A probabilistic approach for the performance assessment of protective measures for masonry walls subjected to dynamic loading

Pressure-impulse (PI) diagrams are commonly employed in the design of protective structures subjected to blast loading. Several methods are available for the definition of the iso-damage curves. Typically, single-degree-of-freedom (SDOF) analytical models validated through experimental testing on structural components are adopted. However, with the availability of adequate computational resources, more refined and complex finite element (FE)analyses can be performed enabling the consideration of a broader range of physical phenomena and damage mechanisms. This is particularly relevant for masonry structures, which are complex composite material systems characterized by highly variable mechanical properties and widespread use in construction worldwide (e.g., infill walls, load-bearing structures, vernacular architecture). In the presented research, a method for the develop-ment of shock fragility curves for masonry walls with a probabilistic approach is presented. A FE model of masonry walls is developed in LS-Dyna and validated against experimental results from shock tube test of scaled masonry specimens. A Monte Carlo analysis is then carried out by introducing uncertainties in the material models (for both mortar and clay bricks), in the geometry, and in the threat scenario. Another probabilistic FE model is established, incorporating a polyurea protective layer applied to the inside surface of the wall. Shock fragility PI curves are generated for both unprotected and protected configurations to assess the performance of the protective measure. The presented method established a basis for the performance assessment of protective measures and enables the generation of generalized results suitable for design applications, ultimately supporting informed decision-making processes among stakeholders.