Damage Effect of RC Frame-Masonry Wall Structures Subjected to Internal Explosion

Conducting 1/3 scale two-story reinforced concrete frame-masonry wall structure internal explosion tests and simulation, the dynamic response, damage characteristics and failure modes of structural components under internal explosion loads were studied. Firstly, the modeling method and the material constitutive model in the numerical simulation were verified by internal explosion test results. Secondly, the propagation process of the internal explosion shock wave and the influence of infill walls on the damage degree of building components were analyzed through the numerical simulation. Finally, frame structures with infill walls under different equivalent charges were carried out to investigate the dynamic response and damage of structural components. Taking 0.249 kg equivalent condition as an example, the damage of masonry wall and floor is more serious than that of beam and column, which is in a state of severe damage. Compared with beam and column joints, the beam-slab transition area is more prone to damage and produce punching cracks. The peak displacement of the pure frame structure member is reduced by more than 60% compared with the peak displacement of the corresponding position of the frame with masonry infilled wall. The failure mode of the floor varies with the increase in the equivalent proportional distance. Specifically, the bending failure occurs when the proportional distance exceeds 1.283 5 m/kg^1/3, while the flexural-shear failure is observed at a proportional distance of 1.143 8 m/kg^1/3. Additionally, when the proportional distance reaches 1.016 8 m/kg^1/3, the punching failure occurs. In the case where the explosive charge amounts to 0.370 kg, the floor slabs and masonry walls are subjected to complete devastation. The vast majority of the beam-slab junction areas are completely severed, whereas the beams and columns merely incur slight damage. When the equivalent charge reaches 7.400 kg, the vast majority of building components reach a state of severe damage or even complete destruction. For the anti-explosion design, the masonry wall should be coated with explosion-proof materials, the floor reinforcement should be designed in double-layer two-way, and the tie bar should be appropriately added in the beam-slab transition area to improve the integrity of the structure when it faces small equivalent internal explosion load.