Retrofitting of Masonry Walls with Reinforced Shotcrete under Blast Load

In passive defense projects, retrofitting of masonry walls has especial importance. One of the commonly used methods for seismic retrofitting of the walls is the implementation of a reinforced shotcrete layer. The behavior of walls strengthened with shotcrete against earthquakes have been studied by many researchers. However, the behavior of the walls against the explosion has received less attention and the effect of the mesh specification and the thickness of the shotcrete against this type of loading has not been investigated. In this research, the damage index is investigated for 700kg TNT explosion located at distances of 3,9 and 15 m from a masonry wall. In steel mesh, when the distance between the bars is 10 and 15 cm, and shotcrete layer thickness of 5, 10 and 15 cm damage index investigation is performed. Finally, 18 different models of steel mesh and thickness of shotcrete are introduced. With shotcrete strengthening, the wall failure index and the maximum displacement of the wall center is decreased. In all models, due to the closeness of the explosion to the wall, the wall was eventually destroyed and the effect of the reinforcement spacings on reducing the wall fracture was negligible. In contrast, the thickness of the wall has a greater role in reducing the tensile damage index of the wall.