Identifying fault-inducing phenomena in an old masonry building

The structural behavior of a masonry farmhouse exhibiting several faults is investigated. The building has an irregular plan, which is probably the outcome of different construction phases; the oldest part dates back to the seventeenth century. The building underwent several interventions of consolidation, including the addition of ties, a buttress, and micropiles. Despite these interventions, the building is still heavily damaged, with vertical and inclined deep cracks. A static monitoring system was installed to track the major cracks for a duration of 18 months: some were found to be still propagating. Interpretation of the crack pattern allows the causes that originated the main faults, including changes in geometry, to be better understood. An in-depth analysis on the building also allows some geometric anomalies to be highlighted. These anomalies can probably be traced back to the different construction phases, and locally weaken the structural strength. A detailed finite element model, taking the properties of the different materials into account, was developed. The main cracks existing in the building were also included in the model. Structural analyses were carried out taking gravity loads, ground settlements, and possible seismic actions into account. The tensile stresses in some parts of the building are found to be sufficiently high to induce further crack growth. The numerical results are used to propose simple retrofitting strategies.