Numerical interpretation of the causes of damage in Chiaravalle Abbey in Milan

This research falls within the field of historic building conservation and focuses on the Chiaravalle Abbey, a medieval Cistercian monument located south of Milan with a lantern tower supported on the crossing. The study aims to identify the causes of the structural damage affecting the transepts through a multidisciplinary approach that integrates historical, architectural, and engineering aspects. The adopted methodology includes a review of technical literature, observation of damage, geometric mapping, and the development of a three-dimensional numerical model. The analysis, conducted using the Finite Element Method (FEM), enables the assessment of internal stress distribution and mechanical damage, and the comparison of results with the crack pattern to determine the underlying causes of deterioration. Given the complexity of the structure and the limited experimental data available, several simplifying assumptions are introduced: the masonry is considered homogeneous, the nonlinear material behavior is addressed through a damage-based plasticity model, and the soil-structure interaction is approximated by imposing vertical displacements at the base. The analysis focuses on the transept of the abbey: additional hypothesis of perfect constraints, replacing the rest of the church, isolate its behavior along the South- North direction, while the weight of the tower is introduced through an equivalent load, consistent with previous studies. The results of the analysis show that, under the weight of the tower, the damage is caused by soil settlements.