismic upgrading of historic monumental buildings

Masonry structures represent a fundamental component of the architectural heritage in many countries, yet their mechanical behaviour remains complex owing to the heterogeneity of the material and the anisotropy introduced by mortar joints. These characteristics, combined with additional factors, render such constructions particularly vulnerable. The safeguarding and rehabilitation of historic and monumental buildings require a delicate balance between preserving the material and formal authenticity of the asset and achieving adequate levels of structural safety, while also complying with recent energy and environmental principles. Attaining this balance entails a complex interdisciplinary process involving structural, architectural, energy-related, and conservation aspects. Within this framework, the present thesis focuses on the three-dimensional numerical modelling of unreinforced and strengthened masonry structures using both macro- and micro-modelling finite element approaches in Abaqus. Particular attention is devoted to simulating the nonlinear behaviour of masonry through the Concrete Damaged Plasticity (CDP) model. The study includes the analysis of innovative composite materials, such as Fibre-Reinforced Cementitious Matrix (FRCM) systems, with the aim of identifying intervention solutions that are compatible with conservation principles, capable of reducing seismic vulnerability without altering the historic and architectural identity of the building, and potentially integrable into energy-improvement strategies. The numerical models developed herein are validated through comparison with experimental data available in the literature, examining significant case studies such as columns and arches subjected to various loading conditions. The results allow for the assessment of the effectiveness of the different modelling approaches, highlighting their advantages, limitations, domains of applicability, and the relationship between accuracy and computational cost. Moreover, the comparison between micro- and macro-modelling provides practical insights for defining sustainable and reliable numerical strategies. Overall, the research contributes to a deeper understanding of the mechanical response of masonry structures and to the development of tools and methodologies for their assessment and strengthening. The ultimate objective is to support the preservation and enhancement of the built heritage, extending the service life of historic masonry works through the informed use of innovative materials and techniques.