Damaged Masonry Structures: A Probabilistic Approach for Fast Structural Safety Assessment

Structural safety assessment of masonry structures is a crucial topic for architectural heritage conservation. Performance indicators are commonly adopted for civil structures and infrastructure made of reinforced/prestressed concrete or steel but are often overlooked in the context of historic structures. Notions such as safety, reliability, robustness, and resilience are accepted concepts in the world of historic buildings, but they rarely translate into quantifiable indicators applicable to structural rehabilitation. The complex mechanical behaviour of masonry, indeed, is affected by uncertainties in the characterization of the material’s properties. Furthermore, when considering damaged masonry structures, uncertainties also include the natural aging and degradation of the component materials. In this context, the proposed research intends to perform a preliminary safety assessment of a masonry building subjected to seismic loads considering a given damage level and its evolution over time. Damage is described by means of a performance parameter that is able to capture the decrease in the characteristic compressive strength related to the presence of a crack pattern and changes in the live loads. The method allows one to address in a probabilistic way the determination of a limit global safety factor, affected by this parameter, and of the time required to attain the failure condition.