Finite-Element-Based Monte Carlo Simulation for Sandwich Panel-Retrofitted Unreinforced Masonry Walls Subject to Air Blast

In this paper, the behavior of three types of masonry walls is assessed subject to blast load as an out-of-plane impulse origin, and they are strengthened by the sandwich panel. The values of displacement and von Mises stress caused by blast loads are calculated using finite-element simulation. The modeled masonry walls are constructed using brick, grouted concrete masonry unit and ungrouted concrete masonry unit. Blast load is modeled by means of the CONWEP (conventional weapon) tool. A reliability analysis is conducted to evaluate outputs statistically and to calculate failure probabilities using Monte Carlo method. Plasticity properties of masonry and steel materials are simulated using concrete damage plasticity and Johnson–Cook (JK) models, respectively. Blast load is applied in three different levels of mild, moderate and severe. Results show that sandwich panel strengthening can efficiently reduce the stress and displacement values for all masonry wall types. Probabilities of failure in strengthened masonry walls are significantly decreased. Moreover, in non-strengthened cases, grouted blockwork wall has a lower stress and displacement comparing to the other masonry walls.